基于扩散模型的低中碳钢渗硼动力学研究

为了研究含碳量对低、中碳钢的渗硼动力学的影响,将纯铁、20钢、40钢和50钢分别在850℃、880℃、910℃和940℃保温3 h、5 h、7 h和9 h进行粉末渗硼。采用面积法测量了渗层厚度。以基本的扩散定律和物质守恒定律等为基础建立硼的扩散模型,计算了低中碳钢渗硼过程中硼原子的扩散激活能和扩散系数。结果表明:渗硼层组织为锯齿状;渗层厚度随时间呈抛物线变化;随着钢的含碳量的增加,硼原子的扩散激活能增大,纯铁中硼原子的扩散激活能为151 kJ/mol,20钢中为159 kJ/mol,40钢中为168 kJ/mol,而50钢中为176 kJ/mol。

Boronizing Kinetics Based on Duffusion Model of Low and Medium Carbon Steels

In order to investigate the effect of carbon content on the boronizing kinetics of low and medium carbon steels, pure iron, 20 steel, 40 steel and 50 steel were pack boronized by heating at 850℃,880℃,910℃and 940℃for 3 h, 5 h, 7 h, and 9 h respectively.The case thicknesses were measured by a planimetric method .Diffusion model of boron was built on the basis of both the basic diffusion and mass conservation laws and , thereby , activation energy and coefficient of boron atom during boronizing of low and medium carbon steels were calculated . The results are as follows：（ a） the case offers a jagged structure;（ b） a parabolic variation of the case thickness with the boronizing time exhibits; （ c） as the crbon content in the steels becomes higher the activation energy of boron atom increases, being 151 kJ/mol in pure iron, 159 kJ/mol in 20 steel, 168 kJ/mol in 40 steel, and 176 kJ/mol in 50 steel .