1、BRITISH STANDARD BS 6587:1985 Method of Acceptance inspection for fasteners UDC 621.882:620.16BS 6587:1985 This British Standard, having been prepared under the directionof the Mechanical Engineering Standards Committee, was published underthe authority of the BoardofBSI and comes intoeffect on 28 F
2、ebruary 1985 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference MEE/60 Draft for comment 74/70958 DC ISBN 0 580 14387 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Mechanical Engineering
3、 Standards Committee (MEE/-) to Technical Committee MEE/60, upon which the following bodies were represented: BEAMA Ltd British Constructional Steelwork Association British Industrial Fasteners Federation British Internal Combustion Engine Manufacturers Association British Railways Board British Ste
4、el Industry (Wire Section) Department of Trade and Industry (National Engineering Laboratory) Federation of British Hand Tool Manufacturers Gauge and Tool Makers Association Ministry of Defence Society of Motor Manufacturers and Traders Limited Telecommunication Engineering and Manufacturing Associa
5、tion (TEAMA) Washer Manufacturers Association of Great Britain The following body was also represented in the drafting of the standard: Electronic Engineering Association Amendments issued since publication Amd. No. Date of issue CommentsBS 6587:1985 BSI 09-1999 i Contents Page Committees responsibl
6、e Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 General 1 4 Acceptance inspection procedure for dimensional and mechanical property characteristics of fasteners 2 Appendix A Examples of acceptance inspection 4 Table 1 Dimensional characteristics 1 Table 2 Mechanical characteristics 2 Ta
7、ble 3 Sampling plans 3 Publications referred to Inside back coverBS 6587:1985 ii BSI 09-1999 Foreword This British Standard has been prepared under the direction of the Mechanical Engineering Standards Committee in order to provide a practical guide to the acceptance inspection procedure for dimensi
8、onal and mechanical property characteristics of fasteners, In this respect, the sampling plans actually included relate to acceptable quality levels (AQLs) of 1.0%, 1.5% and 2.5% for major dimensional characteristics, 2.5% and 4.0% for minor dimensional characteristics, 0.65% with acceptance number,
9、 Ac = 0 for non-destructive tests and 1.5% with Ac = 0 for destructive tests. Sampling plans have been extracted from BS6001. It is primarily intended for use by a purchaser at his receiving inspection in the absence of any prior agreement with the supplier at the time of order. This standard is bas
10、ed on ISO3269 “Fasteners, acceptance inspection” which was prepared with the active participation and approval of the UK by Working Group1 of ISO/TC2 “Fasteners” of the International Organization for Standardization (ISO). A British Standard does not purport to include all the necessary provisions o
11、f 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 a front cover, an inside front cover, pages i and ii, pages1 to 4, an inside
12、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.BS 6587:1985 BSI 09-1999 1 1 Scope This British Standard describes a method of acceptance inspection base
13、d on BS6001 to be used in order to decide whether a lot of fasteners may be accepted or rejected when no other acceptance procedure has been agreed with the supplier at the time of ordering the fasteners, or when conformance to specification is disputed. It applies to fully manufactured products onl
14、y and neither implies, nor includes, any particular in-process control procedure or inspection during production unless otherwise specified in the product standard. NOTE 1Procedures for bolts, screws, studs, nuts and other related fasteners intended for high volume machine assembly, for special purp
15、ose applications or for specially engineered applications requiring greater in-process controls and lot traceability should be specified at the time of ordering. NOTE 2Any plating or other process carried out by the user after receipt of the fasteners invalidates the requirements of this standard. N
16、OTE 3The titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this standard the definitions given in BS5532 and BS6001 apply. 3 General 3.1 The designation of an AQL does not imply that the supplier has the right to supply kno
17、wingly any defective unit of product. 3.2 A rejected lot of fasteners may not be presented for re-inspection unless it has been rectified or sorted. Table 1 Dimensional characteristics Applicable dimensional characteristics a Product group Socket screws, bolts and screws of grades A and B bstuds Bol
18、ts and screws of grade C b Nuts W W class 8 c Nuts class 8 c Machine screws Self-tapping screws AQL d Major dimensions Width across flats Width across corners Width of slot or socket Depth of slot or socket Recess penetration depth Radius under head Go thread gauge No go thread gauge Major diameter
19、1.0 1.0 1.0 1.0 1.5 1.0 1.0 1.5 1.5 1.5 1.5 1.0 1.0 1.5 2.5 1.5 1.5 1.5 2.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 2.5 Minor dimensions All others 2.5 4.0 2.5 4.0 4.0 4.0 a Characteristics shall be individually assessed. b The product grades refer to the classification of the product with regar
20、d to fit and tolerances. Grade A is the most precise and grade C the least precise. (See BS 6322-1.) c Product property class for nuts. (See BS 6104-2.) d For features left in the hot-forged condition use an AQL of 2.5. Hot forged products shall be presented for inspection separately. e Tolerances o
21、n gauge manufacture should not be allowed to reduce product tolerances and where disputes arise direct measurement should be applied.BS 6587:1985 2 BSI 09-1999 4 Acceptance inspection procedure for dimensional and mechanical property characteristics of fasteners NOTEExamples of acceptance inspection
