EN ISO 3506-1:1997

SLOVENSKI STANDARD
SIST EN ISO 3506-1:2001
01-julij-2001
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Mechanical properties of corrosion-resistant stainless-steel fasteners - Part 1: Bolts,
screws and studs (ISO 3506-1:1997)
Mechanische Eigenschaften von Verbindungselementen aus nichtrostenden Stählen -
Teil 1: Schrauben (ISO 3506-1:1997)
Caractéristiques mécaniques des éléments de fixation en acier inoxydable résistant a la
corrosion - Partie 1: Vis et goujons (ISO 3506-1:1997)
Ta slovenski standard je istoveten z: EN ISO 3506-1:1997
ICS:
21.060.10 Sorniki, vijaki, stebelni vijaki Bolts, screws, studs
SIST EN ISO 3506-1:2001 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3506-1:2001

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SIST EN ISO 3506-1:2001
INTERNATIONAL
ISO
STANDARD
3506-1
First edition
19974 2-01
Mechanical properties of corrosion-
resistant stainless-steel fasteners -
Part 1:
Bolts, screws and studs
Caractkristiques mkaniques des Mments de fixation en acier inoxydable
rhsistan t Z3 Ia corrosion -
Partie 1: Vis et goujons
Reference number
ISO 35064 :1997(E)

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SIST EN ISO 3506-1:2001
ISO 35064 :1997(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. Esch 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 patt in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
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.
International Standard ISO 3506-1 was prepared by Technical Committee
ISO/TC 2, Fasteners, Sub-Committee SC 1, Mechanical properties of
fasteners.
This first edition, together with ISO 3506-2 and ISO 3506-3, cancels and
replaces ISO 3506:1979, which has been technically revised.
ISO 3506 consists of the following Parts, under the general title Mechanical
propeflies of corrosion-resistant stainless-steel fasteners.
Part 1: Bolts, screws and studs
- Part2: Nuts
Part 3: Set screws and similar fasteners not under tensile stress
Annex A forms an integral part of this patt of ISO 3506. Annexes B to I are
for information only.
0 ISO 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, including photocopying and
microfilm, without Permission in writing from the publisher.
International Organkation for Standardkation
Case postale 56 l CH-121 1 Geneve 20 l Switzerland
Internet central@ iso.ch
c=ch; a=4OOnet; p=iso; o=isocs; s=central
x.400
Printed in Switzerland
ii

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SIST EN ISO 3506-1:2001
@ ISO ISO 35064 : 1997(E)
trod ucti on
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 a condition as hardened and tempered Parts. These special
features have been recognized in the elaboration of the property classes and
the test procedures for mechanical properties. The latter differ from the
carbon steel and low-alloy steel fastener test procedures with regard to the
measurement of the stress at 0,2 % permanent strain (yield stress) and
ductility (total extension after fracture).

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SIST EN ISO 3506-1:2001
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SIST EN ISO 3506-1:2001
INTERNATIONAL STANDARD @ ISO ISO 3506-1 :1997(E)
Mechanical properties of corrosion-resistant stainless-steel fasteners -
Part 1:
Belts, screws and Stuck
1 Scope
This par-t of ISO 3506 specifies the mechanical properties of bolts, screws and studs made of austenitic, martensitic
and ferritic grades of corrosion-resistant stainless steels when tested over an ambient temperature range of 15 OC to
25 OC. Properties will vary at higher or lower temperatures.
lt applies to bolts, screws and studs
- with nominal thread diameter (d) up to and including 39 mm;
- of triangular ISO metric threads with diameters and pitches in accordance with ISO 68-1, ISO 261 and ISO 262;
- of any shape.
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 E. 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. Some materials tan be used at temperatures down to - 200 “C, some tan be used at temperatures up to
+ 800 “C in air. Information on the influence of temperature on mechanical properties is found in annex F.
Corrosion and Oxidation performances and mechanical properties for use at elevated or sub-zero temperatures must
be the subject of agreement between user and manufacturer in each particular case. Annex G 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 H).
2 Normative references
The following Standards contain provisions which, through reference in this text, constitute provisions of this patt of
ISO 3506. At the time of publication, the editions indicated were valid. All Standards are subject to revision, and
Parties to agreements based on this part of ISO 3506 are encouraged to investigate the possibility of applying the
most recent editions of the normative documents indicated below. Members of IEC and ISO maintain registers of
currently valid International Standards.
ISO 68-1: -1), ISO general purpose screw threads - Basic Profile - Pari 1: Metric screw threads.
ISO 261: -21, ISO general purpose metric screw threads - Genera/ plan.
1) To be published. (Revision of ISO 68:1973)
2) To be published. (Revision of ISO 261:1973)

