SIST EN ISO 3506-4:2004

SLOVENSKI STANDARD
SIST EN ISO 3506-4:2004
01-januar-2004
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,62
Mechanical properties of corrosion-resistant stainless-steel fasteners - Part 4: Tapping
screws (ISO 3506-4:2003)
Mechanische Eigenschaften von Verbindungselementen aus nichtrostenden Stählen -
Teil 4: Blechschrauben (ISO 3505-4:2003)
Caractéristiques mécaniques des éléments de fixation en acier inoxydable résistant a la
corrosion - Partie 4: Vis a tôle (ISO 3506-4:2003)
Ta slovenski standard je istoveten z: EN ISO 3506-4:2003
ICS:
21.060.10 Sorniki, vijaki, stebelni vijaki Bolts, screws, studs
SIST EN ISO 3506-4:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3506-4:2004

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SIST EN ISO 3506-4:2004
EUROPEAN STANDARD
EN ISO 3506-4
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2003
ICS 21.060.10
English version
Mechanical properties of corrosion-resistant stainless-steel
fasteners - Part 4: Tapping screws (ISO 3506-4:2003)
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 3506-4:2003) 3506-4:2003)
This European Standard was approved by CEN on 21 March 2003.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3506-4:2003 E
worldwide for CEN national Members.

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SIST EN ISO 3506-4:2004
EN ISO 3506-4:2003 (E)
CORRECTED  2003-07-16
Foreword
This document (EN ISO 3506-4:2003) has been prepared by Technical Committee ISO/TC 2
"Fasteners" in collaboration with Technical Committee CEN/TC 185 "Threaded and non-
threaded mechanical fasteners and accessories", 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 October 2003, and conflicting national
standards shall be withdrawn at the latest by October 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, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and
the United Kingdom.
Endorsement notice
The text of ISO 3506-4:2003 has been approved by CEN as EN ISO 3506-4:2003 without any
modifications.
NOTE Normative references to International Standards are listed in Annex ZA (normative).
2

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SIST EN ISO 3506-4:2004
EN ISO 3506-4:2003 (E)
Annex ZA
(normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of
any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).
NOTE Where an International Publication has been modified by common modifications, indicated
by (mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 3651-1 1998 Determination of resistance to EN ISO 3651-1 1998
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 1998 Determination of resistance to EN ISO 3651-2 1998
intergranular corrosion of stainless
steels - Part 2: Ferritic, austenitic
and ferritic-a ustenitic (duplex)
stainless steels - Corrosion test in
media containing sulfuric acid
ISO 6507-1 1997 Metallic materials - Vickers EN ISO 6507-1 1997
hardness test - Part 1: Test method
ISO 8044 1999 Corrosion of metals and alloys - EN ISO 8044 1999
Basic terms and definitions
ISO 16048 2003 Passivation of corrosion-resistant EN ISO 16048 2003
stainless-steel fasteners
3

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SIST EN ISO 3506-4:2004

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SIST EN ISO 3506-4:2004


INTERNATIONAL ISO
STANDARD 3506-4
First edition
2003-04-15


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 3506-4:2003(E)
©
ISO 2003

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SIST EN ISO 3506-4:2004
ISO 3506-4:2003(E)
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ii © ISO 2003 — All rights reserved

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SIST EN ISO 3506-4:2004
ISO 3506-4:2003(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. 3
4 Chemical composition. 3
5 Mechanical properties and performance. 4
5.1 General. 4
5.2 Mechanical properties. 5
5.3 Thread forming capability . 5
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. 7
Annex A (informative) Description of groups and grades of stainless steels . 9
Annex B (informative) Stainless steels for cold heading and extruding . 12
Annex C (informative) Time-temperature diagram of intergranular corrosion in austenitic
stainless steels, grade A2 (18/8 steels) . 14
Annex D (informative) Austenitic stainless steels with particular resistance to chloride-induced
stress corrosion . 15
Annex E (informative) Magnetic properties for austenitic stainless steels. 16
Bibliography . 17



© ISO 2003 — All rights reserved iii

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SIST EN ISO 3506-4:2004
ISO 3506-4:2003(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.
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 2003 — All rights reserved

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SIST EN ISO 3506-4:2004
ISO 3506-4:2003(E)
Introduction
In the preparation of this part of ISO 3506 special attention has been given to the fundamentally different
property characteristics of 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 a condition as hardened and tempered parts.
These special features have been recognized in the elaboration of property 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 should be based on the intended application.

© ISO 2003 — All rights reserved v

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SIST EN ISO 3506-4:2004

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SIST EN ISO 3506-4:2004
INTERNATIONAL STANDARD ISO 3506-4:2003(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 from austenitic, martensitic
and ferritic grades of corrosion-resistant stainless steels when tested at an ambient temperature range of
15 °C to 25 °C. Properties vary between higher and 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.
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 D. Regarding definitions of
corrosion and corrosion resistance see ISO 8044.
The aim of this part of ISO 3506 is a classification into property classes of corrosion-resistant stainless-steel
fasteners.
Corrosion and oxidation performances and mechanical properties for use at elevated or sub-zero
temperatures should be agreed between user and manufacturer in each particular case. Annex C 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 may 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 1478:1999, Tapping screws thread
ISO 3651-1:1998, 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 3651-2:1998, 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 6507-1:1997, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 16048:2003 , Passivation of corrosion-resistant stainless-steel fasteners
© ISO 2003 — All rights reserved 1

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SIST EN ISO 3506-4:2004
ISO 3506-4:2003(E)
3 Designation, marking and finish
3.1 Designation
The designation system for stainless-steel grades and property classes for tapping screws is shown 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, the second block the property class.
The designation of the steel grade (first block) consists of the letter
 A for austenitic steels,
 C for martensitic steels,
 F for ferritic steels,
which indicate 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 property 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 property classes in relation
to Vickers hardness
Property class
20H 25H 30H 40H
Vickers hardness, HV min. 200 250 300 400

EXAMPLE 1 A4-25H indicates:
Austenitic steel, cold worked, minimum hardness 250 HV.
EXAMPLE 2 C3-40H indicates:
Martensitic steel, hardened and tempered, minimum hardness 400 HV.
2 © ISO 2003 — All rights reserved

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SIST EN ISO 3506-4:2004
ISO 3506-4:2003(E)

a
The steel groups and steel grades classified in Figure 1 are described in Annex A and specified by chemical
composition given in Table 2.
b
Low carbon austenitic stainless steels with a carbon content not exceeding 0,03 % may additionally be marked with
an L.
EXAMPLE A4L-25H.
Figure 1 — Designation system for stainless-steel grades and property classes for tapping screws
3.2 Marking
3.2.1 Tapping screws
Marking of tapping screws is not mandatory.
If tapping screws are to be marked, they shall be marked and/or described according to the designation
system described in 3.1, only if all requirements in this part of ISO 3506 are fulfilled.
3.2.2 Packages and containers
Marking with the steel grade and property class according to 3.1 and the manufacturer’s identification mark is
mandatory on all packages of all sizes.
3.3 Finish
Unless otherwise specified, tapping screws in accordance with this part of ISO 3506 shall be supplied clean
and bright. For maximum corrosion resistance passivation is recommended. When passivation is required it
shall be performed in accordance with ISO 16048.
4 Chemical composition
The chemical compositions of sta
...