BS 131-4-1972 Notched bar tests - Calibration of pendulum impact testing machines for metals《缺口棒试验方法 金属摆式冲击试验机的校准》.pdf

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1、BRITISH STANDARD BS 131-4:1972 Incorporating Amendment No. 1 Methods for notched bar tests Part 4: Calibration of Izod pendulum impact testing machines for metals UDC 620.178.746BS131-4:1972 This British Standard, having beenapproved by the MechanicalEngineering IndustryStandards Committee, waspubli

2、shed under the authorityofthe Executive Board on 30 March 1972 BSI 02-2000 First published August 1920 First revision August 1933 Part 4 of second revision October 1962 Part 4 of third revision March 1972 The following BSI references relate to the work on this standard Committee reference MEE/37, ME

3、E/37/8 Draft for approval 71/34257 ISBN 0 580 07040 9 Co-operating organizations The Mechanical Engineering Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial or

4、ganizations: The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Associated Offices Technical Committee Engin

5、eering Equipment Users Association Association of Consulting Engineers Gas Council Association of Hydraulic Equipment Institution of Civil Engineers Manufacturers Ltd. Institution of Gas Engineers Association of Mining Electrical and Mechanical Institution of Heating and Ventilating Engineers Engine

6、ers British Chemical Plant Manufacturers Institution of Mechanical Engineers Association Institution of Mechanical Engineers British Compressed Air Society (Automobile Division) British Electrical and Allied Manufacturers Institution of Plant Engineers Association* Institution of Production Engineer

7、s* British Gear Manufacturers Association Locomotive and Allied Manufacturers British Internal Combustion Engine Association of Great Britain Manufacturers Association London Transport Executive British Mechanical Engineering Confederation Machine Tool Trades Association British Pump Manufacturers A

8、ssociation Ministry of Defence British Steel Industry* Ministry of Defence, Army Department* Crown Agents for Oversea Governments and National Coal Board Administrations National Physical Laboratory (Department of Department of Employment and Productivity Trade and Industry)* (H.M.Factory Inspectora

9、te) Royal Institute of British Architects Department of the Environment* Telecommunications Engineering Department of Trade and Industry* Manufacturing Association Department of Trade and Industry National Water Tube Boilermakers Association Engineering Laboratory Electricity Council, the Central El

10、ectricity Generating Board and the Area Boards in England and Wales Aluminium Federation Department of Trade and Industry Forest British Cast Iron Research Association Products Laboratory British Iron and Steel Research Association Institution of Engineering Inspection British Non-ferrous Metals Res

11、earch Lloyds Register of Shipping Association Ministry of Defence, Navy Department Chemical Industries Association Spring Research Association Copper Development Association Tube Investments Department of the Environment Building The Welding Institute Research Station Individual testing machine manu

12、facturers Department of Trade and Industry Aviation Supply Amendments issued since publication Amd. No. Date of issue Comments 7768 August 1993 Indicated by a sideline in the marginBS131-4:1972 BSI 02-2000 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Inspecti

13、on of machine and its installation 1 3 Level 1 4 Bearings 1 5 Location of pendulum 1 6 Initial potential energy 1 7 Impact velocity 1 8 Centre of percussion 2 9 Test piece supports 2 10 Striker 2 11 Indicating equipment 2 12 Friction losses 3 13 Certificates of calibration and verification 3 Appendi

14、x A Accuracy of gauges 4 Figure 1 Details of Izod machine 5 Figure 3 Dimensions for calculations 6BS131-4:1972 ii BSI 02-2000 Foreword This British Standard has been published under the authority of the Mechanical Engineering Industry Standards Committee as part of the further revision of BS131, oth

15、er parts of which deal with the Izod impact test (Part1) and determination of crystallinity (Part5). In preparing this revision due account has been taken of latest international agreements concerning the SI unit to be used in relation to impact testing. The standard, which covers the inspection of

16、machines as installed and gives detailed methods for the calibration and subsequent verification of the constructional elements of the machine, generally conforms with the requirements of ISO Recommendation No. 442, “Verification of pendulum impact testing machines for testing steels”. However, wher

17、eas ISO/R442admits the possibility of direct verification by tests of un-notched test pieces, the methods given in this standard are essentially static in nature and take into account only the energy absorbed in fracturing a test piece. In the interest of continuity, the requirement for the scale gr