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SIST EN ISO 3506-1:2001
@ ISO
ISO 3506-1: 1997(E)
ISO 262:~3), ISO general purpose metric screw threads - Selected sizes for screws, bolts and nuts.
ISO 724: 1993, ISO general purpose metric screw threads - Basic dimensions.
ISO 898-1: -41, Mechanical properties of fasteners made of carbon steel and alloy steel - Part 7: Belts, screws and
studs.
-51, Determination of resistance to intergranular corrosion stainless steels - Part 7: Austenitic and ferritic-
ISO 3651-1:
Corrosion test in nitric acid medium by measurement of loss in mass (Huey
austenitic (duplex) stainless steels -
tes t).
ISO 3651-2:-61, Determination of resistance to intergranular corrosion stainless steels - Part 2: Ferrictic, austenitic
Corrosion test in media containing sulfuric acid.
and ferritic-austenitic (duplex) stainless steels -
ISO 6506: 1981, Metallic materials - Hardness fest - Brinell test.
ISO 6507-1:1997, Metallic materials - Hardness test - Vickers test - Part 7: Test method.
ISO 6508:1986, Metallic materials - Hardness fest - ßockwell test (scales A - B - C - D - E - F- G - H - K).
ISO 6892:-7), Metallic materials - Tensile testing at ambient temperature.
ISO 8044:-*), Corrosion of metals and alloys - Basic terms and definitions.
3 Designation, marking and finish
3.1 Designation
The designation System for stainless steel grades and property classes for bolts, screws and studs 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 letters
A for austenitic steel or
C for martensitic steel or
F for ferritic steel
which indicate the group of steel and a digit which indicates a range of Chemical compositions within this steel
group.
of the property class (second block) consists of 2 digits which indicates l/lO of the tensile strength
The designation
of the fastener.
Examples:
) A2-70 indicates:
austenitic steel, cold worked, minimum 700 N/mm’ (700 MPa) tensile strength.
) C4-70 indicates:
martensitic steel, hardened and tempered, minimum 700 N/mm2 (700 MPa) tensile strength.
3) To be published. (Revision of ISO 262:1973)
4) To be published. (Revision of ISO 898-1:1988)
5) To be published. (Revision of ISO 3651-1:1976)
6) To be published. (Revision of ISO 3651-2:1976)
7) To be published. (Revision of ISO 6892:1984)
8) To be published. (Revision of ISO 8044:1988)
2

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SIST EN ISO 3506-1:2001
@ ISO
ISO 3506-1 :1997(E)
Steelgroupl) Austenitic
i-
I
6 I 1 I 1
AZ*' A3 Ah2' AS
Steelgrade" A'I
I 1
Propertyclass 50 50 30 110 50 70 80 45 60
Soft Cold- High- Soft Hardened Soft Hardened Hardened Soft CoLd-
worked strength and and
and worked
tempered tempered
tempered
The steel groups and steel grades classified in figure 1 are described in annex E3 and specified by the Chemical
composition given in table 1.
Low carbon stainless steels with carbon content not exceeding 0,03 % may additionally be marked with an L.
Example: A4L - 80
Figure 1 - Designation System for stainless steel grades and property classes for bolts, screws and studs
3.2 Marking
Only if all requirements in this part of ISO 3506 are met, Parts shall be marked and/or described according to the
designation System described in 3.1.
3.2.1 Bolts and screws
All hexagon head bolts and screws and hexagon or hexalobular socket head cap screws of nominal thread diameter
d Z= 5 mm shall be clearly marked in accordance with 3.1, figure 1 and figure 2. The marking shall include the steel
grade and property class and also the manufacturer ’s identification mark. Other types of bolts and screws tan be
marked in the same way, where it is possible to do so, and on the head Portion only. Additional marking is allowed
provided it does not Cause confusion.
3.2.2 Studs
Studs of nominal thread diameter d 2 6 mm shall be clearly marked in accordance with 3.1, figure 1 and figure 2. The
marking shall be on the unthreaded part of the stud and shall contain the manufacturer ’s identification mark, steel
grade and property class. If marking on the unthreaded Portion is not possible, marking of steel grade only on the
nut end of the stud is allowed, see figure 2.
3.2.3 Packages
Marking with the designation and manufacturer ’s identification mark is mandatory on all packages of all sizes.
3.3 Finish
Unless otherwise specified, fasteners in accordance with this part of ISO 3506 shall be supplied clean and bright. For
maximum corrosion resistance passivation is recommended.

