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GSO ISO 6310 (2010) (English): Road vehicles -- Brake linings -- Compressive strain test methods (Draft Standard) ﺔﻴﺒﺭﻌﻟﺍ ﺞﻴﻠﺨﻟﺍ لﻭﺩﻟ ﻥﻭﺎﻌﺘﻟﺍ ﺱﻠﺠﻤ لﻭﺩﻟ ﺱﻴﻴﻘﺘﻟﺍ ﺔﺌﻴﻫ GCC STANDARDIZATION ORGANIZATION (GSO) ﻲﺌﺎﻬﻨ : ﻉﻭﺭﺸﻤ GSO 2/1 /FDS/ISO 6310 : 2010 ISO 6310/2009 ﻁﺎﻐﻀﻨﻻﺍ لﺎﻌﻔﻨﺍ ﺭﺎﺒﺘﺨﺍ ﺔﻘﻴﺭﻁ – ﺢﺒﺎﻜﻤﻟﺍ ﺕﺎﻨﺎﻁﺒ – ﺕﺍﺭﺎﻴﺴﻟﺍ Road vehicles -- Brake linings -- Compressive strain test methods ﺩﺍﺩﻋﺇ تارﺎﻃﻹاو تﺎﺒآﺮﻤﻟا تﺎﻔﺻاﻮﻣ عﺎﻄﻘﻟ ﺔﻴﻋﺮﻔﻟا ﺔﻴﺠﻴﻠﺨﻟا ﺔﻴﻨﻔﻟا ﺔﻨﺠﻠﻟا ﻙﻟﺫـﻟ ،ﺎﻬﻨﺄﺸـﺒ ﺕﺎﻅﻭﺤﻠﻤﻟﺍﻭ ﻱﺃﺭﻟﺍ ﺀﺍﺩﺒﻹ ﺎﻬﻌﻴﺯﻭﺘ ﻡﺘ ﺔﻴﺠﻴﻠﺨ ﺔﻴﺴﺎﻴﻗ ﺔﻔﺼﺍﻭﻤﻟ ﻉﻭﺭﺸ ﻤ ﺔﻘﻴﺜﻭﻟﺍ ﻩﺫﻫ ﻥﻤ ﺎﻫﺩﺎﻤﺘﻋﺍ ﺩﻌﺒ ﻻﺇ ﺔﻴﺠﻴﻠﺨ ﺔﻴﺴﺎﻴﻗ ﺔﻔﺼﺍﻭﻤﻜ ﺎﻬﻴﻟﺇ ﻉﻭﺠﺭﻟﺍ ﺯﻭﺠﻴ ﻻﻭ ،لﻴﺩﺒﺘﻟﺍﻭ ﺭﻴﻴﻐﺘﻠﻟ ﺔﻀﺭﻋ ﺎﻬﻨﺈﻓ .ﺔﺌﻴﻬﻟﺍ ﺓﺭﺍﺩﺇ ﺱﻠﺠﻤ Foreword GCC Standardization Organization (GSO) is a regional Organization which consists of the National Standards Bodies of GCC member States. One of GSO main functions is to issue Gulf Standards through specialized technical committees (TCs). GSO through the technical program of committee TC No.:2-1 " The Gulf technical Subcommittee for vehicles and tyres standards " has updated the GSO Standard No. : 6310 : 2007" Road vehicles -- Brake linings -- Compressive strain test methods" The Draft Standard has been prepared by Kingdom of Saudi Arabia. This standard has been approved as Gulf Standard by GSO Board of Directors in its meeting No..../.... …….held on / / / H , / / The approved standard will replace and supersede the standard No. ( GSO ISO 6310:2007 / ) GULF STANDARD GSO ISO 6310/2010 ROAD VEHICLES – BRAKE LININGS — COMPRESSIVE STRAIN TEST METHOD 1. SCOPE AND FIELD OF APPLICATION This Gulf standard specifies a method for test and measurement of the compressive displacement of brake linings or brake pad assemblies due to loading and temperature. It also provides a test method to assess lining thermal swell and growth. This Gulf Standard applies to disc brake pad assemblies or coupon samples cut from the friction material. 2. COMPLEMENTARY REFERENCES 2.1 Gulf Standard GSO ISO 611 “Road vehicles — Braking of automotive vehicles and their trailers — Vocabulary” 3. TERMS AND DEFINITIONS 3.1 compressibility (C) change in pad thickness or deflection, caused by a uniaxial compression load during the final loading cycle, to the maximum test pressure, which is measured in the same direction as the compression force, perpendicular to the friction surface. 3.2 Compressive strain (ε) Ratio of the reduction in thickness of the brake lining, due to compressive load, to its initial thickness, which is measured in the direciton of the application force, perpendicular to the friction surface. 3.3 deflection (D) net deflection of the sample as a result of the subtraction of the deflection of the apparatus itself from the total deflection measured by the apparatus D = D - D tot app where D is the total deflection measured by the apparatus; tot D is the deflection of the apparatus itself app 1 GULF STANDARD GSO ISO 6310/2010 3.4 friction material contact area ( A ) O measure of the area of friction material that carries the test load NOTE It is advisable that slots, chamfers and any other features be accounted for in determining A . O 3.5 hot compressibility ( C ) 400 compressibility with a heated platen temperature of 400 °C 3.6 temperature transfer ( T ) T temperature rise at the backing plate of a brake pad assembly after the friction surface has been in contact with the heating plate at (400 ± 10) °C for a given period at a given pressure T = T − T T 3 2 Where T is the final temperature of the backing plate during the hot 3 test; T is the initial temperature of the backing plate for the hot test 2 3.7 pad thermal growth ( d ) G permanent change in thickness of the sample after the friction surface