EN ISO 3506-1:2020
(Main)Fasteners - Mechanical properties of corrosion-resistant stainless steel fasteners - Part 1: Bolts, screws and studs with specified grades and property classes (ISO 3506-1:2020)
Fasteners - Mechanical properties of corrosion-resistant stainless steel fasteners - Part 1: Bolts, screws and studs with specified grades and property classes (ISO 3506-1:2020)
This document specifies the mechanical and physical properties of bolts, screws and studs, with coarse pitch thread and fine pitch thread, made of corrosion-resistant stainless steels, when tested at the ambient temperature range of 10 °C to 35 °C. It specifies property classes in relation to austenitic, martensitic, ferritic and duplex (austenitic-ferritic) steel grades for fasteners.
The term "fasteners" is used in this document when bolts, screws and studs are considered all together.
ISO 3506‑6 provides general rules and additional technical information on suitable stainless steels and their properties.
Fasteners conforming to the requirements of this document are evaluated at the ambient temperature specified in paragraph 1. It is possible that they do not retain the specified mechanical and physical properties at elevated and/or lower temperatures.
NOTE 1 Fasteners conforming to the requirements of this document are used without restriction in applications ranging from ?20 °C to +150 °C; however, fasteners conforming to this document are also used for applications outside this range down to ?196 °C and up to +300 °C. For more details, see Annex A and ISO 3506‑6.
Outside the temperature range of ?20 °C to +150 °C, it is the responsibility of the user to determine the appropriate choice for a given application in consultation with an experienced fastener metallurgist and by taking into account e.g. stainless steel composition, duration of exposure at elevated or low temperature, the effect of the temperature on the fasteners mechanical properties and clamped parts, and the corrosive service environment of the bolted joint.
NOTE 2 ISO 3506‑5 is developed in order to assist in the selection of appropriate stainless steel grades and property classes intended for use at temperatures up to +800 °C.
This document applies to bolts, screws and studs:
— with ISO metric thread in accordance with ISO 68‑1,
— with diameter/pitch combinations in accordance with ISO 261 and ISO 262,
— with coarse pitch thread M1,6 to M39, and fine pitch thread M8×1 to M39×3,
— with thread tolerances in accordance with ISO 965‑1 and ISO 965‑2,
— with specified property classes, and
— of any shape.
Stainless steel grades and property classes can be used for sizes outside the diameter limits of this document (i.e. for d < 1,6 mm or d > 39 mm), provided that all applicable chemical, mechanical and physical requirements are met.
Certain bolts, screws and studs might not fulfil the tensile or torsional requirements of this document because of the geometry of their head or unthreaded shank, thus resulting in reduced loadability (e.g. when shear area in the head is less than the stress area in the thread; see 8.2.2).
This document does not apply to set screws and similar threaded fasteners not under tensile stress (see ISO 3506‑3).
It does not specify requirements for functional properties such as:
— torque/clamp force properties,
— shear strength,
— fatigue resistance, or
— weldability.
Mechanische Verbindungselemente - Mechanische Eigenschaften von Verbindungselementen aus korrosionsbeständigen nichtrostenden Stählen - Teil 1: Schrauben mit festgelegten Stahlsorten und Festigkeitsklassen (ISO 3506-1:2020)
Dieses Dokument legt die mechanischen und physikalischen Eigenschaften von Schrauben mit Regelgewinde und Feingewinde aus korrosionsbeständigen nichtrostenden Stählen bei Prüfung in einem Umgebungs¬temperaturbereich von 10 °C bis 35 °C fest. Es legt Festigkeitsklassen in Bezug auf austenitische, martensi¬tische, ferritische Stahlsorten sowie austenitisch-ferritische Duplex-Stahlsorten für Verbindungselemente fest.
Der Begriff „Verbindungselemente“ (en: fasteners) wird in diesem Dokument verwendet, wenn „Schrauben mit Schaft“ (en: bolts) oder „Schrauben mit Gewinde bis Kopf“ (en: screws) sowie „Stiftschrauben oder Gewindebolzen“ (en: studs) als Gesamtheit angesprochen werden.
In ISO 3506 6 werden allgemeine Regeln und zusätzliche technische Angaben zu geeigneten nichtrostenden Stählen und ihren Eigenschaften bereitgestellt.
Verbindungselemente, die den Anforderungen dieses Dokuments entsprechen, werden bei der in Absatz 1 angegebenen Umgebungstemperatur bewertet. Eventuell ändern sich die festgelegten mechanischen und physikalischen Eigenschaften bei höheren und/oder niedrigeren Temperaturen.
ANMERKUNG 1 Verbindungselemente, die den Anforderungen dieses Dokuments entsprechen, werden ohne Einschränkung für Anwendungen im Bereich zwischen −20 °C und +150 °C eingesetzt; Verbindungselemente, die diesem Dokument entsprechen, werden jedoch auch für die Anwendung außerhalb dieses Bereiches von −196 °C und bis zu +300 °C eingesetzt. Für weiterführende Einzelheiten siehe Anhang A und ISO 3506 6.
Außerhalb des Temperaturbereichs von −20 °C bis +150 °C liegt es in der Verantwortlichkeit des An-wenders – unter Hinzuziehung eines erfahrenen Metallurgen für Verbindungselemente – eine geeignete Wahl für eine bestimmte Anwendung zu treffen, um z. B. die Zusammensetzung des nichtrostenden Stahls, die Dauer der Beanspruchung bei einer hohen oder niedrigen Temperatur, die Auswirkung der Temperatur auf die mechanischen Eigenschaften der Verbindungselemente und eingespannten Teile und die korrosive Einsatz¬umgebung der Schraubenverbindung zu berücksichtigt.
ANMERKUNG 2 ISO 3506 5 wird erarbeitet, um die Auswahl geeigneter Sorten nichtrostender Stähle und Festigkeits-klassen zu unterstützen, die für die Anwendung bei hohen Temperaturen bis +800 °C vorgesehen sind.
Dieses Dokument gilt für Schrauben:
- mit metrischem ISO Gewinde nach ISO 68 1;
- mit Durchmesser-Steigungs-Kombinationen nach ISO 261 und ISO 262;
- mit Regelgewinde M1,6 bis M39 und Feingewinde M8×1 bis M39×3;
- mit Gewindetoleranzen nach ISO 965 1 und ISO 965 2;
- mit festgelegten Festigkeitsklassen; und
- jeglicher Form.
Sorten nichtrostender Stähle und Festigkeitsklassen können auch für Größen außerhalb der in diesem Doku¬ment festgelegten Grenzen für Durchmesser (d. h. bei d < 1,6 mm oder d > 39 mm) verwendet werden, vorausgesetzt, alle geltenden chemischen, mechanischen und physikalischen Anforderungen werden erfüllt.
Aufgrund der Geometrie ihres Kopfes oder gewindefreien Schaftes, die zu einer reduzierten Belastbarkeit führt, (z. B. wenn die Scherfläche im Kopf gegenüber dem Spannungsquerschnitt im Gewinde verkleinert ist, siehe 8.2.2), erfüllen bestimmte Schrauben möglicherweise nicht die in diesem Dokument festgelegten Anforderungen an die Belastbarkeit unter Zug oder Torsion.
Dieses Dokument gilt nicht für Gewindestifte und ähnliche nicht auf Zug beanspruchte Verbindungselemente mit Gewinde (siehe ISO 3506 3).
Es legt keine Anforderungen an Funktionseigenschaften fest, wie:
- Drehmoment/Vorspannkraft-Eigenschaften;
- Scherfestigkeit;
- Dauerfestigkeit; oder
- Schweißbarkeit.
