Suggestions on the naming of mono crystalline corundum

- Jul 30, 2018 -

Suggestions on the naming of mono crystalline corundum

Key words:

            Single crystal corundum,

Mono crystalline corundum

Variety of corundum


Proposed question

In China, the production of single crystal corundum abrasives has been discontinued for many years due to environmental problems. As a variety of corundum abrasives, it can no longer be supplied to users. However, in the domestic abrasive market, another type of abrasive that The domestic industry has not yet formally identified and named, as a single crystal corundum abrasive, it has been provided to users. The author believes that this is not appropriate. This kind of abrasive is very different from the single crystal corundum abrasive specified by national standards and industry standards. I hope the industry Relevant departments and organizations are concerned about this issue.

Single-crystal corundum abrasive

Single crystal corundum abrasive is a kind of corundum abrasive. It is made from bauxite, pyrite, anthracite and iron filings and is smelted in electric arc furnace. In the smelting process, the impurities in the bauxite are reduced by the carbon of the anthracite to the metal and the iron alloy is deposited on the bottom of the furnace. A part of the impurities react with the sulfur in the pyrite to generate hydrogen sulfide gas. A part of the aluminum in the bauxite is mixed with the vulcanized synthetic aluminum sulfide between the physical corundum. Since aluminum sulfide is soluble in water, it can be obtained by hydrolyzing the cooled crystal frit, and most of the abrasive grains of various sizes composed of a single corundum crystal have an alumina content of 98% or more and a equal-size particle. It is a uniform shape, and is a complete crystal. It has a good multi-angled polygonal cutting edge and has high hardness and toughness. Therefore, the abrasive is not easily broken during grinding, and has strong cutting ability and long service life. Single crystal corundum abrasives are suitable for processing hard or difficult to grind metal materials such as sorghum high speed steel, heat resistant alloy steel, cobalt or nickel based alloy steel, stainless steel, and the like. In particular, high vanadium steel containing 2 to 3% of vanadium has poor grindability and is difficult to grind with ordinary abrasives, while single crystal corundum can be applied. In addition, this abrasive can achieve good grinding results when grinding hardened steel, tool steel and other alloy steels.

Single crystal corundum abrasives have basically stopped production

Although the single crystal corundum abrasive has excellent grinding performance, the abrasive has been intensively produced in the country due to the occurrence of H2S and SO2 gas and waste water in the manufacturing process, which seriously pollutes the environment. The former No. 4 grinding wheel factory is the main production plant of single crystal corundum abrasive. The factory is located in Zibo City, Shandong Province, it has stopped production in the 1990s based on environmental protection issues. Then the main production plant of single crystal corundum abrasives It was transferred to Xixia County, Henan Province, which is relatively remote. The main production plant Xixia County Zhenghong Single Crystal Corundum Factory also stopped production after 2004. So far, the domestic single crystal corundum abrasive has basically stopped production. In the world, with the increasing emphasis on environmental protection, such abrasives have basically stopped production in the late 1990s.

In recent years, some single crystal corundum abrasives supplied by some production plants should not be called single crystal corundum abrasives.

Since the production of single crystal corundum abrasives has been stopped, domestic abrasive manufacturers have developed a new type of corundum abrasive (known as foreign MA88), which can replace single crystal corundum abrasive in some properties. The corundum abrasives have also been mass-produced in China and are supplied to the needs of abrasive manufacturing plants. However, in China, the manufacturer of such corundum abrasives is still called single crystal corundum abrasive when it is supplied to the abrasive manufacturing factory. The author believes that this kind of abrasive cannot be said to be single crystal corundum abrasive for two reasons: First, the single crystal corundum abrasive is made of bauxite and sulfide as the main raw materials. It is smelted by electric arc furnace. The particles are made by hydrolysis. Most of them are monocrystalline crystals with equal content of Al2O3, and the content of Al2O3 is not less than 98%. There is no official authoritative manufacturing data or identification data available for viewing in corundum abrasives. According to the author, aluminum oxide powder is used as the main raw material and is melted by electric arc furnace. The particles are obtained by mechanical crushing method, from the manufacturing process. The difference can be seen that the new corundum abrasive can not be said to be the previous single crystal corundum abrasive; the second is in the use of abrasive properties, it is understood that the new corundum abrasive can not completely replace the original single crystal corundum abrasive.

Recommendations

1) Although the single crystal corundum abrasive has been discontinued, the national standards and industry standards for single crystal corundum abrasives have not been abolished. The terminology of single crystal corundum abrasives has been removed in the Japanese terminology standard of JIS R6004:1998. It is hoped that the National Abrasives Standardization Technical Committee will review the standard organization of single crystal corundum abrasives in accordance with the guidelines and policies of the national standardization, and abolish them as soon as possible.

2) For the variety of corundum abrasives developed in recent years, it is hoped that the Abrasives Association and the Abrasives Standardization Technical Committee will organize product identification work and standardization work as soon as possible to enable this corundum abrasive to be standardized and promote the production of the abrasive industry and the development of technology