BS-HC-404-1977.pdf
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1、BRITISH STANDARD AEROSPACE SERIES CONFIRMED SEPTEMBER 1999 BS HC 404:1977 (Superseding Ministry of Defence Specification DTD 719) Specification for Chromium- molybdenum alloy cast iron ring pots (Suitable for centrifugally cast and sand cast sealing rings, piston rings and cylinder liners) UDC 629.7
2、:62 242.3:669.15.28 196 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 03:18:40 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS HC 404:1977 This British Standard, having been prepared under the direction of the Aerospace Standards Committee, was published under t
3、he authority of the Executive Board on 31 December 1976 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference ACE/60 Draft for comment 73/38194 DC ISBN 0 580 09700 5 A British Standard does not purport to include all the necessary provisions of a contract.
4、 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, pages 1 to 3 and a back cover. This
5、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. Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: London South Bank University, London South Bank Universit
6、y, Sat Dec 09 03:18:40 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS HC 404:1977 BSI 01-2000i Contents Page 1Inspection and testing procedure1 2Chemical composition1 3Condition1 4Heat treatment1 5Selection and preparation of test samples1 6Mechanical properties1 7Microscopic examination2 Appendix A
7、Method for determination of modulus of elasticity3 Appendix B Method for determination of ring tensile strength3 Figure 1 Application of diametral force3 Figure 2 Application of tangential force3 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 03:18:40 GMT+00:00
8、 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 03:18:40 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS HC 404:1977 BSI 01-20001 1 Inspection and testing procedure This British Standard shall be used in conjunction with
9、the relevant sections of the latest issue of BS HC 100 as follows. 2 Chemical composition 2.1 The castings shall contain: 2.2 At the discretion of the Approved Metallurgist, minor deviations from the specified analysis range and impurity elements shall be permitted provided that they do not deleteri
10、ously affect the metallographic structure and mechanical properties. 3 Condition The castings shall be supplied annealed. 4 Heat treatment 4.1 Annealing. The annealing treatment shall consist of heating uniformly at a temperature between 900 C and 1 050 C, for a suitable length of time to achieve th
11、e required degree of carbide breakdown, and cooling slowly. 4.2 Final heat treatment. The final heat treatment applicable to components machined from the castings shall consist of the following. a) Hardening. Heat uniformly at a temperature between 940 C and 970 C and quench in oil. b) Tempering. He
12、at uniformly at a temperature between 500 C and 650 C, depending on the hardness required (see 6.2.2), and cool in air. 5 Selection and preparation of test samples 5.1 The inspector shall select test samples for the modulus of elasticity and ring tensile tests from at least one pot or sand casting f
13、rom each cast. 5.2 The test samples shall be cut from any position not less than 20 mm from the non-flanged end of the pot or either end of the sand casting. 5.3 The test pieces machined from the test samples (see A.1 and B.1) shall not be further mechanically or thermally worked before testing. 6 M
14、echanical properties NOTEInformation on SI units is given in BS 3763 “The International System of units (SI)” and BS 350 “Conversion factors and tables”. 6.1 Modulus of elasticity and ring tensile stress 6.1.1 Initial tests. The properties obtained from the test pieces, machined from the test sample
15、s selected and prepared in accordance with clause 5, shall comply with the following requirements. 6.1.1.1 Modulus of elasticity. When determined as described in Appendix A, the modulus of elasticity shall be not less than 193 000 MPa. Either of the methods described in Appendix A may be used, but i
16、n cases of dispute results from the same method shall be compared, i.e. both tangential loading or both diametral loading. 6.1.1.2 Ring tensile strength. When determined as described in Appendix B, the ring tensile strength shall be not less than 850 MPa. 6.1.2 Retests. If any test piece fails to co
17、mply with the requirements of 6.1.1.1 or 6.1.1.2, all the pots represented shall be withdrawn or, if requested by the founder, the inspector shall adopt one of the following procedures. a) Select for test further samples from two pots from the same cast, one of which shall be taken from the pot from
18、 which the original test sample was taken, unless that pot has been withdrawn by the founder. The properties obtained from test pieces machined from both these further samples shall comply with the requirements of 6.1.1.1 or 6.1.1.2, as appropriate. b) Allow the cast to be reannealed in accordance w
19、ith 4.1 and retested in accordance with 6.1.1, 6.2 and clause 7. Sand castingssections 1 and 4 Centrifugal castingssections 1 and 5 Element % min.max. Total carbon1.52.0 Silicon1.52.0 Manganese0.61.2 Phosphorus0.10 Sulphur0.10 Chromium13.515.0 Molybdenum0.350.5 Nickel0.4 Licensed Copy: London South
20、Bank University, London South Bank University, Sat Dec 09 03:18:40 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS HC 404:1977 2 BSI 01-2000 6.2 Hardness 6.2.1 The hardness of castings heat treated in accordance with 4.1 shall be: 6.2.2 The hardness of material finally heat treated in accordance with
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