Fixations - Caractéristiques mécaniques des fixations en acier inoxydable résistant à la corrosion - Partie 1: Vis, goujons et tiges filetées de grades et classes de qualité spécifiés (ISO 3506-1:2020)
Le présent document spécifie les caractéristiques mécaniques et physiques des vis, goujons et tiges filetées, à filetage à pas gros et à filetage à pas fin, en aciers inoxydables résistant à la corrosion, lorsque soumis à essai dans la plage de température ambiante de 10 °C à 35 °C. Il spécifie les classes de qualité en fonction des grades d'aciers inoxydables austénitiques, martensitiques, ferritiques et duplex (austéno-ferritiques) pour les fixations.
Le terme «fixation» est utilisé dans le présent document lorsque les vis, goujons et tiges filetées sont considérés dans leur ensemble.
L'ISO 3506‑6 fournit des règles générales et des informations techniques supplémentaires sur les aciers inoxydables appropriés ainsi que leurs propriétés.
Les fixations conformes aux exigences du présent document sont évaluées dans la plage de température ambiante spécifiée dans l'alinéa 1. Elles peuvent ne pas conserver les caractéristiques mécaniques et physiques spécifiées à des températures élevées et/ou basses.
NOTE 1 Les fixations conformes aux exigences du présent document sont utilisées sans restriction pour des applications dans la plage de ? 20 °C à + 150 °C; cependant, les fixations conformes au présent document sont également utilisées pour des applications en dehors de cette plage, en températures négatives jusqu'à ? 196 °C et en températures élevées jusqu'à + 300 °C. Pour d'avantage d'explications, voir l'Annexe A et l'ISO 3506‑6.
En dehors de la plage de température de ? 20 °C à + 150 °C , il est de la responsabilité de l'utilisateur de déterminer le choix approprié pour une application donnée en concertation avec un métallurgiste expérimenté en fixations et en prenant en considération plusieurs facteurs, par exemple la composition de l'acier inoxydable, la durée d'exposition à température élevée ou basse, l'effet de la température sur les caractéristiques mécaniques des fixations et des pièces assemblées, ainsi que l'environnement corrosif d'utilisation de l'assemblage vissé.
NOTE 2 L'ISO 3506‑5 est développée afin d'aider à la sélection des grades d'aciers inoxydables et des classes de qualité appropriées destinés à être utilisés à des températures jusqu'à + 800 °C.
Le présent document s'applique aux vis, goujons et tiges filetées:
— à filetage métrique ISO conforme à l'ISO 68‑1;
— de combinaisons diamètre/pas, conformes à l'ISO 261 et à l'ISO 262;
— de filetage M1,6 à M39 pour les pas gros, et de filetage M8×1 à M39×3 pour les pas fins;
— de tolérances de filetage conformes à l'ISO 965‑1 et à l'ISO 965‑2;
— de classes de qualité spécifiées; et
— de forme quelconque.
Les grades d'aciers inoxydales et classes de qualité peuvent être utilisés pour des dimensions en dehors des limites de diamètres du présent document (c'est-à-dire pour d < 1,6 mm ou d > 39 mm), à condition que toutes les exigences chimiques, mécaniques et physiques applicables soient satisfaites.
Certaines vis, goujons et tiges filetées peuvent ne pas satisfaire aux exigences de la résistance à la traction ou à la torsion du présent document en raison de la géométrie de leur tête ou de leur partie lisse (tige), ce qui a pour conséquence une capacité de charge réduite (par exemple lorsque la section cisaillée dans la tête est inférieure à la section résistante dans le filetage, voir 8.2.2).
Le présent document ne s'applique pas aux vis sans tête et fixations filetées similaires non soumises à des contraintes de trac
Vezni elementi - Mehanske lastnosti veznih elementov iz korozijsko odpornega nerjavnega jekla - 1. del: Vijaki z matico, vijaki in zatični vijaki z določenimi razredi in razredi trdnosti (ISO 3506-1:2020)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2020
Nadomešča:
SIST EN ISO 3506-1:2011
Vezni elementi - Mehanske lastnosti veznih elementov iz korozijsko odpornega
nerjavnega jekla - 1. del: Vijaki z matico, vijaki in zatični vijaki z določenimi razredi
in razredi trdnosti (ISO 3506-1:2020)
Fasteners - Mechanical properties of corrosion-resistant stainless steel fasteners - Part
1: Bolts, screws and studs with specified grades and property classes (ISO 3506-1:2020)
Mechanische Eigenschaften von Verbindungselementen aus korrosionsbeständigen
nichtrostenden Stählen - Teil 1: Schrauben mit festgelegten Festigkeitsklassen -
Regelgewinde und Feingewinde (ISO 3506-1:2020)
Caractéristiques mécaniques des fixations en acier inoxydable résistant à la corrosion -
Partie 1: Vis, goujons et tiges filetées de classes de qualité spécifiées - Filetage à pas
gros et filetage à pas fin (ISO 3506-1:2020)
Ta slovenski standard je istoveten z: EN ISO 3506-1:2020
ICS:
21.060.10 Sorniki, vijaki, stebelni vijaki Bolts, screws, studs
77.140.20 Visokokakovostna jekla Stainless steels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 3506-1
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2020
EUROPÄISCHE NORM
ICS 21.060.10 Supersedes EN ISO 3506-1:2009
English Version
Fasteners - Mechanical properties of corrosion-resistant
stainless steel fasteners - Part 1: Bolts, screws and studs
with specified grades and property classes (ISO 3506-
1:2020)
Fixations - Caractéristiques mécaniques des fixations Mechanische Verbindungselemente - Mechanische
en acier inoxydable résistant à la corrosion - Partie 1: Eigenschaften von Verbindungselementen aus
Vis, goujons et tiges filetées de grades et classes de korrosionsbeständigen nichtrostenden Stählen - Teil 1:
qualité spécifiés (ISO 3506-1:2020) Schrauben mit festgelegten Stahlsorten und
Festigkeitsklassen (ISO 3506-1:2020)
This European Standard was approved by CEN on 28 March 2020.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3506-1:2020 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 3506-1:2020) has been prepared by Technical Committee ISO/TC 2 "Fasteners"
in collaboration with Technical Committee CEN/TC 185 “Fasteners” the secretariat of which is held by
BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2020, and conflicting national standards shall
be withdrawn at the latest by October 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 3506-1:2009.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 3506-1:2020 has been approved by CEN as EN ISO 3506-1:2020 without any
modification.
