EA4T钢冷却过程中脉冲电流对组织与性能的影响

Influence of pulse current on the microstructure and mechanical property during continuous cooling of EA4T steel

针对EA4T钢车轴淬火过程中心部会析出大量大尺寸先共析铁素体的问题,采用脉冲电流辅助加热方法,研究冷却过程中脉冲电流与先共析铁素体析出的关系。EA4T钢试样加热至900℃保温20min后,以25℃/min冷速冷却,并在冷却过程中通入一定参数的脉冲电流。结果表明,由于脉冲电流辅助加热的热效应,推迟了相变过程中先共析铁素体在奥氏体晶界处的析出。与未通脉冲电流的试样相比,先共析铁素体的含量降低,尺寸减小,试样的强度、伸长率及冲击值有所提高。

Proeutectoid ferrite was precipitated in the core of the EA4T steel in the quenching process. Based on the research of pulse current heating method, the relation of pulse current and proeutectoid ferrite was studied. Specimen was heated to 900℃ for 20min, the pulse current was exerted on EAdT steel during continuous cooling at cooling rate 25 ℃/min. The exlp-rimental results show that in comparison with specimen without pulse current, and for the reason of auxiliary heating of pulse current, the forming of proeutectoid ferrite at austenite grain boundary is delayed, so that the content and size of proeutectoid ferrite are reduced, and the strength, elongtation and impact value are increased.