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SIST EN ISO 3506-1:2001
ISO 3506=1:1997(E)
1) manufacturer ’s identification mark
2) steel grade
3) propet-ty class
Marking of hexagon head bolts and screws
Marking of hexagon and
cap screws (alternative forms)
Marking of studs (alternative forms, see 3.2.2)
NOTE - For marking of Ieft-hand thread, see ISO 898-1.
Figure 2 - Marking of bolts, screws and studs
4 Chemical composition
The Chemical compositions of stainless steels suitable for fasteners in accordance with this part of ISO 3506 are
given in table 1.
The final choice of Chemical composition within the specified steel grade is at the discretion of the manufacturer
unless by Prior agreement between the purchaser and the manufacturer.
4

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SIST EN ISO 3506-1:2001
@ ISO
ISO 3506-1: 1997(E)
In applications where risk of intergranular corrosion is present, testing in accordance with ISO 3651-1 or ISO 3651-2
is recommended. In such cases, stabilized stainless steels A3 and A5 or stainless steels A2 and A4 with carbon
content not exceeding 0,03 % are recommended.
Table 1 - Stainless steel grades - Chemical composition
Chemical composition,
Group Grade Notes
%(mlm)l)
C Si Mn P S Cr Mo Ni
Cu
Austenitic Al 0,12 1 6 ‘5 0,2 0,15 to 0,35 16 to 19 0,7 5to 10 1,75 to 2,25 2) 3) 4)
A2 0,l 1 2 0,05 0,03 15 to 20 - 5) 8to19 4 7) 8)
2 0,045 0,03 17 to 19 - 5) 9to12 1 9)
A3 0,08 1
2 0,045 0,03 16to18,5 2to3 lOto15 1 8) 10)
A4 0,08 1
A5 0,08 1 2 0,045 0,03 16to18,5 2to3 10,5to14 1 9 10)
Cl 0,09 to 0,15 1 1 0,05 0,03 11,5to14 - 1 10)
tiartensitic
c3 0,17 to 0,25 1 1 0,04 0,03 16to18 - 1,5 to 2,5
c4 0,08 to 0,15 1 1,5 0,06 0,15 to 0,35 12 to 14 0,6 1 2) 10)
1 0,04 0,03 15 to 18 4 1 11)12)
:erritic Fl 0,12 1
NOTES
1 A description of the groups and grades of stainless steels also entering into their specific proper-Ges and application is given in
annex 6.
2 Examples for stainless steels which are standardized in ISO 683-13 and in ISO 4954 are given in annexes C and D respectively.
3 Certain materials for specific application are given in annex E.
1) Values are maximum unless otherwise indicated.
2) Sulfur may be replaced by selenium.
3) If the nicke1 content is below 8 %, the minimum manganese content must be 5 %.
4) There is no minimum limit to the topper content provided that the nicke1 content is greater than 8 %.
5) Molybdenum may be present at the discretion of the manufacturer. However, if for some applications limiting of the molybdenum
content is essential, this must be stated at the time of ordering by the purchaser.
6) Molybdenum may be present at the discretion of the manufacturer.
7) If the chromium content is below 17 %, the minimum nicke1 content should be 12 %.
8) For austenitic stainless steels having a maximum carbon content of 0,03 %, nitrogen may be present to a maximum of 0,22 %.
9) Must contain titanium 2 5 x C up to 0,8 % maximum for stabilization and be marked appropriately in accordance with this table, or
must contain niobium (columbium) and/or tantalum 2 10 x C up to 1,0 % maximum for stabilization and be marked appropriately
in accordance with this table.
10) At the discretion of the manufacturer the carbon content may be higher where required to obtain the specified mechanical
properties at larger diameters, but shall not exceed 0,12 % for austenitic steels.
11) May contain titanrum 2 5 x C up to 0,8 % maximum.
12) May contain niobium (columbium) and/or tantalum 2 10 x C up to 1 % maximum.
5 Mechanical properties
The mechanical proper-Ges of bolts, screws and studs in accordance with this part of ISO 3506 shall conform to the
values given in table 2,3 or 4.
For bolts and screws made of martensitic steel the strength under wedge loading shall not be smaller than the
minimum values for tensile strength shown in table 3.
For acceptance purposes the mechanical proper-Ges specified in this clause apply and shall be tested according to the
test Programme in clause 6.
5

