Carbon steel pipes can be divided into two categories: Hot-rolled and cold-rolled (drawn) steel.


Hot rolled carbon steel pipe is divided into ordinary, low pressure, medium pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe, geological steel pipe and other steel pipes.

Common steel pipe: hot or cold rolled steel, including 10, 20, 30, 35, 45 and other high-quality carbon steel, 16Mn, 5mnv low alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other alloys. 10. 20 etc. low carbon steel seamless pipe is mainly used for fluid pipe. Seamless pipe is made of medium carbon steel of 45, 40Cr, etc., which is used to make mechanical parts, such as the stressed parts of automobiles and tractors. In general, carbon steel pipes shall be tested for strength and flattening. Hot rolled steel can be delivered only when it is in hot rolling state or after heat treatment; cold rolled steel can be delivered after heat treatment.

Cold rolling (distribution) includes not only ordinary carbon steel pipe, low-pressure boiler pipe, high-pressure boiler pipe, steel pipe, stainless steel pipe, petroleum cracking pipe and other steel pipes, but also carbon thin-walled steel pipe, alloy thin-walled steel, stainless steel thin-walled stainless steel pipe, special-shaped steel. The diameter of hot-rolled seamless pipe is generally larger than 32mm, and the wall thickness is 2.5-75mm. The diameter of cold-rolled seamless steel pipe can reach 6 mm, the wall thickness can reach 0.25 mm, the outer diameter of thin-walled pipe can reach 5 mm, and the wall thickness is less than 0.25 mm. The dimensional accuracy of cold rolling is higher than that of hot rolling.


Preparation


The raw material of carbon steel pipe is round billet. The round billets are processed into billets about 1 meter long with a cutting machine. It shall be conveyed to the furnace for heating by conveyor belt. The billet is fed into the furnace and heated at a temperature of about 1200 ℃. The fuel is hydrogen or acetylene. Furnace temperature control is the key problem. After the round pipe comes out, it can be punched by pressure punch. Generally, the more common puncher is the tapered roller puncher. This kind of punching machine has the characteristics of high production efficiency, high product quality, strong ability of punching and reaming, and can pierce all kinds of steel. After piercing, the tube blank has been tilted, rolled or extruded continuously. After extrusion, degumming is carried out. After high-speed rotation of the sizing machine through the taper drill, the billet is punched to form the billet. The inner diameter of the tube is determined by the length of the drill bit of the outer diameter sizing machine. After sizing, the steel tube should be introduced into the cooling tower through spray cooling pipe. After cooling, straighten the steel pipe. After straightening the steel pipe, send its conveyor belt to the metal detector (or pressure test) for internal test. If there are cracks, bubbles and other problems in the internal pipes, they will be detected. After quality control, strict manual selection shall be adopted. If the steel pipe passes the quality inspection, the paint label number, size and production batch number shall be used. And send it to the warehouse by crane.


technical parameter


According to incomplete statistics, there are about 240 steel pipe manufacturers in China, 250 carbon steel pipe plants and an annual production capacity of about 450 million tons. From the perspective of caliber, < φ 76, accounting for 35%, and < φ 159-650, accounting for 25%. In terms of varieties, 1.9 million tons of general-purpose pipes, accounting for 54%; 760000 tons of oil pipes, accounting for 5.7%; 15 million tons of hydraulic props and precision pipes, accounting for 4.3% of stainless steel bearing pipes; 50000 tons of automobile pipes, accounting for 1.4%.

Carbon steel pipes can be divided into two categories: Hot-rolled and cold-rolled (drawn) steel.


Hot rolled carbon steel pipe is divided into ordinary, low pressure, medium pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe, geological steel pipe and other steel pipes.

Common steel pipe: hot or cold rolled steel, including 10, 20, 30, 35, 45 and other high-quality carbon steel, 16Mn, 5mnv low alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other alloys. 10. 20 etc. low carbon steel seamless pipe is mainly used for fluid pipe. Seamless pipe is made of medium carbon steel of 45, 40Cr, etc., which is used to make mechanical parts, such as the stressed parts of automobiles and tractors. In general, carbon steel pipes shall be tested for strength and flattening. Hot rolled steel can be delivered only when it is in hot rolling state or after heat treatment; cold rolled steel can be delivered after heat treatment.

Cold rolling (distribution) includes not only ordinary carbon steel pipe, low-pressure boiler pipe, high-pressure boiler pipe, steel pipe, stainless steel pipe, petroleum cracking pipe and other steel pipes, but also carbon thin-walled steel pipe, alloy thin-walled steel, stainless steel thin-walled stainless steel pipe, special-shaped steel. The diameter of hot-rolled seamless pipe is generally larger than 32mm, and the wall thickness is 2.5-75mm. The diameter of cold-rolled seamless steel pipe can reach 6 mm, the wall thickness can reach 0.25 mm, the outer diameter of thin-walled pipe can reach 5 mm, and the wall thickness is less than 0.25 mm. The dimensional accuracy of cold rolling is higher than that of hot rolling.


Preparation


The raw material of carbon steel pipe is round billet. The round billets are processed into billets about 1 meter long with a cutting machine. It shall be conveyed to the furnace for heating by conveyor belt. The billet is fed into the furnace and heated at a temperature of about 1200 ℃. The fuel is hydrogen or acetylene. Furnace temperature control is the key problem. After the round pipe comes out, it can be punched by pressure punch. Generally, the more common puncher is the tapered roller puncher. This kind of punching machine has the characteristics of high production efficiency, high product quality, strong ability of punching and reaming, and can pierce all kinds of steel. After piercing, the tube blank has been tilted, rolled or extruded continuously. After extrusion, degumming is carried out. After high-speed rotation of the sizing machine through the taper drill, the billet is punched to form the billet. The inner diameter of the tube is determined by the length of the drill bit of the outer diameter sizing machine. After sizing, the steel tube should be introduced into the cooling tower through spray cooling pipe. After cooling, straighten the steel pipe. After straightening the steel pipe, send its conveyor belt to the metal detector (or pressure test) for internal test. If there are cracks, bubbles and other problems in the internal pipes, they will be detected. After quality control, strict manual selection shall be adopted. If the steel pipe passes the quality inspection, the paint label number, size and production batch number shall be used. And send it to the warehouse by crane.


technical parameter


According to incomplete statistics, there are about 240 steel pipe manufacturers in China, 250 carbon steel pipe plants and an annual production capacity of about 450 million tons. From the perspective of caliber, < φ 76, accounting for 35%, and < φ 159-650, accounting for 25%. In terms of varieties, 1.9 million tons of general-purpose pipes, accounting for 54%; 760000 tons of oil pipes, accounting for 5.7%; 15 million tons of hydraulic props and precision pipes, accounting for 4.3% of stainless steel bearing pipes; 50000 tons of automobile pipes, accounting for 1.4%.