普通低(di)(di)(di)(di)(di)(di)合(he)金(jin)(jin)鋼(gang)(gang)(gang)(gang)雖溫(wen)(wen)(wen)(wen)(wen)度降低(di)(di)(di)(di)(di)(di)強(qiang)度有所增(zeng)加，塑(su)韌性(xing)卻(que)急劇降低(di)(di)(di)(di)(di)(di)，這類(lei)鋼(gang)(gang)(gang)(gang)不(bu)能(neng)用(yong)(yong)于低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)下工(gong)(gong)作的(de)(de)(de)結(jie)構(gou)上，而低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)(gang)在(zai)相應的(de)(de)(de)低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)條(tiao)件(jian)下仍(reng)具有良好的(de)(de)(de)韌性(xing)和(he)抗脆斷能(neng)力(li)(li)(li)，能(neng)夠確保(bao)結(jie)構(gou)的(de)(de)(de)使用(yong)(yong)安全。低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)鋼(gang)(gang)(gang)(gang)主要用(yong)(yong)于低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)下工(gong)(gong)作的(de)(de)(de)容器(qi)、管(guan)道和(he)結(jie)構(gou)，如(ru)石油化(hua)(hua)工(gong)(gong)設備（化(hua)(hua)肥(fei)、乙烯、煤液(ye)化(hua)(hua)、液(ye)化(hua)(hua)石油氣等(deng)(deng)）、冷凍設備、食品工(gong)(gong)業及液(ye)態氣體儲(chu)存(cun)設備等(deng)(deng)。低(di)(di)(di)(di)(di)(di)合(he)金(jin)(jin)低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)(gang)一般(ban)用(yong)(yong)于-110~-20℃工(gong)(gong)況條(tiao)件(jian)。按適用(yong)(yong)溫(wen)(wen)(wen)(wen)(wen)度范圍，低(di)(di)(di)(di)(di)(di)合(he)金(jin)(jin)低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)(gang)可(ke)分為(wei)-40℃、-70℃、-90℃、-110℃鋼(gang)(gang)(gang)(gang)；按照鋼(gang)(gang)(gang)(gang)材(cai)的(de)(de)(de)合(he)金(jin)(jin)體系(xi)，低(di)(di)(di)(di)(di)(di)合(he)金(jin)(jin)低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)(gang)可(ke)分為(wei)不(bu)含(han)鎳及含(han)鎳的(de)(de)(de)兩大(da)類(lei)。不(bu)含(han)鎳的(de)(de)(de)低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)(gang)一般(ban)工(gong)(gong)作溫(wen)(wen)(wen)(wen)(wen)度在(zai)-40℃以(yi)上，而含(han)鎳的(de)(de)(de)低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)鋼(gang)(gang)(gang)(gang)根據鎳含(han)量的(de)(de)(de)高(gao)低(di)(di)(di)(di)(di)(di)，可(ke)以(yi)工(gong)(gong)作在(zai)較低(di)(di)(di)(di)(di)(di)的(de)(de)(de)溫(wen)(wen)(wen)(wen)(wen)度下，如(ru)2.5%Ni鋼(gang)(gang)(gang)(gang)可(ke)以(yi)用(yong)(yong)于-60℃以(yi)下，3.5%Ni鋼(gang)(gang)(gang)(gang)可(ke)以(yi)用(yong)(yong)于-110~-90℃。表1-10和(he)表1-11列(lie)出了我國常(chang)用(yong)(yong)低(di)(di)(di)(di)(di)(di)合(he)金(jin)(jin)低(di)(di)(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)壓(ya)力(li)(li)(li)容器(qi)用(yong)(yong)鋼(gang)(gang)(gang)(gang)的(de)(de)(de)化(hua)(hua)學成分及力(li)(li)(li)學性(xing)能(neng)。

  低(di)(di)(di)合(he)金(jin)低(di)(di)(di)溫(wen)(wen)(wen)用鋼(gang)一般是通過合(he)金(jin)元素(su)的(de)固溶強化、晶粒(li)細化，并通過正(zheng)火(huo)或正(zheng)火(huo)＋回火(huo)處理(li)細化組織晶粒(li)，從而獲得良好的(de)低(di)(di)(di)溫(wen)(wen)(wen)韌(ren)性。在低(di)(di)(di)溫(wen)(wen)(wen)用鋼(gang)中(zhong)常用合(he)金(jin)元素(su)是Mn、Ni、V、Nb等，如(ru)我國(guo)低(di)(di)(di)溫(wen)(wen)(wen)壓(ya)力容(rong)器(qi)用鋼(gang)09Mn2VDR、15MnNiDR及(ji)09MnNiDR等，為保證低(di)(di)(di)溫(wen)(wen)(wen)韌(ren)性，在低(di)(di)(di)溫(wen)(wen)(wen)用鋼(gang)中(zhong)盡量降低(di)(di)(di)碳含量，并嚴格(ge)控制硫、磷(lin)含量。低(di)(di)(di)合(he)金(jin)低(di)(di)(di)溫(wen)(wen)(wen)用鋼(gang)還有相應的(de)鑄件、鍛件及(ji)管材，JB4727-2000中(zhong)對5種(zhong)常用的(de)低(di)(di)(di)合(he)金(jin)低(di)(di)(di)溫(wen)(wen)(wen)鋼(gang)鍛件的(de)化學成(cheng)分、力學性能做出了規定，見表1-12及(ji)表1-13所示。