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SIST EN ISO 3506-1:2001
@ ISO
ISO 3506-1: 1997(E)
permanent strain
permanent strain
Hardness
2) To be determined according to 6.2.4 on the actual screw length and not on a prepared test piece. d is the nominal thread diameter.
3) Hardened and tempered at a minimum tempering temperature of 275 OC.
4) Nominal thread diameter d G 24 mm.
Table 4 -
Minimum breaking torque, 1~ B min for austenitic grade bolts and screws
I
Minimum breaking torque values for martensitic and ferritic grade fasteners shall be agreed upon between
manufacturer and User.
6

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SIST EN ISO 3506-1:2001
@ ISO
ISO3506=1:1997(E)
6 Testing
6.1 Test Programme
The tests to be performed, depending on material grade and bolt or stud length, are given in table 5.
Table 5 - Test Programme
Elongation Strength under
after Hardness wedge
loading
fracturel)
1 a 2,5 63) 1 -c 2,5 d 12 2,5 d3) 12 2.5 8)
Al
1 G= 2,5 d3) 1 < 2,5 d 12 2,5 d3) 12 2,5 d3)
A2
13 2.5 d3) 12 2.5 d3)
A3 1 3 2,5 d3) 1-c 2,5 d
A4 1 l a 2,5 d3) 1 2 < 2,5 d 1 Z 2 2,5 d3) Z 3 2,5 d3)
A5 1 Za2.5&) t 2<2,5d 1 l a 2.5 d3) 13 2,5 d3)
12 2,5 8) 12 2,5 d3) Required l,a2d
1 Za2,5&) 1 - 1
I Cl
c3 - 1 Required @=2d
1 Z a 2,5 d3) 1 12 2,5 d3) Z z= 2,5 63)
I
c4 1 Z 2 2,5 d3) 1 - 1 1 a 2,5&) 13 2,5 63) Required 1+2d
I
Fl Z z= 2,5 d3) Required
I 1 D2,5&) 1 - 1 Z 3 2,5 d3)
I is the length of holt
d is the nominal diameter of thread
Zs is the plain shank length
1) For all sizes > M5
2) For sizes c M5 the test applies to all lengths.
3) For studs the requirement is k 2 3,5 d
6.2 Test methods
6.2.1 General
All length measurements shall be made to an accuracy of + 0,05 mm or better.
All tensile and load tests shall be performed with testing machines equipped with self-aligning grips in Order to
prevent any non-axial loading, see figure 3. The lower adapter shall be hardened and threaded for tests according to
6.2.2, 6.2.3 and 6.2.4. The hardness of the lower adapter shall be 45 HRC minimum. Internal thread tolerante shall be
5H6G.
6.2.2 Tensile strength, R,,,
The tensile strength shall be determined on fasteners with a length equal to 2,5 x the nominal thread diameter (2,5 d)
or longer in accordance with ISO 6892 and ISO 898-1.
A free threaded length at least equal to the nominal thread diameter (d) shall be subject to the tensile load.
The fracture shall occur between the bearing face of the screw head and the end of the adapter.
The obtained value for R, shall meet the values given in table 2 or 3.

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SIST EN ISO 3506-1:2001
@ ISO
ISO 3506-1: 1997(E)
6.2.3 Stress at 0,2 % permanent strain Rp,,2
I
The stress at O,2 % permanent strain $0 2 shall be determined only on complete bolts and scr
...