Welding - Determination of Ferrite Number (FN) in austenitic and duplex ferritic-austenitic Cr-Ni stainless steel weld metals (ISO 8249:2018)

This document specifies the method and apparatus for:
— the measurement of the delta ferrite content, expressed as Ferrite Number (FN), in largely austenitic and duplex ferritic-austenitic stainless steel[1] weld metal through the attractive force between a weld metal sample and a standard permanent magnet;
— the preparation and measurement of standard pads for manual metal arc covered electrodes. The general method is also recommended for the ferrite measurement of production welds and for weld metal from other processes, such as gas tungsten arc welding, gas shielded metal arc welding and submerged arc welding (in these cases, the way of producing the pad should be defined);
— the calibration of other instruments to measure FN.
The method laid down in this document is intended for use on weld metals in the as-welded state and on weld metals after thermal treatments causing complete or partial transformation of ferrite to any non-magnetic phase. Austenitizing thermal treatments which alter the size and shape of the ferrite change the magnetic response of the ferrite.
The method is not intended for measurement of the ferrite content of cast, forged or wrought austenitic or duplex ferritic-austenitic steel samples.
[1] The term "austenitic-ferritic (duplex) stainless steel" is sometimes applied in place of "duplex ferritic-austenitic stainless steel".

Schweißen - Bestimmung der Ferrit-Nummer (FN) in austenitischem und ferritisch-austenitischem (Duplex-)Schweißgut von Cr-Ni-Stählen (ISO 8249:2018)

Dieses Dokument legt das Verfahren und Geräte fest für:
—   die Messung des Deltaferrit-Gehaltes, ausgedrückt als Ferritnummer (FN), in nichtrostendem,  großenteils austenitischem und ferritisch austenitischem (Duplex )Schweißgut ) auf der Grundlage der Haftkraft zwischen einem Prüfstück aus Schweißgut und einem genormten Dauermagneten;
—   die Herstellung und Prüfung von Schweißgutprüfstücken aus Stabelektroden. Das Verfahren wird auch empfohlen für die Messung des Deltaferrit-Gehaltes von Fertigungsschweißungen und von Schweißgut, das nach anderen Verfahren hergestellt wurde (z.B. WIG, MIG/MAG, UP – in diesen Fällen müssen die Parameter zur Herstellung der Schweißgutprobe angegeben werden);
—   die Kalibrierung anderer Messgeräte zum Messen der FN.
Die in diesem Dokument festgelegte Verfahren ist vorgesehen für die Verwendung auf Schweißgut im geschweißten Zustand und auf Schweißgut nach Wärmebehandlung, die eine komplette oder teilweise Transformation von Deltaferrit in nichtmagnetische Phasen verursacht. Austenitisierende Wärmebehandlungen, bei denen die Größe und Form des Deltaferrits verändert wird, ändern auch die magnetische Reaktion des Deltaferrits.
Das Verfahren gilt nicht für die Bestimmung des Deltaferritgehaltes von Prüfstücken aus austenitischem oder ferritisch austenitischem (Duplex-)Stahl in gegossener oder gewalzter/geschmiedeter Form.

Soudage - Détermination de l'indice de ferrite (FN) dans le métal fondu en acier inoxydable austénitique et duplex ferritique-austénitique au chrome-nickel (ISO 8249:2018)

Le présent document spécifie l'appareillage et le mode opératoire pour:
— le mesurage de la teneur en ferrite delta, exprimé en Indice de Ferrite (FN), du métal fondu en acier inoxydable en grande partie austénitique et duplex ferritique-austénitique[1] par la force d'attraction entre un échantillon de métal fondu et un aimant permanent étalon;
— la préparation et le mesurage des dépôts obtenus à partir d'électrodes enrobées. La méthode générale est également recommandée pour le mesurage de l'Indice de Ferrite des soudures de production et du métal fondu obtenu par d'autres procédés, tels que le soudage TIG, MIG et sous flux (dans ces cas-là, il convient de définir la méthode d'exécution du dépôt);
— l'étalonnage d'autres instruments de mesurage de l'Indice de Ferrite.
Le présent document est applicable au mesurage de l'Indice de Ferrite du métal fondu à l'état brut de soudage. Elle est également applicable à du métal fondu ayant été soumis à des traitements thermiques provoquant la transformation complète ou partielle de la ferrite en n'importe quelle phase non magnétique. Les traitements thermiques d'austénisation modifiant la taille et la forme de la ferrite modifient également la réponse magnétique de la ferrite.
La méthode n'est pas destinée au mesurage de la teneur en ferrite d'échantillons en acier austénitique ou duplex ferritique-austénitique moulés, forgés ou corroyés.
[1] Le terme «acier inoxydable austénitique-ferritique (duplex)» est parfois utilisé à la place du terme «acier inoxydable duplex ferritique-austénitique».

