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1、BRITISH STANDARD AUTOMOBILE SERIES BS AU 142:1968 Methods of test for Brake linings materials UDC 629.113-59 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 142:1968 This British Standard, having been app
2、roved by the Automobile Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council of the Institution on 30 January 1968 BSI 02-2000 The following BSI reference relates to the work on this standard: Commit
3、tee reference AUE/- ISBN 0 580 00046 X Foreword This British Standard, which is published under the authority of the Automobile Industry Standards Committee of the BSI, is based upon data sheet SMMT C-3E:1964 (as revised in February 1967) of the Society of Motor Manufacturers and Traders Limited. It
4、 should be noted that the tests in this standard are not intended to replace the testing of brakes on a vehicle or dynamometer, it being accepted that a full assessment of a lining can be made only under operating conditions. The tests may, however, be used for checking the consistency of manufactur
5、e. For this purpose, the supplier and the purchaser should reach agreement on the selection of the tests, the sampling procedures and the limits to apply to the results. The test procedures described are for the determination of certain physical and chemical properties; they can be used for any lini
6、ng material, and as a quality control check on that material. The properties should be identified with a particular brake lining and not with the brake or vehicle on which this lining is used. The test procedures are not intended to assist the designer to find suitable materials for any particular a
7、pplication since the properties do not necessarily bear any direct relationship to the performance of the lining in service. 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. Compliance
8、 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 15 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorpora
9、ted. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 142:1968 BSI 02-2000i
10、 Contents Page ForewordInside front cover 1Scope1 2Terms and definitions1 3Tests1 4Assessment of friction and wear for quality control purposes7 5Presentation of test data9 Figure 1 Schematic diagram of typical friction materials test machine10 Figure 2 Typical friction materials test drum11 Figure
11、3 Standard drum heating curve, friction materials test machine12 Figure 4 Standard drum cooling curve, friction materials test machine13 Figure 5 Recommended master form plot sheet14 Figure 6 Recommended master form log sheet15 Table 1 Brinell hardness numbers. Scale A3 Table 2 Brinell hardness numb
12、ers. Scale B4 Table 3 Brinell hardness numbers. Scale C4 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:54 G
13、MT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 142:1968 BSI 02-20001 1 Scope This British Standard gives methods for testing brake lining friction materials to determine certain physical and chemical properties. The tests given include: 1) Density 2) Hardness (Brinell and Rockwell) 3) Crossbreaking
14、 strength, for drum brake linings 4) Acetone extract 5) Loss of weight by ignition 6) Assessment of friction and wear 2 Terms and definitions For the purposes of this British Standard the following definitions apply: 2.1 brake lining a piece of friction material made to a shape specified by a brake
15、manufacturer 2.2 sample a selection of brake linings taken from any batch or delivery of a particular material 2.3 specimen that part of a sample brake lining on which tests are performed 3 Tests 3.1 General. Specimens taken from samples of brake linings shall be subjected to the tests described in
16、this standard. The size of the sample and the number of specimens tested from the sample shall be agreed between the purchaser and the manufacturer. Where alternative methods of testing are given the manufacturer shall, unless otherwise agreed with the purchaser, select the method he considers most
17、suitable for the particular material. 3.2 Density. Two alternative methods are given: 3.2.1 Method 1). The weight in grammes of the specimen shall be determined within an accuracy of 0.1 %. The mean dimensions of the specimen shall be determined within an accuracy of 0.25 % and the volume computed i
