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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 620.178.746 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:15:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 131-4:1972
2、This British Standard, having been approved by the Mechanical Engineering Industry Standards Committee, was published under the authority of the 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
3、revision March 1972 The following BSI references relate to the work on this standard Committee reference MEE/37, MEE/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 w
4、as prepared, consists of representatives from the following Government departments and scientific and industrial organizations: The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on
5、the committee entrusted with the preparation of this British Standard: Associated Offices Technical CommitteeEngineering Equipment Users Association Association of Consulting EngineersGas Council Association of Hydraulic EquipmentInstitution of Civil Engineers Manufacturers Ltd.Institution of Gas En
6、gineers Association of Mining Electrical and MechanicalInstitution of Heating and Ventilating EngineersEngineers British Chemical Plant ManufacturersInstitution of Mechanical Engineers AssociationInstitution of Mechanical Engineers British Compressed Air Society(Automobile Division) British Electric
7、al and Allied ManufacturersInstitution of Plant Engineers Association*Institution of Production Engineers* British Gear Manufacturers AssociationLocomotive and Allied Manufacturers British Internal Combustion EngineAssociation of Great Britain Manufacturers AssociationLondon Transport Executive Brit
8、ish Mechanical Engineering ConfederationMachine Tool Trades Association British Pump Manufacturers AssociationMinistry of Defence British Steel Industry*Ministry of Defence, Army Department* Crown Agents for Oversea Governments andNational Coal Board AdministrationsNational Physical Laboratory (Depa
9、rtment of Department of Employment and ProductivityTrade and Industry)* (H.M. Factory Inspectorate)Royal Institute of British Architects Department of the Environment*Telecommunications Engineering Department of Trade and Industry*Manufacturing Association Department of Trade and Industry NationalWa
10、ter Tube Boilermakers Association Engineering Laboratory Electricity Council, the Central Electricity Generating Board and the Area Boards in England and Wales Aluminium FederationDepartment of Trade and Industry Forest British Cast Iron Research AssociationProducts Laboratory British Iron and Steel
11、 Research AssociationInstitution of Engineering Inspection British Non-ferrous Metals ResearchLloyds Register of Shipping AssociationMinistry of Defence, Navy Department Chemical Industries AssociationSpring Research Association Copper Development AssociationTube Investments Department of the Enviro
12、nment Building The Welding Institute Research StationIndividual testing machine manufacturers Department of Trade and Industry Aviation Supply Amendments issued since publication Amd. No.Date of issueComments 7768August 1993Indicated by a sideline in the margin Licensed Copy: sheffieldun sheffieldun
13、, na, Fri Nov 24 06:15:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 131-4:1972 BSI 02-2000i Contents Page Co-operating organizationsInside front cover Forewordii 1Scope1 2Inspection of machine and its installation1 3Level1 4Bearings1 5Location of pendulum1 6Initial potential energy1 7Impact velo
14、city1 8Centre of percussion2 9Test piece supports2 10Striker2 11Indicating equipment2 12Friction losses3 13Certificates of calibration and verification3 Appendix A Accuracy of gauges4 Figure 1 Details of Izod machine5 Figure 3 Dimensions for calculations6 Licensed Copy: sheffieldun sheffieldun, na,
15、Fri Nov 24 06:15:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 131-4:1972 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 BS 131, other parts of which deal with the I
16、zod impact test (Part 1) and determination of crystallinity (Part 5). 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 machines as installed and gives
17、 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, whereas ISO/R 442 admits the possib
18、ility 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 graduations of Izod machines is
19、 also expressed in the SI unit. However, it is not intended to revise Part 1 of the standard as the Izod test is for the most part being superseded by the Charpy test for material specification purposes. Thus, if an Izod machine is converted to record energy absorbed in joules, the value in ft lbf c
20、an be obtained by using the conversion factor 1 J = 0.737 562 ft lbf; alternatively 1 ft lbf = 1.355 82 J. Whilst testing machines manufactured subsequent to the 1962 edition of this part of the standard should comply with all its requirements, it is recognized that some of the machines still in ser
21、vice 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 been de
22、leted 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 applicati
23、on. 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 6 and a back cover. This standard has been updated (see copyright date) and may have had amendme
24、nts incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:15:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 131-4:1972 BSI 02-20001 1 Scope 1.1 This Part of this British Standard gives methods for the inspec
25、tion, calibration and verification of Izod pendulum impact testing machines, and includes instructions for 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
26、 pendulum, excluding only the foundation); 2) pendulum and striker; 3) test piece supports; 4) indicating equipment (e.g. scale and friction pointer). 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
27、energy is absorbed other than by fracturing the test piece. It is assumed that this energy is absorbed by items 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.
