两种贝氏体塑料模具钢的相变与残余奥氏体

将两种塑料模具钢FT600 和FT600mod 奥氏体化后, 以连续冷却或等温方式, 获得贝氏体组织. 随后分别在350, 580, 700 °C下进行回火, 研究了Si, Mn元素微调后贝氏体组织及残余奥氏体转变情况. 对两种贝氏体钢在不同热处理工艺下的宏观硬度、残余奥氏体含量、微观组织进行了表征及分析. 研究结果表明, 在FT600 钢的基础上降Si 增Mn 得到了FT600mod 钢, 其贝氏体转变后的残余奥氏体含量大幅降低; FT600 钢中的残余奥氏体在不同温度下回火, 其转变机制不同; FT600mod钢中的残余奥氏体含量较少, 组织稳定, 更适用于非调质工艺处理.

Transformation and retained austenite of two kinds of bainite plastic mold steel

FT600 and FT600mod steels are two similar non-quenched plastic mold steels with difference in the content of Si and Mn. Both FT600 and FT600mod were cooled by
continuous and isothermal treatments after austenitizing respectively, and then separately tempered at 350, 580, and 700 °C. Evolution of microstructures and retained austenite of the two bainitic steels after the heat treatments are studied based on the microstructure characterization, content measurement, and Rockwell hardness and dilatometric analysis experiments. It is found that the content of the retained austenite of continuous cooling sample of FT600mod, different from FT600 by decreasing Si and increasing Mn, is decreasing dramatically. The changed amounts of retained austenite of FT600 sample vary after different tempering treatments. FT600mod steels are more stable and more suitable for the non-quenched treatment.