Production Method of Seamless Steel Pipe
Seamless steel pipe is a kind of long steel bar with hollow section and no joint around it. The steel pipe has a hollow cross section, which is widely used for conveying fluids such as oil, natural gas, water and some solid materials. It is also used as an engineering structural component and a mechanical component.
The production process of seamless steel pipe contains raw material preparation, forming, heat treatment, testing and finishing. It is a required compression molding process that is performed by a variety of steps in order to produce a quality seamless steel pipe.
1. Raw material preparation:
The raw material of seamless steel pipe is round steel billet, which can be made of mill hot-rolled, cold-rolled or cold drawn steel. At first, the billet should go through a quality control process. It should be measured, tested and inspected according to the relevant specification standards before forging. In addition, the surface of the steel should be cleaned to ensure the soundness of the forging.
2. Forming:
Forming is one of the most important processes in the production of seamless steel pipe. Generally, the forming process includes hot-rolled and cold rolled forming. The hot-rolled forming process is to heat the billet to suitable temperature and then extruded it with a piercing machine. The cold rolled forming process includes cold drawing and cold rolling.
3. Heat treatment:
The purpose of the heat treatment of steel is to normalize or temper the steel, which can improve the mechanical properties, processing performance and surface properties of steel. According to the requirements of different applications, the heat treatment of seamless steel pipe can be annealing, normalizing, tempering, quenching and tempering, etc.
4. Testing and finishing:
Steps include inspection, marking, threading and surface treatment. The inspection should be conducted according to the inspection qualification standard, including dimension inspection and non-destructive testing (such as ultrasonic testing, hardness testing, etc.). The weld edge shall be no burr and no trimming. In additions, surface treatment should be done to improve the corrosion resistance and wear resistance. Common surface treatment methods are blackening, galvanizing, painting, etc.
Seamless steel pipe has the advantages of high tensile strength, good toughness, small vibration under dynamic and static load, high fatigue resistance and long service life. It is widely used in oil and gas industry, chemical process industry and so on. By following the above producing process, the manufacturers can produce a high-quality seamless steel pipe.
