Large-diameter thick-walled seamless steel pipes are made from steel ingots or solid round steel that are perforated into capillary tubes and then hot-rolled. Large-diameter thick-walled seamless steel pipes play an important role in my country’s steel pipe industry. According to incomplete statistics, there are more than 240 seamless pipe manufacturers in my country and more than 250 large-diameter thick-walled seamless steel pipe units. Large-diameter thick-walled seamless steel pipes are mainly based on the external diameter of the steel pipe. Generally, those with an outer diameter of more than 325 mm are called large-diameter steel pipes. As for thick walls, generally, those with a wall thickness of more than 20 mm are sufficient. The following is the manufacturing process of steel pipes: The raw material of steel pipes is steel pipe blanks. Pipe blanks need to be cut by a cutting machine into a blank with a length of about 1 meter.

And sent to the furnace for heating via a conveyor belt. The billet is fed into the furnace and heated to a temperature of approximately 1200°C. The fuel is hydrogen or acetylene. Temperature control in the furnace is a key issue. After the round tube comes out of the furnace, it must be pierced through a pressure punching machine. Generally, the more common piercing machine is the tapered roller piercing machine. This type of piercing machine has high production efficiency, good product quality, large perforation diameter expansion, and can penetrate a variety of steel types. After perforation, the round tube blank is successively cross-rolled, continuously rolled, or extruded by three rollers. After extrusion, the pipe should be removed and calibrated. The sizing machine rotates a tapered drill bit at high speed into the steel blank to drill holes to form a steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length 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 (in fact, many manufacturers no longer use straightening machines, but directly straighten the steel pipe after it passes through the rolling mill. It has reached the straightness of its steel pipe itself). 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 quality inspection, steel pipes must undergo strict manual selection (now all have laser detection inspections).