BS 7612-1993 Specification for non-circular steel wire for mechanical springs《机械式弹簧用非圆形钢丝规范》.pdf

1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 7612 : 1993 Incorporat

2、ing Amendment No. 1 Not published separately ICS 77.140.25 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Specification for Non-circular steel wire for mechanical springsBS 7612 : 1993 Issue 2, March 1999 This British Standard, having been prepared under the direction of the

3、Iron and Steel Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 February 1993 BSI 03-1999 The following BSI references relate to the work on this standard: Committee reference ISM/26 Draft for comment 89/40727 DC ISBN 0 580 21326 9 Amen

4、dments issued since publication Amd. No. Date Text affected 10289 March 1999 Indicated by a sideline in the margin Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Iron and Steel Standards Policy Committee (ISM/-) to Technical Committee I

5、SM/26, upon which the following bodies were represented: Aluminium Federation Bicycle Association of GB British Cable Makers Confederation British Rubber Manufacturers Association Ltd. British Steel Industry Federation of Wire Rope Manufacturers of Great Britain Forestry Commission Health and Safety

6、 Executive National Centre of Tribology Sheffield Stainless Steel Manufacturers Association Society of Chain Link Fencing Manufacturers Society of Motor Manufacturers and Traders Ltd. Spring Research and Manufacturers Association Stainless Steel Fabricators Association of Great Britain Stainless Ste

7、el Wire Industry Association Welding Manufacturers Association (BEAMA Ltd.) Woven Wire Association Zinc Development AssociationIssue 1, March 1999 BS 7612 : 1993 BSI 03-1999 a Summary of pages The following table identifies the current issue of each page. Issue 1 indicates that a page has been intro

8、duced for the first time by amendment. Subsequent issue numbers indicate an updated page. Vertical sidelining on replacement pages indicates the most recent changes (amendment, addition, deletion). Page Issue Page Issue Front cover Inside front cover a b i ii 1 2 3 4 5 2 2 1 blank 2 2 2 2 2 2 2 6 7

9、8 9 10 11 12 13 14 Inside back cover Back cover 2 2 2 2 2 2 2 2 2 2 2b blankIssue 2, March 1999 BS 7612 : 1993 BSI 03-1999 i Contents Page Committees responsible Inside front cover Foreword ii Specification 1 Scope 1 2 References 1 3 Definitions 1 4 Information and requirements to be agreed and to b

10、e documented 3 5 Manufacture 3 6 Dimensions and tolerances 8 7 Bend requirements 8 8 Hardness requirements 8 9 Freedom from defects in finished wire 8 10 Mechanical testing 9 11 Examination for defects 12 12 Retests 12 13 Packing and identification 12 Annex A (normative) Product analysis and permitt

11、ed variations 13 Tables 1 Quality codes and wire applications 2 2 Chemical compositions and ranges (cast analysis) 4 3 Condition of finished wire 5 4 Helix set test 5 5 Edge bow tolerances 7 6 Tolerances on characteristic dimensions 8 7 Tolerances on length of straight lengths 8 8 Surface defect lim

12、its 8 9 Decarburization limits for carbon and low alloy steel grades 9 10 Material densities 9 11 Minimum surface hardness requirements 11 A.1 Permitted variation of product analysis from specified range 14 Figures 1 Cross sections of typical non-circular wire shapes indicating characteristic dimens

13、ions 2 2 Edge profiles 6 3 Coil curvature 6 4 Edge bow 7 5 Bend test 10 6 Final position of wire after the bend test where b t 11 List of references Inside back coverii BSI 03-1999 BS 7612 : 1993 Issue 2, March 1999 | | Foreword This British Standard has been prepared under the direction of the Iron

14、 and Steel Standards Policy Committee. The use of non-circular wire for mechanical springs is increasing and the Technical Committee ISM/26 considered there was a need to prepare a British Standard. This standard specifies the requirements for non-circular wire up to 12.0 mm characteristic dimension

15、 in carbon, alloy and stainless steels. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. B

16、SI 03-1999 1 Issue 2, March 1999 BS 7612 : 1993 Specification 1 Scope This British Standard specifies the requirements for steel wires of non-circular section supplied in coils or straight lengths, suitable for the manufacture of mechanical springs. It covers flattened, rectangular, square and trape

17、zoidal (also termed keystone or tapered) section wires with square or rounded edges, and special cross section wires, up to a maximum characteristic dimension of 12.0 mm. The standard covers grades of carbon steel in the annealed, prehardened and tempered, cold drawn or cold rolled conditions includ

