Q235钢固体粉末渗硼及渗层生长动力学行为

Technology for Solid-State Pack Boronizing of Q235 Steel and Kinetic Study of Boron Diffusion in Steel

各类材料渗硼工艺不同,硼的扩散也不同,其中有许多现象往往不能定量分析。采用固体粉末法对Q235钢进行了渗硼,得到的渗硼层为锯齿状,垂直于钢表面楔入基体。用Sigma Plot 10.0软件对试验数据进行了分析和拟合,得出了渗硼层等厚度图,为制定渗硼工艺提供了依据:利用此图,既可以对设定的渗硼时间和温度预测渗硼层厚度,又可以用一定的固体渗硼厚度值确定渗硼时间和温度。通过动力学研究得到了渗层相组成为单一的Fe2B相硼,在不同温度下的扩散速率常数:K800℃=1.074×10-13m2/s,K850℃=1.622×10-13m2/s,K900℃=3.921×10-13m2/s,平均扩散激活能为134.473 kJ/mol。

Q235 steel was pack boronized with solid-state agent. An attempt was made to investigate the possibility of predicting the thickness variation of boride layers. The experimental data were fitted with Sigma Plot 10. 0 software. The iso-thickness diagram of the bondinglayer was obtained, making it feasible to predict the thickness of the boriding layer by giving bonding temperature and time,and to determine suitable boriding temperature and time according to the target thickness of the boriding layer. Moreover, the diffusion fac-tors such as diffusion activation energy and diffusion rate constant of the Q235 steel were analyzed with kinetics method according to the thickness of the boronized layers under different temperatures. Results indicate that boriding layer formed on the Q235 steel sur-face has saw-tooth morphology and is composed of single phase Fe, B. The diffusion rate constant (K) of boron atoms in the 0235 steel at 800 ℃, 850℃,and 900 °C were calculated to be 1.074×10-13, 1.622×10-13m2/s, and 3.921×10-13m2/s, respectively, and the average diffusion activation energy ( Q) of boron atoms therein was determined to be 134.473 kJ/mol.