18、n cubic centimetres. The shape of the specimen will determine how this is done; in the case of an undrilled specimen which is in the form of an arc, the volume V is given by: The density of the specimen shall be computed as follows: Density = g/cm3 where W = weight of specimen in grammes where, V =
19、volume in cm3 A1= mean length of outer curved surface in centimetres A2= mean length of inner curved surface in centimetres b = mean width t = mean thickness The mean values in centimetres shall be determined by measurements equally spaced along the specimen. V = A1A2+()bt 2 - W V - - Licensed Copy:
20、 London South Bank University, London South Bank University, Sat Dec 09 01:49:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 142:1968 2 BSI 02-2000 3.2.2 Method 2. Suspend the specimen from a balance pan hook by means of a length of thin thread and determine the weight of the specimen in air wi
21、thin an accuracy of 0.1 %. Immerse the specimen in water at a temperature between 18 C and 24 C in such a way that it is freely suspended and does not touch the surface of the water or the walls of the water-container, and re-weigh within an accuracy of 0.1 %. If the weight of the thread is small (l
22、ess than 0.05 %) compared to the weight of the specimen, it may be ignored. In weighing the specimen in water, air bubbles adhering to the specimen shall be removed. Their removal can be facilitated by the presence of a trace (e.g. one part in 10 000) of detergent in the water, or by dipping the spe
23、cimen momentarily into industrial methylated spirit, provided that it is known that the material is not affected by this treatment. If the latter procedure is adopted, care shall be taken that the minimum amount of spirit is transferred to the water in which the specimen is weighed. The specimen mus
24、t be weighed as quickly as possible after immersing in water. The density of the specimen shall be computed as follows: Density =g/cm3 3.3 Hardness. Two alternative methods are given: 3.3.1 Method 1. Brinell hardness. This test which is based on the Brinell principles described in BS 240-11), shall
25、be carried out with a hardness testing machine fitted with a ball indenter of 5 or 10 mm diameter. The test shall be applied to the working surface of the specimen. If necessary, a small amount of material may be removed from this surface by grinding in order to provide a smooth surface for the test
26、. The ambient temperature at the machine shall be between 18 C and 24 C. The specimen shall be firmly held in position with adequate support from below with the working surface normal to the direction of application of the load, and a piece of aluminium foil 0.020 mm thick, located on the surface of
27、 the specimen so that the result may be observed on the foil. The indenter shall be applied with the specified load for a period of 15 seconds. The load and ball size, selected from one of the following scales, shall be such that the impressed diameter is between one quarter and half of the ball dia
28、meter: Where two of these scales will give results within the above limitation, the scale selected shall be that which gives the greater diameter of impression. The impression created on the foil shall be examined and its mean diameter, taken as the average length of two diameters taken at right ang
29、les to each other, measured in millimetres. The specimen underneath the foil shall also be examined; if it is evident that the indenter has struck a hard inclusion or other particle liable to falsify the result, the reading shall be discarded and another obtained. The result for each specimen shall
30、be determined from the arithmetic mean of the measurements from at least three indentations. These indentations shall be at least 12 mm from any edge and uniformly spaced along the specimen. The hardness shall then be determined as the quotient of the applied load divided by spherical area of the im
31、pression. For the scale used and the average diameter of impression obtained in millimetres the Brinell hardness number can be obtained from Table 1, Table 2 or Table 3. where,Wa= weight in air in grammes Wb= weight in water in grammes 1) BS 240, “Method for Brinell hardness test”, Part 1, “Testing
32、of metals”. ScaleBall diameterLoad A B C mm 10 10 5 kgfa 30 100 75 a 1 kgf = 9.806 65 N Wa Wa Wb - - Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 142:1968 BSI 02-20003 Table 1 Brinell hardness numbers.
