【摘要】 建立了平面、圆柱面和球面工件气体渗碳数学模型 :cτ=D 2 cx2 +shape(x -R0 )cx ,碳的扩散系数取为温度和含碳量的函数 :D =D0 4exp[-Q RT -B(0 4-c) ];碳的传递系数取为温度的函数 :β =β0 exp(-E RT) ;内边界条件为固定碳量 ;碳势和温度取为时间的线性函数。给出了基于渗碳结果计算物理参数的数学模型。结果表明 ,将碳的扩散系数取为温度和碳的质量分数的函数 ,传递系数取为温度的函数以及通过测试渗碳后的碳浓度值计算扩散系数和传递系数中的 5个常数 ,对提高模拟计算结果的正确性非常必要。通过模拟计算还讨论了扩散系数和传递系数中有关参数对碳浓度分布的影响规律更多还原

【Abstract】 The model established in this paper for gas carburizing of plan, cylinder and ball is given by cτ=D\+2cx\+2+shape(x-R\-0)cx, in which carbon diffusivity ( D ) is defined as function of temperature ( T ) and carbon consistence ( c ): D(T,c)=D 0 4 exp (-Q/RT) exp [-B(0 4-c)], carbon transfer coefficient is expressed as a function of temperature, β=β\-0 exp( -E/RT ) and carbon potential and temperature as linear functions of time. Based on this model, the model for calculating carbon diffusivity and carbon transfer coefficient is established. The influences of carbon diffusivity and carbon transfer coefficient on carbon distribution are discussed according to the results of simulating. To improve the accuracy of mold calculation results, it is essential that take carbon diffusivity as the function of temperature and mass fraction of carbon and carbon transfer coefficient as the function of temperature and calculate the five constants of carbon diffusivity and transfer coefficient by measuring carbon concentration. It also discussed the influences of relative parameters of carbon diffusivity and transfer coefficient on the distribution of carbon.更多还原