由整塊(kuai)金(jin)屬制成的(de)，表面上沒有接(jie)縫(feng)的(de)鋼管(guan)(guan)(guan)，稱為無(wu)縫(feng)鋼管(guan)(guan)(guan)。根據生(sheng)產方法，無(wu)縫(feng)管(guan)(guan)(guan)分(fen)(fen)熱軋(ya)管(guan)(guan)(guan)、冷軋(ya)管(guan)(guan)(guan)、冷拔管(guan)(guan)(guan)、擠壓(ya)管(guan)(guan)(guan)、頂管(guan)(guan)(guan)等。按照斷面形(xing)(xing)狀(zhuang)，無(wu)縫(feng)鋼管(guan)(guan)(guan)分(fen)(fen)圓(yuan)形(xing)(xing)和異形(xing)(xing)兩(liang)種(zhong)(zhong)，異形(xing)(xing)管(guan)(guan)(guan)有方形(xing)(xing)、橢圓(yuan)形(xing)(xing)、三角形(xing)(xing)、六角形(xing)(xing)、瓜子形(xing)(xing)、星形(xing)(xing)、 帶翅管(guan)(guan)(guan)多種(zhong)(zhong)復(fu)雜形(xing)(xing)狀(zhuang)。最大(da)直徑達650mm，最小(xiao)直徑為 0.3mm。根據用(yong)(yong)途不(bu)同， 有厚(hou)壁管(guan)(guan)(guan)和薄(bo)壁管(guan)(guan)(guan)。無(wu)縫(feng)鋼管(guan)(guan)(guan)主要用(yong)(yong)做石(shi)油地質鉆探管(guan)(guan)(guan)、石(shi)油化工用(yong)(yong)的(de)裂化管(guan)(guan)(guan)、鍋 爐(lu)管(guan)(guan)(guan)、軸承(cheng)管(guan)(guan)(guan)以及汽車、拖(tuo)拉機(ji)、航空(kong)用(yong)(yong)高精度結構鋼管(guan)(guan)(guan)。

沿其橫截面的(de)周邊上無接縫(feng)的(de)鋼(gang)(gang)管(guan)。根(gen)據生(sheng)產方法不同分為熱軋管(guan)、冷(leng)軋管(guan)、冷(leng)拔(ba)管(guan)、擠壓(ya)管(guan)、頂管(guan)等(deng)(deng)，均(jun)有各(ge)自(zi)工藝規定。材質有普通和優質碳(tan)素結構(gou)鋼(gang)(gang)（Q215-A～Q275-A和10～50號鋼(gang)(gang)）、低合金(jin)(jin)鋼(gang)(gang)（09MnV、16Mn等(deng)(deng)）、合金(jin)(jin)鋼(gang)(gang)、不銹耐酸鋼(gang)(gang)等(deng)(deng)。按用(yong)(yong)(yong)途分為一般用(yong)(yong)(yong)途的(de)（用(yong)(yong)(yong)于(yu)輸水(shui)、氣管(guan)道和結構(gou)件、機械(xie)零件）和專用(yong)(yong)(yong)的(de)（用(yong)(yong)(yong)于(yu)鍋爐、地質勘探(tan)、軸承、耐酸等(deng)(deng)）兩類。