20# steel seamless steel pipe refers to a steel ingot or tube billet with a carbon content of 0.20%, which is perforated into a rough tube, and then hot rolled, cold rolled, or cold drawn. This type of steel pipe is produced in my country and used in large quantities. The main equipment used in production is a steel pipe rolling mill, which belongs to the category of steel rolling.
The raw material for rolling seamless steel pipes is round tube billets, which are cut by a cutting machine into billets with a length of about 1 meter and sent to the furnace for heating via a conveyor belt. The billet is sent to the furnace for heating at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. Temperature control in the furnace is a key issue.
The next step is the centering process. Since the tube billet is heated and is blank with irregular size, the center line of the cylinder must be determined, which is the centering process.
After the round tube billet is out of the furnace, it must be pierced by a pressure-piercing machine. Generally, the more common piercing machine is the tapered roller piercing machine, which has high production efficiency, good product quality, large piercing, and expansion, and can pierce a variety of steel types. There is still no generally accepted conclusion on the mechanical stress of the piercing process.
After piercing, the round tube billet is successively rolled, continuously rolled, or extruded by three rollers. The auxiliary bar in the middle of the steel pipe is called the mandrel. There are three situations of the mandrel in the rolling process, that is, the movement form, which are fixed mandrel, floating mandrel, and semi-floating mandrel. Fixed mandrel means that the mandrel does not move, floating mandrel means that the mandrel moves freely during the rolling process, and semi-floating mandrel means that the mandrel does not move first, and then moves freely when the rolling process is close to the end. Each method has its advantages and disadvantages.
After rolling, heating is carried out. The heating furnace in the picture of the production process shown above is a step-by-step heating furnace. Simply put, the two cam mechanisms in the picture drive the steel pipe to do a cyclic reciprocating motion.
Then the diameter is reduced and the tube is removed and sized. In fact, the production process and technology of sizing and reducing are basically the same, except that the degree of change in the diameter of the steel pipe is larger or smaller. The sizing machine uses a conical drill bit to rotate 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 of the drill bit of the sizing machine. After the steel pipe is sizing, it enters the cooling tower and is cooled by water spray. After cooling, the steel pipe needs to be straightened. Straightening is done by a straightening machine.
After straightening, the steel pipe is sent to the metal flaw detector (or water pressure test) by a conveyor belt for internal flaw detection. If there are cracks, bubbles, and other problems inside the steel pipe, they will be detected. After the steel pipe quality inspection, it must also pass strict manual selection. After the steel pipe quality inspection, the number, specification, production batch number, etc. are sprayed with paint. And it is hoisted into the warehouse by a crane.
Post time: Jun-05-2025