National foreword

This British Standard is the UK implementation of EN ISO 3506‑5:2023. It is identical to ISO 3506‑5:2022. It supersedes BS ISO 3506‑5:2022, which is withdrawn.

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 2022.

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.

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

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
Part 3 1:Set screws and similar fasteners not under tensile stress
Part 4¹⁾: Tapping screws
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

Complementary detailed explanations about definitions of stainless steel grades and properties are specified in ISO 3506‑6.

The properties of stainless steel and nickel alloy fasteners for high temperature applications result from the chemical composition of the material, from the heat treatment process and from the manufacturing process of the fasteners. Static or dynamic properties at room temperature like tensile strength, hardness or fatigue resistance are not sufficient enough to design fasteners for high temperature applications properly.

In fact, at high temperatures e.g. above 300 °C, additional phenomena occur, for instance:

decrease in tensile properties and hardness,
hot oxidation and scaling,
stress relaxation,
creep.

All these phenomena significantly affect the durability and service life of fasteners. Therefore:

a proper choice of material grade is essential to avoid heavy hot oxidation,
qualification of fasteners through dedicated tests should be performed.

Different tests are currently available to assess the behaviour of machined and standardized samples (see for example ASTM E292 or ASTM E328). In addition to these tests, this document specifies test methods on finished fasteners: these are useful when requiring results as representative as possible of the actual service conditions.

All fastener categories included in this document are heat-treated (see Clause 6). Heat treatment processing is crucial to reach mechanical properties and suitable microstructure that are essential to stand phenomena described above and to get adequate durability for the fasteners and the assembled bolted joints.

This European Standard was approved by CEN on 29 October 2023.

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, Türkiye and United Kingdom.

European foreword

The text of ISO 3506‑5:2022 has been prepared by Technical Committee ISO/TC 2 "Fasteners” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 3506‑5:2023 by 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 May 2024, and conflicting national standards shall be withdrawn at the latest by May 2024.

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.

Any feedback and questions on this document should be directed to the users’ national standards body. A complete listing of these bodies can be found on the CEN website.

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, Türkiye and the United Kingdom.

Endorsement notice

The text of ISO 3506‑5:2022 has been approved by CEN as EN ISO 3506‑5:2023 without any modification.

1 Scope

This document specifies the mechanical and physical properties of bolts, screws, studs and nuts, with coarse pitch thread and fine pitch thread, made of corrosion-resistant stainless steels (i.e. martensitic stainless steels and precipitation hardening austenitic stainless steels) and nickel alloys, intended for use at high temperatures up to 800 °C.

Tests in accordance with Clause 9 are performed at the ambient temperature range of 10 °C to 35 °C, and other tests can be performed at higher temperatures, see Clause 10.

NOTE Fasteners specified in this document are also suitable when used at low temperatures, typically down to -50 °C. For more information, see ISO 3506‑6.

The term “fasteners” is used in this document when bolts, screws, studs and nuts are considered all together.

ISO 3506‑6 provides general rules and additional technical information on suitable stainless steels and nickel alloys as well as their properties.

This document applies to fasteners:

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 M3 to M39, and fine pitch thread M8×1 to M39×3,
with thread tolerances in accordance with ISO 965‑1 and ISO 965‑2, and
of any shape but with full loadability.

Stainless steel and nickel alloy fastener symbols can be used for sizes outside the diameter limits of this document (i.e. for bolts, screws and studs with d < 3 mm or d > 39 mm and for nuts with D < 5 mm or D > 39 mm), provided that all applicable chemical, mechanical and physical requirements are met.

Fasteners with reduced loadability (i.e. thin nuts and bolts, screws and studs with head or unthreaded shank weaker than the threaded shank) are not dealt with in this document.

This document does not specify requirements for functional properties such as:

torque/clamp force properties,
shear strength,
fatigue resistance,
weldability,

or

properties of bolted joints and fasteners in high temperature environment (see test methods at high temperature for fasteners in Clause 10).

2 Normative references

3 Terms and definitions

4 Symbols

5 Designation system for fasteners made from stainless steels and nickel alloys

6 Materials and manufacture

6.1 Chemical composition

6.2 Heat treatment for fasteners

6.3 Finish

6.4 Design of bolt/nut assemblies

6.5 Service temperatures for fasteners

7 Mechanical and physical properties

7.1 Mechanical properties of bolts, screws and studs

7.2 Mechanical properties of nuts

8 Applicability of test methods and inspection

8.1 Applicability of test methods

8.2 Manufacturer’s inspection

8.3 Supplier’s inspection

8.4 Purchaser’s inspection

8.5 Delivery of test results

9 Test methods at ambient temperature

9.1 Tensile test for bolts, screws and studs at ambient temperature

9.2 Hardness test for bolts, screws and studs

9.3 Proof load test for nuts

9.4 Hardness test for nuts

10 Test methods at high temperature

10.1 High temperature tensile test for bolts, screws, studs and nuts

10.2 High temperature stress rupture test for bolts, screws, studs and nuts

10.3 Relaxation test for bolts, screws, studs and nuts

10.4 Creep test

11 Fastener marking and labelling

11.1 General requirements for marking

11.2 Manufacturer's identification mark

11.3 Marking on the fasteners

11.4 Marking of the packages (labelling)

Bibliography

BS EN ISO 3506-5:2023

Fasteners. Mechanical properties of corrosion-resistant stainless steel fasteners - Special fasteners (also including fasteners from nickel alloys) for high temperature applications

Current

Published:

30 Nov 2023