INTERNATIONAL ISO
STANDARD 3506-1
Third edition
2020-04
Fasteners — Mechanical properties
of corrosion-resistant stainless steel
fasteners —
Part 1:
Bolts, screws and studs with specified
grades and property classes
Fixations — Caractéristiques mécaniques des fixations en acier
inoxydable résistant à la corrosion —
Partie 1: Vis, goujons et tiges filetées de grades et classes de qualité
spécifiés
Reference number
ISO 3506-1:2020(E)
©
ISO 2020
ISO 3506-1:2020(E)
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
Contents Page
Foreword .v
Introduction .vii
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Symbols . 3
5 Designation system for stainless steel grades and property classes .4
5.1 General . 4
5.2 Designation of stainless steel grades (first block). 5
5.3 Designation of property classes (second block) . 6
6 Materials . 6
6.1 Chemical composition . 6
6.2 Heat treatment for martensitic stainless steel fasteners . 7
6.3 Finish . 8
6.4 Corrosion resistance . 8
7 Mechanical and physical properties . 8
8 Applicability of test methods and inspection .14
8.1 Applicability of test methods .14
8.2 Loadability of fasteners .14
8.2.1 Fasteners with full loadability .14
8.2.2 Fasteners which have reduced loadability due to their geometry .15
8.3 Manufacturer’s inspection .16
8.4 Supplier’s inspection .16
8.5 Purchaser’s inspection .16
8.6 Delivery of test results .17
9 Test methods .17
9.1 Tensile test for fasteners .17
9.1.1 General.17
9.1.2 Test procedure for the simultaneous determination of R , R , and A .18
mf pf
9.1.3 Reference test procedure for the determination of stress at 0,2 % non-
proportional elongation, R .19
pf
9.1.4 Alternative test procedure for the determination of elongation, A .21
9.1.5 Test results and requirements for tensile strength, R .22
mf
9.1.6 Test results and requirements for stress at 0,2 % non-proportional
elongation, R .22
pf
9.1.7 Test results and requirements for elongation after fracture, A .23
9.2 Tensile test for bolts and screws with reduced loadability due to head design .23
9.2.1 General.23
9.2.2 Test procedure .23
9.2.3 Test results and requirements for ultimate tensile load, F .23
mf
9.3 Tensile test for fasteners with reduced loadability due to shank design .23
9.3.1 General.23
9.3.2 Test procedure .24
9.3.3 Test results for tensile strength .24
9.4 Wedge tensile test .24
9.4.1 General.24
9.4.2 Test procedure .26
9.4.3 Test results and requirements .26
9.5 Torsional test .26
9.5.1 General.26
9.5.2 Test procedure .27
ISO 3506-1:2020(E)
9.5.3 Test results and requirements .28
9.6 Hardness test .28
9.6.1 General.28
9.6.2 Test procedure .28
9.6.3 Test results and requirements .28
10 Fastener marking and labelling .29
10.1 Fastener marking .29
10.1.1 General requirements for marking .29
10.1.2 Marking of property class for fasteners with full loadability .29
10.1.3 Marking of property class for fasteners with reduced loadability.29
10.1.4 Additional marking .30
10.2 Manufacturer’s identification mark .30
10.3 Marking on the fasteners .30
10.3.1 Hexagon head bolts and screws .30
10.3.2 Hexagon socket or hexalobular socket bolts and screws .31
10.3.3 Other types of bolts and screws.32
10.3.4 Studs (one-end and double-end studs) .32
10.3.5 Fully threaded studs .33
10.3.6 Left-hand thread marking .33
10.4 Marking of the packages (labelling) .34
Annex A (informative) Mechanical properties at elevated temperatures — Application at
low temperatures.35
Bibliography .37
iv © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 2, Fasteners.
This third edition cancels and replaces the second edition (ISO 3506-1:2009), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— annexes common to several parts of the ISO 3506 series have been withdrawn from this document
and are now included in a new document (ISO 3506-6);
— duplex (austenitic-ferritic) stainless steels for property classes 70, 80 and 100 have been added (see
Figure 1);
— property class 100 for austenitic stainless steel grades as well as grade A8 have been added (see
Figure 1);
— finish (see 6.3) has been added;
— the matching of stainless steel bolt and nut grades (see 6.4) has been added;
— calculated minimum ultimate tensile loads and minimum loads at 0,2 % non-proportional elongation
(see Tables 4 to 7) and rounding rules have been added;
— reduced loadability for fasteners due to head or shank design (see 8.2) has been added;
— requirements and guidance for inspection procedures (see 8.3 to 8.6) have been added;
— operational temperature ranges (see Clause 1) have been clarified;
— the applicability of test methods (see Clause 8), also in relation to full and reduced loadability, has
been added;
— the tensile test procedure (see 9.1) has been entirely amended, and application to fasteners with
reduced loadability (see 9.2 and 9.3) has been added;
ISO 3506-1:2020(E)
— the wedge tensile test (see 9.4) and hardness test (see 9.6) have been improved;
— marking and labelling (see Clause 10) have been improved, and fasteners with reduced loadability
have been included;
— mechanical properties at elevated temperatures and application at low temperatures (see Annex A)
have been improved;
— the structure and content of this document have been brought in line with ISO 898-1.
A list of all parts in the ISO 3506 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
vi © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
Introduction
The ISO 3506 series consists of the following parts, under the general title Fasteners — Mechanical
properties of corrosion-resistant stainless steel fasteners:
— Part 1: Bolts, screws and studs with specified grades and property classes
— Part 2: Nuts with specified grades and property classes
1)
— Part 3 : Set screws and similar fasteners not under tensile stress
1)
— Part 4 : Tapping screws
2)
— Part 5 : Special fasteners (also including fasteners from nickel alloys) for high temperature applications
— Part 6: General rules for the selection of stainless steels and nickel alloys for fasteners
The properties of stainless steel fasteners result from the chemical composition of the material
(especially corrosion resistance) and from the mechanical properties due to the manufacturing
processes. Ferritic, austenitic and duplex (austenitic-ferritic) stainless steel fasteners are generally
manufactured by cold working; they consequently do not have homogeneous local material properties
when compared to quenched and tempered fasteners.
Austenitic-ferritic stainless steels referred to as duplex stainless steels were originally invented in the
1930s. Standard duplex grades used today have been developed since the 1980s. Fasteners made of
duplex stainless steels have been long established in a range of applications. This document was revised
to reflect their standardization.
All duplex stainless steel grades show improved resistance to stress corrosion cracking compared to
the commonly used A1 to A5 austenitic grades. Most duplex grades also show higher levels of pitting
corrosion resistance, where D2 matches at least A2 and where D4 matches at least A4.
Complementary detailed explanations about definitions of stainless steel grades and properties are
specified in ISO 3506-6.
1) It is intended to revise ISO 3506-3 and ISO 3506-4 in the future in order to include the reference to ISO 3506-6.
2) Under preparation.
INTERNATIONAL STANDARD ISO 3506-1:2020(E)
Fasteners — Mechanical properties of corrosion-resistant
stainless steel fasteners —
Part 1:
Bolts, screws and studs with specified grades and
property classes
1 Scope
This document specifies the mechanical and physical properties of bolts, screws and studs, with
coarse pitch thread and fine pitch thread, made of corrosion-resistant stainless steels, when tested at
the ambient temperature range of 10 °C to 35 °C. It specifies property classes in relation to austenitic,
martensitic, ferritic and duplex (austenitic-ferritic) steel grades for fasteners.
The term “fasteners” is used in this document when bolts, screws and studs are considered all together.
ISO 3506-6 provides general rules and additional technical information on suitable stainless steels and
their properties.
Fasteners conforming to the requirements of this document are evaluated at the ambient temperature
specified in paragraph 1. It is possible that they do not retain the specified mechanical and physical
properties at elevated and/or lower temperatures.
NOTE 1 Fasteners conforming to the requirements of this document are used without restriction in
applications ranging from –20 °C to +150 °C; however, fasteners conforming to this document are also used for
applications outside this range down to –196 °C and up to +300 °C. For more details, see Annex A and ISO 3506-6.
Outside the temperature range of –20 °C to +150 °C, it is the responsibility of the user to determine the
appropriate choice for a given application in consultation with an experienced fastener metallurgist
and by taking into account e.g. stainless steel composition, duration of exposure at elevated or low
temperature, the effect of the temperature on the fasteners mechanical properties and clamped parts,
and the corrosive service environment of the bolted joint.
NOTE 2 ISO 3506-5 is developed in order to assist in the selection of appropriate stainless steel grades and
property classes intended for use at temperatures up to +800 °C.
This document applies to bolts, screws and studs:
— with ISO metric thread in accordance with ISO 68-1,
— with diameter/pitch combinations in accordance with ISO 261 and ISO 262,
— with coarse pitch thread M1,6 to M39, and fine pitch thread M8×1 to M39×3,
— with thread tolerances in accordance with ISO 965-1 and ISO 965-2,
— with specified property classes, and
— of any shape.
Stainless steel grades and property classes can be used for sizes outside the diameter limits of this
document (i.e. for d < 1,6 mm or d > 39 mm), provided that all applicable chemical, mechanical and
physical requirements are met.
