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GB/T 37208-2018 English PDF (GBT37208-2018)

GB/T 37208-2018 English PDF (GBT37208-2018)

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GB/T 37208-2018: Nonmetallic paper based wet type frictional materials

This standard specifies the classification, requirements, test methods, inspection rules, marking, packaging, transportation, storage of non-metallic paper-based wet type frictional materials. This standard applies to frictional materials, which are used for friction elements in wet type frictional systems, such as motorcycles, agricultural machinery, industrial machinery, automotive wet type automatic transmissions.
GB/T 37208-2018
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 43.040.50
Q 69
Nonmetallic paper based wet type frictional materials
ISSUED ON: DECEMBER 28, 2018
IMPLEMENTED ON: NOVEMBER 01, 2019
Issued by: General Administration of Quality Supervision, Inspection and Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Categories... 5
5 Requirements ... 5
6 Test method ... 7
7 Inspection rules ... 9
8 Marking, packaging, transportation, storage ... 10
Appendix A (Normative) Model and performance requirements of test oil ... 12 Appendix B (Normative) Size and requirements of standard sample and mating sample ... 13
Appendix C (Normative) Test parameters of friction performance ... 17
Nonmetallic paper based wet type frictional materials
1 Scope
This standard specifies the classification, requirements, test methods, inspection rules, marking, packaging, transportation, storage of non-metallic paper-based wet type frictional materials (hereinafter referred to as "frictional materials").
This standard applies to frictional materials, which are used for friction elements in wet type frictional systems, such as motorcycles, agricultural machinery, industrial machinery, automotive wet type automatic transmissions.
2 Normative references
The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) is applicable to this standard.
GB/T 2828.1 Sampling procedures for inspection by attributes - Part 1:
Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
GB/T 35472.2 Test method for friction element of wet automatic transmission - Part 2: SZBL type friction test machine guidelines
GB/T 35472.3 Test method for friction element of wet automatic transmission - Part 3: Low-speed stepped power test method
GB/T 35472.4 Test method for friction element of wet automatic transmission - Part 4: High-speed stepped power test method
GB/T 35472.5 Test method for friction element of wet automatic transmission - Part 5: Durability test method
GB/T 35472.6 Test method for friction element of wet automatic transmission - Part 6: ??-PVT test method
3 Terms and definitions
The following terms and definitions apply to this document.
6.4.2 The test oil shall meet the requirements of Appendix A. Type 1 frictional materials use No.1 standard test oil. Type 2 frictional materials use No.2 standard test oil. Type 3 frictional materials use No.3 standard test oil. 6.4.3 The size and requirements of the test sample and the mating sample shall meet the requirements of Appendix B. When the size of the inspection lot product is inconsistent with the standard sample, it shall use the standard sample, which is produced at the same time as the inspection lot product, by the same material and process, as the test sample.
6.4.4 Before the test, put the sample in the specified oil. Soak it for more than 30 min, at room temperature.
6.4.5 Carry out the friction performance test, in accordance with the provisions of GB/T 35472.6. The test parameters shall comply with the provisions of Appendix C.
6.5 Determination of wear
After the test samples are soaked, measure and record the thickness of each test sample. For each test sample, measure at least three points
(circumferentially equal-divided), these points are permanently marked AND used in the measurement after the test. Record the thickness of each
measurement point of each test sample. Use its arithmetic average as the thickness value of the test sample before the test. After completing all the test stages, take out the test samples. Measure and record the thickness of each test sample, at the same measurement point, in the same way. Use the
arithmetic mean as the thickness value of the test sample after the test. The thickness difference, before and after the test, is taken as the wear of the test sample. Take the value with the largest wear in a group of test samples, as the reported value.
Use the micron micrometer, which has an accuracy of 0.001 mm, for
measurement. The diameter of the measuring head is not less than 3.2 mm. 6.6 Power increment test
The grade test of low-speed power increment test is carried out, according to GB/T 35472.3. The grade test of the high-speed power increment test is carried out, according to GB/T 35472.4.
6.7 Durability test
The durability test is carried out, according to GB/T 35472.5. For the durability test, it shall carry out 200 running-in first; THEN carry out 10000 test cycles, according to the single condition in the power increment stepwise grade test. material and standard specimen size.
7.3 Judgment of results
7.3.1 Appearance quality, flatness, thickness shall be tested piece by piece; it is judged according to Table 5, respectively.
7.3.2 The friction performance is tested by standard samples. When the
measured midpoint coefficient, the breakaway coefficient, the ratio of the endpoint coefficient to the midpoint coefficient, the wear all meet the requirements of 5.4, THEN, the above four items of the batch of products are determined qualified. If any item does not meet the requirements of 5.4, it shall use the two sets of standard samples, that have not been tested or used, for two repeated tests. If the two repeated test results meet the requirements of 5.4, it is still judged that the four items of the friction performance of the batch of products are qualified; it shall use the first repeated test data as the reported result. If any of the two repeated test results does not meet the requirements of 5.4, then this item of this batch of products is unqualified.
7.3.3 For the low-speed power increment test grade, the high-speed power increment test grade, the durability test result, the judgment rules shall be determined, through negotiation, between the supplier and the buyer.
7.3.4 When all inspection items are qualified, then the batch of products is determined to be qualified. If any item is unqualified, the batch of products shall be determined as unqualified.
8 Marking, packaging, transportation, storage
8.1 Marking
The product's packaging carton (box) shall be marked with the product name, model specification, manufacturer name, address, product quantity, this standard number.
8.2 Packaging
8.2.1 The frictional material shall be packed tightly and neatly in a clean, dry, sturdy, durable carton (box).
8.2.2 Each packing carton (box) shall be accompanied by a product
qualification certificate.
8.3 Transportation and storage
8.3.1 During transportation, the frictional material shall not be squeezed,

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