Varjenje - Določanje feritnega števila (FN) v avstenitnih in dupleksnih feritno-avstenitnih Cr-Ni nerjavnih varih (ISO 8249:2018)

Ta dokument določa metodo in aparat za:
– meritev delta feritne vsebnosti, izražene kot feritno število (FN), v avstenitnih in dupleksnih feritno-avstenitnih krom-nikljevih nerjavnih varih na podlagi privlačne sile med vzorcem zvarne kovine in standardnim trajnim magnetom;
– pripravo in meritve standardnih ploščic za pokrite elektrode za ročno obločno varjenje. Splošna metoda je priporočena tudi za meritve ferita pri proizvodnih varih in za zvarne kovine iz drugih procesov, kot je varjenje TIG, obločno varjenje v zaščitnih plinih in obločno varjenje pod praškom (v teh primerih je treba določiti način proizvodnje ploščice);
– umerjanje drugih instrumentov za merjenje feritnega števila.
Metoda, določena v tem dokumentu, je namenjena za uporabo na zvarnih kovinah v varjenem stanju in na zvarnih kovinah po toplotni obdelavi, ki povzroči popolno ali delno pretvorbo ferita v katero koli nemagnetno fazo. Toplotne obdelave z avstenitizacijo, pri katerih se spremenita velikost in oblika ferita, vključujejo spremembo magnetnega odziva ferita.
Ta metoda ni namenjena za meritve vsebnosti ferita v litih, kovanih ali kovnih vzorcih avstenitnega ali dupleksno feritno-avstenitnega jekla.

General Information

Status
Published
Publication Date
18-Sep-2018
Technical Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
19-Sep-2018
Completion Date
19-Sep-2018

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SLOVENSKI STANDARD
SIST EN ISO 8249:2018
01-december-2018
1DGRPHãþD
SIST EN ISO 8249:2001
9DUMHQMH'RORþDQMHIHULWQHJDãWHYLOD )1 YDYVWHQLWQLKLQGXSOHNVQLKIHULWQR
DYVWHQLWQLK&U1LQHUMDYQLKYDULK ,62

Welding - Determination of Ferrite Number (FN) in austenitic and duplex ferritic-austenitic

Cr-Ni stainless steel weld metals (ISO 8249:2018)
Schweißen - Bestimmung der Ferrit-Nummer (FN) in austenitischem und ferritisch-
austenitischem (Duplex-)Schweißgut von Cr-Ni-Stählen (ISO 8249:2018)
Soudage - Détermination de l'indice de ferrite (FN) dans le métal fondu en acier
inoxydable austénitique et duplex ferritique-austénitique au chrome-nickel (ISO
8249:2018)
Ta slovenski standard je istoveten z: EN ISO 8249:2018
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
SIST EN ISO 8249:2018 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 8249:2018
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SIST EN ISO 8249:2018
EN ISO 8249
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2018
EUROPÄISCHE NORM
ICS 25.160.40 Supersedes EN ISO 8249:2000
English Version
Welding - Determination of Ferrite Number (FN) in
austenitic and duplex ferritic-austenitic Cr-Ni stainless
steel weld metals (ISO 8249:2018)

Soudage - Détermination de l'indice de ferrite (FN) Schweißen - Bestimmung der Ferrit-Nummer (FN) in

dans le métal fondu en acier inoxydable austénitique et austenitischem und ferritisch-austenitischem (Duplex-

duplex ferritique-austénitique au chrome-nickel (ISO )Schweißgut von Cr-Ni-Stählen (ISO 8249:2018)

8249:2018)
This European Standard was approved by CEN on 8 September 2018.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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

© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8249:2018 E

worldwide for CEN national Members.
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SIST EN ISO 8249:2018
EN ISO 8249:2018 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 8249:2018
EN ISO 8249:2018 (E)
European foreword

This document (EN ISO 8249:2018) has been prepared by Technical Committee ISO/TC IIW

"International Institute of Welding" in collaboration with Technical Committee CEN/TC 121 “Welding

and allied processes” the secretariat of which is held by DIN.

