普(pu)通低(di)(di)(di)(di)合(he)金(jin)鋼(gang)(gang)(gang)雖溫(wen)(wen)(wen)(wen)(wen)度(du)降(jiang)(jiang)低(di)(di)(di)(di)強度(du)有(you)所增加，塑韌性卻(que)急劇(ju)降(jiang)(jiang)低(di)(di)(di)(di)，這類鋼(gang)(gang)(gang)不(bu)(bu)能用(yong)(yong)于(yu)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)下工(gong)(gong)作(zuo)的(de)(de)結(jie)構上(shang)，而低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)在(zai)相應的(de)(de)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)條(tiao)件下仍具有(you)良好的(de)(de)韌性和抗脆(cui)斷(duan)能力(li)，能夠確保結(jie)構的(de)(de)使用(yong)(yong)安全。低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)鋼(gang)(gang)(gang)主要用(yong)(yong)于(yu)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)下工(gong)(gong)作(zuo)的(de)(de)容器、管道和結(jie)構，如(ru)(ru)石油(you)化(hua)(hua)工(gong)(gong)設(she)備(bei)(bei)（化(hua)(hua)肥、乙烯、煤(mei)液化(hua)(hua)、液化(hua)(hua)石油(you)氣等(deng)）、冷(leng)凍設(she)備(bei)(bei)、食品工(gong)(gong)業及液態氣體(ti)儲(chu)存設(she)備(bei)(bei)等(deng)。低(di)(di)(di)(di)合(he)金(jin)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)一般用(yong)(yong)于(yu)-110~-20℃工(gong)(gong)況(kuang)條(tiao)件。按(an)適用(yong)(yong)溫(wen)(wen)(wen)(wen)(wen)度(du)范(fan)圍(wei)，低(di)(di)(di)(di)合(he)金(jin)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)可分(fen)(fen)為-40℃、-70℃、-90℃、-110℃鋼(gang)(gang)(gang)；按(an)照鋼(gang)(gang)(gang)材(cai)的(de)(de)合(he)金(jin)體(ti)系，低(di)(di)(di)(di)合(he)金(jin)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)可分(fen)(fen)為不(bu)(bu)含(han)(han)鎳及含(han)(han)鎳的(de)(de)兩大類。不(bu)(bu)含(han)(han)鎳的(de)(de)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)用(yong)(yong)鋼(gang)(gang)(gang)一般工(gong)(gong)作(zuo)溫(wen)(wen)(wen)(wen)(wen)度(du)在(zai)-40℃以(yi)(yi)上(shang)，而含(han)(han)鎳的(de)(de)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)鋼(gang)(gang)(gang)根(gen)據鎳含(han)(han)量(liang)的(de)(de)高低(di)(di)(di)(di)，可以(yi)(yi)工(gong)(gong)作(zuo)在(zai)較低(di)(di)(di)(di)的(de)(de)溫(wen)(wen)(wen)(wen)(wen)度(du)下，如(ru)(ru)2.5%Ni鋼(gang)(gang)(gang)可以(yi)(yi)用(yong)(yong)于(yu)-60℃以(yi)(yi)下，3.5%Ni鋼(gang)(gang)(gang)可以(yi)(yi)用(yong)(yong)于(yu)-110~-90℃。表1-10和表1-11列(lie)出了我國常用(yong)(yong)低(di)(di)(di)(di)合(he)金(jin)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)壓(ya)力(li)容器用(yong)(yong)鋼(gang)(gang)(gang)的(de)(de)化(hua)(hua)學成分(fen)(fen)及力(li)學性能。

  低(di)(di)(di)(di)合(he)金低(di)(di)(di)(di)溫(wen)(wen)用(yong)(yong)(yong)鋼(gang)(gang)一般是(shi)通(tong)過合(he)金元素的(de)固溶強(qiang)化(hua)、晶(jing)粒細化(hua)，并通(tong)過正火或正火＋回火處理細化(hua)組織晶(jing)粒，從而獲得良好的(de)低(di)(di)(di)(di)溫(wen)(wen)韌性。在(zai)低(di)(di)(di)(di)溫(wen)(wen)用(yong)(yong)(yong)鋼(gang)(gang)中(zhong)常用(yong)(yong)(yong)合(he)金元素是(shi)Mn、Ni、V、Nb等，如我國低(di)(di)(di)(di)溫(wen)(wen)壓力(li)容(rong)器用(yong)(yong)(yong)鋼(gang)(gang)09Mn2VDR、15MnNiDR及09MnNiDR等，為保證(zheng)低(di)(di)(di)(di)溫(wen)(wen)韌性，在(zai)低(di)(di)(di)(di)溫(wen)(wen)用(yong)(yong)(yong)鋼(gang)(gang)中(zhong)盡量降低(di)(di)(di)(di)碳含量，并嚴格控制硫(liu)、磷(lin)含量。低(di)(di)(di)(di)合(he)金低(di)(di)(di)(di)溫(wen)(wen)用(yong)(yong)(yong)鋼(gang)(gang)還有相應(ying)的(de)鑄件(jian)、鍛件(jian)及管材，JB4727-2000中(zhong)對5種常用(yong)(yong)(yong)的(de)低(di)(di)(di)(di)合(he)金低(di)(di)(di)(di)溫(wen)(wen)鋼(gang)(gang)鍛件(jian)的(de)化(hua)學成分、力(li)學性能做出(chu)了規定，見(jian)表(biao)1-12及表(biao)1-13所示。