SIST EN ISO 3506-4:2011

SLOVENSKI STANDARD
SIST EN ISO 3506-4:2011
01-junij-2011
Nadomešča:
SIST EN ISO 3506-4:2004
Mehanske lastnosti veznih elementov iz nerjavnega jekla - 4. del: Pločevinski vijaki
(ISO 3506-4:2009)
Mechanical properties of corrosion-resistant stainless steel fasteners - Part 4: Tapping
screws (ISO 3506-4:2009)
Mechanische Eigenschaften von Verbindungselementen aus nichtrostenden Stählen -
Teil 4: Blechschrauben (ISO 3506-4:2009)
Caractéristiques mécaniques des éléments de fixation en acier inoxydable résistant à la
corrosion - Partie 4: Vis à tôle (ISO 3506-4:2009)
Ta slovenski standard je istoveten z: EN ISO 3506-4:2009
ICS:
21.060.10 Sorniki, vijaki, stebelni vijaki Bolts, screws, studs
77.140.20 Visokokakovostna jekla Stainless steels
SIST EN ISO 3506-4:2011 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3506-4:2011

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SIST EN ISO 3506-4:2011


EUROPEAN STANDARD
EN ISO 3506-4

NORME EUROPÉENNE

EUROPÄISCHE NORM
November 2009
ICS 21.060.10 Supersedes EN ISO 3506-4:2003
English Version
Mechanical properties of corrosion-resistant stainless steel
fasteners - Part 4: Tapping screws (ISO 3506-4:2009)
Caractéristiques mécaniques des éléments de fixation en Mechanische Eigenschaften von Verbindungselementen
acier inoxydable résistant à la corrosion - Partie 4: Vis à aus nichtrostenden Stählen - Teil 4: Blechschrauben (ISO
tôle (ISO 3506-4:2009) 3506-4:2009)
This European Standard was approved by CEN on 24 October 2009.

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 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 Management Centre has the same status as the
official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.






EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3506-4:2009: E
worldwide for CEN national Members.

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SIST EN ISO 3506-4:2011
EN ISO 3506-4:2009 (E)
Contents Page
Foreword .3

2

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SIST EN ISO 3506-4:2011
EN ISO 3506-4:2009 (E)
Foreword
This document (EN ISO 3506-4:2009) 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 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 May 2010, and conflicting national standards shall be withdrawn at the
latest by May 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 3506-4:2003.
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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 3506-4:2009 has been approved by CEN as a EN ISO 3506-4:2009 without any modification.

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SIST EN ISO 3506-4:2011

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SIST EN ISO 3506-4:2011

INTERNATIONAL ISO
STANDARD 3506-4
Second edition
2009-11-15


Mechanical properties of corrosion-
resistant stainless steel fasteners —
Part 4:
Tapping screws
Caractéristiques mécaniques des éléments de fixation en acier
inoxydable résistant à la corrosion —
Partie 4: Vis à tôle




Reference number
ISO 3506-4:2009(E)
©
ISO 2009

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SIST EN ISO 3506-4:2011
ISO 3506-4:2009(E)
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©  ISO 2009
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.
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Published in Switzerland

ii © ISO 2009 – All rights reserved

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SIST EN ISO 3506-4:2011
ISO 3506-4:2009(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Designation, marking and finish.2
3.1 Designation .2
3.2 Marking.3
3.3 Finish .4
4 Chemical composition .4
5 Mechanical properties.5
5.1 General .5
5.2 Surface hardness .5
5.3 Core hardness .6
5.4 Torsional strength .6
5.5 Thread forming capability.6
6 Test methods .6
6.1 Surface hardness test.6
6.2 Core hardness test .6
6.3 Torsional strength test.6
6.4 Drive test .8
Annex A (normative) Description of the groups and grades of stainless steels .9
Annex B (informative) Stainless steel for cold heading and extruding.12
Annex C (informative) Austenitic stainless steels with particular resistance to chloride induced
stress corrosion .14
Annex D (informative) Time-temperature diagram of intergranular corrosion in austenitic
stainless steels, grade A2 (18/8 steels).15
Annex E (informative) Magnetic properties for austenitic stainless steels .16
Bibliography.17

© ISO 2009 – All rights reserved iii

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SIST EN ISO 3506-4:2011
ISO 3506-4:2009(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 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 3506-4 was prepared by Technical Committee ISO/TC 2, Fasteners, Subcommittee SC 1, Mechanical
properties of fasteners.
This second edition cancels and replaces the first edition (ISO 3506-4:2003), which has been technically
revised.
ISO 3506 consists of the following parts, under the general title Mechanical properties of corrosion-resistant
stainless steel fasteners:
⎯ Part 1: Bolts, screws and studs
⎯ Part 2: Nuts
⎯ Part 3: Set screws and similar fasteners not under tensile stress
⎯ Part 4: Tapping screws
iv © ISO 2009 – All rights reserved

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SIST EN ISO 3506-4:2011
ISO 3506-4:2009(E)
Introduction
In the preparation of this part of ISO 3506, special attention has been given to the fundamentally different
property characteristics of the stainless steel fastener grades compared with those of carbon steel and
low-alloy steel fasteners. Ferritic and austenitic stainless steels are strengthened only by cold working and
consequently, the components do not have as homogeneous local material properties as hardened and
tempered parts. These special features have been recognized in the elaboration of the hardness classes and
the test procedures for mechanical properties.
The primary objective of this part of ISO 3506 is to ensure that corrosion-resistant austenitic, martensitic and
ferritic stainless steel tapping screws will form mating threads in materials such as aluminium into which they
are normally driven without deforming their own thread and without breaking during assembly or service.
Selection of the steel group is based on the intended application.


