BS 5138-1974 Specification for magnetic particle flaw inspection of finished machined solid forged and drop stamped crankshafts《成品机制整体锻造和落锻冲压曲轴的磁粉探伤规范》.pdf

1、BRITISH STANDARD BS 5138:1974 Incorporating Amendment No. 1 Specification for Magnetic particle flaw inspection of finished machined solid forged and drop stamped crankshafts UDC 621.824.3:669.14 134:620.19:620.179.14 CONFIRMED DECEMBER 2007BS5138:1974 This British Standard, having been approved by

2、the MechanicalEngineering IndustryStandards Committee,was published underthe authority of the Executive Boardon 31 October 1974 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference MEE/123 Draft for comment 71/38107 ISBN 0 580 08138 9 Co-operating organiz

3、ations The Mechanical Engineering Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and professional and industrial organizations: The Government departments and scientific and industrial or

4、ganizations marked with an asterisk in the above list, together with the following, were directely represented on the committee entrusted with the preparation of this British Standard. Associated Offices Technical Committee Department of Trade and Industry, National Association of Consulting Enginee

5、rs Engineering Laboratory Association of Hydraulic Equipment Electricity Supply Industry in England Manufacturers Ltd and Wales Association of Mining Electrical and Engineering Equipment Users Association Mechanical Engineers Federation of Manufacturers of Construction British Compressed Air Society

6、 Equipment and Cranes British Electrical and Allied Institution of Gas Engineers Manufacturers Association* Institution of Heating and Ventilating British Gas Corporation Engineers British Gear Manufacturers Association Institution of Mechanical Engineers British Internal Combustion Engine Instituti

7、on of Plant Engineers Manufacturers Association* Institution of Production Engineers British Mechanical Engineering London Transport Executive Confederation Machine Tool Trades Association British Pump Manufacturers Association Ministry of Defence* British Steel Corporation Ministry of Defence, Army

8、 Department* British Steel Industry National Coal Board Crown Agents for Oversea Governments Process Plant Association and Administrations Railway Industry Association of Great Britain Department of Employment (HM Factory Royal Institute of British Architects Inspectorate) Telecommunication Engineer

9、ing and Department of the Environment Manufacturing Association Department of Trade and Industry Diesel Engineers and Users Association Society of Motor Manufacturers and Traders Ltd Amendments issued since publication Amd. No. Date of issue Comments 4439 December 1983 Indicated by a sideline in the

10、 marginBS5138:1974 BSI 09-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Method of test 1 4 Assessment of results 1 5 Inspection and rectification of defects 3 6 Certificate of test 3 Appendix A The effects of dimpling on crankshafts: result

11、s of an investigationona known crankshaft 7 Figure 1 Inspection zones: crankshaft in which the pin and journaldoesnotoverlap 4 Figure 2 Inspection zones: crankshaft with overlap between pin andjournal 5 Figure 3 Permissible sizes of inclusions 6 Figure 4 Bending stress distribution in the crankpin f

12、illet of a typicalcrankshaft 10 Figure 5 Torsional stress distribution in the crankpin fillet of a typicalcrankshaft 11 Figure 6 Stress concentration factor against r/h in bending and torsion,showing minimum permitted values of r/h for a crankpin witha360groove 12 Figure 7 Percentage reduction in lo

13、ad-carrying capacity of a crankshaftbearing 13 Figure 8 Non-dimensional load-carrying capacity of a crankshaftbearing 14 Table 1 Maximum equivalent median stress (! =30 =0 ) 7 Table 2 Maximum equivalent semi-range alternating stresses (! = 30 = 0 ) 7 Table 3 Maximum equivalent median stress 8 Table

14、4 Maximum equivalent semi-range alternating stresses 8 Publications referred to Inside back coverBS5138:1974 ii BSI 09-1999 Foreword This British Standard has been prepared under the authority of the Mechanical Engineering Industry Standards Committee. The use of the magnetic particle technique for

15、the inspection of crankshafts has increased. This British Standard defines the criteria for acceptance of finished machined solid forged crankshafts. A survey has been made of the results of investigations carried out on crankshafts and bearings which have failed in service. Few reported failures we

16、re attributed to major material defects or to the presence of non-metallic inclusions. Similarly, another survey has revealed evidence of satisfactory bearing performance on crankshafts which have been dimpled and, in some cases, these dimples were beyond the limits stated in this standard. Stress d

