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This post was last edited by hesonchang214 on 2020-3-21 at 18:00. Oxidative loss during the rolling and heating process of billets is difficult to avoid; for ordinary steel, manufacturers do not mind an oxidative loss rate of 1% to 3%. However, for certain low-alloy steels, oxidative burnout is not only a problem that reduces the yield rate, but it also has an adverse effect on the surface quality and mechanical properties of the rolled sheets (coils). Low-alloy steel typically contains less than 5% (by mass) of alloying elements. During the heating process of rolling the steel billet, selective oxidation of certain alloying elements leads to a depletion of these elements on the surface of the steel, thereby deteriorating its mechanical properties. Furthermore, in some low-alloy steels containing elements such as Ni, Mo, Mn, Si, V, Ti, etc., the oxide layer formed during heating adheres very firmly to the steel billet. Experts from Zhiseng Weihua on anti-oxidation coatings point out that even after treatment with high-pressure water and descaling devices, this oxide layer cannot be removed. The pressing in of iron oxide scale often causes pitting and deep pits on the surface of the rolled sheets, requiring grinding and repair; in severe cases, it can result in the scrapped sheets. Some manufacturers have also taken various measures to reduce oxidation-induced losses, such as controlling the atmosphere inside the heating furnace, increasing the pressure of high-pressure water, and covering the steel billets with iron sheets, but the results have not been satisfactory. Using anti-oxidation coatings to prevent oxidation and burnout of steel during heating is a good method. However, these coatings require stringent application conditions; the surface of the workpiece often needs to be sandblasted and cleaned with solvents, and they are used at temperatures ranging from 900 to 1100°C. Additionally, the heating temperature during steel billet rolling is much higher than that used in metal treatment, with some billets being heated to temperatures as high as 1300–1400°C. Therefore, traditional anti-oxidation coatings used for metal heat treatment are not suitable for the heating process of certain types of steel. The ZS-1021 high-temperature resistant sealing coating, developed and produced by Beijing Zhisheng Weihua Chemical Co., Ltd. along with research institutions from various universities, can fully meet the aforementioned requirements for preventing oxidation of steel at high temperatures. This high-temperature resistant sealing coating uses a special high-temperature solution developed by Beijing ZhiSheng WeiHua; it can withstand temperatures of up to 1800°C and resist fire exposure for extended periods. The material features a nanoceramic structure in the form of fish-scale-like particles, which, at high temperatures, form a sintered network in a glassy state, resulting in excellent density. It prevents oxidation and decarburization on the metal surface by blocking contact between gases and steel. Its hardness ranges from 7 to 8H, giving it good impact resistance. The ZS-1021 high-temperature resistant sealing coating is acid and alkali resistant; it does not emit any volatile substances at either high or normal temperatures. It is an inorganic, water-based, environmentally friendly coating that does not react with quenching media. It can effectively protect metals from chemical reactions at high temperatures, and helps to prevent the oxidation of steel metals from reaching levels above 95%. The ZS-1021 high-temperature resistant, sealed antioxidant coating provides an excellent anti-oxidation effect; it can reduce the oxidation scale generated by ordinary hot-rolled steel plates from 5% to around 0.5%, and reduce the oxidation scale produced by stainless steel hot-rolled plates from 3% to below 0.2%. Multiple experiments have shown that the high-temperature resistant sealing coating ZS-1021 can serve as a protective layer for the anti-oxidation coatings used in billet heating. A liquid oxide layer composed mainly of ferroolivine, along with a coating made primarily of magnesium oxide, are formed on the surface; through diffusion and penetration at high temperatures, these layers create a dense protective barrier that effectively reduces the oxidation and thermal damage to the billets. Through physical and chemical reactions between the coating components, sintering phases are formed at different temperatures, providing oxidation protection at both low and high temperatures.