焊管是燃气管道中的常见管材，直径大于426mm（或508mm）的焊管一般被称为大口径焊管，按照焊接成管方式，可分为螺旋焊管和直缝焊管两种。螺旋焊管是将低碳碳素结构钢或低合金结构钢钢带按一定的螺旋线的角度（又叫成型角）卷成管坯，然后将管缝焊接起来制成，它可以用较窄的带钢生产大直径的钢管。螺旋焊管主要是螺旋埋弧焊管（SSAW），在我国广泛用于各种燃气管道的建设，其规格用外径*壁厚表示。螺旋焊管有单面焊的和双面焊的，焊管应保证水压试验、焊缝的抗拉强度和冷弯性能要符合规定。
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. 直缝焊管是将热轧板卷经过成型机成型后，使钢卷变形为圆滑的圆筒状，利用高频电流的集肤效应和邻近效应或焊剂层下燃烧的电弧进行焊接，使管坯边缘加热熔化，并在一定的挤压力作用下熔合，经最终冷却成型。其中管坯边缘利用高频电流熔化的被称为高频直缝焊管（ERW），利用电弧熔化的被称为直缝埋弧焊管（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).
直缝焊管主要原料是低碳钢热轧板卷、热轧带，在石油、冶金、建筑、煤矿、港口、机械等行业广泛用于石油天然气输送、低压水煤气输送、矿用流体输送、带式输送机托辊、汽车传动轴等等。
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, automobile transmission shaft, etc.