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 March 2019, and conflicting national standards shall

be withdrawn at the latest by March 2019.

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 8249:2000.

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, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 8249:2018 has been approved by CEN as EN ISO 8249:2018 without any modification.

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SIST EN ISO 8249:2018
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SIST EN ISO 8249:2018
INTERNATIONAL ISO
STANDARD 8249
Third edition
2018-07
Welding — Determination of Ferrite
Number (FN) in austenitic and duplex
ferritic-austenitic Cr-Ni stainless steel
weld metals
Soudage — Détermination de l'indice de ferrite (FN) dans le
métal fondu en acier inoxydable austénitique et duplex ferritique-
austénitique au chrome-nickel
Reference number
ISO 8249:2018(E)
ISO 2018
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SIST EN ISO 8249:2018
ISO 8249:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

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 2018 – All rights reserved
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SIST EN ISO 8249:2018
ISO 8249:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 1

5 Calibration .................................................................................................................................................................................................................. 2

5.1 Coating thickness standards ....................................................................................................................................................... 2

5.2 Magnet ............................................................................................................................................................................................................ 2

5.3 Instruments ............................................................................................................................................................................................... 2

5.4 Calibration curve ................................................................................................................................................................................... 3

6 Standard method for covered electrode test pads ............................................................................................................ 5

6.1 Dimensions of weld metal test specimens ...................................................................................................................... 5

6.2 Depositing weld metal test specimens ............................................................................................................................... 5

6.3 Measuring .................................................................................................................................................................................................... 6

6.3.1 Surface finishing ............................................................................................................................................................... 6

6.3.2 Individual measurements ........................................................................................................................................ 6

6.3.3 Reporting ................................................................................................................................................................................ 7

7 Standard methods for test pads of other processes and for production welds ..................................7

7.1 Standard method for test pads for other weld metals .......................................................................................... 7

7.2 Production welds .................................................................................................................................................................................. 7

8 Other methods ........................................................................................................................................................................................................ 7

8.1 Methods ......................................................................................................................................................................................................... 7

8.2 Maintaining calibration ................................................................................................................................................................... 8

9 Procedures used to prepare secondary standards for delta ferrite in austenitic

stainless steel weld metal ........................................................................................................................................................................... 8

Annex A (informative) Manufacture of secondary standards by strip cladding .....................................................9

Annex B (informative) Manufacture of secondary standards by centrifugal chill casting ........................19

Bibliography .............................................................................................................................................................................................................................27

© ISO 2018 – All rights reserved iii
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SIST EN ISO 8249:2018
ISO 8249:2018(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 IIW, the International Institute of Welding, Commission II.

Any feedback, question or request for official interpretation related to any aspect of this document

should be directed to IIW via your national standards body. A complete listing of these bodies can be

found at www .iso .org/members .html.

This third edition cancels and replaces the second edition (ISO 8249:2000), which has been technically

revised. The main changes compared to the previous edition are as follows:
— corrections have been made to Table 2 (previously Table 1);

— minor editorial changes in Clause 9 (previously Clause 8) and throughout the document have

been made.
iv © ISO 2018 – All rights reserved
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SIST EN ISO 8249:2018
ISO 8249:2018(E)
Introduction

At present, there is no universal opinion concerning the best experimental method that gives an absolute

measurement of the amount of ferrite in a weld metal, either destructively or non-destructively. This

situation has led to the development and use, internationally, of the concept of a "Ferrite Number" or FN.

A Ferrite Number is a description of the ferrite content of a weld metal determined using a standardized

procedure. Such procedures are laid down in this document. The Ferrite Number of a weld metal has

been considered approximately equivalent to the percentage ferrite content, particularly at low FN

values. More recent information suggests that the FN can overstate the volume percent ferrite at higher

FN by a factor in the order of 1,3 to 1,5, which depends to a certain extent on the actual composition of

the alloy in question.

Although other methods are available for determining the Ferrite Number, the standardized measuring

procedure, laid down in this document, is based on assessing the tear-off force needed to pull the weld

metal sample from a magnet of defined strength and size. The relationship between tear-off force and

FN is obtained using primary standards consisting of a non-magnetic coating of specified thickness on

a magnetic base. Each non-magnetic coating thickness is assigned an FN value.

