1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 11891:2012Hot formed helical compressionsprings TechnicalspecificationsBS ISO 11891:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of
2、 ISO 11891:2012.The UK participation in its preparation was entrusted to TechnicalCommittee FME/9/3, Fasteners - Product Standards.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions
3、 of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 66828 9ICS 21.160Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under th
4、e authority of theStandards Policy and Strategy Committee on 31 May 2012.Amendments issued since publicationDate Text affectedBS ISO 11891:2012 ISO 2012Hot formed helical compression springs Technical specificationsRessorts de compression hlicodaux forms chaud Spcifications techniquesINTERNATIONAL S
5、TANDARDISO11891First edition2012-04-15Reference numberISO 11891:2012(E)BS ISO 11891:2012ISO 11891:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by an
6、y means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyr
7、ightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 11891:2012ISO 11891:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope 12 Normative references . 13 Terms, definitions and symbols 13.1 Terms and definitions . 13.2 Symbols and units 14 Material . 24.1 Adoption of material
8、 . 24.2 Diameter and tolerance of bars . 25 Spring construction 25.1 Direction of helix . 25.2 Types of coil end 36 Spring characteristics 36.1 General . 36.2 Length at a specified load . 36.3 Load at a specified length . 36.4 Spring rate . 37 Tolerances of spring dimensions and characteristics 37.1
9、 General . 37.2 Free length 47.3 Diameter of coils 47.4 Total coils 47.5 Perpendicularity . 47.6 Parallelism . 47.7 Irregularity of pitch . 57.8 Solid length . 57.9 Tolerances on spring characteristics 58 Requirements for manufacturing 68.1 Heat treatment 68.2 Hardness 68.3 Decarburization 68.4 Grai
10、n size . 68.5 Surface conditions 68.6 End surface machining 68.7 Shot peening . 68.8 Setting (presetting) . 68.9 Surface protection . 69 Test methods 69.1 General . 69.2 Spring characteristics 79.3 Dimensions and shapes 79.4 Surface conditions 89.5 Hardness 89.6 Decarburization 89.7 Grain size . 89.
11、8 Shot peening . 89.9 Surface protection . 8Bibliography . 9BS ISO 11891:2012ISO 11891:2012(E)ForewordISO (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
12、 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
13、 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
14、 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 element
15、s 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 reservedBS ISO 11891:2012INTERNATIONAL STANDARD ISO 11891:2012(E)Hot formed
16、 helical compression springs Technical specifications1 ScopeThis 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
17、 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: 500 3,5 % of L05 % of L07 % of L07.6 ParallelismIf
18、 perpendicularity for both ends is specified, parallelism shall not be required. For heavy-weight springs, one-end perpendicularity plus parallelism may be specified (see 9.3.3, Figure 3). Normally the parallelism of the two ends is not required for springs with end types a, d (see Figure 1). For sp
19、rings with end types b, c, e and f, the parallelism should not be more than the limit specified in Table 6.Table 6 Tolerances for parallelismDimensions in millimetresGrade Grade 1 Grade 2 Grade 3Tolerance 2,6 % of De3,5 % of De5 % of De4 ISO 2012 All rights reservedBS ISO 11891:2012ISO 11891:2012(E)
20、7.7 Irregularity of pitchFor a spring of uniform pitch, whenever 80 % of the total deflection has been compressed, the active coils shall not come into contact with each other.7.8 Solid lengthIn general, the solid length is not specified. The maximum solid length of springs, Lc, for specified end ty
21、pes can be calculated using Formulae (1) and (2)8:a) for spring end type b, e:Ln dct() 03,max(1)b) for spring end type a, d:Ln dct+()11,max(2)c) the solid length for springs with end type c and f should be agreed between the purchaser and the supplier.7.9 Tolerances on spring characteristics7.9.1 Ge
22、neralIn general, there are three grades of tolerance based on spring characteristics for different applications.7.9.2 Tolerances on length at a specified loadTolerance should be x % of s (deflection), subject to the minimum absolute value in Table 7.Table 7 Tolerances on length at a specified loadDi
23、mensions in millimetresGrade Grade 1 Grade 2 Grade 3Tolerance 5 % of s, min. 2,5 10 % of s, min. 5,0 15 % of s, min. 7,57.9.3 Tolerances on load at a specified lengthTolerances should be x % of F (spring load), subject to the minimum absolute value in Table 8.Table 8 Tolerances on load at a specifie
24、d lengthUnits in newtonsGrade Grade 1 Grade 2 Grade 3Tolerance 5 % of F, min. 2,5 R 10 % of F, min. 5 R 15 % of F, min. 7,5 R7.9.4 Tolerances on spring rateTolerances should be 10 % of axial spring rate, R. For high accuracy application, 5 % R may be specified. Other tolerances should be agreed betw
25、een the purchaser and the supplier. ISO 2012 All rights reserved 5BS ISO 11891:2012ISO 11891:2012(E)8 Requirements for manufacturing8.1 Heat treatmentAfter hot forming, the springs shall be quenched and tempered.8.2 HardnessUnless otherwise agreed, the hardness of springs after heat treatment should
26、 be specified according to the application condition, material and dimension. The guidance values for tensile strength and hardness for quenched and tempered springs and test pieces should be according to the values given in ISO 683-14 and ISO 18265. Whenever the hardness range is specified, it shou
27、ld be less than 75 HBW.8.3 DecarburizationNo harmful decarburization is allowed on the surface of springs; in particular, the decarburization of the springs under dynamic loading shall be minimized. The depth of decarburization of the spring surface should be agreed between the purchaser and the sup
