The blank used for welding steel pipe is steel plate or strip steel, which is divided into furnace welding pipe, electric welding (resistance welding) pipe and automatic arc welding pipe because of the different welding process. Because of its different welding form is divided into straight seam welding pipe and spiral welding pipe two kinds. Because of its end shape is divided into circular welded pipe and shaped (square, flat, etc.) welded pipe. The welded pipe is divided into several varieties as follows because of its different materials and uses:

GB/T3091-1993(Galvanized welded steel tubes for low pressure fluid transport) Mainly used for conveying water, gas, air, oil and heating hot water or steam and other general low pressure fluids and other purposes. Its representative material Q235A steel.

GB/T3092-1993(Galvanized welded steel tubes for low pressure fluid transport) Mainly used for conveying water, gas, air, oil and heating hot water or steam and other general low pressure fluids and other purposes. Its representative material is: Q235A steel.