热变形对塑料模具钢SDFT600贝氏体相变的影响

Effect of thermal deformation on bainite transformation of plastic mould steel SDFT600

利用热模拟试验机、热膨胀仪、扫描电镜等研究了热变形对塑料模具钢SDFT600连续冷却过程贝氏体相变的影响。结果表明,在适用于塑料模具钢模块锻造生产的参数条件下,热变形会促进贝氏体相变。相同连续冷却速率下,动态CCT试样贝氏体开始转变温度高于静态CCT试样,0.5℃/s时两者差值达到96℃;热变形会降低过冷奥氏体的稳定性,0.5℃/s时动态CCT试样的贝氏体含量较高;连续冷却速率小于0.1℃/s时,动态CCT试样残留奥氏体含量低于静态CCT试样;热变形条件下试样的硬度均匀性较好,有利于提高大模块的最终质量。

Effect of thermal deformation on bainite transformation of plastic mould steel SDFT600 during continuous cooling was analyzed by means of thermal simulation machine, thermal dilatometer, scanning electron microscope, etc. The results show that with the parameters suitable for forging production of large plastic mould steel blocks, thermal deformation promotes bainite transformation. At same continuous cooling rate, the bainite transformation start temperature of dynamic CCT specimen is higher than that of static CCT specimen, at cooling rate of 0.5 ℃/s, the temperature difference reaches 96 ℃. Thermal deformation reduces the stability of retained austenite, and at cooling rate of 0.5 ℃/s, the bainite content of dynamic CCT specimen is higher than that of static CCT specimen. When the continuous cooling rate is less than 0.1 ℃/s, the content of retained austenite of dynamic CCT specimen is lower than that of static CCT specimen. Hardness uniformity under thermal deformation condition is better, which is beneficial to the final quality of mould blocks.