ISO 3506-1:2020(E)
Certain bolts, screws and studs might not fulfil the tensile or torsional requirements of this document
because of the geometry of their head or unthreaded shank, thus resulting in reduced loadability (e.g.
when shear area in the head is less than the stress area in the thread; see 8.2.2).
This document does not apply to set screws and similar threaded fasteners not under tensile stress
(see ISO 3506-3).
It does not specify requirements for functional properties such as:
— torque/clamp force properties,
— shear strength,
— fatigue resistance, or
— weldability.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1891-4, Fasteners — Vocabulary — Part 4: Control, inspection, delivery, acceptance and quality
ISO 3506-6, Fasteners — Mechanical properties of corrosion-resistant stainless steel fasteners — Part 6:
General rules for the selection of stainless steels and nickel alloys for fasteners
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Calibration and verification of the force-measuring system
ISO 9513, Metallic materials — Calibration of extensometer systems used in uniaxial testing
ISO 16228, Fasteners — Types of inspection documents
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
stainless steel bolt and screw with full loadability
bolt and screw with head stronger than the threaded and unthreaded shanks (with unthreaded shank
diameter d ≈ d or d > d ) or screw threaded to the head, and fulfilling the minimum ultimate tensile load
s 2 s 2
3.2
stainless steel stud with full loadability
stud with unthreaded shank diameter d ≈ d or d > d , and fulfilling the minimum ultimate tensile load
s 2 s 2
2 © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
3.3
stainless steel bolt and screw with reduced loadability
bolt and screw with head weaker than the threaded and unthreaded shanks, or with an unthreaded
shank diameter d < d
s 2
3.4
stainless steel stud with reduced loadability
stud with unthreaded shank diameter d < d
s 2
3.5
stainless steel
steel with at least 10,5 % (mass fraction) of chromium (Cr) and maximum 1,2 % (mass fraction) of
carbon (C)
3.6
austenitic stainless steel
stainless steel (3.5) with high amounts of chromium and nickel which usually cannot be hardened by
heat treatment, providing excellent resistance to corrosion, good ductility, and usually low or non-
magnetic properties
3.7
martensitic stainless steel
stainless steel (3.5) with high amounts of chromium but very little nickel or other alloying elements,
which can be hardened by heat treatment for increasing strength but with reduced ductility, and with
highly magnetic properties
3.8
ferritic stainless steel
stainless steel (3.5) containing less than 0,1 % carbon and typically 11 % to 18 % chromium, which
usually cannot be hardened by heat treatment, and with highly magnetic properties
3.9
duplex stainless steel
stainless steel (3.5) with a micro-structure that includes both austenitic and ferritic phases providing
excellent resistance to corrosion, containing a higher amount of chromium and a reduced quantity of
nickel compared to austenitic steel, with high strength, and with magnetic properties
4 Symbols
For the purposes of this document, the following symbols apply.
A total elongation after fracture, mm
A nominal stress area in thread, mm
s,nom
A cross-sectional area of waisted shank, mm
ds
b thread length, mm
d nominal thread diameter of the fastener, mm
d basic minor diameter of external thread, mm
d basic pitch diameter of external thread, mm
d minor diameter of external thread (for nominal stress area calculation), mm
d inner diameter of the bearing face, mm
a
ISO 3506-1:2020(E)
d hole diameter for adaptors and wedge, mm
h
d diameter of unthreaded shank, mm
s
F ultimate tensile load, N
mf
F load at 0,2 % non-proportional elongation for full-size fastener, N
pf
H height of the fundamental triangle of the thread, mm
k height of the head, mm
l nominal length of fastener, mm
L total length of fastener before tensile test, mm
L total length of fastener after fracture, mm
L clamping length before tensile test, mm
l length of unthreaded shank, mm
s
l overall length of stud, mm
t
l free threaded length of fastener in testing device, mm
th
M breaking torque, Nm
B
P pitch of the thread, mm
R tensile strength for fastener with reduced loadability due to shank design, MPa
mds
R tensile strength for full-size fastener, MPa
mf
R stress at 0,2 % non-proportional elongation for full-size fastener, MPa
pf
α wedge angle, °
5 Designation system for stainless steel grades and property classes
5.1 General
The standardized combinations of stainless steel grades and property classes are specified in Clause 7,
Table 2 or 3.
The designation system for stainless steel grades and property classes for bolts, screws and studs
consists of two blocks, separated by a hyphen, as specified in Figure 1. The first block designates the
stainless steel grade, and the second block the property class of the fastener.
4 © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
a
For low carbon austenitic stainless steels with carbon content not exceeding 0,030 %, fasteners can additionally
be marked or designated with the letter "L" just after the grade. Example: A4L-80.
b
For information only.
Figure 1 — Designation system for stainless steel grades and property classes for fasteners
The marking, labelling and designation of fasteners with stainless steel grade and property class shall
be as specified in Clause 10. For bolts, screws and studs with reduced loadability which can be tensile
tested in the threaded shank, the digit “0” shall precede the property class as specified in 10.1.3. For
fasteners with reduced loadability which cannot be tensile tested due to a too short thread length
(b < 3d), the property class shall not be referenced.
The designation system of this document may be used for sizes outside the diameter limits specified in
Clause 1 (i.e. d < 1,6 mm or d > 39 mm), provided that all applicable chemical, mechanical and physical
requirements are met.
5.2 Designation of stainless steel grades (first block)
The designation of the stainless steel grade (first block) consists of one letter which specifies the
stainless steel group:
— A for austenitic,
— C for martensitic,
— F for ferritic,
— D for duplex (austenitic-ferritic),
ISO 3506-1:2020(E)
and
— a digit which specifies the range of chemical compositions within this stainless steel group.
The chemical compositions of stainless steel groups and grades classified in Figure 1 are specified in
Table 1.
5.3 Designation of property classes (second block)
The designation of the property class (second block) consists of a number corresponding to 1/10 of the
minimum tensile strength of the fastener in accordance with Table 2 or 3.
EXAMPLE 1 A2-70 specifies an austenitic stainless steel fastener, work hardened, with a minimum tensile
strength of 700 MPa.
EXAMPLE 2 C1-110 specifies a martensitic stainless steel fastener, quenched and tempered, with a minimum
tensile strength of 1 100 MPa.
6 Materials
6.1 Chemical composition
Table 1 specifies the limits for chemical composition of the stainless steel grades for fasteners. The
chemical composition shall be assessed in accordance with the relevant International Standards.
The final choice of the chemical composition within the specified stainless steel grade is at the discretion
of the manufacturer, unless otherwise agreed between the purchaser and the manufacturer.
The stainless steel grade suitable for an application shall be selected in accordance with the
specifications defined in ISO 3506-6.
