1、BRITISH STANDARD BS7254-5: 1990 Orthopaedic implants Part5: Specification for production ofcastings made of cobalt-chromium-molybdenum alloy UDC 615.461:616.71-74:006.3/.8BS7254-5:1990 This BritishStandard, having been prepared under the directionof the Health Care Standards Policy Committee, waspub
2、lished under the authorityof the Board of BSI andcomes into effect on 31August1990 BSI11-1999 First published as BS3531 July1962 First part revision (Part1 only) December1968 Second part revision (Part4only)July1980 Third revision February1987 Fourth revision as BS7254-5 August1990 The following BSI
3、 references relate to the work on this standard: Committee referenceHCC/18 Draft announced BSI News, October1989 ISBN 0 580 18323 8 Committees responsible for this BritishStandard The preparation of this BritishStandard was entrusted by the Health Care Standards Policy Committee (HCC/-) to Technical
4、 CommitteeHCC/18, upon which the following bodies were represented: British Forging Industry Association British Industrial Ceramic Manufacturers Association British Institute of Surgical Technologists British Investment Casting Trade Association British Orthopaedic Association British Steel Industr
5、y British Surgical Trades Association Department of Health Department of Trade and Industry (Laboratory of the Government Chemist) Department of Trade and Industry (National Engineering Laboratory) Department of Trade and Industry (National Physical Laboratory) Ministry of Defence Royal College of S
6、urgeons of England Royal Veterinary College Scottish Office Sterilised Suture Manufacturers Association Coopted members The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Ceramic Research Ltd. British Dental Association British Medic
7、al Association Institute of Sterile Services Management Amendments issued since publication Amd. No. Date CommentsBS7254-5:1990 BSI 11-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Composition of re-melting stock 1 4 Process control 1 5 Chemic
8、al analysis of castings 1 6 Mechanical testing 1 7 Non-destructive testing 2 8 Rectification of defects in castings 2 9 Identification and delivery 2 Appendix A Information to be supplied by the purchaser 4 Publications referred to Inside back coverBS7254-5:1990 ii BSI 11-1999 Foreword This Part of
9、BS7254 has been prepared under the direction of the Health Care Standards Policy Committee and supersedes BS3531-4:1987 which is withdrawn. Requirements for orthopaedic implants (then termed “surgical implants”) were first published in1962 as BS3531. In1968 a part revision of BS3531:1962 was issued
10、as BS3531-1, which dealt with surgical implants made of all materials. In1980 the first four Parts of a multi-part version of BS3531 were published. Part4:1980 gave requirements for cast implants made of cobalt-chromium-molybdenum alloy. Part4:1980 was revised in1987 in the form of a process specifi
11、cation applying to the production of castings as intermediate products for conversion into implants by means of machining or other finishing operations. Such castings may either be purchased by an implant manufacturer or finisher from a subcontracted foundry, or be produced in the foundry department
12、 of an implant manufacturer. This change was considered necessary because of different production control methods adopted by different manufacturers and because different finishing operations are required for different types of implant. It is strongly recommended that castings should be manufactured
13、 according to the recommendations given in the “Guide to Good Manufacturing Practice for Orthopaedic Implants” 1) . In view of the increase in the number of Parts, and with a view to facilitating the implementation of published or forthcoming international implant standards, the BritishStandard rela
14、ting to implants has been restructured. Accordingly, the number BS3531 is reserved for standards on implants for osteosynthesis, BS7251 covers joint prostheses, BS7252 covers metallic materials for surgical implants, BS7253 covers non-metallic materials for surgical implants and BS7254 covers orthop
15、aedic implants, i.e.aspects common to both osteosynthesis and joint replacement. This edition of BS7254-5 introduces editorial changes to reflect this restructuring and up-dates cross-references but otherwise makes no changes to the specification for production of castings previously published as BS
16、3531-4:1987. It does not reflect a full review or revision of the standard, which will be undertaken in due course. Product certification. Users of this BritishStandard are advised to consider the desirability of third party certification of product conformity with this BritishStandard based on test