has been in contact with the heating plate at (400 ± 10) °C for a given period at a given pressure and then cooled down to room temperature 3.8 pad thermal swell ( d ) S change in thickness of the sample after the friction surface has been in contact with the heating plate at (400 ± 10) °C for a given period at a given pressure 4. SYMBOLS AND UNITS Table 1 lists the symbols and corresponding units used in this Gulf standard 2 GULF STANDARD GSO ISO 6310/2010 Table 1 – Symbols and units Symbol Definition Unit Accuracy A friction material contact area cm2 0.5 cm2 0 C Compressibilitya µm 1 µm C hot compressibility µm 1 µm 400 d average thickness of coupon sampleb Mm 0.1 mm d pad growth or thermal expansion back at µm 1 µm G ambient temperature d pad swell or thermal expansion µm 1 µm S D net deflection of test samplec µm 1 µm D deflection of the test apparatus itself at d µm 1 µm app pA D total deflection measured by the test µm 1 µm tot apparatus at the maximum test pressure F Pre-load MPa e 1% f B F Test load MPa e 1% f P p test pressure at sample contact area or unit MPa e 1% f A area pressure g p simulated hydraulic line pressure h MPa e 1% f D T test temperature of the heating plate for hot oC ± 2 oC 1 test T initial temperature of the backing plate for hot oC ± 2 oC 2 test T final temperature of the backing plate during oC ± 2 oC 3 hot test T temperature transfer oC 2% T ε compressive strain at i -- 0.0002 pA pA a D at . Used in test method B. pD b Average of five measurements. c D - D . tot app d No sample installed. e 1 bar = 0,1 MPa. f 1 % full-span accuracy. g Test method A. h Test method B. i D/d. Used in test method A. 5. PRINCIPLE 5.1 General The test measures either: - the compressive strain of a friction material coupon (test method A), or - the compressive deflection of a brake pad assembly (test method B). 3 GULF STANDARD GSO ISO 6310/2010 Depending upon the type of sample, one of two alternative test methods is followed for applying the test load. Test results from test method A and test method B should not be directly compared. 5.2 Test method A — Coupon sample and/or airbrake pad Test method A loads a sample coupon to the force required to achieve a unit-area pressure at the contact interface. Test method A can be used to assess pad materials for drum brake assemblies, commercial vehicle disc or drum brakes and material coupons for research and development purposes. For large pads used on a commercial vehicle, measure the compressive strain at the left and the right halves separately or use a segment cut in the radial direction. In other cases, sample sizes should be large enough to account for material not being homogeneous. Surfaces of coupon samples should be flat and parallel. Unless otherwise specified, report the compressive strain value, ε . pA 5.3 Test method B — Hydraulic disc brake pad assembly Test method B loads the brake lining assembly to simulate a hydraulic line pressure of 10 MPa (100 bar) or 16 MPa (160 bar). NOTE In common practice, the line pressure is expressed in bar in order to differentiate it from the face pressure at the contact area. Test method B is typically used for passenger car and light truck hydraulic disc brake pad assemblies. Unless otherwise specified, report the compressive deflection or compressibility value, C, in µm. 6 Test apparatus The test apparatus shall consist of the following. 6.1 Compressibility test-stand or uniaxial material-testing load frame to provide a uniform load over the surface of the test sample. 6.2 Loading cylinder to simulate - a calliper piston configuration for test method B; - loading ram surface larger than the sample contact area for test method A. 4 GULF STANDARD GSO ISO 6310/2010 6.3 Compression platen. 