33、 Scale A Diameter of ball = 10 mm; load = 30 kgf Diameter of impression mm 0.00.01.02.03.04.05.06.07.08.09 2.50 2.60 2.70 2.80 2.90 3.00 3.10 3.20 3.30 3.40 3.50 3.60 3.70 3.80 3.90 4.00 4.10 4.20 4.30 4.40 4.50 4.60 4.70 4.80 4.90 5.00 6.01 5.55 5.14 4.77 4.44 4.15 3.88 3.63 3.41 3.21 3.02 2.85 2.6
34、9 2.55 2.41 2.29 2.17 2.07 1.97 1.87 1.79 1.70 1.63 1.56 1.49 1.43 5.97 5.51 5.10 4.74 4.41 4.12 3.85 3.61 3.39 3.19 3.00 2.83 2.68 2.53 2.40 2.28 2.16 2.05 1.96 1.86 1.78 1.70 1.62 1.55 1.48 1.42 5.92 5.47 5.07 4.71 4.38 4.09 3.83 3.59 3.37 3.17 2.98 2.82 2.66 2.52 2.39 2.26 2.15 2.04 1.95 1.85 1.7
35、7 1.69 1.61 1.54 1.48 1.41 5.87 5.43 5.03 4.67 4.35 4.06 3.80 3.56 3.35 3.15 2.97 2.80 2.65 2.50 2.37 2.25 2.14 2.03 1.94 1.85 1.76 1.68 1.61 1.54 1.47 1.41 5.82 5.38 4.99 4.64 4.32 4.04 3.78 3.54 3.33 3.13 2.95 2.78 2.63 2.49 2.36 2.24 2.13 2.02 1.93 1.84 1.75 1.67 1.60 1.53 1.46 1.40 5.78 5.34 4.9
36、5 4.61 4.29 4.01 3.75 3.52 3.31 3.11 2.93 2.77 2.62 2.48 2.35 2.23 2.12 2.01 1.92 1.83 1.74 1.67 1.59 1.52 1.46 1.40 5.73 5.30 4.92 4.57 4.26 3.98 3.73 3.50 3.29 3.09 2.92 2.75 2.60 2.46 2.34 2.22 2.11 2.00 1.91 1.82 1.73 1.66 1.58 1.52 1.45 1.39 5.69 5.26 4.88 4.54 4.23 3.95 3.70 3.47 3.26 3.07 2.9
37、0 2.74 2.59 2.45 2.32 2.21 2.10 1.99 1.90 1.81 1.73 1.65 1.58 1.51 1.44 1.38 5.64 5.22 4.85 4.51 4.20 3.93 3.68 3.45 3.25 3.06 2.88 2.72 2.57 2.44 2.31 2.19 2.09 1.98 1.89 1.80 1.72 1.64 1.57 1.50 1.44 1.38 5.60 5.18 4.81 4.48 4.17 3.90 3.66 3.43 3.23 3.04 2.86 2.71 2.56 2.42 2.30 2.18 2.08 1.98 1.8
38、8 1.79 1.71 1.64 1.56 1.50 1.43 1.37 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 142:1968 4 BSI 02-2000 Table 2 Brinell hardness numbers. Scale B Table 3 Brinell hardness numbers. Scale C Diameter of
39、ball = 10 mm; load = 100 kgf Diameter of impression mm 0.00.01.02.03.04.05.06.07.08.09 2.50 2.60 2.70 2.80 2.90 3.00 3.10 3.20 3.30 3.40 3.50 3.60 3.70 3.80 3.90 4.00 4.10 4.20 4.30 4.40 4.50 4.60 4.70 4.80 4.90 5.00 20.0 18.5 17.1 15.9 14.8 13.8 12.9 12.1 11.4 10.7 10.1 9.50 8.97 8.49 8.04 7.63 7.2
40、4 6.88 6.55 6.24 5.95 5.68 5.43 5.19 4.06 4.75 19.9 18.4 17.0 15.8 14.7 13.7 12.8 12.0 11.3 10.6 10.0 9.44 8.92 8.44 8.00 7.59 7.20 6.85 6.52 6.21 5.92 5.65 5.40 5.16 4.94 4.73 19.7 18.2 16.9 15.7 14.6 13.6 12.8 12.0 11.2 10.6 9.95 9.39 8.87 8.39 7.95 7.55 7.17 6.82 6.49 6.18 5.90 5.63 5.38 5.14 4.9
41、2 4.71 19.6 18.1 16.8 15.6 14.5 13.5 12.7 11.9 11.2 10.5 9.89 9.33 8.82 8.35 7.91 7.51 7.13 6.78 6.46 6.15 5.87 5.60 5.35 5.12 4.90 4.69 19.4 17.9 16.6 15.5 14.4 13.5 12.6 11.8 11.1 10.4 9.83 9.28 8.77 8.30 7.87 7.47 7.10 6.75 6.42 6.12 5.84 5.58 5.33 5.10 4.88 4.67 19.3 17.8 16.5 15.4 14.3 13.4 12.