18、ing music wire, grades of alloy steel in the annealed and prehardened and tempered conditions, and grades of cold drawn or rolled stainless steel. In addition to the definitive requirements, this standard also requires the items detailed in clause 4 to be documented. For compliance with this standar

19、d, both the definitive requirements and the documented items have to be satisfied. NOTE. The grades of steel wire specified in this standard have been selected from those specified in BS 1429, BS 2056, BS 2803, and BS 5216. 2 References 2.1 Normative references This British Standard incorporates, by

20、 reference, provisions from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this British Standar

21、d only when incorporated in it by updating or revision. 2.2 Informative references This British Standard refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference

22、should be made to the latest editions. 3 Definitions For the purposes of this British Standard the following definitions apply. 3.1 flattened wire A wire having a cross section with two parallel sides (see figure 1a) which are much longer than the other rounded sides. 3.2 rectangular section wire A

23、special case of flattened wire, having a cross section with two sets of parallel sides at right angles to each other, but with one set longer than the other (see figure 1b). 3.3 square section wire A wire having a cross section with two sets of parallel sides of equal length at right angles to each

24、other (see figure 1c). 3.4 trapezoidal section wire A wire having a cross section with two parallel sides, one shorter than the other, and with the other two sides of equal length (see figure 1d). The special feature of this wire is that, when coiled into a spring such that the shorter minor charact

25、eristic dimension is located on the inside of the coil, the cross section of the material takes on either an approximately square or rectangular cross section. 3.5 characteristic dimension The dimensions of a wire which best identify the shape, e.g. for rectangular wire the major characteristic dime

26、nsion is the width and the minor characteristic dimension the thickness, for trapezoidal wire the height is the major characteristic dimension and the two parallel faces are minor characteristic dimensions. 3.6 cast The cast of wire characterized by the diameter of the free laying unrestrained wap o

27、f wire taken from a coil or reel. NOTE 1. For the purposes of this standard, the term reel is synonymous with the term spool. NOTE 2. For coil, ends can be together (closed cast), or apart (open cast). NOTE 3. See also BS 2056 and/or BS 5216.2 BSI 03-1999 BS 7612 : 1993 Issue 2, March 1999 a) Flatte

28、ned wire b) Rectangular section wire c) Square section wire d) Trapezoidal section wire Key b=major characteristic dimension t=minor characteristic dimension a = angle of taper Figure 1. Cross sections of typical non-circular wire shapes indicating characteristic dimensions 3.7 carbon gradient The d

29、ifference between the total depth of decarburization and the depth of functional decarburization. 3.8 static duty Applications where springs are subjected to static stresses or infrequent dynamic loading, or a combination of both. Where the stresses are high, the term high duty static is applicable

30、and for lower levels of stress the term normal duty static is appropriate (see table 1). 3.9 dynamic duty Applications where springs are subjected to frequent dynamic loading of a regular or irregular frequency and amplitude. Where the stresses are high, the term high duty dynamic is applicable, and

31、 for lower levels of stress the term normal duty dynamic is appropriate (see table 1). 3.10 music wire A cold drawn wire, uniform in strength and hardness, intended especially for the manufacture of springs (see table 1). Table 1. Quality codes and wire applications Wire applications Quality codes M

32、usic wire M Normal duty static NS High duty static HS Normal duty dynamic ND High duty dynamic HD BSI 03-1999 3 Issue 2, March 1999 BS 7612 : 1993 4 Information and requirements to be agreed and to be documented 4.1 Information to be supplied by the purchaser The following information to be supplied

33、 by the purchaser shall be fully documented. Both the definitive requirements specified throughout this British Standard and the following documented items shall be satisfied before a claim of compliance with the standard can be made and verified: a) the number of this British Standard, i.e. BS 7612

34、; b) the steel grade and quality code (see 3.8,t o 3.10 and tables 1 and 2) c) the wire condition, i.e. patented cold drawn, or cold rolled, cold drawn or cold rolled, annealed or prehardened and tempered; d) the wire shape and nominal characteristic dimensions; for trapezoidal wires, the angle of t

35、aper; e) the tensile strength (see 10.3); f) the form of supply, i.e. coils or straight lengths; g) any applicable requirements from the appropriate clauses for: edge conditions (see 5.4.6), hardness testing (see 10.6), packing and identification (see clause 13); h) any other special requirements. E

36、xample: 4.0 mm3 2.0 mm natural edges cold rolled wire, normal duty dynamic, to grade 735A50, tensile strength 800 N/mm 2 max., annealed, in coil. Ordered as: BS 7612 ND 4.0 mm 3 2.0 mm 735A50 800 N/mm 2 max. annealed coil natural edges. 4.2 Items for agreement The following items to be agreed betwee

