General welded pipe: General welded pipe is used to transport low-pressure fluid. Made of Q195A, Q215A and Q235A steel. It can also be made of other soft steels which are easy to weld. Self-propelled hollow bolts need to be tested by hydraulic pressure, bending and flattening, which requires certain surface quality. Usually, the length of delivery is 4-10m, and the delivery of fixed length (or double length) is often required. The specification of welded pipe is different from the actual one in nominal diameter (millimeter or inch). There are two kinds of welded pipe according to the prescribed wall thickness: ordinary pipe and thick pipe. The pipe is divided into threaded pipe and non-threaded pipe according to the end form.
Galvanized steel pipes: In order to improve the corrosion resistance of steel pipes, galvanized common steel pipes (black pipes). Galvanized steel pipes are divided into hot-dip galvanizing and steel galvanizing. The hot-dip galvanizing layer is thick and the galvanizing cost is low.
Oxygen-blowing welded pipe: used as steel-making oxygen-blowing pipe, generally with small-caliber welded steel pipe, specifications from 3/8 inch to 2 inch eight kinds. It is made of 08, 10, 15, 20 or Q195-Q235 steel strips. In order to prevent corrosion, some are aluminized.
Wire sleeve: It is also common carbon steel welded steel pipe, used in concrete and various structural distribution projects, commonly used nominal diameter from 13 to 76 mm. The sleeve wall of wire sleeve is thin, and most of them are used after coating or galvanizing, so cold bending test is required.
Metric welded pipes: welded pipes with hollow anchor rods in specifications, expressed in millimeters of outer diameter and wall thickness, welded in hot and cold zones of common carbon steel, high quality carbon steel or general energy low alloy steel, or welded in hot zones and then made by cold drawing method. Metric welded pipes are commonly used as structural parts, such as transmission shafts, or conveying fluids, and thin-walled pipes are used to produce furniture, lamps, etc. The strength and bending test of steel pipes should be guaranteed.
Roller pipe: Used for welding steel pipe of belt conveyor roller. It is generally made of Q215, Q235A, B steel and 20 steel with diameter of 63.5-219.0mm. There are certain requirements for pipe bending, end face to be perpendicular to the center line and ellipticity. Generally, hydraulic and flattening tests are carried out.
Transformer tube: It is used to manufacture transformer radiator tube and other heat exchangers. It is made of common carbon steel. Flattening, flaring, bending and hydraulic test are required. There are certain requirements for bending of steel pipes when they are delivered in fixed or multiple sizes.
Special-shaped pipes: square pipes, hollow bolts, cap-shaped pipes, hollow rubber steel doors and windows welded by ordinary carbon-bonded structural steel and 16Mn steel strips, mainly used for agricultural machinery, steel windows and doors.