【作者】 吴凡； 王宝； 刘青； 卢新春；

【Author】 Wu Fan;Wang Bao;Liu Qing;Lu Xinchun;State Key Laboratory of Refractories & Metallurgy, Wuhan University of Science &Technology;State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing;Fangda Special Steel of Science and Technology Co., Ltd,R&D;

【机构】 武汉科技大学省部共建耐火材料与冶金国家重点实验室； 北京科技大学钢铁冶金新技术国家重点实验室； 方大特钢科技股份有限公司技术中心；

【摘要】 本文以国内某企业生产的含硼60Si2Mn弹簧钢为研究对象,采用热膨胀法进行了含硼弹簧钢的临界相变温度和动态CCT曲线的测定,并应用高温共聚焦激光扫描显微镜对弹簧钢在连续冷却过程中先共析铁素体的生长过程进行了原位观察。研究发现,含硼26 ppm与不含硼弹簧钢发生完全马氏体转变的临界冷却速率分别为10℃/s和13℃/s。硼元素的加入,使临界冷却速率降低,冷却曲线局部右移,提高了过冷奥氏体的稳定性,抑制了晶界处先共析铁素体的析出,阻碍了奥氏体的共析分解转变。另外,随着冷却速率的增大,晶界处的先共析铁素体明显减少。更多还原

【Abstract】 The continuous cooling transformation curves of the B-bearing and B-free 60Si2Mn spring steel were measured by thermal dilation method using Gleeble-1500 thermo-simulation machine. The precipitation and growth of pre-eutectoid ferrite during continuous cooling transformation was in-situ observed and analyzed by confocal laser scanning microscope. The results show that, the critical cooling rate of martensitic transformation was 10 ℃/s and 13 ℃/s for boron-bearing and boron-free spring steel, respectively. Compared with that of the steel without boron, the critical cooling rate decreases, cooling curve shifted to the right locally,and the eutectoid transformation of austenite was restrained. With increasing the cooling rate, the pre-eutectoid ferrite on the grain boundaries significantly reduced.更多还原