4340H钢高速转子锻件的热处理

Heat Treatment of 4340H Steel High Speed Rotor Forging

高速转子服役条件苛刻,要求具有很高的力学性能。起初,4340H钢高速转子锻件的热处理工艺为870℃正火、850℃水淬、450℃回火空冷,但锻件易淬火开裂,冲击韧度也达不到要求。为此,改进了热处理工艺:将正火改为870℃退火,随后850℃加热PAG水溶液-空气交替冷却淬火,回火后在PAG水溶液冷却10min空冷。结果,转子锻件淬火不再开裂,力学性能也达到了要求。

High-speed rotor is used in a hard environment, therefore, needs to have excellent mechanical properties. Initially, 4340H steel high-speed rotor forgings were normalized at 870℃, then quenched from 850 ℃in water , and tempered at 450 ℃ and cooled in air. The forging , however , was frequently cracked during the quenching , and exhibited insufficient impact toughness. For this reason , the heat treating processes were modified as follows: the normalizing was changed into annealing at 870℃;the alternative quenching in PAG aqueous solution and in air instead of in water was used;and direct cooling in air was replaced by cooling in PAG aqueous solution for 10 min then in air after tempering. In so doing , the 4340H steel high-speed rotor forgings cracked no longer during quenching , and also showed desirable mechanical properties.