回火对感应淬火10CrNi3MoV球扁钢组织和性能的影响

Effects of tempering on microstructure and mechanical properties of induction hardened 10CrNi3MoV bulb flat steel

利用SEM、TEM等检测方法研究了回火工艺参数对感应加热淬火10Cr Ni3Mo V球扁钢组织和性能的影响。结果表明,感应淬火后,10Cr Ni3Mo V球扁钢淬火组织为细小的板条马氏体和少量贝氏体。随着回火温度的升高,10Cr Ni3Mo V钢球头与腹板处的强度与硬度单调下降,塑韧性得到改善;板条界面逐渐消失,晶界处析出的渗碳体长大和球化趋势越来越明显。随着回火时间延长,10Cr Ni3Mo V钢球头与腹板处的强度与硬度略有下降,塑韧性明显改善;碳化物的析出量减少,原有的粒状碳化物有聚集长大趋势。本试验钢获得良好强韧性匹配的最佳回火工艺为:回火温度630~650℃,回火时间3~3.5 h。

Influences of tempering parameters on microstructure and properties of 10CrNi3MoV bulb flat steel were studied by TEM , SEM and mechanical property tests .The results show that the microstructure of 10CrNi3MoV steel after induction hardening is composed of martensite and a little bainite .With the increase of tempering temperature , the strength and hardness of 10CrNi3MoV steel decrease , while the plasticity and toughness increase .And the laths boundary of tempering martensite disappear and the cementite tends to grow and sphericize.With the increase of tempering time , the strength and hardness of 10CrNi3MoV steel decrease slightly , while the plasticity and toughness improve obviously .The amount of precipitated cementite decreases and the size of cementite tends to coarsen .For this steel, the best tempering process to get good match of strength and toughness is tempering at 630-650 ℃for 3-3.5 h.