Carbon steel pipes are made of steel ingots or solid round steel through perforation into capillary tubes, and then made by hot rolling, cold rolling or cold drawing. According to the production process, carbon steel pipes can be divided into two categories: hot-rolled and cold-rolled (drawn) steel pipes.

Carbon steel welded steel pipe

Welded steel pipe, also known as welded pipe, is a steel pipe made of steel plate or strip steel after crimping and welding. Welded steel pipe has simple production process, high production efficiency, many varieties and specifications, and less equipment investment, but its general strength is lower than that of seamless steel pipe.Commonly used materials for welded pipes are: Q235A, Q235C, Q235B, 16Mn, 20#, Q345, L245, L290, X42, X46, X60, X80, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.

Carbon steel seamless pipe

A seamless pipe is a long strip of steel with a hollow section and no seams around it. According to different production methods, it can be divided into hot-rolled tubes, cold-rolled tubes, cold-drawn tubes, extruded tubes, etc. Generally used in fluid conveying pipes, boiler plants, engineering, mechanical processing plants.

 Key Attributes

Common materials and chemical compositions of carbon steel welded pipes

Classification by use:

General welded pipe: used to transport low pressure fluids. It is mainly made of Q195A, Q215A, Q235A steel, and can also be made of other mild steels that are easy to weld.

Galvanized welded pipe: In order to improve the corrosion resistance of steel pipes, general steel pipes (black pipes) are galvanized. Galvanized steel pipes are divided into two types: hot-dip galvanizing and electro-galvanizing. The hot-dip galvanizing layer is thick and the cost of electro-galvanizing is low.

Oxygen-blown welded pipe: used as a steel-making oxygen-blown pipe, generally small-diameter welded steel pipes. Made with 08, 10, 15, 20 or Q195-Q235 steel strip. In order to prevent corrosion, some are aluminized.

Wire casing: that is, ordinary carbon steel electric welded steel pipe, used in concrete and various structural power distribution projects. The walls are thin, and most of them are used after coating or galvanizing.

Metric welded pipe: It is made by hot and cold strip welding of ordinary carbon steel, high-quality carbon steel or general low-alloy steel, or welded by hot strip and then cold drawn.

Roller tube: It is used for electric welded steel pipe of belt conveyor idler, generally made of Q215, Q235A, B steel and 20 steel. There are certain requirements for the curvature of the tube, the end face should be perpendicular to the center line, and the ovality.

Transformer tube: used to manufacture transformer radiator tubes and other heat exchangers, made of ordinary carbon steel.

Electric welding thin-walled tube: mainly used for making furniture, toys, lamps, etc.

Special-shaped pipe: square pipe, rectangular pipe, hat-shaped pipe, hollow rubber steel door and window steel pipe welded by ordinary carbon structure steel and 16Mn steel strip, mainly used for agricultural machinery parts, steel windows and doors, etc.

Welded steel pipe classification supplement:

Carbon steel pipe production method

The raw material for carbon steel pipe is round tube billet, and the round tube embryo should be cut by cutting machine to grow billets with a length of about 1 meter, and transported to the furnace by conveyor belt. Billet is fed into the furnace to heat, the temperature is about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature control in the furnace is a key issue. After the round tube is out of the furnace, it must be pierced by a pressure piercer. Generally, the more common piercer is the cone roll piercer. This kind of piercer has high production efficiency, good product quality, large perforation diameter expansion, and can wear a variety of steel types. After piercing, the round tube billet is successively cross-rolled, continuous rolled or extruded by three rolls. After extrusion, the tube should be taken off for sizing. Sizing by high-speed rotary cone drill holes into the billet to form a tube. The inner diameter of the steel pipe is determined by the length of the outer diameter of the drill bit of the sizing machine. After the steel pipe is sized, it enters the cooling tower and is cooled by spraying water. After the steel pipe is cooled, it will be straightened. After straightening, the steel pipe is sent to the metal flaw detector (or hydraulic test) by the conveyor belt for internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe, they will be detected. After the quality inspection of steel pipes, strict manual selection is required. After the quality inspection of the steel pipe, paint the serial number, specification, production batch number, etc. with paint. And hoisted into the warehouse by crane.