18、aduations of Izodmachines is also expressed in the SI unit. However, it is not intended to revise Part1of the standard as the Izod test is for the most part being supersededby the Charpy test for material specification purposes. Thus, if anIzod machine is converted to record energy absorbed in joule

19、s, the value inftlbfcan be obtained by using the conversion factor1J=0.737562ftlbf; alternatively1ftlbf = 1.355 82J. Whilst testing machines manufactured subsequent to the1962edition of this part of the standard should comply with all its requirements, it is recognized that some of the machines stil

20、l in service may not comply with all requirements and guidance for the verification of such machines is included. As in the previous edition, an appendix gives the accuracy requirements for gauges used in checking machine components. All references to the verification of Charpy testing machines have

21、 been deleted from this Part of BS 131 and the verification of Charpy testing machines should now be carried out in accordance with BS EN 10045-2. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct a

22、pplication. 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, pagesi andii, pages1to6and a back cover. This standard has been updated (see copyright date) and may have had amend

23、ments incorporated. This will be indicated in the amendment table on the inside front cover.BS131-4:1972 BSI 02-2000 1 1 Scope 1.1 This Part of this British Standard gives methods for the inspection, calibration and verification of Izod pendulum impact testing machines, and includes instructions for

24、 certificates of calibration and verification. The methods cover the following elements of the machine, which are illustrated in Figure 1: 1) machine framework (i.e. the structure supporting the pendulum, excluding only thefoundation); 2) pendulum and striker; 3) test piece supports; 4) indicating e

25、quipment (e.g. scale and frictionpointer). 1.2 In applying the methods all the absorbed energy indicated by the machine is attributed to the fracturing of the test piece. NOTEIt is known that energy is absorbed other than by fracturing the test piece. It is assumed that this energy is absorbed by it

26、ems such as the test piece supports, the machine foundation and framework, the pendulum and striker, translation of the broken part of the test piece and drag of a partially broken test piece. This energy is not determined as suitable methods and apparatus have not yet been developed formeasuring ei

27、ther its total or constituent parts. 2 Inspection of machine and its installation Before carrying out the calibration of machine components as described in 3 to12, the machine shall be inspected to ensure that: 1) A reference surface on the base of the machine is level. If the machine is installed i

28、n its permanent position it shall be securely bolted to a concrete floor not less than150mm thick, or where this is not available shall be bolted to a foundation having a mass not less than40times that of the pendulum. 2) The pendulum swings freely between the limits of its travel, and that friction

29、 losses are not excessive. (See12). 3) There are no visible signs of damage to the pendulum, or damage to or wear of the striker and test piece supports. 4) The indicating equipment appears to function correctly throughout its range and the scale divisions are legible. 5) The pendulum bearings have

30、not developed excessive play. 6) The release mechanism is functioning correctly and does not impede the swing of the pendulum or impart vibration to it. 7) The test piece can be securely gripped. NOTEIt is recommended that the user carries out the above inspection frequently and in any case before t

31、he machine is verified. (See 13.) 3 Level For all types of machine both the axis of rotation of the pendulum and a reference surface on the base of the machine shall be horizontal to within1 : 1 000. 4 Bearings The play of the pendulum spindle in its bearings shall be measured. The sideplay shall no

32、t exceed0.25mm and the radial play shall not exceed0.03mm. 5 Location of pendulum The pendulum shall be located so that the line of contact between the striking edge and the test piece is22 0.5mm above the top surface of the test piece supports, and the angle between the underside of the striker and

33、 the face of the test piece is100 1 (seeFigure 1b). 6 Initial potential energy 6.1 The initial potential energy, A, shall not differ from the nominal value by more than1%. The initial potential energy is equal to M (1 cos ) where M is the moment of the pendulum and is the angle of fall. 6.2 The mome

34、nt of the pendulum is determined bysupporting the pendulum at a convenient distance, R (which should preferably be not lessthan L/2), from the axis of rotation on a balanceor dynamometer in such a manner that theline through the axis of rotation which joins thecentreofgravity of the pendulum is hori

35、zontal (see Figure 3a). The force, G, and the length R, shallbe measured to an accuracy of 0.2%. The moment, M, is the product G R. 6.3 The angle of fall, , (see Figure 3b) shall be measured to an accuracy of 4minutes of arc. NOTEIn certain cases, it may be necessary to remove the pendulum from the

