Hot formed helical compression springs -- Technical specifications

This International Standard specifies the materials, shapes, spring characteristics, tolerances, manufacturing requirements and test methods for common helical compression springs, which are made from hot coiled round section steel bar, and then quenched and tempered (hereinafter simply "springs"). The following limit values apply to springs conforming to this International Standard: — free length: ≤ 900 mm; — spring index: 3 to 12; — slenderness ratio: 0,8 to 4; — active coils: ≥ 3; — spring pitch: D; — wire diameter: 8 mm to 60 mm; — mean diameter of coil: ≤ 460 mm. This International Standard is not applicable to coil springs with special performance requirements, such as railway and automotive suspensions.

Ressorts de compression hélicoïdaux formés à chaud -- Spécifications techniques

General Information

Status
Published
Publication Date
10-Apr-2012
Technical Committee
Drafting Committee
Current Stage
6060 - International Standard published
Start Date
23-Mar-2012
Completion Date
11-Apr-2012
Ref Project

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ISO 11891:2012 - Hot formed helical compression springs -- Technical specifications
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INTERNATIONAL ISO
STANDARD 11891
First edition
2012-04-15
Hot formed helical compression
springs — Technical specifications
Ressorts de compression hélicoïdaux formés à chaud —
Spécifications techniques
Reference number
ISO 11891:2012(E)
ISO 2012
---------------------- Page: 1 ----------------------
ISO 11891:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012

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.
ISO copyright office
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Published in Switzerland
ii © ISO 2012 – All rights reserved
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ISO 11891:2012(E)
Contents Page

Foreword ............................................................................................................................................................................iv

1 Scope ...................................................................................................................................................................... 1

2 Normative references ......................................................................................................................................... 1

3  Terms, definitions and symbols ...................................................................................................................... 1

3.1  Terms and definitions ......................................................................................................................................... 1

3.2  Symbols and units .............................................................................................................................................. 1

4 Material ................................................................................................................................................................... 2

4.1 Adoption of material ........................................................................................................................................... 2

4.2  Diameter and tolerance of bars ....................................................................................................................... 2

5  Spring construction ............................................................................................................................................ 2

5.1 Direction of helix ................................................................................................................................................. 2

5.2  Types of coil end .................................................................................................................................................. 3

6 Spring characteristics ........................................................................................................................................ 3

6.1 General ................................................................................................................................................................... 3

6.2  Length at a specified load ................................................................................................................................. 3

6.3  Load at a specified length ................................................................................................................................. 3

6.4 Spring rate ............................................................................................................................................................. 3

7 Tolerances of spring dimensions and characteristics .............................................................................. 3

7.1 General ................................................................................................................................................................... 3

7.2 Free length ............................................................................................................................................................ 4

7.3 Diameter of coils .................................................................................................................................................. 4

7.4 Total coils .............................................................................................................................................................. 4

7.5  Perpendicularity ................................................................................................................................................... 4

7.6 Parallelism ............................................................................................................................................................. 4

7.7  Irregularity of pitch ............................................................................................................................................. 5

7.8 Solid length ........................................................................................................................................................... 5

7.9 Tolerances on spring characteristics ............................................................................................................ 5

8  Requirements for manufacturing .................................................................................................................... 6

8.1 Heat treatment ...................................................................................................................................................... 6

8.2 Hardness ................................................................................................................................................................ 6

8.3  Decarburization .................................................................................................................................................... 6

8.4  Grain size ............................................................................................................................................................... 6

8.5  Surface conditions .............................................................................................................................................. 6

8.6  End surface machining ...................................................................................................................................... 6

8.7 Shot peening ......................................................................................................................................................... 6

8.8 Setting (presetting) ............................................................................................................................................. 6

8.9  Surface protection ............................................................................................................................................... 6

9 Test methods ........................................................................................................................................................ 6

9.1 General ................................................................................................................................................................... 6

9.2 Spring characteristics ........................................................................................................................................ 7

9.3 Dimensions and shapes .................................................................................................................................... 7

9.4  Surface conditions .............................................................................................................................................. 8

9.5 Hardness ................................................................................................................................................................ 8

9.6  Decarburization .................................................................................................................................................... 8

9.7  Grain size ............................................................................................................................................................... 8

9.8 Shot peening ......................................................................................................................................................... 8

9.9  Surface protection ............................................................................................................................................... 8

Bibliography ....................................................................................................................................................................... 9

© ISO 2012 – All rights reserved iii
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ISO 11891:2012(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 11891 was prepared by Technical Committee ISO/TC 227, Springs.
iv © ISO 2012 – All rights reserved
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INTERNATIONAL STANDARD ISO 11891:2012(E)
Hot formed helical compression springs — Technical
specifications
1 Scope

This International Standard specifies the materials, shapes, spring characteristics, tolerances, manufacturing

requirements and test methods for common helical compression springs, which are made from hot coiled

round section steel bar, and then quenched and tempered (hereinafter simply “springs”).

The following limit values apply to springs conforming to this International Standard:

— free length: ≤ 900 mm;
— spring index: 3 to 12;
— slenderness ratio: 0,8 to 4;
— active coils: ≥ 3;
— spring pitch: < 0,5D;
— wire diameter: 8 mm to 60 mm;
— mean diameter of coil: ≤ 460 mm.

This International Standard is not applicable to coil springs with special performance requirements, such as

railway and automotive suspensions.
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 643, Steels — Micrographic determination of the apparent grain size

ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1: Tension/compression

testing machines — Verification and calibration of the force-measuring system
ISO 18265, Metallic materials — Conversion of hardness values
ISO 26909, Springs — Vocabulary
3  Terms, definitions and symbols
3.1  Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 26909 apply.

3.2  Symbols and units
For the purposes of this document, the symbols and units given in Table 1 apply.
© ISO 2012 – All rights reserved 1
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ISO 11891:2012(E)
Table 1 — Symbols and units
Symbol Parameter Unit
D mean diameter of coil mm
D outside diameter of spring mm
d diameter of wire mm
d maximum diameter of wire (or bar) mm
max
F spring load N
L solid length mm
L free length mm
n total coils —
spring rate N/mm
deflection mm
e perpendicularity mm
e parallelism mm
4 Material
4.1 Adoption of material

Unless otherwise agreed by the purchaser and the supplier, springs should be made from the material

conforming to ISO 683-14.
4.2  Diameter and tolerance of bars
4.2.1  Hot rolled bars

The tolerances of the dimensions and shapes of specified hot rolled bars should be according to ISO 1035-4,

unless otherwise agreed between the purchaser and the supplier.
4.2.2  Bars with cold-worked surface

Tolerances of the dimensions and shapes of cold-worked surface bars (i.e. with cold-drawn, turned, peeled,

ground or a combination thereof) specified should be as specified in Table 2, unless otherwi

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