【摘要】 研究了经脉冲电流和常规电阻炉奥氏体化热处理后30钢晶粒大小的变化,结果表明在同等的奥氏体化加热温度和加热时间及冷却速度的实验条件下,经电阻炉处理后试样的金相组织与原始组织相同即仍为先共析铁素体加珠光体组织,而经脉冲电流处理后的试样其金相组织则为魏氏组织.经过深入分析魏氏体组织的形成条件及对晶粒尺寸的比对,可知经脉冲电流热处理后的试样的奥氏体化的晶粒较常规热处理的晶粒要粗大得多,进一步的理论分析显示:促使奥氏体晶粒显著长大的机制在于脉冲电流增大了原子的扩散系数从而促进了原子扩散所致.该结论提示,脉冲电流显著促进了钢的奥氏体化过程,脉冲电流条件下的奥氏体化热处理的温度与时间与常规的热处理工艺参数相比将大为降低和减少,从而大幅度节省能源与提高效率.更多还原

【Abstract】 This paper studies the effects of impulse current treatment and conventional heat treatment on the austenitic grain sizes of 30 steel.It is shown that,under the same temperature,heating time and cooling rate,the Widmanstatten structure is acquired after impulse current treatment,while proeutectoid ferrite and pearlite remain unchanged after the conventional treatment.Through further analysis of the formation condition of Widmanstatten structure and comparison of the grain sizes,it can be found that grain sizes of austenite after impulse current treatment is much larger than those after conventional heat treatment.Theoretical analysis shows that the significant growth of austenite grains is due to the increasing of the diffusion coefficient,which is caused by the impulse current.Therefore,impulse current greatly promotes the steel’s austenitic process.The austenitizing temperature and time of impulse current treatment is noticeably decreased,when compared with the parameters of conventional heat treatment,which greatly saves the energy and enhances the conversion efficiency.更多还原