How to treat steel when quenching it after forging
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After the steel is forged and formed, it is heated to 1200 degrees and then quenched. After quenching, it is found that there are many defects on the surface. Is this caused by improper quenching operation and how to avoid it?
Yes, the quenching of steel is a heat treatment process in which the steel is heated to a temperature above the critical temperature Ac3 (hypoeutectoid steel) or Ac1 (hypereutectoid steel), kept for a period of time to make it fully or partially austenitized, and then rapidly cooled to below Ms (or isothermally near Ms) at a cooling rate greater than the critical cooling rate to undergo martensite (or bainite) transformation. The purpose of quenching is to transform the supercooled austenite into martensite or bainite to obtain a martensite or bainite structure, which is then combined with tempering at different temperatures to greatly improve the strength, hardness, wear resistance, fatigue strength and toughness of the steel, thereby meeting the different use requirements of various mechanical parts and tools. Quenching can also be used to meet the special physical and chemical properties of certain special steels such as ferromagnetism and corrosion resistance. Quenching is more suitable for parts with smaller thickness and diameter. For parts that are too large, the quenching depth is not enough, and carburizing also has the same problem. At this time, you should consider adding alloys such as chromium to the steel to increase the strength. It may be caused by the fact that you did not keep the parts warm after heating them and cooled them directly. Moreover, it is best to carry out tempering treatment after quenching to eliminate surface residual stress. This post was last edited by yutr on 2009-3-29 11:13 ]