Constrained groove pressing is a simple and effective method of grain refinement. Using the experimental data obtained by regression analysis, this paper analyzes the simulation of the four pass constrained groove pressing deformation of 7050 aluminum alloy. The simulation results show that the grain size of the billet is refined significantly after four pass constrained groove pressing deformation and decreases from the original 90 μm to a minimum of 14.0 μm. With the increase of the number of deformation passes, refinement effect becomes weakened gradually, the grain size tends to stabilize and the organization is more uniform.

It is one of the effective way to apply JIT (just in time) mode in the management of discrete job shop to improve the productivity of job shop. A kind of JIT management mode for discrete job shop is proposed in this paper. The machining tools such as cutters and frocks are distributed with materials in JIT mode, so that the inventory of machining tools is reduced, and productivity is improved. The process of distribution plan under this mode is studied. The JIT distribution management information system is developed based on the proposed studies, and is applied in a traditional machining job shop with satisfactory result.

This paper considers for transformation behavior of Nb microalloyed steels, experiments had demonstrated the effect of Nb was obvious: lowered start temperature of ferrite transformation remarkably and forming more refined ferrite grain size. In this study, computer simulation of Nb-containing steels transformation during continuous cooling was carried out by adopting a classical nucleation and growth theory, the model was derived based on the theories and the experimental results, and the calculated start temperatures of ferrite transformation were compared with the results of experimental.