Natural mineral-based high-temperature anti-oxidation decarbonization coating

Abstract

The invention discloses a natural mineral-based high-temperature anti-oxidation decarbonization coating. According to coating dry powder, the coating comprises the following components in percentage by weight: 15 to 35 percent of Al2O3, 35 to 55 percent of SiO2, 2 to 12 percent of Fe2O3, 2 to 10 percent of MgO, 3 to 10 percent of C, 5 to 20 percent of Na2O, 0 to 5 percent of CaO, 0 to 5 percent of K2O, and water which enables the density of the final coating slurry to be 1,100 to 1,500kg / m<3>. After the raw materials are weighed according to proportions, the water is added into the raw materials, the mixture is ground by a ball mill, the mixture is sieved by a 200-mesh sieve, and a binding agent, i.e. sodium water glass, and water are added into the mixture until the final density of slurry is adjusted to 1,100 to 1,500kg / m<3>. The coating can be directly coated onto the surface of a steel material to form a protecting layer, the oxidation burning loss of the steel material in a heating process can be obviously reduced, the surface quality of the steel material is improved, the cost is low, and the preparation process is simple.

Description

technical field [0001] The invention belongs to the technical field of high-temperature anti-oxidation and decarburization coatings, and in particular relates to a high-temperature anti-oxidation and decarburization coating based on natural minerals. Background technique [0002] The hazards of oxidation and decarburization in the heat treatment process of steel are very serious. Usually, the burning loss rate caused by oxidation during the heating process of steel is as high as 0.5~2.5%. This oxidation burning loss not only reduces the yield, but also affects the surface quality of steel. Among the existing methods of preventing high-temperature oxidation and decarburization of steel, the most convenient and economical method is to apply an anti-oxidation and decarburization coating on the surface of the steel to form a protective layer to prevent the oxidation / decarburization of the steel surface during heating, and in the subsequent cooling process In the process, the pro...

AI Technical Summary

Problems solved by technology

Although these coatings have good protective effects, they are expensive and not widely used. The anti-oxidation coatings for steel slabs announced by Chinese patent CN101760599 effectively reduce the oxidation and burning of steel plates and improve the surface quality of steel plates.

However, due to the volume instability of magnesium and chromium in the coating, it is easy to cause cracking of the coating during use, which affects the integrity of the coating and reduces the anti-oxidation effect.

Chinese patent CN1036396 uses ordinary magnesia, clay silicate frit, industrial chromium trioxide and sodium tripolyphosphate as the main raw materials for anti-oxidation coatings, which have achieved good anti-oxidation and burning effect on silicon steel plates. However, the disadvantage is that the clay silicate frit needs to be fired in advance, and contains high-priced zirconia components, resulting in complicated process and high cost.

Although the anti-oxidation and decarburization coatings of patents CN101426938 and 200610076257.0 all use minerals as the main raw materials, they respectively added a large amount of high-cost raw materials such as chromium trioxide and zirconia, which increased their cost.