热处理工艺一般分为退火、正火、淬火和回火。它们是将金属加热到不同温度并保温一定的时间,然后以不同的冷却速度冷却下来。其过程可用热处理工艺曲线表示,如图1所示。一、退火。退火一般是将工件加热到A3温度(对于含碳量小于0.8%的亚共析钢)或A1温度(对于含碳量在0.8%～2%的 Heat treatment process is generally divided into annealing, normalizing, quenching and tempering. They heat the metal to different temperatures and hold it for a certain amount of time and then cool it at different cooling rates. The process can be heat treatment process curve, as shown in Figure 1. First, annealing. Annealing is generally the workpiece is heated to A3 temperature (less than 0.8% for carbon hypo-eutectoid steel) or A1 temperature (for carbon content of 0.8% to 2% of