17、ing and continuing surveillance, which may be coupled with assessment of a suppliers quality systems against the appropriate Part of BS5750. Enquiries as to the availability of third party certification schemes will be forwarded by BSI to the Association of Certification Bodies. If a third party cer
18、tification scheme does not already exist, users should consider approaching an appropriate body from the list of Association members. 1) Complied by the Department of Health and Social Security; published and available from Her Majestys Stationery Office. ISBN0113208464.BS7254-5:1990 BSI 11-1999 iii
19、 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. Summary of pages This document comprises
20、 a front cover, an inside front cover, pagesi toiv, pages1to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS7254-5:1990 BSI 11-199
21、9 1 1 Scope This Part of BS7254 specifies requirements for the production of castings made of cobalt-chromium-molybdenum alloy for use in the manufacture of surgical implants. NOTE 1This Part of BS7254 applies to castings produced by a subcontractor and dispatched to an implant manufacturer and to c
22、astings produced by an implant manufacturers foundry for conversion into finished implants by the same manufacturer. SeeAppendix A for information to be supplied by the purchaser. NOTE 2The titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For
23、 the purposes of this Part of BS7254, the definitions given in BS6324 apply, together with the following. 2.1 implant manufacturer the person or company that markets the finished implant 2.2 tree an integral group of castings, together with the material contained within the feed system, produced by
24、casting into a multi-cavity mould 2.3 purchaser the company that commissions and buys castings from a subcontracted foundry, or the department of an implant manufacturing company that requisitions castings produced in that companys foundry 3 Composition of re-melting stock Castings shall be made of
25、re-melting stock that is certificated to comply with the requirements for cast cobalt-chromium-molybdenum alloy specified in BS7252-4, and to which no additions shall be made see clause9 g). NOTEAll re-melting stock should be stored and identified in order to prevent use of an incorrect alloy and/or
26、 contamination with other materials. If furnaces are used for melting alloys of different compositions, care should be taken to prevent contamination of the alloy. 4 Process control At the initiation of the casting process for a new design of product (involving casting design, gating, tree assembly,
27、 coating, casting method or casting temperature parameters) or on subsequent modification of any design feature or process parameter, castings shall be metallographically examined to determine that no abrupt change in grain size or other detrimental metallographic features occur in regions expected
28、to be most highly stressed in service. The validated casting process shall be documented and all products produced by this process shall be certificated to this effect see clause9 h). 5 Chemical analysis of castings Analysis of test samples shall be carried out as follows. a) In foundries where only
29、 cobalt-chromium-molybdenum alloy complying with BS7252-4 is in use, the first and last unit cast of each master melt shall be analysed quantitatively. If the composition of the first unit cast does not comply with that given in Table1 of BS7252-4:1990, that consignment of master melt shall be rejec
30、ted. If the last unit cast does not comply with the composition given in Table1 of BS7252-4:1990 each tree of components cast from that master melt shall be checked quantitatively and any tree of which the composition is found not to comply with that given in Table1 of BS7252-4:1990 shall be rejecte
31、d. b) In foundries where other alloys are in use, the first and last unit cast of each master melt shall be tested as described ina). All other unit casts shall be monitored and any unit casts of incorrect composition shall be rejected. 6 Mechanical testing 6.1 Tensile test pieces shall be obtained
32、by one or both of the following methods see itema) of Appendix A: a) tensile test pieces cast integrally with, or gated to, castings; b) tensile test pieces, cast under similar conditions to the castings they represent, but cast in a separate mould from the same melt.BS7254-5:1990 2 BSI 11-1999 6.2
33、Tensile test pieces shall be of the dimensions of one of the proportional round test pieces specified in BS18 see itema) of Appendix A. 6.3 If castings are to be supplied in the as-cast condition, a minimum of two as-cast tensile test pieces shall be tested from each master melt. If castings are hea
34、t treated, tensile test pieces shall be heat treated together with the castings they represent and one tensile test piece shall be tested after heat treatment. If castings are to be supplied in any other special condition see itemb) of Appendix A, the relevant test pieces shall be in the same condit