37、n the contracting parties, which are specified in the clauses referred to, shall be fully documented. Both the definitive requirements specified throughout this British Standard and the following documented items shall be satisfied before a claim of compliance with the standard can be made and verif

38、ied. a) If a cast analysis other than that specified in table 2 shall be used, it shall be agreed at the time of enquiry and/or order (see 5.2.1). b) If corner radius other than that specified shall be used, it shall be agreed at the time of enquiry and/or order (see 5.4.6). c) If tolerances other t

39、han those specified in table 6 are stipulated they shall be agreed at the time of enquiry and/or order (see 6.1) d) If the tensile strength shall be calculated using other than the actual cross-sectional area of the wire, the method shall be agreed at the time of enquiry and/or order (see 10.3). e)

40、If the bend test shall be over other than the major dimension, it shall be agreed at the time of enquiry and/or order (see 10.5.2). f) If wire for use in dynamic duty springs shall be inspected by eddy current or ultrasonic methods of non-destructive testing, the methods shall be agreed at the time

41、of enquiry and/or order (see note to 11.3). 5 Manufacture 5.1 Steelmaking process 5.1.1 Carbon and alloy steels The steel may be made by any process except that air and mixed air-oxygen bottom blown basic converter processes shall not be used. In the case of the oxygen process, the nitrogen content

42、of the steel shall not exceed 0.008 %. 5.1.2 Stainless steel The steel shall be made by an electric furnace process. 5.2 Chemical composition 5.2.1 The cast analysis shall conform to the composition ranges given in table 2 for the appropriate steel grade unless otherwise agreed by the manufacturer a

43、nd purchaser at the time of enquiry and/or order. (See 4.2a.) NOTE 1. On request, the wire manufacturer should supply the cast analysis for the specified elements. NOTE 2. Suitability for purpose is the governing factor for acceptance of the wires and in certain cases in order to meet this the manuf

44、acturer may wish to deviate from the cast analysis given in table 2. 5.2.2 Any subsequent analytical checks on the product shall take into consideration the heterogeneity normal to the steel (see also annex A). 5.3 Freedom from defects in input material 5.3.1 The ingots, blooms or billets shall be s

45、o prepared as to remove surface imperfections that might produce defects in the wire made from them. 5.3.2 The rod from which the wire is processed shall be free from harmful surface defects, such as pipe and other flaws. 5.3.3 Should it be necessary to grind the round or input wire to meet the spec

46、ified defect and decarburization limits (see tables 8 and 9, the grinding shall be at a stage during the manufacture such that all residual grinding marks are completely eliminated by subsequent processing.4 BSI 03-1999 BS 7612 : 1993 Issue 2, March 1999 Table 2. Chemical compositions and ranges (ca

47、st analysis) Steel grade Quality codes C %( m/m) Si %( m/m) Mn %( m/m) S %( m/m) P %( m/m) Cr %( m/m) Ni %( m/m) Others %( m/m) min. max. min. max. min. max. max. max. min. max. min. max. Carbon steels, cold worked NS, HS, ND, HD, M 0.35 0.85 0.45 0.85 0.60 1.00 0.35 0.35 0.35 0.40 1.00 0.30 1.00 0.

48、25 0.75 0.05 0.03 0.03 0.05 0.03 0.03 Annealed carbon and low alloy steels 090A65 070A72 060A96 735A50 685A55 NS, ND, HD NS, ND, HD NS, ND, HD NS, ND, HD NS, ND, HD 0.55 0.75 0.70 0.75 0.93 1.00 0.46 0.54 0.50 0.60 0.30 0.10 0.35 0.10 0.35 0.10 0.35 1.20 1.60 0.60 1.20 0.60 0.80 0.50 0.70 0.60 0.90

49、0.50 0.80 See note. See note. 0.80 1.10 0.50 0.80 V 0.15 min. Prehardened and tempered carbon and low alloy steels 095A65 094A65 093A65 735A50 730A65 685A55 NS HS, ND HD HS, ND, HD HS, ND, HD HS, ND, HD 0.55 0.75 0.55 0.75 0.55 0.75 0.46 0.54 0.57 0.72 0.50 0.60 0.30 0.30 0.30 0.10 0.35 0.15 0.30 1.20 1.60 0.60 1.20 0.60 1.20 0.60 1.20 0.60 0.90 0.50 0.90 0.50 0.80 0.05 0.04 0.03 0.035 0.025 0.025 0.05 0.04 0.03 0.035 0.03 0.03 0.80 1.10 0.35 0.60 0.50 0.80 V