厚壁鋼管的(de)20是指(zhi)含(han)碳(tan)量(liang)為0.2%，屬(shu)于低(di)碳(tan)鋼(gang)。鋼(gang)中可分為低(di)碳(tan)鋼(gang)、中碳(tan)鋼(gang)和高碳(tan)鋼(gang)。

碳含量：低(di)碳鋼(gang)(gang)一(yi)(yi)般(ban)小(xiao)于0.25%；中碳鋼(gang)(gang)一(yi)(yi)般(ban)在(zai)0.25～0.60%之間(jian)；高碳鋼(gang)(gang)一(yi)(yi)般(ban)大于0.60%。

厚壁鋼管就是我們平常所說的A3厚壁鋼管、碳素普通厚壁鋼管、美標A106厚壁鋼管

厚壁鋼管是用鋼(gang)錠(ding)或實心管(guan)坯(pi)經穿(chuan)孔制成毛(mao)管(guan)，然后經熱軋、冷(leng)軋或冷(leng)撥制成。20#厚壁(bi)鋼(gang)管(guan)在我(wo)國鋼(gang)管(guan)業中(zhong)具有重要的地位。

厚壁鋼管分(fen)熱軋和冷軋（撥(bo)）厚壁鋼管兩類。

厚壁鋼管常用標準

1、結構用厚壁(bi)鋼管：GB/T8162-2008

2、輸送流體用厚壁鋼管：GB/T8163-2008

3、冷拔(ba)或冷軋精密(mi)厚(hou)壁鋼管：GB/T3639-2009

據不(bu)(bu)完(wan)全(quan)統計(ji)，我國現有20#厚(hou)壁鋼管(guan)生(sheng)產(chan)企(qi)業約6500多(duo)家，厚(hou)壁鋼管(guan)機組約12057多(duo)套，年產(chan)能力約2450多(duo)萬噸(dun)。從口徑看，<φ76的，占(zhan)35%，<φ159-650的，占(zhan)25%。從品(pin)種看，一般(ban)用途管(guan)1190萬噸(dun)，占(zhan)54%；石油(you)管(guan)76萬噸(dun)，占(zhan)5.7%；液(ye)壓支柱、精密管(guan)15萬噸(dun)，占(zhan)4.3%；不(bu)(bu)銹管(guan)、軸承管(guan)、汽車(che)管(guan)共5萬噸(dun)，占(zhan)1.4%。

軋制厚壁鋼管的(de)(de)原料是圓管(guan)(guan)坯(pi)，圓管(guan)(guan)胚要(yao)經過切割機(ji)(ji)(ji)的(de)(de)切割加工成長(chang)度約為(wei)1米的(de)(de)坯(pi)料，并(bing)經傳送(song)(song)(song)帶送(song)(song)(song)到熔爐內加熱(re)。鋼(gang)(gang)(gang)坯(pi)被送(song)(song)(song)入熔爐內加熱(re)，溫度大(da)約為(wei)1200攝氏度。燃(ran)料為(wei)氫氣(qi)(qi)或乙炔。爐內溫度控制是關鍵性(xing)的(de)(de)問(wen)題.圓管(guan)(guan)坯(pi)出爐后要(yao)經過壓力穿(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)(kong)機(ji)(ji)(ji)進行穿(chuan)(chuan)(chuan)(chuan)(chuan)空。一(yi)般(ban)較常見的(de)(de)穿(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)(kong)機(ji)(ji)(ji)是錐形輥(gun)穿(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)(kong)機(ji)(ji)(ji)，這(zhe)種穿(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)(kong)機(ji)(ji)(ji)生(sheng)產效(xiao)率高，產品(pin)質(zhi)量好，穿(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)(kong)擴徑(jing)(jing)(jing)量大(da)，可(ke)穿(chuan)(chuan)(chuan)(chuan)(chuan)多種鋼(gang)(gang)(gang)種。穿(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)(kong)后，圓管(guan)(guan)坯(pi)就(jiu)先后被三輥(gun)斜軋(ya)(ya)、連軋(ya)(ya)或擠(ji)(ji)壓。擠(ji)(ji)壓后要(yao)脫管(guan)(guan)定(ding)徑(jing)(jing)(jing)。定(ding)徑(jing)(jing)(jing)機(ji)(ji)(ji)通過錐形鉆頭(tou)(tou)高速旋轉入鋼(gang)(gang)(gang)胚打(da)孔(kong)(kong)(kong)(kong)，形成鋼(gang)(gang)(gang)管(guan)(guan)。鋼(gang)(gang)(gang)管(guan)(guan)內徑(jing)(jing)(jing)由定(ding)徑(jing)(jing)(jing)機(ji)(ji)(ji)鉆頭(tou)(tou)的(de)(de)外(wai)徑(jing)(jing)(jing)長(chang)度來確定(ding)。鋼(gang)(gang)(gang)管(guan)(guan)經定(ding)徑(jing)(jing)(jing)后，進入冷卻(que)塔(ta)中(zhong)，通過噴水冷卻(que)，鋼(gang)(gang)(gang)管(guan)(guan)經冷卻(que)后，就(jiu)要(yao)被矯直。鋼(gang)(gang)(gang)管(guan)(guan)經矯直后由傳送(song)(song)(song)帶送(song)(song)(song)至金屬探(tan)(tan)傷機(ji)(ji)(ji)（或水壓實驗）進行內部(bu)探(tan)(tan)傷。若鋼(gang)(gang)(gang)管(guan)(guan)內部(bu)有裂(lie)紋，氣(qi)(qi)泡等問(wen)題，將(jiang)被探(tan)(tan)測(ce)出。鋼(gang)(gang)(gang)管(guan)(guan)質(zhi)檢(jian)后還要(yao)通過嚴格(ge)的(de)(de)手(shou)工挑(tiao)選。鋼(gang)(gang)(gang)管(guan)(guan)質(zhi)檢(jian)后，用油漆噴上編(bian)號(hao)、規格(ge)、生(sheng)產批號(hao)等。并(bing)由吊(diao)車吊(diao)入倉(cang)庫中(zhong)。

20#厚壁鋼管小口徑常用規格