| Title |
Analysis of Hot Rolling Characteristics of Austenitic Stainless Steels ( Part 2 ) : Deformation and Temperature Distribution in Workpiece Surface Layer |
| Authors |
김영환(Young Hwan Kim) ; 손성강(Cheng Gang Sun) ; 황상무(Sang Moo Hwang) ; 심상대(Sang Dae Shim) ; 이용득(Yong Deuk Lee) |
| Abstract |
The roll bite deformation and heat transfer during hot rolling of commercial austenitic stainless steels were investigated by means of finite element simulation of hot rolling process. Particular attention was focused on the thermo-mechanical factors which are responsible for the formation of surface crack during hot rolling. It was found that a severe concentration of tensile stress and a large temperature drop developed on the workpiece surface at the roll exit region, particulary under rough rolling conditions. The high surface tensile stress at roll exit was caused by the constrained plastic deformation in surface layer at roll exit due to the surface chilling effect and the friction between roll and workpiece. The formation of surface crack could be attributed to the surface tensile stress and the loss of ductility of surface layer due to the temperature drop at roll exit region. The stainless steals containing high nitrogen, which exhibited a higher temperature dependency of flow stress, were more susceptible to surface crack formation during hot rolling. Higher possibility of surface cracking was also predicted in a slower roll speed and,%or in sticking friction condition. |