The use of corten steel plates is very difficult. Cracks in corten plates can shorten the life of the wear plate and lead to industrial equipment safety incidents and claims. Therefore, cracks in corten steel plates are generally not allowed, and cracks in corten steel plates will immediately cause reports. It is very necessary to prevent the corten steel plate from cooling and cracking. Effective preventive measures to avoid cooling and cracking of corten steel plates:
1. Improvement of refrigeration form
Cooling and cooling methods are different, the size, type and distribution of internal forces are different, the structure of hardened steel is different, the crack resistance is different. Finally, the cooling trend is markedly different. In the whole cooling process, in order to avoid the low resistance ferrite core system, on the one hand, it must be cooled quickly to avoid the isothermal diagram of the "nose"; Martensitic stainless steel, on the other hand, is expected to enter the martensite and then gradually refrigerate to obtain a highly wear-resistant martensite. Social practice has shown that in all processes from heating and cooling temperature to martensitic transformation, the structure of steel is still martensitic stainless steel, which itself has the characteristics of high plastic deformation and low tensile properties. Compressive strength, because there is no structural change, only welding stress. In this link, wear-resistant stainless steel plate is generally not easy to crack. The core of the crack is located in the martensitic phase transition region. In order to avoid heat treatment crack, martensite heat treatment, fractional quenching and binary heat treatment should be used. It is found that the martensite with low carbon concentration can be obtained when the weathering steel is cooled slowly in the martensitic phase transition zone, thus reducing the rectangularity of the martensite and the structural stress, and improving the cracking resistance. This is mainly due to the martensite superheat protection that occurs during slow cooling below the Ms point. The lower the cooling rate, the higher the self-filling level and the lower the carbon content in martensite.
2. Turn off immediately after cooling
When the corten steel plate is turned off, the temperature of the cooling heat treatment material is generally higher than the internal temperature, and when the corten steel plate is cooled to the raw material temperature, there is still a part of the martensitic stainless steel plate that does not change into martensite. Once the corten steel plate is removed from the raw material, it will change from martensitic stainless steel to martensite again during the overall paving process at room temperature. In fact, it is the second time of the entire cooling process. It belongs to a relatively wear-resistant casting system. The ground stress continues to increase and may crack. Therefore, heat treatment immediately after heat treatment can reduce the internal stress of heat treatment and prevent cracking of wear-resistant castings.