The ferrite content determined by this method is arbitrary and is not necessarily the true or absolute

ferrite content. In recognition of this fact, the term "Ferrite Number" (FN) is used instead of "ferrite per

cent" when quoting a ferrite content determined by this method. To help convey the message that this

standardized calibration procedure has been used, the terms "Ferrite Number" and "FN" are capitalized

as proper nouns.
© ISO 2018 – All rights reserved v
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SIST EN ISO 8249:2018
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SIST EN ISO 8249:2018
INTERNATIONAL STANDARD ISO 8249:2018(E)
Welding — Determination of Ferrite Number (FN) in
austenitic and duplex ferritic-austenitic Cr-Ni stainless
steel weld metals
1 Scope
This document specifies the method and apparatus for:

— the measurement of the delta ferrite content, expressed as Ferrite Number (FN), in largely austenitic

and duplex ferritic-austenitic stainless steel weld metal through the attractive force between a

weld metal sample and a standard permanent magnet;

— the preparation and measurement of standard pads for manual metal arc covered electrodes. The

general method is also recommended for the ferrite measurement of production welds and for weld

metal from other processes, such as gas tungsten arc welding, gas shielded metal arc welding and

submerged arc welding (in these cases, the way of producing the pad should be defined);

— the calibration of other instruments to measure FN.

The method laid down in this document is intended for use on weld metals in the as-welded state and

on weld metals after thermal treatments causing complete or partial transformation of ferrite to any

non-magnetic phase. Austenitizing thermal treatments which alter the size and shape of the ferrite

change the magnetic response of the ferrite.

The method is not intended for measurement of the ferrite content of cast, forged or wrought austenitic

or duplex ferritic-austenitic steel samples.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.

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/
4 Principle

The measurement of the ferrite content of largely austenitic stainless steel weld metal through the

attractive force between a weld metal sample and a permanent magnet is based on the fact that the

attractive force between a two-phase (or multiphase) sample containing one ferromagnetic phase

and one (or more) non-ferromagnetic phase(s) increases as the content of the ferromagnetic phase

increases. In largely austenitic and duplex ferritic-austenitic stainless steel weld metal, ferrite is

magnetic, whereas austenite, carbides, sigma phase and inclusions are non-ferromagnetic.

1) The term "austenitic-ferritic (duplex) stainless steel" is sometimes applied in place of "duplex ferritic-austenitic

stainless steel".
© ISO 2018 – All rights reserved 1
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SIST EN ISO 8249:2018
ISO 8249:2018(E)
5 Calibration
5.1 Coating thickness standards

The coating thickness standards shall consist of non-magnetic copper applied to an unalloyed steel

base of size 30 mm × 30 mm. The thickness of the unalloyed steel base shall be equal to or greater than

the experimentally determined minimum thickness at which a further increase of the thickness does

not cause an increase of the attractive force between the standard permanent magnet and the coating

thickness standard. The thickness of the non-magnetic copper coating shall be known to an accuracy of

±5 % or better. The chemical composition of unalloyed steel shall be within the limits given in Table 1.

Table 1 — Chemical composition limits – unalloyed steel
Element Limit
% (by mass)
C 0,08 to 0,13
Si 0,10 maximum
Mn 0,30 to 0,60
P 0,040 maximum
S 0,050 maximum

The copper coating may be covered by a chromium flash. The force required to tear off a given

permanent magnet from the copper coating side of such a standard increases as the thickness of the

copper coating decreases.

To ensure adequate reproducibility of the calibration, the coating thickness standards defined above

should be used. In particular, coating thickness standards produced by the US National Institute of

Standards and Technology (NIST, formerly National Bureau of Standards or NBS) may be used.

5.2 Magnet

The standard magnet shall be a permanent magnet of cylindrical shape, 2 mm in diameter and about

50 mm in length. One end of the magnet shall be hemispherical, with a 1 mm radius and polished.

As an example, such a magnet can be made of 36 % cobalt magnet steel, 48,45 mm ± 0,05 mm long,

magnetically saturated and then diluted to 85 %. The magnetic strength of the magnet shall be such

that the force needed to tear off the standard magnet from the different coating thickness standards

is within ±10 % of the relationship shown in Figure 1 (the weight of the magnet excluded). This is

equivalent to a relationship between tear-off force and Ferrite Number of 5,0 FN/g ± 0,5 FN/g.

5.3 Instruments

The measurement by this method shall be made by an instrument enabling an increasing tear-off force

to be applied to the magnet perpendicularly to the surface of the test specimen. The tear-off force shall

be increased until the permanent magnet is detached from the test specimen. The instrument shall

accurately measure the tear-off force which is required for detachment. The reading of the instrument

may be directly in FN or in grams-force or in other units. If the reading of the instrument is in units

other than FN, the relationship between the FN and the instrument reading shall be defined by a

calibration curve.