6 © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
Table 1 — Stainless steel grades — Chemical composition
a
Chemical composition
Stainless b Other elements
(cast analysis, mass fraction in %)
steel grade and notes
C Si Mn P S Cr Mo Ni Cu N
0,15 to 16,0 to 5,0 to 1,75 to
c,d,e
A1 0,12 1,00 6,5 0,020 0,70 —
0,35 19,0 10,0 2,25
15,0 to 8,0 to
f g,h
A2 0,10 1,00 2,00 0,050 0,030 — 4,0 —
20,0 19,0
17,0 to 9,0 to 5C ≤ Ti ≤ 0,80 and/or
f
A3 0,08 1,00 2,00 0,045 0,030 — 1,00 —
19,0 12,0 10C ≤ Nb ≤ 1,00
Austenitic
16,0 to 2,00 to 10,0 to
h,i
A4 0,08 1,00 2,00 0,045 0,030 4,0 —
18,5 3,00 15,0
16,0 to 2,00 to 10,5 to 5C ≤ Ti ≤ 0,80 and/or
A5 0,08 1,00 2,00 0,045 0,030 1,00 —
i
18,5 3,00 14,0 10C ≤ Nb ≤ 1,00
19,0 to 17,5 to
A8 0,030 1,00 2,00 0,040 0,030 6,0 to 7,0 1,50 — —
22,0 26,0
0,09 to 11,5 to
i
C1 1,00 1,00 0,050 0,030 — 1,00 — —
0,15 14,0
0,17 to 16,0 to 1,50 to
Martensitic C3 1,00 1,00 0,040 0,030 — — — —
0,25 18,0 2,50
0,08 to 0,15 to 12,0 to
c,i
C4 1,00 1,50 0,060 0,60 1,00 — —
0,15 0,35 14,0
15,0 to
f j
Ferritic F1 0,08 1,00 1,00 0,040 0,030 — 1,00 — —
18,0
Cr + 3,3Mo +16N
19,0 to 0,10 to 1,50 to 0,05 to
D2 0,040 1,00 6,0 0,040 0,030 3,00 ≤ 24,0
24,0 1,00 5,5 0,20
k
24,0 < Cr + 3,3Mo
21,0 to 0,10 to 1,00 to 0,05 to
D4 0,040 1,00 6,0 0,040 0,030 3,00 + 16N
25,0 2,00 5,5 0,30
Duplex k
21,0 to 2,50 to 4,5 to 0,08 to
D6 0,030 1,00 2,00 0,040 0,015 — —
23,0 3,5 6,5 0,35
24,0 to 3,00 to 6,0 to 0,20 to
D8 0,030 1,00 2,00 0,035 0,015 2,50 W ≤ 1,00
26,0 4,5 8,0 0,35
a
According to material standards, values are maximum unless otherwise indicated and the number of digits shown is in accordance with usual rules,
see e.g. EN 10088 (all parts).
b
In case of dispute, product analysis applies.
c
Selenium can be used to replace sulphur, however restrictions may apply to its use.
d
If the nickel content is below 8,0 %, the minimum manganese content shall be 5,0 %.
e
There is no minimum limit to the copper content provided that the nickel content is greater than 8,0 %.
f
Molybdenum may be present at the discretion of the manufacturer. However, if for some applications limiting of the molybdenum content is essential,
this shall be stated at the time of ordering by the purchaser.
g
If the chromium content is below 17,0 %, the minimum nickel content should be 12,0 %.
h
For austenitic stainless steels having a maximum carbon content of 0,030 %, nitrogen may be present but shall not exceed 0,22 %.
i
At the discretion of the manufacturer the carbon content may be higher as necessary in order to obtain the specified mechanical properties for larger
diameters, but shall not exceed 0,12 % for austenitic steels.
j
Titanium and/or niobium may be included to improve corrosion resistance.
k
This formula is used solely for the purpose of classifying duplex steels in accordance with this document (it is not intended to be used as a selection
criterion for corrosion resistance).
For the choice of the appropriate stainless steel grade suitable for a specific application, see ISO 3506-6.
Examples of stainless steels in accordance with Table 1 are also given in ISO 3506-6.
6.2 Heat treatment for martensitic stainless steel fasteners
Fasteners of grades and property classes C1-70, C3-80 and C4-70 shall be quenched and tempered.
Fasteners of grade and property class C1-110 shall be quenched and tempered, with a minimum
tempering temperature of 275 °C.
ISO 3506-1:2020(E)
6.3 Finish
Unless otherwise specified, fasteners in accordance with this document shall be supplied clean and bright.
For maximum corrosion resistance, passivation is recommended. Fasteners that are passivated in
accordance with ISO 16048 may additionally be referenced on the label with the letter “P” immediately
after the property class symbol (see 10.4).
NOTE 1 Passivated fasteners do not always show a bright surface finish.
Bolts, screws and studs are often used in bolted joints where the preload is achieved by torque
tightening. Therefore, lubrication of stainless steel fasteners is recommended in order to avoid galling
during tightening.
NOTE 2 Several parameters can increase the risk of galling for stainless steel fasteners in bolted assemblies
during tightening such as thread damage, high preload, high tightening speed.
NOTE 3 For the time being, requirements concerning surface discontinuities and torque/clamp force
properties are not specified in International Standards for stainless steel fasteners.
A controlled torque/clamp force relationship can be obtained for stainless steel fasteners by means
of an adequate finish, either just with a lubricant or with a coating, top coat and/or sealer including
lubricant. In this case, the designation and/or labelling should include the letters “Lu” immediately
after the symbol of the property class, e.g. A4-80Lu. In conjunction, appropriate measures and means of
tightening should be selected in order to achieve the required preload.
When specific requirements are necessary, it shall be agreed between the supplier and the purchaser at
the time of the order.
6.4 Corrosion resistance
For corrosion resistance purpose, bolts, screws and studs should be mated with nuts and washers of
the same stainless steel grade (e.g. nuts A2 with bolts A2, etc.). Other combinations are possible (e.g.
nuts A4 with bolts D4), providing that:
— the component with the lowest corrosion resistance shall always be taken into account,
— the risk of galling should be considered, and
— it is strongly recommended that an experienced fastener metallurgist be consulted.
When using stainless steel fasteners with non-stainless steel parts in bolted joints, e.g. galvanized
steels, it is advised that the use of isolation components be considered in order to avoid galvanic
corrosion.
7 Mechanical and physical properties
When tested by the methods specified in Clause 9, the bolts, screws and studs of the specified stainless
steel grade and property class shall meet, at ambient temperature, all the applicable requirements
specified in Tables 2 to 8, regardless of which tests are performed during manufacture or final
inspection.
Clause 8 specifies the applicability of test methods for verifying that fasteners of different types and
dimensions fulfil the requirements in accordance with Tables 2 to 8.
Even if the material of the fasteners meets all relevant requirements specified in Clause 6, it is possible
that certain fasteners would
...
SLOVENSKI STANDARD
01-julij-2020
Nadomešča:
SIST EN ISO 3506-1:2011
Vezni elementi - Mehanske lastnosti veznih elementov iz korozijsko odpornega
nerjavnega jekla - 1. del: Vijaki z matico, vijaki in zatični vijaki z določenimi razredi
in razredi trdnosti (ISO 3506-1:2020)
Fasteners - Mechanical properties of corrosion-resistant stainless steel fasteners - Part
1: Bolts, screws and studs with specified grades and property classes (ISO 3506-1:2020)
Mechanische Eigenschaften von Verbindungselementen aus korrosionsbeständigen
nichtrostenden Stählen - Teil 1: Schrauben mit festgelegten Festigkeitsklassen -
Regelgewinde und Feingewinde (ISO 3506-1:2020)
Caractéristiques mécaniques des fixations en acier inoxydable résistant à la corrosion -
Partie 1: Vis, goujons et tiges filetées de classes de qualité spécifiées - Filetage à pas
gros et filetage à pas fin (ISO 3506-1:2020)
Ta slovenski standard je istoveten z: EN ISO 3506-1:2020
ICS:
21.060.10 Sorniki, vijaki, stebelni vijaki Bolts, screws, studs
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 3506-1
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2020
EUROPÄISCHE NORM
ICS 21.060.10 Supersedes EN ISO 3506-1:2009
English Version
Fasteners - Mechanical properties of corrosion-resistant
stainless steel fasteners - Part 1: Bolts, screws and studs
with specified grades and property classes (ISO 3506-
1:2020)
Fixations - Caractéristiques mécaniques des fixations Mechanische Verbindungselemente - Mechanische
en acier inoxydable résistant à la corrosion - Partie 1: Eigenschaften von Verbindungselementen aus
Vis, goujons et tiges filetées de grades et classes de korrosionsbeständigen nichtrostenden Stählen - Teil 1:
qualité spécifiés (ISO 3506-1:2020) Schrauben mit festgelegten Stahlsorten und
Festigkeitsklassen (ISO 3506-1:2020)
This European Standard was approved by CEN on 28 March 2020.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3506-1:2020 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 3506-1:2020) has been prepared by Technical Committee ISO/TC 2 "Fasteners"
in collaboration with Technical Committee CEN/TC 185 “Fasteners” the secretariat of which is held by
BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2020, and conflicting national standards shall
be withdrawn at the latest by October 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 3506-1:2009.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 3506-1:2020 has been approved by CEN as EN ISO 3506-1:2020 without any
modification.
