Study Of Hot Rolling Technology In α-Region For IF Steel

Nowadays the development of automobile industry needs to improve the Plastic strain ratio r-value of IF steel, in order to achieve this aim, the technology ofα-region hot rolling was designed, and by the measurement of Plastic strain ratio r-value, tensile strain hardening exponents n-value and the analysis of microstructure and micro texture, the drawability of a Ti+Nb-IF steel which was lubricious hot rolled in ferrite region and produced in Baoshan Iron & Steel Co. was investigated in this paper. In addition, the resistance of IF steel was discussed. The main work and results are as following:1. The relationship between resistance of IF steel and rolling parameters was got by means of regression, and three kinds of curves such asσ? t ,σ?ε,σ?ε? was also given, in which the relation between resistance of IF steel and rolling parameters could be seen.2. The experiment of resistance was done on the Gleeble machine.3. In (α+γ) region, owing to the composition of IF steel, the attraction between atoms is the main factor in the change of resistance. The resistance of IF steel decreases with the declining of rolling temperature, therefore, the resistance at 800℃is almost the same with that at 1000℃.4. The relationship between resistance of IF steel and rolling parameters was got by means of regression, and three kinds of curves such asσ? t ,σ?ε,σ?ε? was also given, in which the relation between resistance of IF steel and rolling parameters could be seen.5. In (α+γ) region, owing to the composition of IF steel, the attraction between atoms is the main factor in the change of resistance. The resistance of IF steel decreases with the declining of rolling temperature, therefore, the resistance at 800℃is almost the same with that at 1000℃.6. With the help of r-value, ODF and the microstructure, the formation mechanism of {111}//ND recrystallization texture was analyzed.7. Author got the following ideas in reference to some relevant researches: In-grain shear bands fragmented ND fiber grains, this general fragmentation leads to the nucleation of ND fiber grains at sites situated both within the grain interior and at the grain boundary. As a result, the amount of ND fiber grains increased and {111}//ND recrystallization texture is intensified after annealing.8. Analyzed the change of texture in the direction of sample's thickness which influenced by friction and got a conclusion that cold rolled with favorable lubrication can improve the draw ability of IF steel.