高强高韧低合金马氏体钢的静态软化行为

摘要

With the new developed high-strength and high-toughness 20SiMn3NiA low-alloy martensite steel as a research object, the double-pass compression tests were conducted on the steel by a thermal simulator at 900-1 000 ℃ and strain rate of 1.0 s-1 for pass intervals between 1 s and 100 s.And the static softening behavior of the steel was studied.The results show that at the deformation temperature of 900 ℃, with the pass interval prolonging, the true stress-true strain curves during second pass deformation of the tested steel exhibited a change from dynamic recrystallization character (namely greater trend of softening than hardening) to static recrystallization character (namely greater trend of hardening than softening).The static recrystallization fraction increased from 6.48% with pass interval of 1 s to a nearly stable value of 85%.At the deformation temperature of 1 000 ℃, the true stress-true strain curves during second pass deformation had a static recrystallization character.The static recrystallization fraction increased from 84.48% with pass interval of 1 s to 96% with pass interval of 100 s.The static active energy of the tested steel was 448 kJ·mol-1.%以新开发的高强高韧20SiMn3NiA低合金马氏体钢为研究对象,用热模拟试验机对其在900~1 000 ℃进行了双道次压缩,应变速率为1.0 s-1,道次间隔时间为1~100 s,研究了其静态软化行为.结果表明:当变形温度为900 ℃时,随着道次间隔时间的延长,试验钢在第二道次变形时的真应力-真应变曲线由动态再结晶型(软化趋势大于硬化趋势)变为静态再结晶型(硬化趋势大于软化趋势),静态再结晶率由道次间隔时间为1 s时的6.48%增至稳定值85%;当变形温度为1 000 ℃时,其第二道次变形时的真应力-真应变曲线均为静态再结晶型,静态再结晶率由道次间隔时间为1 s时的84.48%增至100 s时的96%;试验钢的静态再结晶激活能为448 kJ·mol-1.