說是外徑小的鋼管，就可以稱為小口徑鋼管，小口徑厚壁鋼管還可以分為：無縫小口徑鋼管和直縫（也可以稱為焊接）小口徑鋼管，一般在鋼管的外徑89以下的，都可以統(tǒng)稱為小口徑鋼管按生產(chǎn)方法不同可分為熱軋管 、冷軋管 、冷拔管 、擠壓管等， 熱軋無縫管一般在自動(dòng)軋管機(jī)組上生產(chǎn)。實(shí)心管坯經(jīng)檢查并清除表面缺陷截成所需長(zhǎng)度， 在管坯穿孔端端面上定心 然后送往加熱爐加熱 在穿孔機(jī)上穿孔 在穿孔同時(shí)不斷旋轉(zhuǎn)和前進(jìn)， 在軋輥和頂頭的作用下， 管坯內(nèi)部逐漸形成空腔稱毛管， 再送至自動(dòng)軋管機(jī)上繼續(xù)軋制后經(jīng)均整機(jī)均整壁厚， 經(jīng)定徑機(jī)定徑， 達(dá)到規(guī)格要求， 利用連續(xù)式軋管機(jī)組生產(chǎn)熱軋小口徑鋼管是較先進(jìn)的方法， 若欲獲得尺寸更小和質(zhì)量更好的小口徑鋼管， 必須采用冷軋 冷拔或者兩者聯(lián)合的方法冷軋通常在二輥式軋機(jī)上進(jìn)行，小口徑鋼管在變斷面圓孔槽和不動(dòng)的錐形頂頭所組成的環(huán)形孔型中軋制， 冷拔通常在單鏈?zhǔn)交螂p鏈?zhǔn)嚼浒螜C(jī)上進(jìn)行 擠壓法即將加熱好的管坯放在密閉的擠壓圓筒內(nèi)穿孔棒與擠壓桿一起運(yùn)動(dòng)， 使擠壓件從較小的模孔中擠出， 此法可生產(chǎn)直徑較小的鋼管。

英文版：Small diameter steel pipe, can be called small diameter steel pipe, small diameter thick-walled steel pipe can also be divided into: seamless small diameter steel pipe and longitudinal seam (also known as welding) small diameter steel pipe, generally in the steel pipe under the outer diameter of 89, can be collectively called small diameter steel pipe according to different production methods can be divided into hot-rolled pipe, cold-rolled pipe The hot rolled seamless pipe is usually produced on the automatic tube rolling mill. The solid billet is inspected and the surface defects are cleared and cut to the required length. The billet is centered on the end face of the piercing end of the billet and then sent to the heating furnace for heating. The piercing machine rotates and advances continuously during the piercing. Under the action of the roll and the head, the billet gradually forms a cavity called capillary, which is then sent to the automatic pipe mill to continue. It is an advanced method to produce hot-rolled small-diameter steel pipes by continuous rolling mill. If small-diameter steel pipes with smaller size and better quality are to be obtained, cold-rolled cold-drawn or combined cold-rolled two-roll mill is necessary. The small diameter steel pipe is rolled in a circular pass consisting of a variable section circular groove and a stationary tapered plug. Cold drawing is usually carried out on a single or double chain cold drawing machine by extrusion. The heated billet is placed in an airtight extrusion cylinder and the punch rod moves with the extrusion rod, so that the extruded part is smaller. This method can produce smaller diameter steel pipes.