Investigation of Flow Stress and Microstructure Evolution of 403Nb Under Hot Compression

In order to establish and improve the hot strip rolling quantitative process modeling of 403Nb, the flow stress and microstructure evolution of this alloy under hot compression were investigated. The hot compression was carried out on the thermo-force simulation system Gleeble 3500, the temperature range was 850∼1150°C and strain rate was 0.01∼1OS−1. The results show that at the same strain rate, the compression temperature higher, DRX happens easer and at the same temperature, the strain rate smaller, DRX happens easer. At 1150°C, the steel happened DRX whatever the strain rate was. A kind of very thin twins was formed in DRX and dynamic recovery microstructures. The width of these thin twins was about 10∼30nm. The Zener-Hollomon parameters and flow stress formula of 403Nb under hot compression are described as follows: Z= exp(68696.8968/T)=9.8647×1010exp(0.06853σp), σp=14.59261n+1002406.111-T−1−604.613658. The hot deformation activation energy of 403Nb is 571.146KJ/mol○