35、ion. In the case of castings which are given repeated, or a series of, heat treatments, sufficient tensile test pieces shall be prepared to allow one test after each heat treatment and any retests. See itema) of Appendix A. 6.4 Tensile test pieces shall be tested in accordance with BS18 and shall co
36、mply with the values given in Table2 of BS7252-4:1990 see itema) of Appendix A. 6.5 If any tensile test piece does not comply with6.4, one or both of the following procedures shall be adopted see clause9 j) and itema) of Appendix A. a) Two further tensile test pieces from the same batch shall be tes
37、ted. If either tensile test piece does not comply with6.4, the batch shall be rejected. b) The batch shall be re-heat treated and two tensile test pieces shall be tested. If either tensile test piece does not comply with6.4, the batch shall be rejected. 7 Non-destructive testing 7.1 Radiographic exa
38、mination If castings are to be radiographically examined seeitemc) of Appendix A, the examination shall be made by a technique shown to be sensitive to better than2%, in order to achieve an acceptable quality of radiographic image. If the casting being tested is subsequently to be converted into a f
39、inished implant that will bear a unique reference number see itemd) of Appendix A, the radiograph(s) of that casting shall be marked so as to allow traceability of the radiograph and casting see clause9 d) andk). NOTEGuidance may be obtained from BS2737, BS3683, BS3971, BS4080 and BS M34. 7.2 Penetr
40、ant flaw detection If castings are to be examined by a liquid penetrant flaw detection technique see iteme) of Appendix A, the examination shall be made in accordance with BS6443 see clause9 k). NOTEThe results of penetrant flaw detection testing during manufacture may not be an indication of the in
41、tegrity of the finished component. 8 Rectification of defects in castings 8.1 Any rectification of defects by welding shall exclude repairs in the regions stated to be subjected to high stress in service see itemf) of Appendix A. 8.2 Following any repair by welding of castings to be supplied in the
42、heat-treated condition, the castings shall be heat treated see clause9 i) and itemb) of Appendix A. 9 Identification and delivery Each batch of castings shall be accompanied by a release certificate giving at least the following information and statements: a) the purchase or requisition number; b) t
43、he master melt identity; c) the batch number; d) if appropriate, the traceability numbers unique to each casting in the batch (see7.1); e) the results of all testing performed on the batch, including the chemical composition (seeclause5); f) a statement that the castings have been produced in accord
44、ance with this Part of BS7254, for example, by recording the number and date of this BritishStandard, i.e.BS7254-5:1990 2) g) a statement that the re-melting stock complied with BS7252-4 (see clause3); h) a statement that the castings were produced by the documented process (see clause4); i) a state
45、ment as to whether the castings and associated tensile test pieces are in the as-cast or heat-treated condition, or any other special condition; j) a statement that the batch has passed the tensile tests detailed in clause6, including whether retests and/or re-heat treatment was necessary; 2) Markin
46、g BS7254-5:1990 or in relation to a product represents a manufacturers declaration of conformity, i.e.a claim by or on behalf of the manufacturer that the product meets the requirements of the standard. The accuracy of the claim is therefore solely the responsibility of the person making the claim.
47、Such a declaration is not be confused with third party certification of conformity, which may also be desirable.BS7254-5:1990 BSI 11-1999 3 k) if appropriate, a statement that the batch has passed the non-destructive tests detailed in7.1 and/or7.2; l) if appropriate, a statement that defects have be
48、en repaired and the requirements of clause8 have been satisfied. NOTEIf a batch of castings is shipped from a subcontractor or foundry, it should be packaged so as to prevent transit damage. A batch may be subdivided for shipment, in which case each package should be identifiable with regard to the
49、other packages and to the accompanying documentation listed in a) to l). If a batch of castings is transferred within the same manufacturing premises (e.g.from the foundry to the machining department) it should be accompanied by the release certificate, but packaging may not be required.BS7254-5:1990 4 BSI 11-1999 Appendix A Information to be supplied by the purchaser The following information should be supplied to the foundry by the purchaser of the castings when placing an order or requisition. a) The method of obtaining tensile test piec
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