EN ISO 7091:2000

Plain washers - Normal series - Product grade C (ISO 7091:2000)

Migrated from Progress Sheet (TC Comment) (2000-07-10): Crash 1996: Await ISO decision  as to the withdrawal of ISO 7091 & 7094.

Flache Scheiben - Normale Reihe - Produktklasse C (ISO 7091:2000)

Diese Internationale Norm legt Eigenschaften für flache Scheiben, normale Reihe, Produktklasse C, mit Härteklasse 100 HV und mit Nenngrößen (Gewinde-Nenndurchmesser) von 1,6 mm bis 64 mm fest. Scheiben mit Härteklasse 100 HV werden vorzugsweise verwendet für: - Sechskantschrauben der Produktklasse C mit Festigkeitsklassen <= 6.8; - Sechskantmuttern der Produktklasse C mit Festigkeitsklassen <= 6; - einsatzgehärtete gewindefurchende Schrauben. Werden andere Maße als die in der vorliegenden Norm benötigt, so sollten diese aus ISO 887 entnommen werden.

Rondelles plates - Série normale - Grade C (ISO 7091:2000)

La présente Norme internationale spécifie les caractéristiques des rondelles plates, série normale, de grade C, de classe de dureté 100 HV et de diamètre nominal (diamètre nominal de filetage) de 1,6 mm à 64 mm inclus.  Les rondelles de classe de dureté 100 HV conviennent à des  - vis hexagonales de grade C et de classes de qualité jusqu'à 6.8 inclus;  - écrous hexagonaux de grade C et de classes de qualité jusqu'à 6 inclus;  - vis autotaraudeuses par déformation, cémentées et trempées.  Si des dimensions différentes de celles données dans la présente Norme internationale sont requises, il convient de les choisir parmi celles données dans l'ISO 887. En cas de serrage d'éléments en métal doux ou de larges trous de passage dans la pièce, il convient que l'utilisateur vérifie l'aptitude à l'emploi de ce type de rondelle.

Okrogle ravne podložke - Normalne vrste - Razred izdelave C (ISO 7091:2000)

General Information

• Status: Published
• Publication Date: 31-May-2000
• ICS: 21.060.30 - Washers, locking elements
• Technical Committee: CEN/TC 185 - Threaded and nonthreaded mechanical fasteners and accessories
• Drafting Committee: CEN/TC 185 - Threaded and nonthreaded mechanical fasteners and accessories
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 28-Feb-2006
• Completion Date: 28-Feb-2006
• Ref Project: SIST EN ISO 7091:2002 - Plain washers - Normal series - Product grade C (ISO 7091:2000)

Overview

EN ISO 7091:2000 defines the specifications for plain washers belonging to the normal series, product grade C. These washers are manufactured to a hardness class of 100 HV and cover nominal thread diameters from 1.6 mm to 64 mm. This international standard, developed by ISO Technical Committee ISO/TC 2 on Fasteners, ensures consistency in the dimensions, material properties, and tolerances of plain washers used with bolts, screws, and nuts in engineering and industrial applications.

As a widely adopted European Norm (CEN) standard, EN ISO 7091:2000 supports uniformity in fastening components, facilitating interoperability and reliability across different manufacturers and industries.

Key Topics

• Scope and Application
  Specifies normal-series plain washers in product grade C with hardness class 100 HV, suitable for hexagon bolts and screws up to property class 6.8, nuts up to property class 6, and case-hardened thread rolling screws. It addresses nominal sizes from 1.6 mm through 64 mm.

• Dimensions
  Provides detailed preferred and non-preferred dimensions including clearance hole diameter, outside diameter, and thickness for washers aligned with nominal thread diameters. This helps engineers select the correct washer size to ensure proper fit and mechanical performance.

• Material and Hardness
  Specifies steel as the default material with a hardness class of 100 HV (Vickers hardness). Other metallic materials can be agreed upon by supplier and customer. Hardness testing methods conform to ISO 6507-1.