NOTE Many instruments used to measure the thickness of a non-magnetic coating over a ferromagnetic

base are suitable (e.g. MAGNE-GAGE of USA origin) and some commercially available instruments are designed

directly for measurement of ferrite content (e.g. ALPHA-PHASE-METER of former USSR origin). In addition, after

suitable in-house alterations, some laboratory balances can be used.
2 © ISO 2018 – All rights reserved
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SIST EN ISO 8249:2018
ISO 8249:2018(E)
Key
x non-magnetic coating thickness, millimetres (mm)
y tear-off force, gram force (gf)

Figure 1 — Relationship between the tear-off forces of the standard magnet defined in 5.2 and

the coating thickness standards defined in 5.1
5.4 Calibration curve

In order to generate a calibration curve, determine the force needed to tear off the standard magnet

defined in 5.2 from several coating thickness standards defined in 5.1. Then, convert the thickness

of non-magnetic coating of the coating thickness standards into FN in accordance with Table 2, or in

[4]
accordance with Formula (1) :
2 3 4

FN = exp{1,805 9 −1,118 86 [ln(t)] − 0,177 40 [ln(t)] − 0,035 02 [ln(t)] − 0,003 67 [ln(t)]} (1)

where t is the non-magnetic coating thickness, expressed in millimetres.

Finally, plot the calibration curve as the relationship between the tear-off force in the units of the

instrument reading and the corresponding FN.

To calibrate the instrument for measurement of ferrite content within the range from 0 FN to

approximately 30 FN, which is appropriate for nominally austenitic stainless steel weld metals, a set

© ISO 2018 – All rights reserved 3
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SIST EN ISO 8249:2018
ISO 8249:2018(E)

consisting of a minimum of eight standards with copper coating thicknesses between approximately

0,17 mm and approximately 2 mm is recommended.

NOTE This calibration procedure can give misleading results if used on instruments measuring the ferrite

content in ways other than through the attractive force or on instruments measuring ferrite through the

attractive force but employing other than the standard magnet defined in 5.2. Instruments which cannot be

calibrated by the coating thickness standards and by the procedure specified in 5.2 to 5.4 can be calibrated as

described in Clause 8.

To extend the calibration from approximately 30 FN to 100 FN, which is appropriate for duplex ferritic-

austenitic stainless steel weld metals, a set consisting of a minimum of five standards with coating

thicknesses between 0,03 mm and 0,17 mm is recommended.

Table 2 — Relationship between Ferrite Number and thickness of non-magnetic coating of

coating thickness standards (specified in 5.1) for calibration of instruments for measurement

of ferrite content through attractive force (specified in 5.3) using the standard magnet