28、plier, based on the spring application and the nature of the spring material.8.4 Grain sizeThe grain size of the finished spring should be agreed between the purchaser and the supplier.8.5 Surface conditionsThe surface of the springs should not present any defects, such as laminations, grooves, tool
29、ing marks, cracks, crevices, burning or oxides, which are harmful in use.8.6 End surface machiningWhenever taper processing and/or grinding is carried out on the portion of the seat of the spring, the length of the tapered part or ground part should be approximately of a three-quarters turn, and the
30、 thickness of the tip end should be approximately one quarter of the diameter of the material.8.7 Shot peeningWhenever shot peening is required, the process should be determined according to ISO 26910-1. The intensity and coverage of shot peening should be as agreed between the purchaser and the sup
31、plier.8.8 Setting (presetting)Whenever setting is required, the setting conditions should be agreed between the purchaser and the supplier.8.9 Surface protectionIn general, the springs should be coated for temporary corrosion prevention. Whenever specific coatings or plating is required for certain
32、environmental conditions, it should be agreed between the purchaser and the supplier. If the surface treatment implies a risk of hydrogen embrittlement, an embrittlement-relief heat treatment, according to ISO 9588, should be carried out.9 Test methods9.1 GeneralIn accordance with the number of lots
33、 or the purchasers requirements, sampling should be agreed between the purchaser and the supplier.6 ISO 2012 All rights reservedBS ISO 11891:2012ISO 11891:2012(E)9.2 Spring characteristicsMeasure the spring force using a testing machine calibrated to class 1 of ISO 7500-1 or better.Compress the spri
34、ng to the maximum test load of the spring at least once before the inspection of the spring characteristics. If the maximum test load is higher than the solid length load, the solid length load shall be considered the maximum testing load.9.3 Dimensions and shapes9.3.1 DimensionsThe inspection of sp
35、ring dimensions is carried out by means of direct measurement, a limit gauge or other means.9.3.2 PerpendicularityThe perpendicularity of the ground or tapered outer spring and end plane, the second coil close to the half coil from the end, shall be measured by means of a flat surface and a fixed sq
36、uare, as shown in Figure 2, in the no-load state. The maximum deviation from the vertical, whenever the spring is turned through 360 around its long axis, shall be defined as the perpendicularity of the spring. If the parallelism measurement is not implemented, perpendicularity for both ends should
37、be measured, and the maximum value shall be taken as the result.Figure 2 Measurement of perpendicularity9.3.3 ParallelismIf perpendicularity for one end plus parallelism is specified, and in order to measure the parallelism between two ends of the spring (as shown in Figure 3), place the springs on
38、the lower plate and measure the largest deviation of the upper coil end and the upper plate in a no-load state. If the perpendicularity of both ends is tested, the parallelism test is not required. ISO 2012 All rights reserved 7BS ISO 11891:2012ISO 11891:2012(E)Figure 3 Measurement of parallelism9.4
39、 Surface conditionsThe spring surface conditions should be inspected visually. If specified, magnetic particle testing should be agreed between the purchaser and the supplier. The methods and procedures for such an inspection should be agreed between the purchaser and the supplier.9.5 HardnessThe in
40、spection of spring hardness should be performed according to ISO 6506-1; the act of inspection shall be not detrimental to the life of the spring.9.6 DecarburizationThe depth of decarburization should be determined according to ISO 3887. The measurement method, the number of samples and the sample p
41、osition should be agreed between the purchaser and the supplier.9.7 Grain sizeThe grain size should be determined according to ISO 643. The measurement method, the number of samples and the sample position should be agreed between the purchaser and the supplier.9.8 Shot peeningThe intensity and cove
42、rage of shot peening should be determined according to ISO 26910-1.9.9 Surface protectionThe test method of surface protection should be agreed between the purchaser and the supplier.8 ISO 2012 All rights reservedBS ISO 11891:2012ISO 11891:2012(E)Bibliography1 ISO 683-14, Heat-treatable steels, allo
43、y steels and free-cutting steels Part 14: Hot-rolled steels for quenched and tempered springs2 ISO 1035-4, Hot-rolled steel bars Part 4: Tolerances3 ISO 3887, Steels Determination of depth of decarburization4 ISO 6506-1, Metallic materials Brinell hardness test Part 1: Test method5 ISO 9588, Metalli
44、c and other inorganic coatings Post-coating treatments of iron or steel to reduce the risk of hydrogen embrittlement6 ISO 26910-1, Springs Shot peening Part 1: General procedures7 ISO 80000-1, Quantities and units Part 1: General8 EN 13906-1:2002, Cylindrical helical springs made from round wire and
45、 bars Calculation and design Part 1: Compression springs ISO 2012 All rights reserved 9BS ISO 11891:2012ISO 11891:2012(E) ISO 2012 All rights reservedICS 21.160.00Price based on 9 pagesThis page deliberately left blankBSI is the independent national body responsible for preparing British Standards a
46、nd other standards-related publications, information and services. It presents the UK view on standards in Europe and at the international level. BSI is incorporated by Royal Charter. British Standards and other standardisation products are published by BSI Standards Limited.British Standards Instit
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