38MnVTi非调质钢的TTT曲线的测定与分析

Determination and analysis of TTT curve of 38MnVTi non-quenchedand tempered steel

研究了38MnVTi非调质钢在等温冷却过程中的奥氏体转变产物及转变量与时间的关系。通过Gleeble-1 500D热模拟试验机获得不同等温温度的膨胀曲线。采用膨胀法,通过Gleeble-1 500D热模拟试验机获得不同等温温度的膨胀曲线,再计算和运用Origin软件拟合得到38MnVTi非调质钢的等温转变曲线(TTT曲线)。结果表明:38MnVTi非调质钢渗碳体的析出温度为750℃、铁素体析出温度为840℃、马氏体析出温度为360℃以及马氏体转变终止温度为212℃。在540、510、480、430℃等温冷却条件下贝氏体的最大转变量分别为16.9%、26.8%、38.5%、55.3%。

This paper studies austenite transformation products of 38MnVTi non-quenched and tempered steel during isothermal cooling and the relations between transformation amount and time.The expansion curves of different isothermal temperatures are obtained by Gleeble-1500D thermal simulation tester.The expansion curves at different isothermal temperatures are acquired by expansion method on Gleeble-1500D thermal simulation testing machine.The isothermal transformation curve(TTT curve)of 38MnVTi non-quenched and tempered steel is calculated and fitted by Origin software.Our results show the precipitation temperature of cementite is 750℃,the ferrite precipitation temperature 840℃,the martensite precipitation temperature 360℃and the martensite transformation termination temperature 212℃.Under the isothermal cooling conditions of 540,510,480 and 430℃,the maximum transformation amounts of bainite are 16.9%,26.8%,38.5%and 55.3%,respectively.