GB/T 17469-2024 PDF EnglishUS$275.00 · In stock · Download in 9 seconds
GB/T 17469-2024: Characteristics evaluation of brake linings for automobile - Small sample bench test method Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Valid GB/T 17469: Historical versions
Similar standardsGB/T 17469-2024: Characteristics evaluation of brake linings for automobile - Small sample bench test method---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT17469-2024 GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 43.040.40 CCS Q 69 GB/T 17469-2024 Replacing GB/T 17469-2012 Characteristics evaluation of brake linings for automobile - Small sample bench test method Issued on. SEPTEMBER 29, 2024 Implemented on. APRIL 01, 2025 Issued by. State Administration for Market Regulation; Standardization Administration of the People’s Republic of China. Table of ContentsForeword... 3 1 Scope... 5 2 Normative references... 5 3 Terms and definitions... 5 4 Test equipment... 5 5 Test preparation... 8 6 Test procedure... 10 7 Result processing... 11 8 Friction coefficient classification and friction coefficient level marking... 12 9 Test report... 13 Annex A (informative) Test data record table and data curve graph... 14 Annex B (informative) Product test result report format... 161 ScopeThis document specifies the test equipment, test preparation, test procedure, result processing, friction coefficient classification and friction coefficient grade marking, and test report for the small sample bench test method for friction performance evaluation of brake linings for automobile. This document applies to automotive disc brake linings and automotive drum brake linings (hereinafter referred to as “linings”). This document does not apply to parking brake linings.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 5620 Road vehicles - Vocabulary and definition for braking of automotive vehicles and their trailers3 Terms and definitionsFor the purpose of this document, the terms and definitions defined in GB/T 5620 apply.4 Test equipment4.1 Test machine The schematic diagram of small sample bench test machine for friction materials is shown in Figure 1.The test machine shall have the following functions. 4.2 Temperature measurement system 4.2.1 The temperature measurement system shall consist of a welded thermocouple and a measuring and recording device capable of rotating temperature measurement. 4.2.2 The accuracy of the temperature measurement system is ±2 % of the full scale. 4.3 Friction measurement system The accuracy of the friction measurement system is ±2 % of the full scale, and the deviation of the test load is ±2 %. 4.4 Brake drum 4.4.1 The accuracy of the brake drum speed measurement system is ±2 % of the full scale. 4.4.2 The temperature rise of the brake drum is adjusted as follows and maintained during the test. the brake drum speed is 417 r/min, cool the brake drum from 149 ℃ to 93 ℃ with cooling air, then turn off the cooling air; when it cools naturally to 82 ℃, turn on the heater and start timing, and heat for 10 min. The brake drum temperature shall rise to 221 ℃ ± 14 ℃ in 10 min. 4.4.5 The brake drum shall be used within the range of inner diameter 277.4 mm to 279.9 mm. There are three thermocouple installation positions as shown in Table 2, which are (2.55 ± 0.10) mm (position 1), (3.05 ± 0.10) mm (position 2) and (3.55 ± 0.10) mm (position 3) from the surface of the brake drum with an inner diameter of 277.4 mm. 4.5 Other apparatus Apparatus for measuring the thickness, mass and top height of test pieces.5 Test preparation5.1 Preparation of test pieces Installation position Brake drum’s inner diameter φ/mm 5.1.1 Randomly select 5 linings from each batch of products. Prepare a test piece from each lining. 5.1.2 The test piece shall be cut from the middle part of the lining, and the distance from the sampling position to the periphery of the lining shall be roughly equal. 5.1.3 The length and width of the test piece is (25.4 ± 0.2) mm × (25.4 ± 0.2) mm; the test friction surface is arc-shaped, and the radius of the arc shall match the brake drum; the back is flat, and the thickest thickness (or the test piece plus the silencer) is (6.0 ± 0.5) mm. 5.1.4 For test pieces that have been ground, at least 0.3 mm shall be ground off from the friction surface, but not more than 0.5 mm. For unground test pieces (taken directly from the mold), 1.0 mm ~ 1.2 mm shall be ground off from the friction surface so that the resin impregnation layer on the lining surface can be completely removed. 