铝镇静钢连续退火相变行为与抗应变时效性能

Phase transformation behavior and strain aging resistance of Al-killed steel during continuous annealing

针对冷轧态低碳铝镇静钢,基于连续升温过程中的物相转变行为解析,开展连续退火过程中两相区保温时间对其物相组织及抗应变时效性能的试验研究。结果表明,试验用低碳铝镇静钢在890℃高温保温5 s时,铁素体基体中仍残留有少量珠光体,渗碳体及氮化物析出不明显;延长保温时间至60 s后,铁素体晶粒粗化、珠光体基本消失,碳化物在晶内大量析出,同时析出部分纳米级AlN和Ti(C,N)颗粒。另外,随着保温时间从5 s延长至60 s,平均时效指数由64.1 MPa大幅降至31.5 MPa。本研究可为低碳铝镇静钢连续退火工艺优化提供参考。

For a cold-rolled low-carbon Al-killed steel,based on the phase transition behavior analysis during continuous heating,the experimental study on the effect of holding time in the two-phasfe region on the phase structure and strain aging resistance during continuous annealing was carried out.The results show that a small amount of pearlite remains in the ferrite matrix,and the precipitation of cementite and nitride is not obvious when the low-carbon Al-killed steel is kept at 890 ℃ for 5 s.After prolonging the holding time to 60 s,the ferrite grains coarsens,pearlite basically disappears,a large amount of inter-grain carbides precipitate in the crystal,and some nano-scale AlN and Ti(C,N) particles are precipitated.In addition,the average aging index strikingly decreases from 64.1 MPa to 31.5 MPa with the increase of holding time from 5 s to 60 s.This study can provide a reference for the optimization of low-carbon Al-killed steel continuous annealing process.