相平衡热力学方法在超细碳化物高碳合金钢合金设计中的应用

Under normal forging and annealing conditions, there are different ultra fine carbides (M3C, M23C6, M7C3, M6C and MC) in high carbon alloy steels when alloy composition design is carried out properly. On the basis of carbides transformation orderliness in Cr-W-Mo-V high carbon alloy steel at annealing temperature, the structure and composition of the phases and its transformation orderliness in the steel at different temperature were estimated by phase-equilibrium thermodynamic calculation for Fe-Cr-W-Mo-V-Si-Mn-C system. The rational heat treatment technics were concluded on the basis of the matrix composition at different austenitizing temperature, and the hardness of quenching and secondary hardening was doped out. The yield strength and the toughness can be forecasted on the basis of average cohesive-energy of martensit matrix by the calculation at electronic and atomic scale. As a demand of mechanical properties of new steel, the eligible chemical composition of the high canbon alloy steel was finally corfirmed according to the comparison with all calculating results for other conceivable chemical composition. A series of the high carbon medium and high alloy steels with ultra-fine carbides were studied by aforesaid method. The practice of production should that the prospective objective can be obtained by theoretic design adding a small quantity of technical tests.