• Tolerances and Surface Finish
  Adheres to tolerances detailed in ISO 4759-3 which ensures precision manufacturing. Surface finish options vary including natural finish or protective lubricants, as well as electroplated coatings per ISO 4042 or zinc flake coatings under ISO 10683. These surface treatments provide corrosion resistance and functional performance.

• Quality and Inspection
  Washers must be free of burrs, irregularities, or defects. Acceptability and inspection follow procedures in ISO 3269, ensuring high-quality components for mechanical fastening assemblies.

• Designation Format
  The standard defines a clearised naming convention, e.g., Washer ISO 7091-8-100 HV for a washer with 8 mm nominal diameter and 100 HV hardness.

Applications

EN ISO 7091:2000 washers are essential components in mechanical engineering, manufacturing, and construction, widely used for:

• Securing hexagonal bolts, screws, and nuts to distribute load and prevent damage to surfaces
• Serving in automotive, aerospace, machinery, and structural assemblies where precise hardness and dimensional control are required
• Facilitating reliable fastening in cases where thread rolling screws or case-hardened screws are employed
• Providing consistent, standardized parts for global supply chains ensuring compatibility across multiple industries

Engineers and designers rely on this standard to select washers that meet functional requirements for hardness, size, and surface characteristics, thereby optimizing assembly strength and durability.

Related Standards

• ISO 887:2000 – Plain washers for metric bolts, screws, and nuts for general purposes - General plan
• ISO 4759-3:2000 – Tolerances for fasteners - Part 3: Plain washers for bolts, screws, and nuts - Product grades A and C
• ISO 4042:1999 – Fasteners - Electroplated coatings
• ISO 10683 (forthcoming) – Fasteners - Non-electrolytically applied zinc flake coatings
• ISO 6507-1:1997 – Metallic materials - Vickers hardness test - Test method
• ISO 3269:2000 – Fasteners - Acceptance inspection

These complementary standards cover related aspects such as dimensional requirements, testing methods, coatings, and quality control to ensure the full reliability of washers and fasteners.

---

Keywords: EN ISO 7091, plain washers, product grade C, hardness 100 HV, fastener washers, ISO 7091, mounting washers, metric washers, steel washers, dimensional standards, coating standards, mechanical fastening components, engineering washers, hex bolt washers, ISO fastener standards.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2002
1DGRPHãþD
SIST ISO 7091:1996
Okrogle ravne podložke - Normalne vrste - Razred izdelave C (ISO 7091:2000)
Plain washers - Normal series - Product grade C (ISO 7091:2000)
Flache Scheiben - Normale Reihe - Produktklasse C (ISO 7091:2000)
Rondelles plates - Série normale - Grade C (ISO 7091:2000)
Ta slovenski standard je istoveten z: EN ISO 7091:2000
ICS:
21.060.30 Podložke, varovalni elementi Washers, locking elements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 7091
Second edition
2000-06-01
Plain washers — Normal series — Product
grade C
Rondelles plates — Série normale — Grade C
Reference number
ISO 7091:2000(E)
©
ISO 2000
ISO 7091:2000(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body
in the country of the requester.
ISO copyright office
Case postale 56 � CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 734 10 79
E-mail [e-mail]
Web www.iso.ch
Printed in Switzerland
ii © ISO 2000 – All rights reserved

ISO 7091:2000(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 7091 was prepared by Technical Committee ISO/TC 2, Fasteners.
This second edition cancels and replaces the first edition (ISO 7091:1983), which has been technically revised.
INTERNATIONAL STANDARD ISO 7091:2000(E)
Plain washers — Normal series — Product grade C
1 Scope
This International Standard specifies the characteristics of normal-series, product-grade-C plain washers in the
100 HV hardness class and of nominal sizes (nominal thread diameters) ranging from 1,6 mm to 64 mm inclusive.
Washers of hardness cla
...