(specified in 5.2)
Coating Coating Coating Coating Coating
thickness thickness thickness thickness thickness
FN FN FN FN FN
t t t t t
mm mm mm mm mm
0,020 110,5 0,049 68,3 0,078 51,0 0,134 35,3 0,300 19,1
0,021 108,0 0,050 67,5 0,079 50,6 0,136 34,9 0,320 18,1
0,022 105,7 0,051 66,7 0,080 50,2 0,138 34,5 0,340 17,2
0,023 103,4 0,052 65,9 0,082 49,3 0,140 34,2 0,360 16,4
0,024 101,3 0,053 65,1 0,084 48,6 0,142 33,8 0,380 15,7
0,025 99,2 0,054 64,4 0,086 47,8 0,144 33,5 0,400 15.0
0,026 97,3 0,055 63,7 0,088 47,1 0,146 33,2 0,420 14,4
0,027 95,4 0,056 63,0 0,090 46,4 0,148 32,8 0,440 13,8
0,028 93,6 0,057 62,3 0,092 45,7 0,150 32,5 0,460 13,2
0,029 91,9 0,058 61,6 0,094 45,1 0,155 31,7 0,480 12,7
0,030 90,3 0,059 60,9 0,096 44,4 0,160 31,0 0,500 12,3
0,031 88,7 0,060 60,3 0,098 43,8 0,165 30,3 0,550 11,2
0,032 87,2 0,061 59,7 0,100 43,2 0,170 29,7 0,600 10,3
0,033 85,8 0,062 59,1 0,102 42,6 0,175 29,0 0,650 9,6
0,034 84,4 0,063 58,5 0,104 42,1 0,180 28,4 0,700 8,9
0,035 83,0 0,064 57,9 0,106 41,5 0,185 27,9 0,750 8,3
0,036 81,7 0,065 57,3 0,108 41,0 0,190 27,3 0,800 7,7
0,037 80,5 0,066 56,8 0,110 40,5 0,195 26,8 0,900 6,8
0,038 79,3 0,067 56,2 0,112 40,0 0,200 26,3 1,000 6,1
0,039 78,1 0,068 55,7 0,114 39,5 0,205 25,8 1,200 4,93
0,040 77,0 0,069 55,2 0,116 39,0 0,210 25,3 1,400 4,09
0,041 75,9 0,070 54,7 0,118 38,6 0,220 24,4 1,600 3,45
0,042 74,8 0,071 54,2 0,120 38,1 0,230 23,6 1,800 2,94
0,043 73,8 0,072 53,7 0,122 37,7 0,240 22,8 2,000 2,54
0,044 72,8 0,073 53,2 0,124 37,2 0,250 22,1 2,200 2,21
0,045 71,8 0,074 52,8 0,126 36,8 0,260 21,4 2,400 1,94
4 © ISO 2018 – All rights reserved
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SIST EN ISO 8249:2018
ISO 8249:2018(E)
Table 2 (continued)
Coating Coating Coating Coating Coating
thickness thickness thickness thickness thickness
FN FN FN FN FN
t t t t t
mm mm mm mm mm
0,046 70,9 0,075 52,3 0,128 36,4 0,270 20,8 2,600 1,72
0,047 70,0 0,076 51,9 0,130 36,0 0,280 20,2 2,800 1,53
0,048 69,1 0,077 51,4 0,132 35,6 0,290 19,6 3,000 1,36
6 Standard method for covered electrode test pads
6.1 Dimensions of weld metal test specimens

Standard weld metal test specimens for manual electrodes shall be of the size and shape indicated

in Figure 2. For the measurement of ferrite content by instruments/magnets or processes other than

those specified in 5.2 and 5.3, a larger specimen can be necessary. In such cases, the size and way of

producing the pad shall be clearly and carefully defined.
6.2 Depositing weld metal test specimens

a) The weld pad shall be built up between two copper bars laid parallel on the base plate. Spacing

shall be adjusted to accommodate the electrode size to be used as specified in Table 3.

b) The weld pad shall be built up by depositing layers one on top of the other to a minimum height

of 12,5 mm (see the Note on Figure 2). Each layer shall be made in a single pass for electrode

diameters ≥4 mm. For small diameters, each layer except the top layer shall be constituted by two

or more beads deposited with a maximum weave of 3 times the core wire diameter. The arc shall

not be allowed to come into contact with the copper bar.
Dimension in millimetres
Key
1 copper bar of dimensions 70 × 25 × 25
l length of the area where ferrite content is measured (see Table 3)
w width of the area where ferrite content is measured (see Table 3)

NOTE The base metal is preferably austenitic Cr-Ni steel type X2CrNi18-9 or X5CrNi18-9 (see ISO 15510)

and, in this case, the minimum pad height is 13 mm. Mild steel (C-Mn steel) can also be used and, in this case, the

minimum pad height is 18 mm.
Figure 2 — Weld metal specimen for ferrite determination
© ISO 2018 – All rights reserved 5
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SIST EN ISO 8249:2018
ISO 8249:2018(E)
c) The arc length shall be as short as practicable.

d) The welding currents shall comply with the values given in Table 3. The weld stops and starts shall

be located at the ends of the weld build-up. The welding direction shall be changed after each pass.

e) The weld pad may be cooled between passes by water quenching no sooner than 20 s after the

completion of each pass. The maximum temperature between passes shall be 100 °C. Each pass

of the last layer shall be air cooled to a temperature below 425 °C before water quenching.

f) Each weld pass shall be cleaned before the next is deposited.

g) In all cases, the topmost layer, at least, shall consist of a single bead deposited with a maximum

weave of 3 times the core wire diameter.
Table 3 — Welding parameters and deposit dimensions
Electrode diameter Welding current Approximate dimensions
Width, w Length, l
mm A mm mm
1,6 35 to 45 12,5 30
2 45 to 55 12,5 30
2,5 65 to 75 12,5 40
3,2 90 to 100 12,5 40
4 120 to 140 12,5 40
5 165 to 185 15 40
6,3 240 to 250 18 40
...

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