36、machine to determine its moment by the method described above. Other methods of determining M are not precluded. 7 Impact velocity 7.1 The impact velocity, V, shall be determined and shall be 3 m/s to 4 m/s (see BS 131-1). 7.2 When the pendulum strikes the test piece atthelowest point of its swing t

37、he impact velocity,V, is determined from the formula V=where L is the distance in metres from the axis of the pendulum to the point ofimpact. 2gL1cos ()BS131-4:1972 2 BSI 02-2000 7.3 For the purpose of this determination, thelength, L, shall be measured to an accuracy of 0.2% and the value g shall b

38、e taken as9.81m/s 2 . 8 Centre of percussion 8.1 The distance, P, of the centre of percussion from the axis of rotation is derived from the time of swing of the pendulum, and it shall be within1% of L. 8.2 The distance shall be determined by swinging the pendulum through an angle not exceeding5 , an

39、d measuring the time, t, of a complete oscillation in seconds. 8.3 P is derived from the expression:; where the value of ; 2is taken as9.87, and g as9.81m/s 2i.e. P (metres) = 0.2485t 2 . 8.4 The value of t shall be determined with an accuracy of0.2%. For example, with a pendulum having a periodic t

40、ime of approximately2seconds, this accuracy may be achieved by ascertaining the mean value of t derived from four determinations of the total duration, T, of100complete oscillations provided the repeatability, Tmax Tmin, of the four determinations is not more than0.5second. 9 Test piece supports The

41、 following requirements of the test piece supports shall be checked. 9.1 Izod machines 9.1.1 Level of supports. The top surface of the supports shall be parallel to the reference surface on the base of the machine within1 : 1 000. 9.1.2 Locating groove for test pieces. The locating groove in the sup

42、port block shall be checked with a gauge. For square section test pieces its width shall be 10.15mm to10.25mm. For circular section test pieces it shall be of semi-circular cross section having a diameter of11.506mm to11.557mm. 9.1.3 Angle between the axis of the clamped test piece and the top surfa

43、ce of the supports. A square or circular section gauge bar, having dimensions as given in the appendix, shall be clamped in the grips. The angle between the axis of the clamped gauge bar and the top surface of the supports shall be checked by a gauge, and shall be90 0.5 . 9.1.4 Orientation of locati

44、ng groove. When the striking edge of the pendulum is brought into contact with the clamped square section gauge bar, coincidence between the striking edge and the face of the bar shall be within0.03mm over the full width. 9.1.5 Location of notch. The provisions made for locating the test piece notch

45、 in relation to the top surface of the supports shall be checked by a gauge to ascertain that the plane of symmetry of the notch coincides with the top surface of the supports within 0.1mm. 9.2 Text deleted 9.2.1 Orientation of supports. The square section gauge bar referred to in 9.1.3 shall be loc

46、ated in the test piece supports. The horizontal axis of the gauge bar shall be parallel to the top surface of the supports within1:1 000. When the striking edge of the pendulum is brought into contact with the bar, coincidence between the striking edge and the face of the bar shall be within0.03mm o

47、ver the full width. 9.2.2 Angle of supports. The angle between the two supporting faces, which are radial and tangential to the axis of the pendulum, shall be checked by a gauge, and shall be90 0.1 . 9.2.3 Distance between supports. This distance shall be checked by a gauge and shall be 40 mm. 9.2.4

48、 Taper of supports. The taper shall be checked by a gauge, and shall be 1 0.1in 5 (i.e. a slope of0.18to0.22, approximately11 1 ). 9.2.5 Radius of curvature of supports. The radius of curvature shall be checked with a gauge, and shall be1.0mm to1.5mm. 10 Striker 10.1 Direction of striker. When the s

49、triking edge of the pendulum makes contact with the test piece, it shall be perpendicular to the longitudinal axis of the test piece within2 . 10.2 Striking edge. The striking edge shall be rounded with a smooth profile blending tangentially with the faces of the striker. 10.3 Radius of curvature. The radius of curvature of thestriking edge shall be checked with a gauge, and shall be0.5 mm to 1.0 mm. 10.4 Angle of tip. The angle of tip of the striker shall be checked with a gauge, and shall be 75 1 . 11 Indicating equipment 11.1