Silicon carbide entry and exit chemical inspection standards

I. Product Overview:
Silicon carbide is also known as: gold steel sand, refractory sand. Silicon carbide is made of quartz sand, petroleum coke (anthracite), wood chips (the need to add salt to produce green silicon carbide) and is smelted in a resistance furnace at a high temperature. At present, China's industrial production of silicon carbide can be divided into black silicon carbide and green silicon carbide products, all of which are hexagonal crystals.

2. Physical characteristics:
Silicon carbide is very hard, has excellent thermal and electrical conductivity, and is resistant to oxidation at high temperatures. The specific gravity is 3.20~3.25g/cm3, the microhardness is 2840~3320kg/mm2, and the internal impurity content of the crystal is very small.

Product use:
1. As an abrasive, it can be used as a grinding tool, such as grinding wheel, oil stone, grinding head, sand tile, etc.
2. As a metallurgical deoxidizer and high temperature resistant material.
3. High-purity single crystals, which can be used in the manufacture of semiconductors, in the manufacture of silicon carbide fibers, in the electronics industry, etc.

4. Areas producing silicon carbide: China's production of silicon carbide mainly includes: Qinghai, Ningxia, Henan, Sichuan, Guizhou and Other provinces.
Exported to countries and regions: the United States, Japan, South Korea, Taiwan, Southeast Asia, Europe and so on.

V. Inspection standards and main inspection items:
Inspection standards:
(1) GB/T3045-2003 "Chemical Analysis Method of Silicon Carbide", suitable for the determination of chemical composition of abrasive grade silicon carbide and silicon carbide content: more than 95%.
(2) SN/T0256-1993 "Chemical Analysis Method of Silicon Carbide", suitable for the determination of chemical composition of abrasive grade silicon carbide and silicon carbide content: 90% or less.
(3) SN/T0355-1995 is suitable for the inspection of export silicon carbide abrasives.
(4) GB/T4676-2003 is suitable for sampling methods of ordinary abrasives.
(5) The weight identification is carried out according to the SN/T0188-1993 “Import and Export Commodity Weight Identification Procedure Weighing Instrument” standard. The main testing items of silicon carbide: silicon carbide content, ferric oxide, free carbon and so on.

Inspection and supervision methods:
At present, the inspection of exporting silicon carbide is divided into two ways.
1. Batch-by-batch on-site inspection method (batch inspection method);
2. Enterprise classification management inspection and supervision methods.

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