INTERNATIONAL ISO
STANDARD 3506-1
Third edition
2020-04
Fasteners — Mechanical properties
of corrosion-resistant stainless steel
fasteners —
Part 1:
Bolts, screws and studs with specified
grades and property classes
Fixations — Caractéristiques mécaniques des fixations en acier
inoxydable résistant à la corrosion —
Partie 1: Vis, goujons et tiges filetées de grades et classes de qualité
spécifiés
Reference number
ISO 3506-1:2020(E)
©
ISO 2020
ISO 3506-1:2020(E)
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
Contents Page
Foreword .v
Introduction .vii
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Symbols . 3
5 Designation system for stainless steel grades and property classes .4
5.1 General . 4
5.2 Designation of stainless steel grades (first block). 5
5.3 Designation of property classes (second block) . 6
6 Materials . 6
6.1 Chemical composition . 6
6.2 Heat treatment for martensitic stainless steel fasteners . 7
6.3 Finish . 8
6.4 Corrosion resistance . 8
7 Mechanical and physical properties . 8
8 Applicability of test methods and inspection .14
8.1 Applicability of test methods .14
8.2 Loadability of fasteners .14
8.2.1 Fasteners with full loadability .14
8.2.2 Fasteners which have reduced loadability due to their geometry .15
8.3 Manufacturer’s inspection .16
8.4 Supplier’s inspection .16
8.5 Purchaser’s inspection .16
8.6 Delivery of test results .17
9 Test methods .17
9.1 Tensile test for fasteners .17
9.1.1 General.17
9.1.2 Test procedure for the simultaneous determination of R , R , and A .18
mf pf
9.1.3 Reference test procedure for the determination of stress at 0,2 % non-
proportional elongation, R .19
pf
9.1.4 Alternative test procedure for the determination of elongation, A .21
9.1.5 Test results and requirements for tensile strength, R .22
mf
9.1.6 Test results and requirements for stress at 0,2 % non-proportional
elongation, R .22
pf
9.1.7 Test results and requirements for elongation after fracture, A .23
9.2 Tensile test for bolts and screws with reduced loadability due to head design .23
9.2.1 General.23
9.2.2 Test procedure .23
9.2.3 Test results and requirements for ultimate tensile load, F .23
mf
9.3 Tensile test for fasteners with reduced loadability due to shank design .23
9.3.1 General.23
9.3.2 Test procedure .24
9.3.3 Test results for tensile strength .24
9.4 Wedge tensile test .24
9.4.1 General.24
9.4.2 Test procedure .26
9.4.3 Test results and requirements .26
9.5 Torsional test .26
9.5.1 General.26
9.5.2 Test procedure .27
ISO 3506-1:2020(E)
9.5.3 Test results and requirements .28
9.6 Hardness test .28
9.6.1 General.28
9.6.2 Test procedure .28
9.6.3 Test results and requirements .28
10 Fastener marking and labelling .29
10.1 Fastener marking .29
10.1.1 General requirements for marking .29
10.1.2 Marking of property class for fasteners with full loadability .29
10.1.3 Marking of property class for fasteners with reduced loadability.29
10.1.4 Additional marking .30
10.2 Manufacturer’s identification mark .30
10.3 Marking on the fasteners .30
10.3.1 Hexagon head bolts and screws .30
10.3.2 Hexagon socket or hexalobular socket bolts and screws .31
10.3.3 Other types of bolts and screws.32
10.3.4 Studs (one-end and double-end studs) .32
10.3.5 Fully threaded studs .33
10.3.6 Left-hand thread marking .33
10.4 Marking of the packages (labelling) .34
Annex A (informative) Mechanical properties at elevated temperatures — Application at
low temperatures.35
Bibliography .37
iv © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 2, Fasteners.
This third edition cancels and replaces the second edition (ISO 3506-1:2009), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— annexes common to several parts of the ISO 3506 series have been withdrawn from this document
and are now included in a new document (ISO 3506-6);
— duplex (austenitic-ferritic) stainless steels for property classes 70, 80 and 100 have been added (see
Figure 1);
— property class 100 for austenitic stainless steel grades as well as grade A8 have been added (see
Figure 1);
— finish (see 6.3) has been added;
— the matching of stainless steel bolt and nut grades (see 6.4) has been added;
— calculated minimum ultimate tensile loads and minimum loads at 0,2 % non-proportional elongation
(see Tables 4 to 7) and rounding rules have been added;
— reduced loadability for fasteners due to head or shank design (see 8.2) has been added;
— requirements and guidance for inspection procedures (see 8.3 to 8.6) have been added;
— operational temperature ranges (see Clause 1) have been clarified;
— the applicability of test methods (see Clause 8), also in relation to full and reduced loadability, has
been added;
— the tensile test procedure (see 9.1) has been entirely amended, and application to fasteners with
reduced loadability (see 9.2 and 9.3) has been added;
ISO 3506-1:2020(E)
— the wedge tensile test (see 9.4) and hardness test (see 9.6) have been improved;
— marking and labelling (see Clause 10) have been improved, and fasteners with reduced loadability
have been included;
— mechanical properties at elevated temperatures and application at low temperatures (see Annex A)
have been improved;
— the structure and content of this document have been brought in line with ISO 898-1.
A list of all parts in the ISO 3506 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
vi © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
Introduction
The ISO 3506 series consists of the following parts, under the general title Fasteners — Mechanical
properties of corrosion-resistant stainless steel fasteners:
— Part 1: Bolts, screws and studs with specified grades and property classes
— Part 2: Nuts with specified grades and property classes
1)
— Part 3 : Set screws and similar fasteners not under tensile stress
1)
— Part 4 : Tapping screws
2)
— Part 5 : Special fasteners (also including fasteners from nickel alloys) for high temperature applications
— Part 6: General rules for the selection of stainless steels and nickel alloys for fasteners
The properties of stainless steel fasteners result from the chemical composition of the material
(especially corrosion resistance) and from the mechanical properties due to the manufacturing
processes. Ferritic, austenitic and duplex (austenitic-ferritic) stainless steel fasteners are generally
manufactured by cold working; they consequently do not have homogeneous local material properties
when compared to quenched and tempered fasteners.
Austenitic-ferritic stainless steels referred to as duplex stainless steels were originally invented in the
1930s. Standard duplex grades used today have been developed since the 1980s. Fasteners made of
duplex stainless steels have been long established in a range of applications. This document was revised
to reflect their standardization.
All duplex stainless steel grades show improved resistance to stress corrosion cracking compared to
the commonly used A1 to A5 austenitic grades. Most duplex grades also show higher levels of pitting
corrosion resistance, where D2 matches at least A2 and where D4 matches at least A4.
Complementary detailed explanations about definitions of stainless steel grades and properties are
specified in ISO 3506-6.
1) It is intended to revise ISO 3506-3 and ISO 3506-4 in the future in order to include the reference to ISO 3506-6.
2) Under preparation.
INTERNATIONAL STANDARD ISO 3506-1:2020(E)
Fasteners — Mechanical properties of corrosion-resistant
stainless steel fasteners —
Part 1:
Bolts, screws and studs with specified grades and
property classes
1 Scope
This document specifies the mechanical and physical properties of bolts, screws and studs, with
coarse pitch thread and fine pitch thread, made of corrosion-resistant stainless steels, when tested at
the ambient temperature range of 10 °C to 35 °C. It specifies property classes in relation to austenitic,
martensitic, ferritic and duplex (austenitic-ferritic) steel grades for fasteners.
