This standard applies to cast bearing alloy ingots for bimetallic bearings. GB/T 8740-1988 Cast bearing alloy ingots GB/T8740-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Bearing alloy ingots for casting
Bearing alloy ingots for casting This standard applies to the casting of bearing alloy ingots for bimetallic bearings. 1 Technical requirements
1.1 The chemical composition of the tin-based bearing alloy ingots shall comply with the provisions of Table 1. 1.2 The chemical composition of the lead-based bearing alloy ingots shall comply with the provisions of Table 2. 1.3 The shape and specifications of the ingots shall comply with the provisions of the following figure. 255—10
1.4 The surface of the ingot shall be clean and free of melt bays, burrs and foreign inclusions. 1.5 The fracture structure of the ingot shall be uniform and dense, and there shall be no slag, non-metallic inclusions and obvious segregation. 1.6 When the purchaser has special requirements for the chemical composition, shape and specifications of the ingot, the supply and demand parties shall negotiate separately. 2 Test method
UDC:669.15.018
.24621.741.7
GB 8740 -- 88
2.1 The arbitration analysis method for the chemical composition of cast tin-based bearing alloy ingots shall be agreed upon by the supply and demand parties. The arbitration analysis method for the chemical composition of cast lead-based bearing alloy ingots shall be carried out in accordance with GB4103.1~4103.12~83 "Chemical Analysis Method for Lead-Based Alloys". 2.2 The surface and fracture of the ingot shall be inspected with the naked eye. 3 Inspection rules
3.1 Inspection and acceptancewwW.bzxz.Net
3.1.1 The ingot shall be inspected by the supplier's technical supervision department to ensure that the product quality meets the requirements of this standard and fill in the quality certificate. 3.1.2 The purchaser may inspect the received products. If the inspection results do not meet the requirements of this standard, it shall be reported to the supplier within three months from the receipt of the product, and the supply and demand parties shall negotiate to resolve the problem. If arbitration is required, the supply and demand parties shall jointly take samples at the demand side. 3.1.3 If the surface quality of the ingot does not meet the requirements of Article 1.4 of this standard, the ingot shall be unqualified. 3.2 Batches
Products shall be submitted for acceptance in batches, and each batch shall consist of the same furnace number and weigh no less than 100kg. 3.3 Sampling rules
3.3.1 The sample for arbitration analysis is taken from any ingot in the batch of ingots, obtained by drilling or sawing. However, the samples obtained must be magnetized to remove the ferromagnetic materials brought in during processing and mixed evenly. 3.3.1.1 Drilling: Drill three points at medium speed on the diagonal line of the upper surface of the ingot, with a spacing of no less than 50mm and a drilling depth of more than 2/3 of the ingot thickness.
3.3.1.2 Sawing: Make the saw blade perpendicular to the upper surface of the ingot and saw three places on the side of the ingot, with a spacing of not less than 50mm and a cutting depth of not less than 100mm. Approved by China National Nonferrous Metals Industry Corporation on February 4, 1988 and implemented on February 1, 1989
GB 8740-
（Y）
800°0
800°0
800°0
°9~9°g
9*8~92
u'S~0\
06~0°2
0°01~08
0°8~0°2
GB8740
011~06
9( 10)
0*91~0°11
oz1~09
171~8*
1-1~80
1/3 of the width of the small ingot.
GB 87 40
3.3.2 The fracture test specimen is taken from any ingot of the batch of ingots and is broken at a position other than the middle of the ingot length. 3.4 Repeated test
When the chemical composition and fracture structure test results do not meet the requirements of this standard, double samples of the items that do not meet the requirements of this standard are taken from the batch of products for re-testing. If one result still does not meet the requirements of this standard after re-testing, the batch of products is unqualified. Packaging, marking, storage and quality certificate 4.1
The brand (or code), batch number and production date should be clearly marked on the surface of the ingot. Ingots are packaged and supplied by brand, with a net weight of no more than 50kg per piece, and the following shall be marked on the package with paint that does not fade easily: ingot name and brand or code;
ingot net weight;
production date;
supplier name or code.
Ingots are stored and transported by brand, and should be protected from rain, moisture and corrosion. Ingots shall be accompanied by a quality certificate when leaving the factory, which shall indicate: supplier name or code;
ingot name, brand or code and registered trademark; chemical composition test results and stamp of the technical supervision department; batch number:
batch weight and number of pieces;
this standard recommendation number;
product ex-factory date.
Additional remarks:
This standard was drafted by Benxi Alloy Factory
The main drafter of this standard is Huang Tieliang.
Since the implementation of this standard, the former Ministry of Metallurgical Industry Standard YB187-75 "Casting Bearing Alloy Ingots" will be invalid. 1.)
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