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1、BRITISH STANDARD AEROSPACE SERIES BS HC 402:1977 (Superseding Ministry of Defence Specification DTD 233A) Specification for Cast iron ring pots (centrifugally cast) (Suitable for piston rings up to 200 mm in diameter) UDC 629.7:62 242.3:669.13 Licensed Copy: London South Bank University, London Sout
2、h Bank University, Sat Dec 09 03:12:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS HC 402:1977 This British Standard, having been prepared under the direction of the Aerospace Standards Committee, was published under the authority of the Executive Board on 31 December 1976 BSI 01-2000 The followin
3、g BSI references relate to the work on this standard: Committee reference ACE/60 Draft for comment 73/38194 DC ISBN 0 580 09680 7 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. Compl
4、iance 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 and 2 and a back cover. This standard has been updated (see copyright date) and may have had amendments inco
5、rporated. 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 University, Sat Dec 09 03:12:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS HC 402:197
6、7 BSI 01-2000i Contents Page 1Inspection and testing procedure1 2Chemical composition1 3Condition1 4Selection and preparation of test samples1 5Mechanical properties1 6Microscopic examination1 Appendix A Method for determination of modulus of elasticity2 Appendix B Method for determination of ring t
7、ensile strength2 Figure 1 Application of diametral force2 Figure 2 Application of tangential force2 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 03:12:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: London South Bank University, London S
8、outh Bank University, Sat Dec 09 03:12:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS HC 402:1977 BSI 01-20001 1 Inspection and testing procedure This British Standard shall be used in conjunction with sections 1 and 5 of the latest issue of BS HC 100. 2 Chemical composition 2.1 The castings shall
9、 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 deleteriously affect the metallographic structure and mechanical properties. 3 Condition The castings shall be supplied
10、as cast. 4 Selection and preparation of test samples 4.1 The inspector shall select test samples for the modulus of elasticity and ring tensile tests from at least one pot from each cast. 4.2 The test samples shall be cut from any position not less than 20 mm from the non-flanged end of the pot. 4.3
11、 The test pieces machined from the test samples (see A.1 and B.1) shall not be further mechanically or thermally worked before testing. 5 Mechanical properties NOTEInformation on SI units is given in BS 3763 “The International System of units (SI)” and BS 350 “Conversion factors and tables”. 5.1 Mod
12、ulus of elasticity and ring tensile strength 5.1.1 Initial tests. The properties obtained from the test pieces, machined from the test samples selected and prepared in accordance with clause 4, shall comply with the following requirements. 5.1.1.1 Modulus of elasticity. When determined as described
13、in Appendix A, the modulus of elasticity shall be not less than 114 000 MPa. Either of the methods described in Appendix A may be used, but in cases of dispute results from the same method shall be compared, i.e. both tangential loading or both diametral loading. 5.1.1.2 Ring tensile strength. When
14、determined as described in Appendix B, the ring tensile strength shall be not less than 475 MPa. 5.1.2 Retests. If any test piece fails to comply with the requirements of 5.1.1.1 or 5.1.1.2, all the pots represented shall be withdrawn or, if requested by the founder, the inspector shall adopt the fo
15、llowing procedure. Select for test further samples from two pots from the same cast, one of which shall be taken from the pot from 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 sa
16、mples shall comply with the requirements of 5.1.1.1 or 5.1.1.2, as appropriate. 5.2 Hardness. The hardness of the material shall be: 6 Microscopic examination 6.1 The inspector shall select a sample from each pot for microscopic examination. 6.2 The sample shall be selected from a discard ring cut f
17、rom any position not less than 20 mm from the non-flanged end of the pot and the area prepared for examination shall be representative of the area which will be left after machining. 6.3 The prepared area shall be examined microscopically and, except as provided in 6.4, shall comply with the followi
18、ng requirements. 6.3.1 The unetched surface shall reveal no undue variation in graphite size. 6.3.2 After etchings, the structure shall be a steadite network in a pearlite matrix, the associated free ferrite shall not exceed 10 % and the free cementite shall be well dispersed and shall not exceed 5
19、% locally or 3 % overall. 6.4 Alternatively to 6.3, standards of acceptance shall be agreed between the founder and the purchaser, and photomicrographs depicting the agreed standards shall be prepared. Element % min.max. Total carbon3.13.4 Silicon2.12.5 Manganese0.71.0 Phosphorus0.400.65 Sulphur0.08
20、 Chromium0.30.6 Molybdenum0.51.0 min.max. HB or HV or HRC 255 265 25 293 310 32 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 03:12:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS HC 402:1977 2 BSI 01-2000 Appendix A Method for determination of modulus of ela
21、sticity A.1 Test piece The test piece required is a ring machined from the test sample to a radial thickness of not less than and with a piece cut out so as to leave a free gap of not less than 2.75 times or more than 3 times the radial thickness. A.2 Procedure Use the following procedure. a) Measur
22、e the width of the free gap. b) Apply to the ring, either diametrally, as shown in Figure 1, or tangentially, as shown in Figure 2, a force sufficient to close the gap to less than 0.25 times the radial thickness. c) Allow the ring to open and then apply the force again as in b). d) Measure the circ
23、umference of the ring in the closed position, by means of a calibrated tape or other equivalent method, and calculate the mean external diameter. e) Measure the width of the gap in the closed position and calculate the change in width of the gap. A.3 Determination of result Determine the modulus of
24、elasticity (E) from the appropriate formula as follows. a) Diametral loading b) Tangential loading where Appendix B Method for determination of ring tensile strength B.1 Test piece The test piece required is a ring machined from the test sample to an approximately square section, or to a section app
25、roximating to that of a finished ring, and slit radially. B.2 Procedure Use the following procedure. a) Mount the test piece in a suitable testing machine. b) At radially opposite points on the diameter perpendicular to the diameter through the slit, gradually apply a tensile force until fracture oc
26、curs. c) Note the force at fracture. B.3 Determination of result Determine the ring tensile strength (S) from the following formula. Figure 1 Application of diametral force Figure 2 Application of tangential force diameter 26 - - dis the mean outside diameter of the closed ring (mm), tis the radial
27、thickness of the ring (mm), Qis the diametral force (N), Tis the tangential force (N), bis the axial breadth of ring (mm), xis the change in width of gap (mm). where D is the nominal outside diameter of the unsplit ring (mm), P is the tensile force at fracture (N), bis the axial breadth at back of r
28、ing (mm), tis the radial thickness at back of ring (mm). Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 03:12:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 03:12:31 GMT+
29、00:00 2006, Uncontrolled Copy, (c) BSI BS HC 402:1977 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is inco
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35、substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel: 020 8996 7002. Fax: 020 8996 7001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the inter
36、national standardization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, photocopying, recording or otherwise without prior written permission from BSI. Thi
37、s does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel: 020 8996 7070. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 03:12:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI
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