扩散应力对圆筒结构中渗C的影响

Effect of diffusion-induced stresses on carburization in cylindrical structure

运用数值方法模拟C浓度和扩散应力沿壁厚方向随扩散时间的演变规律,研究圆筒结构在平面应变情况下扩散应力对渗C的影响.结果表明:扩散应力增大了C的有效扩散系数,从而加速了质量传递的过程;当扩散时间一定时,C浓度和平均浓度随着圆筒外径与内径比值的增大而减小.圆筒中内表面渗C导致径向应力从内壁到外壁始终为压应力,周向和轴向应力在内壁附近为压应力,在外壁附近为拉应力.

To obtain the effect of diffusion-induced stresses in carbon diffusion process on the cylindrical structure for a plane strain, the distribution of carbon concentration and diffusion-induced stresses with time and diffusion depth were simulated by a numerical method. Results showed that the diffusion-induced stres- ses enhanced the mass transfer because of the increasing effective diffusion coefficient of the carbon. For a given time, both the concentration and the average concentration of the carbon decreased with increasing the ratio of outer radius to inner one. The radial stress was always compressive from inner to outer surfaces because of inner surface carburization in cylindrical structure, and the circumferential stress and the axial stress near the inner surface were compressive, but both of them near the outer surface were tensile.