22、 are given inAppendix A. 4.1 Find the description of the fastener to be inspected for dimensional characteristics inTable 1, note the appropriate characteristic to be inspected fromTable 2. 4.2 Choose the appropriate discrimination ratio LQ/10 : AQL. NOTE 1Multiplying this ratio by the AQL value giv
23、es the LQ/10. The LQ/10 should correspond to the function and utilization of the fastener. For more important functions or utilizations of the fasteners the limiting quality (LQ) value may be smaller; but this requires greater sample sizes and higher inspection costs. It may be possible to reduce th
24、e amount of inspection for fasteners from known sources with continuous production controls by choosing a greater ratio LQ/10 : AQL, if the lots inspected so far have shown good quality. It may be necessary to increase the amount of inspection if the lot cannot be presumed to be uniform or is not fr
25、om one manufacturer. It is at the purchasers judgement only which ratio LQ/10 : AQL he uses. NOTE 2The sampling plans inTable 3 are determined by the choice of AQL and of consumers risk (LQ/10). Once these two parameters have been chosen, the sample size, acceptance number, and producers risk follow
26、 automatically. Hence the lot size/sample size relationship in Table 1 of BS 6001:1972, which is intended to apply primarily to the case of the production of a continuous series of lots, is not appropriate. Table 3 can be applied to such a case, but is also applicable to isolated lots by suitable ch
27、oice of LQ/10. NOTE 3In case of dispute it is recommended that a sampling plan be chosen according to which the producers risk is not higher than 5% for dimensional characteristics and 12% for mechanical property characteristics. 4.3 Knowing the AQL and the chosen ratio LQ/10 : AQL find the sample s
28、ize and the acceptance number fromTable 3. 4.4 Select the sample. For each characteristic carry out the inspection, note the number of defects and accept the lot if the number of defects is equal to or lower than the acceptance number. 4.5 Use the same sample for the tensile test (seeTable 2) that w
29、as used for the hardness test and that had the lowest and/or the highest hardness figures. NOTE 1The tensile test, being destructive, requires fewer samples than the non-destructive hardness test. NOTE 2The proof load test given in BS 6104-2 is regarded as a destructive test. Table 2 Mechanical char
30、acteristics Applicable mechanical characteristics a Carbon or alloy steel Stainless steel Socket screws, bolts, screws and studs Nuts Machine screws Self tapping screws Bolts, screws and studs Nuts u u M5 M5 Tensile strength Hardness b c c Stress at 0.2% permanent strain Extension value at fracture
31、d Stress under proof load d Stress under wedge loading Surface discontinuities b Decarburization (class W 8.8) Application test Torque test a See product standard. Other characteristics may also be required according to the specification applicable, for example, performance of prevailing torque type
32、 nuts. For BS 6104-1 use test programme B only. b For the non-destructive hardness and surface discontinuities tests. Use sample size 20. Ac = 0 (based on AQL 0.65). c Where applicable according to the steel grades concerned. d For all destructive tests use sample size 8. Ac = 0 (based on AQL 1.5).B
33、S 6587:1985 BSI 09-1999 3 Table 3 Sampling plans a Acceptance number Ac AQL Discrimination ratio dLQ/10 : AQL Producers risk e 0.65 1.0 1.5 2.5 4.0 Sample size c 0 b 20 (13) 8 (5) (3) 16.5 % 12 1 80 50 32 20 13 7.5 9 2 125 80 50 32 20 6.2 5 3 200 125 80 50 32 5.2 4 5 315 200 125 80 50 4.4 2 7 500 31
34、5 200 125 80 3.7 2 10 500 315 200 125 3.1 2 14 500 315 200 2.6 2 21 500 315 2.2 1 a All figures in this table have been extracted from BS 6001. b Zero acceptance number plans should only be used for testing mechanical characteristics. This standard does not specify a sample size for AQLs 1.0, 2.5 an
35、d 4.0 at Ac 0; the sample sizes in parentheses are given for information only. c If the lot size is less than the required sample size, 100% inspection has to be carried out. d LQ/10 is the percentage of defects in the characteristic of the submitted product which has a one-in-ten chance of being ac
36、cepted by the sampling plan; it is often known as the consumers risk. e The producers risk is the chance that the sampling plan will reject a lot of the submitted product of quality equal to or better than the AQL.BS 6587:1985 4 BSI 09-1999 Appendix A Examples of acceptance inspection A.1 Inspection
37、 of threads for hexagon grade A bolt lots of a supplier well known for his steady quality; therefore ratio LQ/10 : AQL equal to 6.2 is applicable: AQL 1.0 sample size 80, acceptance number Ac 2. A.2 Inspection of the driving media for hexagon socket head screws of an unknown supplier; therefore the
38、ratio LQ/10 : AQL has to be lowered to3.1: AQL 1.0 sample size 500, acceptance number Ac 10. A.3 Inspection of the mechanical property; stress under proof load for nuts: AQL 1.5 sample size 8, acceptance number Ac 0.BS6587:1985 BSI 09-1999 Publications referred to BS 5532, Statistics Vocabulary and
39、symbols. BS 6001, Specification for sampling procedures and tables for inspection by attributes. BS 6104, Mechanical properties of fasteners. BS 6104-1, Specification for bolts, screws and studs. BS 6104-2, Specification for nuts with specified proof load values. BS 6322, Tolerances for fasteners. B
40、S 6322-1, Specification for tolerances of bolts, screws and nuts with thread diameters 1.6 mm and 150 mm and product grades A, B and C. ISO 3269, Fasteners Acceptance inspection 1) . 1) Referred to in the foreword only.BS 6587:1985 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitut
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