摘要
利用维氏硬度计、OM、TEM对在600℃回火不同时间后的钛、钒微合金化马氏体钢的维氏硬度、微观组织及钢中析出相随回火时间的演变进行了研究,并采用现有计算方法对马氏体钢中析出相的析出动力学进行了计算。结果表明:两钢在600℃回火,随回火时间的增加,其硬度变化均呈现先下降后升高再下降的规律,且在回火1 h后,两钢出现峰值硬度,且回火过程中钛钢的硬度均大于钒钢。分析认为,前期硬度下降是由于位错密度的降低所致,而当MC相析出时起到沉淀强化作用,引起硬度上升并出现峰值,而回火时间更长时,由于MC相粗化及基体回复导致硬度再次下降。钛钢中由于析出相粒子析出动力学比钒钢的快,而其粗化速率却低于钒钢中析出相,因此钛钢在回火过程中沉淀强化效果及对基体回复抑制的作用更为明显,故而其回火时比钒钢的硬度高。
The evolutions of Vickers hardness,microstructure and precipitates in Ti and V microalloyed martensite steels with different tempering time at 600 ℃ were studied by Vickers,OM and TEM. Moreover,the precipitation kinetics of precipitates in martensite steels was calculated using the existing methods. The results showed that hardness of two steels firstly decreased,then increased and finally decreased with the prolonging of tempering time at 600 ℃. The peak hardness of both steel was observed after tempering for 1 h. Besides,the hardness of Ti-steel was always higher than that of Vsteel in tempering process. It was found that the decrease of hardness at the beginning stage was due to the decrease of dislocation density. The precipitation of MC phase played the role of precipitation strengthening effect,leading to the increase of hardness to the peak value. With the prolonging of tempering time,the hardness decreased again due to the coarsening of MC phase and the recovery of matrix microstructure. Since the precipitation kinetics of Ti-steel was faster than that of V-steel and its coarsening rate was slower,the effect of precipitation strengthening and the restraint of matrix recovery in Ti-steel were more obvious than those in V-steel. As a result,the hardness of Ti-steel was always higher than that of V-steel in tempering process.
出处
《钢铁》
CAS
CSCD
北大核心
2015年第10期64-70,共7页
Iron and Steel
基金
国家自然科学基金资助项目(51201036)
关键词
TIC
VC
微合金钢
沉淀强化
析出
粗化
TiC
VC
microalloyed steel
precipitation strengthening
precipitation
coarsening