6.4 Device to measure the applied compression force to an accuracy of 1 % of full-scale of the test apparatus. 6.5 Gauge to measure the time-based deflection of the sample with an accuracy of 0,001 mm. Position the gauge on the loading cylinder or on the platen and in contact with the loading ram as near to its centre line as possible. 6.6 Recording device or computer to log load, pressure, displacements and temperatures as function of time. 6.7 Heating device to raise the temperature of the platen to a specified temperature. 6.8 Thermocouple (1,5 mm diameter recommended) to measure the temperature of the platen. The position of the thermocouple should be as close as possible to the centre line of the loading ram and embedded 3 mm below the test surface of the platen. 6.9 Thermocouple or device to measure the temperature of the test sample. 6.10 Micrometer to measure sample thickness. 7. Test stand specifications 7.1 Loading 7.1.1 Test method A Recommended maximum pressure and pressure ramp rates are listed in Table 2. When determining actual sample contact area and contact face pressure, remove the areas of any slots, chamfers and holes. Table 2 — Maximum contact face pressure and ramp rates for test method A Maximum pressure Apply pressure Apply rate in at ramp rate crosshead Type of brake assembly contact interface MPa/s speed control MPa mm/min Commercial 8a 4.0 ± 0.5 15 vehicle disc Commercial 5 2.5 ± 0.5 10 vehicle drum Drum brake 3 1.5 ± 0.5 6 linings a For large pads, 5 MPa is an alternative pressure used. 5 GULF STANDARD GSO ISO 6310/2010 7.1.2 Test method B Apply a force corresponding to a simulated hydraulic line pressure of 10 MPa (100 bar) or 16 MPa (160 bar). The pressure used shall be clearly identified on the test report. The recommended loading rate is 8 MPa/s (80 bar/s) simulated line pressure when testing in constant loading rate control, or 15 mm/min when testing in crosshead speed control. 7.2 Heated platen For the hot test, the test temperature of the heating plate, T , on the surface shall be (400 ± 10) °C. 1 7.3 Loading ram 7.3.1 Test method A — Coupon sample The face of the loading ram shall be flat and the periphery shall at least circumscribe the periphery of the sample in order to distribute the load uniformly over the surface (see Figure 1). To calculate the unit-area pressure, use the actual friction material area in contact with the mating face. For commercial vehicle (CV) pads, the standard loading ram is an annular piston shape with a 60 mm outer diameter and a 50 mm inner ring diameter. 7.3.2 Test method B — Disc brake pad assembly A fixture representing a piston is introduced between the ram and the friction material pad, such that the loading surface has the same form (e.g. solid or annular piston) and location as the actual contact surface of the calliper piston in which the pad will be used in service, or alternatively an agreed position that provides reproducible measurements (see Figure 2). If the intended brake system has a calliper with more than one piston, use an adequate piston-shaped loading fixture. Alternatively, an agreed piston adaptor different from the brake design can be used in order to provide reproducible measurements. 8. Sampling 8.1 It is recommended that a minimum of five samples be measured at room temperature, and three samples at elevated temperature. 8.2 To avoid influencing the test results, the flatness and surface roughness of the sample should be the same as that of normal production. 8.3 When testing to measure friction material properties, it is recommended that backing materials, such as anti-noise shims or rubber coatings, be removed prior to testing, and this information should be reported. 6