38MnVS4微合金非调质钢涨断连杆控锻控冷工艺

Controlled forging and cooling process of expansion broken connecting rod for 38MnVS4 microalloy non-quenched and tempered steel

采用4种不同的控锻控冷工艺,利用热模锻压力机对38MnVS4微合金非调质钢涨断连杆进行锻造成形。当感应加热温度为1250~1280℃时,辊锻后采用空冷和吹风两种方式进行冷却;当感应加热温度为1200~1230℃和1170~1200℃时,辊锻后采用空冷进行冷却。研究不同控锻控冷工艺对38MnVS4微合金非调质钢涨断连杆的晶粒度和力学性能的影响。结果表明:38MnVS4微合金非调质钢涨断连杆经辊锻后进行吹风冷却,其杆部晶粒度由辊锻后空冷的10级提高至11级,同时,其屈服强度提升了25~30 MPa,抗拉强度提升了20~60 MPa;连杆锻造时的感应加热温度从1250~1280℃降低至1170~1200小时,虽然可以细化杆部晶粒度,但其抗拉强度会下降;采用相同锻造工艺获得的连杆,其杆部晶粒度比大头部位的晶粒度小2~3级。

The expansion broken connecting rod of 38 MnVS4 microalloy non-quenched and tempered steel was forged by the hot die forging press with four different controlled forging and cooling processes,and the influences of different controlled forging and cooling processes on its grain sizes and mechanical properties were studied under the induction heating temperature of 1250-1280℃and air cooling and blast cooling after roll forging,as well as induction heating temperature of 1200-1230℃and 1170-1200℃and air cooling after roll forging.The results show that comparied with the air cooling after roll forging,when the expansion broken connecting rod of 38 MnVS4 microalloy non-quenched and tempered steel is cooled by air after roll forging,the grain size of rod is increased from 10 to 11 grade.At the same time,the yield strength is increased by 25-30 MPa,and the tensile strength is increased by 20-60 MPa.Furthermore,the induction heating temperature of connecting rod during forging decreases from 1250-1280℃to 1170-1200℃,although the grain of connecting rod is refined,but its tensile strength decreases.And for the connecting rod produced by the same forging process,the grain size of rod part is 2-3 grade smaller than that of large end part.