2.4 课堂讨论二钢的热处理(精品)

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,课堂讨论课二,辅导教材,64,页：二、,1,和,3,题,32,页：,33,题,图,2-39,标注组织的,Fe-Fe,3,C,相图,P,M+A,M,回,+A,过冷,A,M+B,下,+A,B,下,T+M+A,S,P,S,材料,热处理工艺,硬度,显微组织,加热温度,冷却方式,回火温度,HRB,HRC,HB,45,钢,860,炉冷,85,148,空冷,13,196,油冷,38,349,水冷,55,538,水冷,200,53,515,水冷,400,40,369,水冷,600,24,243,760,水冷,45,422,T12,钢,760,炉冷,93,176,空冷,26,257,油冷,46,437,水冷,66,693,水冷,200,63,652,水冷,400,51,495,水冷,600,30,283,860,水冷,61,637,表2-1,F+P,F+S,T+M,+B+F,M,M,回,T,回,S,回,F+M,P+Fe,3,C,II,S+Fe,3,C,II,T+M+A+Fe,3,C,II,M+A+Fe,3,C,II,M,回,+A+Fe,3,C,II,T,回,+Fe,3,C,II,S,回,+Fe,3,C,II,M(,粗大,)+A,(,多,),33.,低碳钢（,0.2%C,）小件经,930,，,5h,渗碳后，表面碳含量增至,1.0%,，试分析以下处理后表层和心部的组织：,1,）渗碳后慢冷；,2,）渗碳后直接水淬并低温回火；,3,）由渗碳温度预冷到,820,，保温后水淬，再低温回火；,4,）渗碳后慢冷至室温，再加热到,780,，保温后水淬，再低温回火,1,）表层：,P+Fe,3,C,II,，心部：,P+F,2,）表层：粗大高碳,M,回,+,较多,A,，心部：低碳,M,回,3,）表层：粗大高碳,M,回,+,较多,A,心部：低碳,M,回,+F,4,）表层：高碳,M,回,+A+,粒状,Fe,3,C,II,，心部：低碳,M,回,+F,