42、5 11.7 11.0 10.4 9.77 9.23 8.72 8.26 7.83 7.43 7.06 6.71 6.39 6.09 5.81 5.55 5.30 5.07 4.86 4.65 19.1 17.7 16.4 15.2 14.2 13.3 12.4 11.7 11.0 10.3 9.72 9.18 8.68 8.21 7.79 7.39 7.02 6.68 6.36 6.06 5.79 5.53 5.28 5.05 4.83 4.63 19.0 17.5 16.3 15.1 14.1 13.2 12.3 11.6 10.9 10.2 9.66 9.12 8.63 8.17 7.7
43、5 7.35 6.99 6.65 6.33 6.04 5.76 5.50 5.26 5.03 4.81 4.61 18.8 17.4 16.2 15.0 14.0 13.1 12.3 11.5 10.8 10.2 9.61 9.07 8.58 8.13 7.71 7.32 6.95 6.62 6.30 6.01 5.73 5.48 5.23 5.01 4.79 4.59 18.7 17.3 16.0 14.9 13.9 13.0 12.2 11.4 10.8 10.1 9.55 9.02 8.53 8.08 7.67 7.28 6.92 6.58 6.27 5.98 5.71 5.45 5.2
44、1 4.98 4.77 4.57 Diameter of ball = 5 mm; load = 75 kgf Diameter of impression mm 0.00.01.02.03.04.05.06.07.08.09 1.20 1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00 2.10 2.20 2.30 2.40 2.50 65.3 55.5 47.7 41.5 36.3 32.1 28.5 25.5 22.9 20.7 18.7 17.0 15.6 14.3 64.3 54.7 47.1 40.9 35.9 31.7 28.2 25.2 22.6 2
45、0.4 18.5 16.9 15.4 14.1 63.2 53.8 46.4 40.4 35.4 31.3 27.8 24.9 22.4 20.2 18.4 16.7 15.3 14.0 62.1 53.0 45.7 39.8 35.0 30.9 27.5 24.6 22.2 20.0 18.2 16.6 15.2 13.9 61.1 52.2 45.1 39.3 34.5 30.6 27.2 24.4 21.9 19.8 18.0 16.4 15.0 13.8 60.1 51.4 44.4 38.8 34.1 30.2 26.9 24.1 21.7 19.7 17.9 16.3 14.9 1
46、3.7 59.2 50.7 43.8 38.3 33.7 29.8 26.6 23.9 21.5 19.5 17.7 16.1 14.8 13.5 58.2 49.9 43.2 37.8 33.3 29.5 26.3 23.6 21.3 19.3 17.5 16.0 14.6 13.4 57.3 49.2 42.6 37.3 32.9 29.2 26.0 23.4 21.1 19.1 17.4 15.8 14.5 13.3 56.4 48.5 42.0 36.8 32.5 28.8 25.7 23.1 20.9 18.9 17.2 15.7 14.4 13.2 Licensed Copy: L
47、ondon South Bank University, London South Bank University, Sat Dec 09 01:49:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 142:1968 BSI 02-20005 3.3.2 Method 2. Rockwell hardness. This test is based on the Rockwell principles described in BS 891-12). Rockwell hardness is defined in terms of the
48、 depth of penetration of a spherical indenter into the specimen. The ball shall be applied to the working surface of the specimen. If necessary, a small amount of material may be removed from the surface by grinding in order to provide a smooth surface for the test, but the specimen may be flat or r
49、adiused provided that it is firmly held in position, with the working surface normal to the direction of application of the load, and with adequate support from below. The ambient temperature at the machine shall be between 18 C and 24 C. The machine shall be capable of applying loads of 10, 60, 100 and 150 kgf, of utilising balls of 3.175 mm, 6.35 mm and 12.7 mm diameter and of indicating the depth of penetration of the indenter in units of 0.002 mm. A direct reading Rockwell har
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