5.1.5 The test friction surface of the prepared test pieces shall not be touched by hand, and foreign impurities shall be avoided. 5.2 Processing of brake drum surface 5.2.1 When using a new or re-ground brake drum, before the first test, remove all wear marks with 320 sandpaper or emery cloth, then polish with 320 sandpaper, and remove dust on the brake drum with clean dry air or soft cloth. Finally, use the reference test piece to run continuously at a speed of 417 r/min, a load of 440 N, and a temperature below 93 ℃ until the friction coefficient stabilizes. 5.2.2 Before each test, the surface of the brake drum shall be polished with 320 sandpaper or emery cloth, and then polished with 320 sandpaper. Remove dust on the brake drum with clean dry air or soft cloth. 5.3 Running-in of test pieces Under the conditions of brake drum speed of 312 r/min, load of 440 N, and maximum temperature of 93℃, the test piece is run-in for not less than 20 min. If the contact area of the test piece is still less than 95 % after running-in for 20 min, the test piece is abandoned and re-prepared. 5.4 Measurement of initial thickness and mass Take out a run-in test piece, take three points (outside, center, inside) on the center line parallel to the axis of the test piece and the brake drum to measure the thickness (to the nearest 0.1 mm) and record it. At the same time, weigh the mass of the test piece (to the nearest 1 mg) and record it.6 Test procedure6.1 First baseline At a brake drum speed of 417r/min, load (load 667 N) the test piece for 10 s and unload for 20 s, for a total of 20 times. The test starts from the brake drum temperature of 82 ℃ ~ 93 ℃, and the cooling air is used to maintain the brake drum temperature at 82 ℃ ~ 104 ℃ during each loading. The cooling air is turned off for the 20th loading. 6.2 First decay Turn off the heating and air cooling, and let the brake drum rotate at 417 r/min to cool naturally. When the brake drum temperature drops to 82 ℃, load the test piece and turn on the heater at the same time. Continuously drag-wear at a speed of 417 r/min and a loading force of 667 N. 6.3 First recovery After the first decay (6.2) is completed, turn off the heater and turn on the cooling air. At a test speed of 417 r/min, during the process of brake drum temperature dropping from 288 ℃ to 93 ℃, load (load 667 N) the test piece for 10 s at 260 ℃, 204 ℃, 149 ℃ and 93 ℃, and record the friction force and friction coefficient at each loading. 6.4 Second wear measurement Perform wear measurement according to 5.5. 6.5 Wear test At a brake drum speed of 417 r/min, load (load 667 N) the test piece for 20 s and unloaded for 10 s, for a total of 100 times. The test starts from the brake drum temperature of 193 ℃ ~ 204 ℃, and the brake drum temperature shall be kept between 193 ℃ ~ 216 ℃, which can be achieved by using a heater or air cooling. 6.6 Third wear measurement After the wear test (6.5) is completed, when it cools to 88 ℃ ~ 99 ℃, perform wear measurement again according to 5.5. 6.7 Second decay After the third wear measurement (6.6) is completed, turn off the heater and cooling air immediately, and let the brake drum rotate at 417 r/min to cool naturally. When the brake drum temperature drops to 82 ℃, turn on the heater, and continue to drag-wear at a speed of 417 r/min and a load of 667 N. When the temperature reaches 343 ℃, the test is completed. If the temperature cannot reach 343 ℃, the drag-wear time can reach 10 min, and the result at the end of 10 min shall prevail. Starting from 93 ℃, record the friction force and friction coefficient every 28 ℃, and record the time, friction force and friction coefficient to reach 343 ℃. 6.8 Second recovery After the second decay (6.7) is completed, turn off the heater and turn on the cooling air. At a test speed of 417 r/min, during the process of brake drum temperature dropping from 343 ℃ to 93 ℃, load (load 667 N) the test piece for 10 s at 316 ℃, 260 ℃, 204 ℃, 149 ℃ and 93 ℃, and record the friction force and friction coefficient at each loading. 6.9 Second baseline Repeat the steps in 6.1. 6.10 Final wear measurement Perform wear measurement according to 5.5. 6.11 Final thickness and mass measurement Take out the test piece after the test and measure the thickness and weigh the mass according to 5.4.7 Result processing7.1 Data collection and processing In the intermittent loading test, the friction coefficient is taken as the value at the end of loading. The measurement data retains three significant digits. 