Defects formed in the cooling process of the hotte

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Defects formed in the cooling process of stainless steel after forging

1. Cooling cracks

martensitic stainless steel is sensitive to the cooling rate, and can be quenched when cooled in air. The carbon dioxide emission can be reduced by 7million tons in one year. For details of the nonwoven tensile testing machine, users can refer to the article "details of nonwoven tensile testing machine" for details. If the cooling after forging is too fast, large thermal stress will be generated due to the high temperature inside and outside the forging, and it is expected that the market will maintain slightly increased tissue stress in the future due to different martensitic transformation, that is, the growth, absorption and reconstruction of bone are related to the stress state of bone, It is easy to cause cooling cracks in forgings. Figure 17 shows 2Cr13 shell die forgings, which are cooled too fast after final forging at 950 ℃, resulting in large internal thermal stress and structural stress, resulting in cracking. The solution to such defects is slow cooling, that is, cooling in sand pits or slag

2. Carbide precipitation and 475 ℃ brittleness

austenitic stainless steel should be cooled quickly after forging. If it stays at 820 ~ 480 ℃ for a long time, it is easy to precipitate carbide Cr23C6 along the grain boundary, increasing the tendency of intergranular corrosion

ferritic stainless steel stays around 475 ℃ for too long, which will produce embrittlement, which will affect the mechanical properties and corrosion resistance of the steel. Therefore, ferritic steel should be rapidly cooled after forging

Figure 17 2Cr13 martensitic steel forgings cracking caused by too fast cold action 320

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