QCT582-99标准（英文版）

Internal standardAutomobile Industry Standard of the Peoples Republic of ChinaQuality grading of the hydraulic brake hose assemblies used on the vehicles using non-petroleum base brake fluidQC/T 29079-921. Subject content and scope of application This standard specifies quality grades, test procedures and sampling evaluation method for the hydraulic brake hose (inside diameter: 3.2 mm) assemblies used on the vehicles using non-petroleum base brake fluid. It can also be referenced for the brake hose assemblies with inside diameters of 4.8 mm and 6.3 mm respectively. This standard applies to supervision and grading of product quality of the hydraulic brake hose assemblies used on the vehicles using non-petroleum base brake fluid by the departments in charge of enterprises and product manufacturing enterprises. This standard does not apply to inspection and product acceptance during regular production of enterprises. 2. Reference standards GB 4784Brake Hose Assemblies for Hydraulic Braking Systems of Motor Vehicles Used with a Non-Petroleum Base Hydraulic Fluids GB 197General Purpose Screw Threads-Tolerances and Fits ZB T04 002 60 Thread Angle System Taper Thread GB/T 12707 Directives for the Grading of Industrial Product Quality3 Quality grading principle According to the quality levels of the hydraulic brake hose assemblies used on the vehicles using non-petroleum base brake fluid, the products are divided into quality product, first-class product and top-class product. See Article 2 of GB/T12707 for the specific requirements. 4 Quality grading indexes See Table 1 for the quality grading indexes. 5. Test procedures See Table 1 for the test procedures. 6 Sampling evaluation method6.1 Sampling principle Enable to reflect the actual level of product quality of the enterprise during a period of time truly. 6.2 Sampling objectsCAIEC Approval on 14-4-1992 implementment on 01-01-1993Conduct finished product inspection by randomly sampling among the in-warehouse products eligible at the customer or the manufacturing plant (for rubber hoses, within one year after delivered).Table 1 Quality Grading Indexes for the Hydraulic Brake Hose Assemblies Used On the Vehicles Using Non-Petroleum Base Brake FluidSNItem sortingInspection itemQuality grading indexTest procedureNumber of samplesInspection content and requirementsQuality productFirst-class productTop-class productUnitKey itemPressure withstanding capability100% pressure test with water as test medium; test pressure: 20.7-24 Mpa; dwell time: 1025S. 20.724MPaPer Article 4.2 of GB4784 302Important itemAccuracy of threadThe item/times percent of pass of the joint thread fit accuracy should conform to the standard of the grade.9095When checking accuracy of thread per GB197 and ZBJ04002, use the 6H (6h) measuring tools specified or the comprehensive measuring tools of corresponding grade of precision approved by metrological service. 303Throughput of boreThe gauge of standard size required in Table 2 of Article 4.3 in GB4784 can be inserted. Before compatibility test Number of nonconforming joints 4PiecePer Articles 4.3 and 4.6 in GB 4784 30After compatibility test 4ExtendabilityUnder a pull of 25 mm/min, the couplers on the hose can not be pulled off or the hose can not be snapped. Before water uptake144617502000NPer Article 4.8 in GB 4784 4After water uptake45Resistance to ozoneWrap the hose around the specified spindle and place it under room temperature and hold for 240.5h; then, put it in an exposed room filled with the mixture (ozone : air=50 5/hundreds of millions) and hold for another 70-72h. During this period, the air temperature in the exposed room should be 403. After the test, when checked in x7 zoom-in, there should be no cracks on its external surface (the area at the binding place and that close to it are not counted in).Meet the requirements of this standardPer Article 4.11 in GB 4784 16Cold bending propertyAfter the test, there should be no cracks and breakage and it can withstand the pressure specified for the corresponding grade standard.There should be no cracks or breakage that can be seen by naked eyes on external surface of the hose (do not hit and press).20.734.5MPaPer Article 4.10 in GB 478417Expansion extentUnder the specified intrinsic pressure, the volumetric expansion extent along free length of the brake hose assembly should not be higher than the amount specified for the corresponding grade standard.HRHLGradePer Article 4.4 in GB 478448Explosion protection performanceWhen applying a hydraulic pressure at a rate of 172.5+69 MPa/min, the hose assembly must withstand the pressure specified for the corresponding grade standard. Before compatibility test 49.03MPaPer Articles 4.5, 4.6 and 4.9 in B 47844After water uptake34.542.149.03After compatibility test 9Resistance to flex fatigueTest a hose assembly (bore: 3.2 mm; free length: 200600 mm) on a flex fatigue tester and its shortest life should meet the hours specified for the corresponding grade standard. For a quality product, use tow and pressure as major evaluation bases. For first-class and top-class products, stop to check every 5 hours after a 35h test for full ring disconnection on external surfaces of the hoses.Before water uptake354555hPer Articles 4.7 and 4.9 in GB 47844410General itemAppearanceThe hose should be flexible without scars, bubbles and other defects. Meet the requirements of this standardObserve by hand touch and naked eyes. 30LabelingThe label of the year and month of manufacture of the rubber hose should be obvious and clear. Number of rubber hoses with unsharp date of manufacture or without the label 5PieceNote: sharing one group samples.6.3 Sample size For finished product inspection, the sampling quantity for each kind of products to be assessed should not be less than 30 (piece); additionally, sample 8 pieces as spare parts for retest. If sampling in finished products warehouse, the sampling base should not be less than 20 times of sample size. 6.4 Grouping principle After all samples have gone through the inspection of general items, conduct the inspection of key items. After accepted, conduct the inspection of important items after grouping all samples in accordance with the requirements in Table 1. 6.5 Evaluation method6.5.1 In case the sample fails the inspection of key items, the quality of the product will be evaluated to be nonconforming and the other inspection items will not be conducted further.6.5.2 Except the key items, in case one item fails during an item inspection, reinspect this item with doubled samples, but doubled spot test is not permitted for evaluation of first-class and top-class products. In case the item passes the reinspection, the product can only be evaluated as acceptable; in case the items still fails the