National foreword

This British Standard is the UK implementation of ISO 3506‑7:2024.

The UK participation in its preparation was entrusted to Technical Committee FME/9, Fasteners.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2024.

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 document 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).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

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.

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.

Introduction

This document is issued as an addition to the ISO 3506 series to provide a single point of reference for flat stainless steel washers, in order to standardize market expectations for users, distributors and manufacturers.

For mechanical properties of flat washers made of carbon steel and alloy steel, see ISO 898‑3.

1 Scope

This document specifies the mechanical and physical properties of flat washers made of corrosion resistant austenitic, ferritic and duplex stainless steels, designed to be used in bolted joints in combination with bolts, screws, studs and nuts with specified grades and property classes in accordance with ISO 3506‑1 and ISO 3506‑2.

These types of washers are also used with other stainless steel fasteners such as screws forming their own mating thread (see e.g. ISO 3506‑4).

ISO 3506‑6 provides general rules and additional technical information on suitable stainless steels and their properties (detailed properties of stainless steel grades, corrosion behaviour with regards to pitting, crevice and intergranular corrosion, magnetic properties, etc.)

WARNING — Washers conforming to the requirements of this document are tested at the ambient temperature range of 10 °C to 35 °C and are used in applications ranging from –20 °C to +150 °C. However, these washers are also used outside this range down to –196 °C and up to +300 °C for specific applications. It is possible that they do not retain the specified mechanical and physical properties at lower and/or elevated temperatures. Therefore, it is the responsibility of the user to determine the appropriate choices based on the service environment conditions of the assembly (see also Clauses 6 and 7).

This document applies to the following flat non-captive and captive washers with thickness 0,2 mm to 6 mm (see 5.1):

plain washers and flat washers (with or without knurls, ribs or chamfers),
square washers,
square hole washers,
shaped plates.

The term “washer” is used in the following for all types of washers and plates within the scope of this document.

This document does not specify requirements for functional properties such as weldability.

2 Normative references

3 Terms and definitions

4 Symbols

5 Designation system for stainless steel grades and property classes of washers, and combination with bolts, screws, studs and nuts

5.1 General

5.2 Designation of stainless steel grades (first block)

5.3 Designation of property classes (second block)

5.4 Combination of washers with bolts, screws, studs and nuts

6 Materials

6.1 Chemical composition

6.2 Surface condition (finish and/or coating)

6.3 Corrosion resistance

6.4 Magnetic properties

7 Requirements for mechanical and physical properties

8 Inspection

8.1 Manufacturer’s inspection

8.2 Supplier’s inspection

8.3 Purchaser’s inspection

8.4 Delivery of test results

9 Hardness test

9.1 General

9.2 Test procedure

9.3 Requirements

10 Marking and labelling

10.1 General

10.2 Marking on the washers

10.3 Marking of the packages (labelling)

Bibliography

BS ISO 3506-7:2024

Fasteners. Mechanical properties of corrosion-resistant stainless steel fasteners - Flat washers with specified grades and property classes

Current

Published:

31 Jul 2024