The term “fasteners” is used in this document when bolts, screws and studs are considered all together.
ISO 3506-6 provides general rules and additional technical information on suitable stainless steels and
their properties.
Fasteners conforming to the requirements of this document are evaluated at the ambient temperature
specified in paragraph 1. It is possible that they do not retain the specified mechanical and physical
properties at elevated and/or lower temperatures.
NOTE 1 Fasteners conforming to the requirements of this document are used without restriction in
applications ranging from –20 °C to +150 °C; however, fasteners conforming to this document are also used for
applications outside this range down to –196 °C and up to +300 °C. For more details, see Annex A and ISO 3506-6.
Outside the temperature range of –20 °C to +150 °C, it is the responsibility of the user to determine the
appropriate choice for a given application in consultation with an experienced fastener metallurgist
and by taking into account e.g. stainless steel composition, duration of exposure at elevated or low
temperature, the effect of the temperature on the fasteners mechanical properties and clamped parts,
and the corrosive service environment of the bolted joint.
NOTE 2 ISO 3506-5 is developed in order to assist in the selection of appropriate stainless steel grades and
property classes intended for use at temperatures up to +800 °C.
This document applies to bolts, screws and studs:
— with ISO metric thread in accordance with ISO 68-1,
— with diameter/pitch combinations in accordance with ISO 261 and ISO 262,
— with coarse pitch thread M1,6 to M39, and fine pitch thread M8×1 to M39×3,
— with thread tolerances in accordance with ISO 965-1 and ISO 965-2,
— with specified property classes, and
— of any shape.
Stainless steel grades and property classes can be used for sizes outside the diameter limits of this
document (i.e. for d < 1,6 mm or d > 39 mm), provided that all applicable chemical, mechanical and
physical requirements are met.
ISO 3506-1:2020(E)
Certain bolts, screws and studs might not fulfil the tensile or torsional requirements of this document
because of the geometry of their head or unthreaded shank, thus resulting in reduced loadability (e.g.
when shear area in the head is less than the stress area in the thread; see 8.2.2).
This document does not apply to set screws and similar threaded fasteners not under tensile stress
(see ISO 3506-3).
It does not specify requirements for functional properties such as:
— torque/clamp force properties,
— shear strength,
— fatigue resistance, or
— weldability.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1891-4, Fasteners — Vocabulary — Part 4: Control, inspection, delivery, acceptance and quality
ISO 3506-6, Fasteners — Mechanical properties of corrosion-resistant stainless steel fasteners — Part 6:
General rules for the selection of stainless steels and nickel alloys for fasteners
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Calibration and verification of the force-measuring system
ISO 9513, Metallic materials — Calibration of extensometer systems used in uniaxial testing
ISO 16228, Fasteners — Types of inspection documents
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
stainless steel bolt and screw with full loadability
bolt and screw with head stronger than the threaded and unthreaded shanks (with unthreaded shank
diameter d ≈ d or d > d ) or screw threaded to the head, and fulfilling the minimum ultimate tensile load
s 2 s 2
3.2
stainless steel stud with full loadability
stud with unthreaded shank diameter d ≈ d or d > d , and fulfilling the minimum ultimate tensile load
s 2 s 2
2 © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
3.3
stainless steel bolt and screw with reduced loadability
bolt and screw with head weaker than the threaded and unthreaded shanks, or with an unthreaded
shank diameter d < d
s 2
3.4
stainless steel stud with reduced loadability
stud with unthreaded shank diameter d < d
s 2
3.5
stainless steel
steel with at least 10,5 % (mass fraction) of chromium (Cr) and maximum 1,2 % (mass fraction) of
carbon (C)
3.6
austenitic stainless steel
stainless steel (3.5) with high amounts of chromium and nickel which usually cannot be hardened by
heat treatment, providing excellent resistance to corrosion, good ductility, and usually low or non-
magnetic properties
3.7
martensitic stainless steel
stainless steel (3.5) with high amounts of chromium but very little nickel or other alloying elements,
which can be hardened by heat treatment for increasing strength but with reduced ductility, and with
highly magnetic properties
3.8
ferritic stainless steel
stainless steel (3.5) containing less than 0,1 % carbon and typically 11 % to 18 % chromium, which
usually cannot be hardened by heat treatment, and with highly magnetic properties
3.9
duplex stainless steel
stainless steel (3.5) with a micro-structure that includes both austenitic and ferritic phases providing
excellent resistance to corrosion, containing a higher amount of chromium and a reduced quantity of
nickel compared to austenitic steel, with high strength, and with magnetic properties
4 Symbols
For the purposes of this document, the following symbols apply.
A total elongation after fracture, mm
A nominal stress area in thread, mm
s,nom
A cross-sectional area of waisted shank, mm
ds
b thread length, mm
d nominal thread diameter of the fastener, mm
d basic minor diameter of external thread, mm
d basic pitch diameter of external thread, mm
d minor diameter of external thread (for nominal stress area calculation), mm
d inner diameter of the bearing face, mm
a
ISO 3506-1:2020(E)
d hole diameter for adaptors and wedge, mm
h
d diameter of unthreaded shank, mm
s
F ultimate tensile load, N
mf
F load at 0,2 % non-proportional elongation for full-size fastener, N
pf
H height of the fundamental triangle of the thread, mm
k height of the head, mm
l nominal length of fastener, mm
L total length of fastener before tensile test, mm
L total length of fastener after fracture, mm
L clamping length before tensile test, mm
l length of unthreaded shank, mm
s
l overall length of stud, mm
t
l free threaded length of fastener in testing device, mm
th
M breaking torque, Nm
B
P pitch of the thread, mm
R tensile strength for fastener with reduced loadability due to shank design, MPa
mds
R tensile strength for full-size fastener, MPa
mf
R stress at 0,2 % non-proportional elongation for full-size fastener, MPa
pf
α wedge angle, °
5 Designation system for stainless steel grades and property classes
5.1 General
The standardized combinations of stainless steel grades and property classes are specified in Clause 7,
Table 2 or 3.
The designation system for stainless steel grades and property classes for bolts, screws and studs
consists of two blocks, separated by a hyphen, as specified in Figure 1. The first block designates the
stainless steel grade, and the second block the property class of the fastener.
4 © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
a
For low carbon austenitic stainless steels with carbon content not exceeding 0,030 %, fasteners can additionally
be marked or designated with the letter "L" just after the grade. Example: A4L-80.
b
For information only.
Figure 1 — Designation system for stainless steel grades and property classes for fasteners
The marking, labelling and designation of fasteners with stainless steel grade and property class shall
be as specified in Clause 10. For bolts, screws and studs with reduced loadability which can be tensile
tested in the threaded shank, the digit “0” shall precede the property class as specified in 10.1.3. For
fasteners with reduced loadability which cannot be tensile tested due to a too short thread length
(b < 3d), the property class shall not be referenced.
The designation system of this document may be used for sizes outside the diameter limits specified in
Clause 1 (i.e. d < 1,6 mm or d > 39 mm), provided that all applicable chemical, mechanical and physical
requirements are met.
5.2 Designation of stainless steel grades (first block)
The designation of the stainless steel grade (first block) consists of one letter which specifies the
stainless steel group:
— A for austenitic,
— C for martensitic,
— F for ferritic,
— D for duplex (austenitic-ferritic),
ISO 3506-1:2020(E)
and
— a digit which specifies the range of chemical compositions within this stainless steel group.
The chemical compositions of stainless steel groups and grades classified in Figure 1 are specified in
Table 1.
5.3 Designation of property classes (second block)
The designation of the property class (second block) consists of a number corresponding to 1/10 of the
minimum tensile strength of the fastener in accordance with Table 2 or 3.
