Effects Of Processing Parameters On Microstructure,Properties And Texture Of S08Al Cold-rolled Deep Drawing Steel

The production procedures of S08A1cold-rolled deep drawing steel are very complex including smelting, hot rolling, acid washing, cold rolling, annealing and temper rolling etc.. Quality of processing system in each procedure affects the quality of final product. Through optimizing chemical composition, advancing hot-rolling and cold-rolling processes, the Tangshan jianlong industry Co. Ltd. has obtained elementary success. However, the market and downstream client put forward the higher requirement on the cold-rolled products with increasing competition in market, the incessant extension of product purpose and continuous increase in cost of manufacture.In this paper, through optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermomechanical simulation, the hot deformation behavior under different condition of S08A1cold-rolled deep drawing steel produced by Tangshan jianlong industry Co Ltd., as well as the effects of coiling temperature and annealing temperature on microstructure, properties and texture,were investigated. The obtained major conclusions are as follows:1. The hot deformation behavior of the experimental steel at700～1050℃and with strain rates of0.01～10s-1was studied through single-pass compression experiment. The experimental results showed that:(1) The activation energy of hot deformation of the experimental steel in austenite range is273kJ/mol, and the hot deformation equation can be depicted as:(2) The dynamic softening activation energy of the experimental steel in ferrite range is282kJ/mol, and the hot deformation equation can be depicted as: 2. In the range of coiling temperatures designed in this study, the volume fraction of {111}<UVW> texture component is the highest and the ratio of{111}<UVW>/{001}<110> is the largest for annealed cold-rolled experimental steel sheets when coiling temperature was592℃through integrating the mechanical properties of hot rolled plate and annealled plate. Therefore, the experimental steel can obtain the excellent deep drawability when coiled at592℃.3. Microstructure and mechanical properties are the best, the volume fraction of {111}<UVW> texture component is the highest and the ratio of{111}<UVW>/{001}<110> is the largest when the experimental steels of cold rolling ratio73.3%and90%are annealled at690℃. Therefore the experimental steel annealed at690℃can obtain the optimum deep drawing property.4. The large grains, semi-network and network cementites which harms the deep drawability appeared in the microstructure of steels when the experimental steels were annealed at700℃. Therefore, the annealing temperature should be controlled to be lower than700℃.