© ISO 2009 – All rights reserved v

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SIST EN ISO 3506-4:2011

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SIST EN ISO 3506-4:2011
INTERNATIONAL STANDARD ISO 3506-4:2009(E)

Mechanical properties of corrosion-resistant stainless steel
fasteners —
Part 4:
Tapping screws
1 Scope
This part of ISO 3506 specifies the mechanical properties of tapping screws made of austenitic, martensitic
and ferritic steel grades of corrosion-resistant stainless steels, when tested over an ambient temperature
range of 10 °C to 35 °C. Properties vary at higher or lower temperatures.
It applies to tapping screws with threads from ST2,2 up to and including ST8, in accordance with ISO 1478.
It does not apply to screws with special properties, such as weldability.
NOTE The designation system of this part of ISO 3506 can be used for sizes outside the limits given in this clause
(e.g. d > ST8), provided that all applicable mechanical and physical requirements of the hardness classes are met.
This part of ISO 3506 does not define corrosion or oxidation resistance in particular environments. However,
some information on materials for particular environments is given in Annex C. Regarding definitions of
corrosion and corrosion resistance, see ISO 8044.
The aim of this part of ISO 3506 is the classification of corrosion-resistant stainless steel tapping screws into
hardness classes.
Corrosion and oxidation performances and mechanical properties for use at elevated or sub-zero
temperatures can be agreed on between the user and the manufacturer in each particular case. Annex D
shows how the risk of intergranular corrosion at elevated temperatures depends on the carbon content.
All austenitic stainless steel fasteners are normally non-magnetic in the annealed condition; after cold working,
some magnetic properties can be evident (see Annex E).
2 Normative references
The following referenced documents are indispensable for the application 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 1478, Tapping screws thread
ISO 3651-1, Determination of resistance to intergranular corrosion of stainless steels — Part 1: Austenitic and
ferritic-austenitic (duplex) stainless steels — Corrosion test in nitric acid medium by measurement of loss in
mass (Huey test)
ISO 3651-2, Determination of resistance to intergranular corrosion of stainless steels — Part 2: Ferritic,
austenitic and ferritic-austenitic (duplex) stainless steels — Corrosion test in media containing sulfuric acid
© ISO 2009 – All rights reserved 1

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SIST EN ISO 3506-4:2011
ISO 3506-4:2009(E)
ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 16048, Passivation of corrosion-resistant stainless-steel fasteners
ISO 16426, Fasteners — Quality assurance system
3 Designation, marking and finish
3.1 Designation
The designation system for stainless steel grades and hardness classes for tapping screws is given in
Figure 1. The designation of the material consists of two blocks, which are separated by a hyphen. The first
block designates the steel grade and the second block, the hardness class.
The designation of the steel grade (first block) consists of one of the letters
⎯ A for austenitic steel,
⎯ C for martensitic steel, or
⎯ F for ferritic steel
which indicates the group of steel and a digit, which indicates a range of chemical compositions within this
steel group (see Table 2).
The designation of the hardness class (second block) consists of two digits representing 1/10 of the minimum
Vickers hardness and the letter H, referring to hardness (see Table 1).
Table 1 — Designations of hardness classes in relation to Vickers hardness
Hardness class 20H 25H 30H 40H
Vickers hardness, HV min. 200 250 300 400
EXAMPLE 1 A4-25H indicates: austenitic steel of steel grade A4, cold worked, minimum hardness 250 HV.
EXAMPLE 2 C3-40H indicates: martensitic steel of steel grade C3, hardened and tempered, minimum hardness
400 HV.

2 © ISO 2009 – All rights reserved

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SIST EN ISO 3506-4:2011
ISO 3506-4:2009(E)

a
The steel groups and steel grades classified in Figure 1 are described in Annex A and specified by the chemical
composition given in Table 2.
b
Low-carbon austenitic stainless steels with carbon content not exceeding 0,03 % may additionally be marked with
an “L”.
EXAMPLE A4L-25H
c
Tapping screws passivated in accordance with ISO 16048 may additionally be marked with a “P”.
EXAMPLE A4-25HP
Figure 1 — Designation system for stainless steel grades and hardness classes for tapping screws
3.2 Marking
3.2.1 General
Marking of tapping screws is not mandatory.
When tapping screws manufactured according to the requirements of this part of ISO 3506 are designated
and marked, they shall be designated in accordance with the designation system described in 3.1 and marked
in accordance with 3.2.2 and 3.2.3. However, the designation system described in 3.1 and the provisions for
marking according to 3.2.3 shall be used only if all relevant requirements of this part of ISO 3506 are met.
3.2.2 Manufacturer's identification mark
A manufacturer's identification mark shall be included during the manufacturing process on all tapping screws
which are marked with a hardness class symbol, provided this is possible for technical reasons.
Manufacturer's identification marking is also recommended on tapping screws which are not marked with a
hardness class symbol.
3.2.3 Tapping screws
When tapping screws are marked, they shall be clearly marked in accordance with 3.1. The marking should
include the steel grade and hardness class.
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SIST EN ISO 3506-4:2011
ISO 3506-4:2009(E)
3.2.4 Packages
All packages for all types of tapping screws of all sizes shall be marked (e.g. through labelling). The marking
shall include the manufacturer's and/or distributor's identification and the marking symbol for the steel grade
and hardness class according to Figure 1 and the manufacturing lot number, as defined in ISO 16426.
3.3 Finish
Unless otherwise specified, tapping screws in accordance with this part of ISO 3506 shall be supplied clean
and bright. For maximum corrosio
...