双道次热压缩条件下403Nb钢再结晶与组织演变

为给403Nb马氏体热强钢热连轧组织性能预报积累数据,用Gleeble-3500热模拟试验机对403Nb进行了双道次热压缩试验.热压缩试验进行的温度为950～1150℃,应变速率为0.01～10 s-1,道次间隔时间(ISDT)为1～300 s.研究了变形参数,如温度,应变速率和道次间隔时间对静态再结晶和组织的影响,结果表明:第一道次的峰值应力随应变速率的增加而增加,但第二道次的峰值应力随着变形温度的降低和道次间隔时间的缩短而增加;当变形温度一定时,应变速率的增加可以提高静态再结晶率;静态再结晶率随着道次间隔时间的增加先增后降.403Nb在道次间隔时间为100 s时,静态再结晶率最高.

Recrystallization and microstructure evolution of 403Nb steel under double-hit hot compression

In order to provide basic data for prediction of microstructure and properties of tandem rolled 403Nb martensitic heat-resistant steel, double-hit hot compressions were carried out using a Gleeble-3500 thermo-mechanical simulator. The hot compressions were performed at 950-1150 ℃ with the strain rates of 0.01-10 s-1 and the inter-stage delay time (ISDT) of 1-300 s. The effects of compression parameters, such as temperature, strain rate and ISDT, on the static recrystallization rate and microstructure of the steel were investigated. Results show that the peak stress of the first hit increases with increasing the strain rate, however, that of the second hit increases with decreasing deformation temperature and shortening ISDT. Under a given compression temperature, increasing strain rate increases the static recrystallization rate. The static recrystallization rate increases at first part and decreases subsequently with increasing ISDT. For 403Nb steel, the peak ISDT is 100 s.