EXAMPLE 1 A2-70 specifies an austenitic stainless steel fastener, work hardened, with a minimum tensile
strength of 700 MPa.
EXAMPLE 2 C1-110 specifies a martensitic stainless steel fastener, quenched and tempered, with a minimum
tensile strength of 1 100 MPa.
6 Materials
6.1 Chemical composition
Table 1 specifies the limits for chemical composition of the stainless steel grades for fasteners. The
chemical composition shall be assessed in accordance with the relevant International Standards.
The final choice of the chemical composition within the specified stainless steel grade is at the discretion
of the manufacturer, unless otherwise agreed between the purchaser and the manufacturer.
The stainless steel grade suitable for an application shall be selected in accordance with the
specifications defined in ISO 3506-6.
6 © ISO 2020 – All rights reserved
ISO 3506-1:2020(E)
Table 1 — Stainless steel grades — Chemical composition
a
Chemical composition
Stainless b Other elements
(cast analysis, mass fraction in %)
steel grade and notes
C Si Mn P S Cr Mo Ni Cu N
0,15 to 16,0 to 5,0 to 1,75 to
c,d,e
A1 0,12 1,00 6,5 0,020 0,70 —
0,35 19,0 10,0 2,25
15,0 to 8,0 to
f g,h
A2 0,10 1,00 2,00 0,050 0,030 — 4,0 —
20,0 19,0
17,0 to 9,0 to 5C ≤ Ti ≤ 0,80 and/or
f
A3 0,08 1,00 2,00 0,045 0,030 — 1,00 —
19,0 12,0 10C ≤ Nb ≤ 1,00
Austenitic
16,0 to 2,00 to 10,0 to
h,i
A4 0,08 1,00 2,00 0,045 0,030 4,0 —
18,5 3,00 15,0
16,0 to 2,00 to 10,5 to 5C ≤ Ti ≤ 0,80 and/or
A5 0,08 1,00 2,00 0,045 0,030 1,00 —
i
18,5 3,00 14,0 10C ≤ Nb ≤ 1,00
19,0 to 17,5 to
A8 0,030 1,00 2,00 0,040 0,030 6,0 to 7,0 1,50 — —
22,0 26,0
0,09 to 11,5 to
i
C1 1,00 1,00 0,050 0,030 — 1,00 — —
0,15 14,0
0,17 to 16,0 to 1,50 to
Martensitic C3 1,00 1,00 0,040 0,030 — — — —
0,25 18,0 2,50
0,08 to 0,15 to 12,0 to
c,i
C4 1,00 1,50 0,060 0,60 1,00 — —
0,15 0,35 14,0
15,0 to
f j
Ferritic F1 0,08 1,00 1,00 0,040 0,030 — 1,00 — —
18,0
Cr + 3,3Mo +16N
19,0 to 0,10 to 1,50 to 0,05 to
D2 0,040 1,00 6,0 0,040 0,030 3,00 ≤ 24,0
24,0 1,00 5,5 0,20
k
24,0 < Cr + 3,3Mo
21,0 to 0,10 to 1,00 to 0,05 to
D4 0,040 1,00 6,0 0,040 0,030 3,00 + 16N
25,0 2,00 5,5 0,30
Duplex k
21,0 to 2,50 to 4,5 to 0,08 to
D6 0,030 1,00 2,00 0,040 0,015 — —
23,0 3,5 6,5 0,35
24,0 to 3,00 to 6,0 to 0,20 to
D8 0,030 1,00 2,00 0,035 0,015 2,50 W ≤ 1,00
26,0 4,5 8,0 0,35
a
According to material standards, values are maximum unless otherwise indicated and the number of digits shown is in accordance with usual rules,
see e.g. EN 10088 (all parts).
b
In case of dispute, product analysis applies.
c
Selenium can be used to replace sulphur, however restrictions may apply to its use.
d
If the nickel content is below 8,0 %, the minimum manganese content shall be 5,0 %.
e
There is no minimum limit to the copper content provided that the nickel content is greater than 8,0 %.
f
Molybdenum may be present at the discretion of the manufacturer. However, if for some applications limiting of the molybdenum content is essential,
this shall be stated at the time of ordering by the purchaser.
g
If the chromium content is below 17,0 %, the minimum nickel content should be 12,0 %.
h
For austenitic stainless steels having a maximum carbon content of 0,030 %, nitrogen may be present but shall not exceed 0,22 %.
i
At the discretion of the manufacturer the carbon content may be higher as necessary in order to obtain the specified mechanical properties for larger
diameters, but shall not exceed 0,12 % for austenitic steels.
j
Titanium and/or niobium may be included to improve corrosion resistance.
k
This formula is used solely for the purpose of classifying duplex steels in accordance with this document (it is not intended to be used as a selection
criterion for corrosion resistance).
For the choice of the appropriate stainless steel grade suitable for a specific application, see ISO 3506-6.
Examples of stainless steels in accordance with Table 1 are also given in ISO 3506-6.
6.2 Heat treatment for martensitic stainless steel fasteners
Fasteners of grades and property classes C1-70, C3-80 and C4-70 shall be quenched and tempered.
Fasteners of grade and property class C1-110 shall be quenched and tempered, with a minimum
tempering temperature of 275 °C.
ISO 3506-1:2020(E)
6.3 Finish
Unless otherwise specified, fasteners in accordance with this document shall be supplied clean and bright.
For maximum corrosion resistance, passivation is recommended. Fasteners that are passivated in
accordance with ISO 16048 may additionally be referenced on the label with the letter “P” immediately
after the property class symbol (see 10.4).
NOTE 1 Passivated fasteners do not always show a bright surface finish.
Bolts, screws and studs are often used in bolted joints where the preload is achieved by torque
tightening. Therefore, lubrication of stainless steel fasteners is recommended in order to avoid galling
during tightening.
NOTE 2 Several parameters can increase the risk of galling for stainless steel fasteners in bolted assemblies
during tightening such as thread damage, high preload, high tightening speed.
NOTE 3 For the time being, requirements concerning surface discontinuities and torque/clamp force
properties are not specified in International Standards for stainless steel fasteners.
A controlled torque/clamp force relationship can be obtained for stainless steel fasteners by means
of an adequate finish, either just with a lubricant or with a coating, top coat and/or sealer including
lubricant. In this case, the designation and/or labelling should include the letters “Lu” immediately
after the symbol of the property class, e.g. A4-80Lu. In conjunction, appropriate measures and means of
tightening should be selected in order to achieve the required preload.
When specific requirements are necessary, it shall be agreed between the supplier and the purchaser at
the time of the order.
6.4 Corrosion resistance
For corrosion resistance purpose, bolts, screws and studs should be mated with nuts and washers of
the same stainless steel grade (e.g. nuts A2 with bolts A2, etc.). Other combinations are possible (e.g.
nuts A4 with bolts D4), providing that:
— the component with the lowest corrosion resistance shall always be taken into account,
— the risk of galling should be considered, and
— it is strongly recommended that an experienced fastener metallurgist be consulted.
When using stainless steel fasteners with non-stainless steel parts in bolted joints, e.g. galvanized
steels, it is advised that the use of isolation components be considered in order to avoid galvanic
corrosion.
7 Mechanical and physical properties
When tested by the methods specified in Clause 9, the bolts, screws and studs of the specified stainless
steel grade and property class shall meet, at ambient temperature, all the applicable requirements
specified in Tables 2 to 8, regardless of which tests are performed during manufacture or final
inspection.
Clause 8 specifies the applicability of test methods for verifying that fasteners of different types and
dimensions fulfil the requirements in accordance with Tables 2 to 8.
Even if the material of the fasteners meets all relevant requirements specified in Clause 6, it is possible
that certain fasteners would not fulfil the tensile or torsional requirements b
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