影響17crnimo6圓鋼晶粒大小的主因素

　　①加(jia)(jia)熱溫度(du)。加(jia)(jia)熱溫度(du)越(yue)高(gao)，保溫時(shi)間越(yue)長，晶(jing)粒長大的傾(qing)向越(yue)大。

　　②機(ji)械(xie)阻礙物。一(yi)(yi)般來(lai)說，金屬的(de)(de)晶(jing)粒(li)(li)隨著溫(wen)度的(de)(de)升高不斷長(chang)(chang)(chang)大(da)(da)(da)，幾(ji)乎成正比關系。但是(shi)(shi)，也(ye)不完全如此(ci)，有(you)時候加熱(re)到(dao)較高溫(wen)度時，晶(jing)粒(li)(li)仍很細小，可以說沒(mei)有(you)長(chang)(chang)(chang)大(da)(da)(da)，而當溫(wen)度再(zai)升高一(yi)(yi)些(xie)時，晶(jing)粒(li)(li)突然長(chang)(chang)(chang)大(da)(da)(da)。并且有(you)些(xie)材料，隨加熱(re)溫(wen)度升高，晶(jing)粒(li)(li)分階段突然長(chang)(chang)(chang)大(da)(da)(da)。一(yi)(yi)般稱前一(yi)(yi)種長(chang)(chang)(chang)大(da)(da)(da)方(fang)式為(wei)正常長(chang)(chang)(chang)大(da)(da)(da)，后一(yi)(yi)種為(wei)異(yi)常長(chang)(chang)(chang)大(da)(da)(da)。金屬異(yi)常長(chang)(chang)(chang)大(da)(da)(da)的(de)(de)原因是(shi)(shi)金屬材料中(zhong)存在機(ji)械(xie)阻礙物，對晶(jing)界有(you)釘札作用，阻止晶(jing)界的(de)(de)遷移。

　　③變(bian)(bian)形(xing)(xing)(xing)程(cheng)度和變(bian)(bian)形(xing)(xing)(xing)速度。變(bian)(bian)形(xing)(xing)(xing)程(cheng)度對晶(jing)粒大(da)(da)(da)(da)(da)(da)小(xiao)(xiao)(xiao)的影響的規(gui)律總的來說，隨(sui)著變(bian)(bian)形(xing)(xing)(xing)程(cheng)度由(you)小(xiao)(xiao)(xiao)到大(da)(da)(da)(da)(da)(da)，晶(jing)粒尺寸(cun)由(you)大(da)(da)(da)(da)(da)(da)變(bian)(bian)小(xiao)(xiao)(xiao)，但是晶(jing)粒大(da)(da)(da)(da)(da)(da)小(xiao)(xiao)(xiao)有兩個(ge)峰值，即出(chu)現兩個(ge)晶(jing)粒區(qu)，第一個(ge)大(da)(da)(da)(da)(da)(da)晶(jing)粒區(qu)叫做臨(lin)(lin)界變(bian)(bian)形(xing)(xing)(xing)區(qu)。不(bu)同材料和不(bu)同變(bian)(bian)形(xing)(xing)(xing)溫度的臨(lin)(lin)界變(bian)(bian)形(xing)(xing)(xing)程(cheng)度的大(da)(da)(da)(da)(da)(da)小(xiao)(xiao)(xiao)不(bu)一樣，臨(lin)(lin)界變(bian)(bian)形(xing)(xing)(xing)區(qu)是一個(ge)小(xiao)(xiao)(xiao)變(bian)(bian)形(xing)(xing)(xing)量范圍，在某(mou)些情況下，當變(bian)(bian)形(xing)(xing)(xing)量足夠大(da)(da)(da)(da)(da)(da)時，可能出(chu)現第二個(ge)大(da)(da)(da)(da)(da)(da)晶(jing)粒區(qu)。

　　④固(gu)(gu)溶(rong)(rong)(rong)(rong)處(chu)(chu)理(li)前(qian)(qian)的(de)組(zu)織(zhi)情況。固(gu)(gu)溶(rong)(rong)(rong)(rong)處(chu)(chu)理(li)后(hou)(hou)的(de)晶(jing)粒(li)(li)大(da)(da)小除(chu)了受(shou)固(gu)(gu)溶(rong)(rong)(rong)(rong)溫度和機械阻礙物的(de)影響外，受(shou)固(gu)(gu)溶(rong)(rong)(rong)(rong)加(jia)熱前(qian)(qian)的(de)組(zu)織(zhi)情況影響很大(da)(da)。如果鍛(duan)后(hou)(hou)是(shi)未再(zai)結晶(jing)組(zu)織(zhi)，而且處(chu)(chu)于(yu)臨界變形(xing)程度時，固(gu)(gu)溶(rong)(rong)(rong)(rong)處(chu)(chu)理(li)后(hou)(hou)將(jiang)形(xing)成粗大(da)(da)晶(jing)粒(li)(li);如果鍛(duan)后(hou)(hou)是(shi)完(wan)(wan)全再(zai)結晶(jing)組(zu)織(zhi)，固(gu)(gu)溶(rong)(rong)(rong)(rong)處(chu)(chu)理(li)后(hou)(hou)一(yi)般可(ke)以獲得細小而均勻的(de)晶(jing)粒(li)(li);如果鍛(duan)后(hou)(hou)是(shi)不完(wan)(wan)全再(zai)結晶(jing)組(zu)織(zhi)，即半熱變形(xing)混合(he)組(zu)織(zhi)，固(gu)(gu)溶(rong)(rong)(rong)(rong)加(jia)熱時，由(you)于(yu)各處(chu)(chu)形(xing)核的(de)時間先(xian)后(hou)(hou)、數(shu)量多少和長 大(da)(da)條件等不一(yi)樣，固(gu)(gu)溶(rong)(rong)(rong)(rong)處(chu)(chu)理(li)后(hou)(hou)晶(jing)粒(li)(li)大(da)(da)小將(jiang)是(shi)不均勻的(de)。

　　⑤原(yuan)始晶(jing)粒(li)度。按傳統觀念，鋼在(zai)加熱至(zhi)正火溫度時即發生相變和重結(jie)晶(jing)，使粗(cu)大晶(jing)粒(li)得(de)到細化。但(dan)是有些鋼種(zhong)(主要是馬氏(shi)體鋼和貝氏(shi)體鋼)過熱后形成的(de)粗(cu)晶(jing)，經(jing)正火后仍為(wei)粗(cu)大晶(jing)粒(li)。這種(zhong)部分(fen)或全部由原(yuan)粗(cu)大奧氏(shi)體晶(jing)粒(li)復原(yuan)的(de)現象稱為(wei)晶(jing)粒(li)遺傳。