7.2 Test record Test data and curve graphs shall be recorded for each test piece. The test data record table and curve graph are shown in Annex A. 7.3 Calculation of results 7.3.1 Calculation of room temperature friction coefficient Calculate the arithmetic mean (retain three significant figures) of the friction coefficient of each test piece at the four temperature points of 93 ℃, 121 ℃, 149 ℃ and 204 ℃ in the second decay test. The room temperature friction coefficient is the arithmetic mean (retain two significant figures) of the results of 5 test pieces.8 Friction coefficient classification and friction coefficientlevel marking 8.1 Friction coefficient classification For ease of description, the friction coefficient is divided into six categories. C, D, E, F, G, and H, see Table 3. 8.2 Friction coefficient level marking The friction coefficient level of each batch of linings is marked according to the friction coefficient at room temperature and friction coefficient at high temperature calculated in 7.3.1 and 7.3.2, and the category code in Table 3. 8.3 Reconfirmation of friction coefficient level 8.3.1 For linings, when the friction coefficient is near the boundary value of Table 3 (0.15, 0.25, 0.35, 0.45, 0.55), due to differences in laboratory operations and natural changes in friction materials, the room temperature friction coefficient and high temperature friction coefficient obtained by the retest will cross the category boundary, resulting in inconsistency between the two friction coefficient levels, so the friction coefficient level needs to be reconfirmed. 8.3.2 When the friction coefficient is near the boundary value of Table 3 and needs to be reconfirmed, the friction coefficient obtained by the retest shall be within the allowable range of ±0.05 of the original friction coefficient to keep the original friction coefficient level unchanged.9 Test reportThe product test result report is shown in Annex B. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of English version of GB/T 17469-2024 be delivered?Answer: The full copy PDF of English version of GB/T 17469-2024 can be downloaded in 9 seconds, and it will also be emailed to you in 9 seconds (double mechanisms to ensure the delivery reliably), with PDF-invoice.Question 2: Can I share the purchased PDF of GB/T 17469-2024_English with my colleagues?Answer: Yes. The purchased PDF of GB/T 17469-2024_English will be deemed to be sold to your employer/organization who actually paid for it, including your colleagues and your employer's intranet.Question 3: Does the price include tax/VAT?Answer: Yes. Our tax invoice, downloaded/delivered in 9 seconds, includes all tax/VAT and complies with 100+ countries' tax regulations (tax exempted in 100+ countries) -- See Avoidance of Double Taxation Agreements (DTAs): List of DTAs signed between Singapore and 100+ countriesQuestion 4: Do you accept my currency other than USD?Answer: Yes. www.ChineseStandard.us -- GB/T 17469-2024 -- Click this link and select your country/currency to pay, the exact amount in your currency will be printed on the invoice. Full PDF will also be downloaded/emailed in 9 seconds.Question 5: Should I purchase the latest version GB/T 17469-2024?Answer: Yes. Unless special scenarios such as technical constraints or academic study, you should always prioritize to purchase the latest version GB/T 17469-2024 even if the enforcement date is in future. Complying with the latest version means that, by default, it also complies with all the earlier versions, technically.How to buy and download a true PDF of English version of GB/T 17469-2024?A step-by-step guide to download PDF of GB/T 17469-2024_EnglishStep 1: Visit website https://www.ChineseStandard.net (Pay in USD), or https://www.ChineseStandard.us (Pay in any currencies such as Euro, KRW, JPY, AUD).Step 2: Search keyword "GB/T 17469-2024". Step 3: Click "Add to Cart". If multiple PDFs are required, repeat steps 2 and 3 to add up to 12 PDFs to cart. Step 4: Select payment option (Via payment agents Stripe or PayPal). Step 5: Customize Tax Invoice -- Fill up your email etc. Step 6: Click "Checkout". Step 7: Make payment by credit card, PayPal, Google Pay etc. After the payment is completed and in 9 seconds, you will receive 2 emails attached with the purchased PDFs and PDF-invoice, respectively. Step 8: Optional -- Go to download PDF. Step 9: Optional -- Click Open/Download PDF to download PDFs and invoice. See screenshots for above steps: Steps 1~3 Steps 4~6 Step 7 Step 8 Step 9 |