17、istributions in various crankshaft designs have been taken into account in the preparation of this standard to ensure that the permitted defects do not give rise to stresses in excess of the intended maximum values. Appendix A gives the results of an investigation made on the effects of dimpling on

18、a known crankshaft. This is based on information available at the time of preparation of this standard. Subsequent photo-elastic analysis of specific dimple profiles has confirmed that the requirements in this standard are of a conservative nature 1) . A British Standard does not purport to include

19、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 a front cover, an inside front cover, pages i a

20、nd ii, pages1 to 14, 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. 1) See the following: DIVER P and HESSLER H. Stress concentrations at dim

21、ples in crankshafts. Journalofstrainanalysis, Vol 9, No. 2. Institution of Mechanical Engineers, 1974.BS5138:1974 BSI 09-1999 1 1 Scope This standard specifies the conditions for the magnetic particle flaw inspection of solid forged and drop stamped crankshafts with pin or journal finished machined

22、diameter of80mm and over, excluding built-up shafts and automotive types. It also specifies levels for acceptance and for local removal of defects. This British Standard is applicable to any shaft proportioned in accordance with the rules of Lloyds Register of Shipping. 2 References The titles of th

23、e British Standards referred to in this standard are listed on the inside back cover. 3 Method of test 3.1 The surface condition of the crankshaft or of parts under examination shall be such that there is no interference with the test. All areas to be examined shall be free from dirt, grease or pain

24、t or any other foreign matter which may interfere with the application of the test. 3.2 The crankshaft shall be magnetized to reveal both longitudinal and transverse defects. 3.3 Great care shall be taken when applying the contacts to ensure that these are not applied in critical areas and that scor

25、ch or burn marks are avoided. Where crankshafts are too large to be magnetized by other methods, prods may be used only by agreement with the engine builder and the Inspecting Authority. The prods shall be designed to give the largest possible contact area, and special care shall be taken to ensure

26、cleanness in order that good electrical contact is achieved. Where contacts or prods are used to magnetize they shall be applied only to zone4 areas (seeFigure 1 and Figure 2). 3.4 The continuous wet method of magnetic flaw detection shall be used wherein a suspension of fine magnetic particles in p

27、araffin or similar medium is applied whilst the current is flowing. The magnetic ink used shall comply with the requirements of BS4069. 3.5 Magnetization shall be generally in accordance with the requirements of BS 6072. 3.5.1 Where the current is fed into the ends of the crankshaft, the current str

28、ength shall be not less than5300 A/m of diameter for a.c. (r.m.s. value) or7500 A/m of diameter for d.c. or a.c. peak value. 3.5.2 Where prods are used, the distance between them shall be normally200 20mm. With prods at a distance apart of200mm, the current strength shall be not less than600A (a.c.

29、r.m.s. value) or850A (d.c. or a.c. peak value). Where it is necessary to use prods at less than200mm apart, the current strength may be reduced in direct proportion to the distance between the prods. The positioning of the prods between successive checks shall be staggered to provide a minimum overl

30、ap of half the distance apart in a longitudinal direction and quarter the distance apart in a lateral direction. 3.5.3 The use of a magnetic field strength meter is recommended and will ensure that the technique employed provides an adequate field strength. Generally a magnetic field strength of not

31、 less than2400 A/m is required. 3.5.4 The use of excessive field strengths shall be avoided, as micro-structural and segregation effects may be over-emphasized. In addition, magnetic saturation causing the build up of particles on the edges and corners of the crankshaft shall not be allowed to occur

32、. 3.6 If specified by the purchaser, the crankshaft shall be adequately demagnetized after tests. 3.7 On completion of the test, the crankshaft shall be thoroughly cleaned and protected against corrosion. 4 Assessment of results Isolated inclusions less than0.5mm long should be ignored. For the asse

33、ssment of results the crankshaft shall be divided into four zones as shown in Figure 1 and Figure 2. NOTEFor the purpose of this standard, dimples may be hemispherical, longitudinal, transverse or at any intermediate angle. 4.1 Zone 1 4.1.1 Permissible indications. Defects in this zone are acceptabl

