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A comparison was made for the deformation, microstructure, mechanical properties and formability of SUS436L stainless steel in tandem and reversible cold rolling processes. At first, the thermophysical parameters and stress–strain curves of SUS436L steel were measured in temperature range of 293–573 K and a flow stress model was regressed from the data of these curves. An analytical model based on the elasto-plastic finite element method was then established to simulate the tandem and the reversible cold rolling processes of SUS436L stainless steel strip where the flow stress model was introduced. The difference in shear strain distribution, microstructure, mechanical properties and formability of SUS436L steel strip in the two rolling processes was analyzed. The results showed that the larger shear strain, the enhanced intensity of γ fiber texture and the excellent formability of the strip can be easily obtained in the tandem rolling process with the larger work roll rather than the reversible rolling process with the smaller work roll.

For the recycling of ferrous sludge from steel industry, the carbonation pellet process should be considered as a "green" process, since no impurities are added as well as CO 2 can be sequestrated and consumed. Through the thermodynamic calculation, the carbonation reaction can occur spontaneously and is an exothermic reaction. Based on the kinetic analysis through unreacted core model, the interfacial chemical reaction was the rate controlling step in the initial fast stage of carbonation, and the CO 2 diffusion through the CaC03 product layer was the rate controlling step in the following extremely slow stage. For the carbonation bonded mechanism, the pellet strength was gained by the formation and growing of CaC03 product layer. Since the interfacial chemical reaction was the critical stage of the entire carbonation process, the emphasizes should be focused on the improvement of sorbent activity and the optimi­ zation of process parameters, such as pore structure, pore surface area, and total pressure, CO 2 partial pressure, re­ action temperature, etc to accelerate the reaction rate and to improve the quality of carbonation pellets.

Hot plasticity of a nitrogen alloyed 25Cr-7Ni-4Mo duplex stainless steel was investigated. The results indicate that the main factors affecting the hot plasticity of duplex stainless steel are listed as follows: coalescent force of phase interface, microstructure, and the phase ratio and difference between the mechanical properties of ferrite and austenite. The heat treatment and sulphur contents have a notable effect on the hot plasticity. The reasonable heat treatments and the increased interfacial coalescent force will effectively enhance the hot plasticity of duplex stainless steel.