焊管是燃氣（qì）管道中的常見管材，直徑大（dà）於426mm（或508mm）的焊管（guǎn）一般被稱為大口徑焊管，按照焊接成管方式，可（kě）分為螺旋焊管和直縫焊管兩種。螺旋焊管是將低（dī）碳碳素結構鋼或低合金結（jié）構鋼鋼帶按一定（dìng）的螺（luó）旋線的角度（又叫成型（xíng）角）卷成管坯，然後將管縫焊接起（qǐ）來製成，它可以用較窄的帶鋼（gāng）生產大直徑的鋼管（guǎn）。螺旋焊管主要是螺旋埋弧焊管（SSAW），在我國廣泛用於各種燃氣管道的建設，其規格用（yòng）外徑*壁厚表示。螺旋焊管有單麵焊的和雙（shuāng）麵焊的，焊管應保證水壓試驗、焊縫的抗拉強度和冷彎性（xìng）能要符合規定。
Welded pipe is a common material in gas pipeline. Welded pipe whose diameter is larger than 426 mm (or 508 mm) is generally called large diameter welded pipe. According to the way of pipe forming, it can be divided into spiral welded pipe and straight welded pipe. Spiral welded pipe is made by coiling low carbon structural steel or low alloy structural steel strip into billet according to a certain angle of helix (also known as forming angle), and then welding the pipe seam. It can produce large diameter steel pipe with narrow strip. Spiral welded pipes are mainly spiral submerged arc welded pipes (SSAW), which are widely used in the construction of various gas pipelines in China. Their specifications are expressed by external diameter * wall thickness. Spiral welded pipe has one-sided welding and two-sided welding. Welded pipe should ensure that hydraulic test, tensile strength and cold bending properties of weld seam meet the requirements. 直縫焊管是將熱軋板卷經（jīng）過成型機成型後，使鋼卷變形為圓滑的圓筒狀，利用高頻電流（liú）的集膚效應和鄰近效應或焊（hàn）劑層下燃燒的電弧進行焊接，使管坯邊緣（yuán）加熱熔（róng）化，並在一定的擠（jǐ）壓力作用下熔合（hé），經最終冷卻成型。其（qí）中（zhōng）管坯邊緣利用高頻電流熔化的被（bèi）稱為（wéi）高頻直縫（féng）焊管（ERW），利（lì）用電弧熔化的被稱為直縫埋弧焊管（LSAW）。
Straight seam welded pipe is formed by hot-rolled sheet coil through forming machine, so that the coil is transformed into a smooth cylindrical shape, using skin effect and proximity effect of high frequency current or arc burning under flux layer to weld, so that the edge of the billet is heated and melted, and fused under certain extrusion force, and finally cooled and formed. The billet edge melted by high frequency current is called high frequency straight seam welded pipe (ERW), and the tube edge melted by arc is called straight seam submerged arc welded pipe (LSAW).
直縫焊管主要原料是低碳鋼熱軋板卷、熱軋帶（dài），在石油、冶金、建（jiàn）築、煤礦、港口、機械等行業廣泛用（yòng）於石油天然氣輸送、低壓水煤氣輸送、礦用流體輸送、帶式輸送機托輥、汽（qì）車傳動軸等等。
The main raw materials of straight seam welded pipe are low carbon steel hot rolled sheet coil and hot rolled strip. It is widely used in petroleum, metallurgy, construction, coal mine, port, machinery and other industries for oil and gas transmission, low pressure water gas transmission, mine fluid transmission, belt conveyor roller, automobiles transmission shaft, etc.
