Cr25Ni35Nb和Cr35Ni45Nb合金高温渗碳浓度场的数值模拟  

Numerical simulation of concentration field of Cr25Ni35Nb and Cr35Ni45Nb alloys during carburization at high temperature

作　　者：秦小燕[1] 巩建鸣[1] 耿鲁阳[1] 

机构地区：[1]南京工业大学机械与动力工程学院,江苏南京210009

出　　处：《材料热处理学报》2010年第7期151-156,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金项目(50775107);国家"863"计划项目(2007AA04Z407);江苏省"333工程"培养资金资助项目

摘　　要：以Cr25Ni35Nb和Cr35Ni45Nb炉管钢为研究对象,以菲克第二定律和"平衡常数法"为理论基础,采用有限差分数值方法,实现了这两种高Cr-Ni裂解炉管材料高温渗碳时碳的扩散和碳化物析出的模拟,给出了渗层的总碳含量、基体中的碳含量、基体中合金元素含量在不同渗碳时间沿壁厚的分布。在1000℃对两种材料进行了固体渗碳实验,分析比较了高温下两种材料的渗碳动力学规律。结果表明,浓度场模拟结果与实验测量值吻合较好。从渗碳增重曲线和浓度场模拟结果可以看出,Cr35Ni45Nb钢的抗渗碳能力强于Cr25Ni35Nb钢。A carburization model consisting of carbon diffusion and carbide precipitation for high Cr-Ni alloy at elevated temperature was established based on Fick ’s second law and equilibrium constant method.The concentration field of carbon in Cr25Ni35Nb and Cr35Ni45Nb alloys for ethylene cracking furnace tube during carburization was simulated by means of finite difference method.The distribution of total carbon content,carbon and metallic elements in matrix along thickness of the tube at different time in the process of carburizing was investigated.The pack solid carburization tests of the two alloys were carried out at 1000℃.In the meantime,carburization kinetic curves and carburizing resistance of the two alloys were studied.It shows that the calculated results are in agreement with the experimental results.The comparison of the weight gain profiles and carbon distribution profiles between the two alloys obviously shows that the anti-carburization property of Cr35Ni45Nb alloy is better than that of Cr25Ni35Nb alloy.

关 键 词：渗碳 菲克第二定律 平衡常数法 数值模拟 

分 类 号：TG156.81[金属学及工艺—热处理]