28、 This energy is not determined as suitable methods and apparatus have not yet been developed for measuring either its total or constituent parts. 2 Inspection of machine and its installation Before carrying out the calibration of machine components as described in 3 to 12, the machine shall be inspe
29、cted to ensure that: 1) A reference surface on the base of the machine is level. If the machine is installed in its permanent position it shall be securely bolted to a concrete floor not less than 150 mm thick, or where this is not available shall be bolted to a foundation having a mass not less tha
30、n 40 times that of the pendulum. 2) The pendulum swings freely between the limits of its travel, and that friction losses are not excessive. (See 12). 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 app
31、ears to function correctly throughout its range and the scale divisions are legible. 5) The pendulum bearings have 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 securel
32、y gripped. NOTEIt is recommended that the user carries out the above inspection frequently and in any case before the 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 wi
33、thin 1 : 1 000. 4 Bearings The play of the pendulum spindle in its bearings shall be measured. The sideplay shall not exceed 0.25 mm and the radial play shall not exceed 0.03 mm. 5 Location of pendulum The pendulum shall be located so that the line of contact between the striking edge and the test p
34、iece is 22 0.5 mm above the top surface of the test piece supports, and the angle between the underside of the striker and the face of the test piece is 100 1 (see Figure 1b). 6 Initial potential energy 6.1 The initial potential energy, A, shall not differ from the nominal value by more than 1 %. Th
35、e 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 moment of the pendulum is determined by supporting the pendulum at a convenient distance, R (which should preferably be not less than L/2), from the axis of rotation on a balance
36、 or dynamometer in such a manner that the line through the axis of rotation which joins the centre of gravity of the pendulum is horizontal (see Figure 3a). The force, G, and the length R, shall be measured to an accuracy of 0.2 %. The moment, M, is the product G R. 6.3 The angle of fall, , (see Fig
37、ure 3b) shall be measured to an accuracy of 4 minutes of arc. NOTEIn certain cases, it may be necessary to remove the pendulum from the 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
38、 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 at the lowest point of its swing the 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 of impact. 2gL 1cos() Licens
39、ed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:15:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 131-4:1972 2 BSI 02-2000 7.3 For the purpose of this determination, the length, L, shall be measured to an accuracy of 0.2 % and the value g shall be taken as 9.81 m/s2. 8 Centre of percussion 8.1
40、 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 within 1 % of L. 8.2 The distance shall be determined by swinging the pendulum through an angle not exceeding 5, and measuring the time, t, of a complete oscilla
41、tion in seconds. 8.3 P is derived from the expression:; where the value of ;2 is taken as 9.87, and g as 9.81 m/s2 i.e. P (metres) = 0.2485t2. 8.4 The value of t shall be determined with an accuracy of 0.2 %. For example, with a pendulum having a periodic time of approximately 2 seconds, this accura
42、cy may be achieved by ascertaining the mean value of t derived from four determinations of the total duration, T, of 100 complete oscillations provided the repeatability, Tmax Tmin, of the four determinations is not more than 0.5 second. 9 Test piece supports The following requirements of the test p
43、iece 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 within 1 : 1 000. 9.1.2 Locating groove for test pieces. The locating groove in the support block shall be checked with a g
44、auge. For square section test pieces its width shall be 10.15 mm to 10.25 mm. For circular section test pieces it shall be of semi-circular cross section having a diameter of 11.506 mm to 11.557 mm. 9.1.3 Angle between the axis of the clamped test piece and the top surface of the supports. A square
45、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 be 90 0.5. 9.1.4 Orientation of locating groove. When the striking
46、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 within 0.03 mm over the full width. 9.1.5 Location of notch. The provisions made for locating the test piece notch in relation to the top sur
47、face 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 0.1 mm. 9.2 Text deleted 9.2.1 Orientation of supports. The square section gauge bar referred to in 9.1.3 shall be located in the test piece sup
48、ports. The horizontal axis of the gauge bar shall be parallel to the top surface of the supports within 1 : 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 within 0.03 mm over the full width. 9
49、.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 be 90 0.1. 9.2.3 Distance between supports. This distance shall be checked by a gauge and shall be 40 mm. 9.2.4 Taper of supports. The taper shall be checked by a gauge, and shall be 1 0.1 in 5 (i.e. a slope of 0.18 to 0.22, approximately 11 1). 9.2.5 Radius of curvature of supports. The radius of curvature shall be checked with a gauge, and shall be 1.0 mm