According to the traditional theory, there are two conditions for coating shelling: one is that the inner coating does not adhere to sand (chemical bonded sand, thermochemical bonded sand, mechanical bonded sand permeability bonded sand), the other is that the whole coating can be sintered into a hard disk.
Professor Liu Yuman put forward a new coating Theory — porcelain coating at high temperature, which is the innovation and development of coating sintering theory.
According to the traditional theory, FeO on the surface of molten steel infiltrates into the coating layer excessively, which reduces and improves the sintering degree of the coating layer and forms the “Guoba layer”. For the reduced aggregate coating, the surface of molten iron is not easy to produce excessive FeO, so it can not be sintered into a “pot layer” or peeled off. Professor Liu’s research and invention is that the addition of additives can make the coating ceramic rapidly above 1000 ℃, so as to form a hard chip that can be shelled. This additive is the Guilin No.5 replacement product produced by Zhongnan casting and Metallurgy Co., Ltd. since August 2013.
The new generation of Guilin No. 5 steel casting can be produced, even if the aggregate powder is 100% quartz powder, it can also be ideal shelling. The use of “modified quartz powder” is obviously more beautiful, and it is not clear that it is self shelling.
According to the traditional theory, no matter quartz powder or graphite powder with the strongest anti sticking ability is used as aggregate, it is very difficult to flake and shelling, because graphite powder is not sintered at high temperature. When a new generation of Guilin No. 5 is used with graphite powder, a little quartz powder can be added to realize high-temperature ceramic self shelling, or graphite powder for inner aggregate and quartz powder for outer layer, then composite ceramic chips are formed inside and outside at high temperature, which is very easy to shelling, which is the secret of coating layer ceramic self shelling.
Whether it is an ideal sintering layer or a high-temperature ceramic layer, it is necessary to have the same prerequisite – no sand sticking in the inner layer of coating, so the scientific selection of additives and aggregate powder in the inner layer cannot be ignored.