34、e only if they can be rectified in accordance with the requirements of 4.1.2. 4.1.2 Other indications. Surface defects in the fillet radius only may be removed, except in the case of fillet rolled crankshafts, by local grinding, provided a large arc of the fillet is smoothed away so that no local de

35、pressions remain and provided the fillet does not lose its specified form. Defects in the mouth of the lubricating oil holes may be removed, provided the radius of curvature of the ground newly formed surface is not less than that of the oil hole. The depth of metal removed shall not exceed1% of the

36、 adjacent bearing diameter. 4.1.3 In other areas of zone1, no rectification is permitted, except with the approval of the engine builder and any Inspecting Authority concerned.BS5138:1974 2 BSI 09-1999 4.2 Zone 2 4.2.1 Permissible indications. In the fillet radius and adjacent surface of the pin or

37、journal, well dispersed non-metallic inclusions are acceptable provided that they are in a substantially longitudinal direction (parallel to the shaft axis) and that the length of the individual inclusions does not exceed the value given in Figure 3. In the crankweb surfaces non-metallic inclusions

38、are acceptable, irrespective of direction, provided they are reasonably dispersed and that the length of individual inclusions does not exceed the value given in Figure 3. The total length of non-metallic inclusions in each fillet area, plus those in the appropriate part of the crankweb, shall not e

39、xceed three times the individual maximum length given in Figure 3 and subject to 5.8, ignoring those inclusions that are less than20% of maximum permitted length. 4.2.2 Other indications. Non-metallic inclusions falling outside the permitted limits and other surface defects are unacceptable. Surface

40、 defects in the fillet radius may be removed, except in the case of fillet rolled crankshafts, provided that: a) a large arc of the fillet is smoothed away so that no local depressions remain; b) the fillet does not lose its specified form; c) the depth of the metal removed does not exceed1% of the

41、adjacent bearing diameter. Rectification of defects on the surface of the crankwebs shall be in accordance with 5.9 and the dimple shall be not deeper than1% of the adjacent bearing diameter. The dimple length shall not exceed5% of the adjacent bearing diameter and the total length of all such dimpl

42、es on any crankweb shall not exceed three times the permitted individual length. 4.2.3 In other areas of zone2, no rectification is permitted except with the approval of the engine builder and any Inspecting Authority concerned. 4.3 Zone 3 4.3.1 Permissible indications. Non-metallic inclusions are a

43、cceptable, provided that the length of individual inclusions does not exceed the value given inFigure 3, and that the inclusions are in a substantially longitudinal direction and are reasonably dispersed. The total length of such defects in each bearing surface shall not exceed three times the permi

44、tted maximum individual length specified inFigure 3 and subject to 5.8, ignoring those inclusions that are less than20% of maximum permitted length. 4.3.2 Other indications. Non-metallic inclusions falling outside the permitted limits, and other surface defects are not acceptable. Surface defects ma

45、y be removed by local dressing (dimpling) provided that: a) the length of any single dimple does not exceed5% of the bearing diameter; b) the depth of the dimple shall not exceed1% of the bearing diameter; c) the profile of the dimple is in accordance with the form stated in 4.9; d) there are no mor

46、e than two dimples on any one crankpin or journal surface and the length of the bearing surface between dimples is not less than4% of the bearing diameter. 4.3.3 The limitations in 4.3 may only be exceeded by agreement between the purchaser and the manufacturer. 4.4 Zone 4 4.4.1 Permissible indicati

47、ons. Non-metallic inclusions are acceptable irrespective of direction provided their length does not exceed the value given in Figure 3. The total length of non-metallic inclusions allowed in each crankweb may be up to30% of the journal diameter, provided that these indications are dispersed and sub

48、ject to 5.8, ignoring those inclusions that are less than20% of maximum permitted length. 4.4.2 Other indications. Non-metallic inclusions falling outside the permitted limits, and other surface defects are not acceptable. Surface defects may be removed by local dressing provided that: a) the depth

49、of any single dimple is less than2%; b) the length is less than12% of the journal diameter; c) the profile of the dimple is in accordance with5.9. Where several defects are ground away in any one crankweb, the total area ground off shall not exceed twice that permitted for a single groove. 4.4.3 The limitations in 4.4 may only be exceeded by agreement between the purchaser and the manufacturer.BS5138:1974 BSI 09-1999 3 5 Inspection and rectification of defects 5.1 Certain defects may be removed by local dimpling, but before any local dimp