What are the annealing types of seamless steel pipes?
The annealing process of seamless steel pipes can be divided into various types, including complete annealing, spheroidizing annealing, stress relief annealing, etc.:
Complete annealing: The seamless steel pipe is heated to a predetermined temperature, kept warm for a period of time and then slowly cooled in the furnace. The purpose is to reduce the hardness of the steel pipe and eliminate the uneven structure and internal stress in the steel.
Spheroidizing annealing: The seamless steel pipe is heated to a specific temperature (such as 750 degrees), kept warm for a period of time, slowly cooled to a lower temperature (such as below 500 degrees), and finally cooled in the air. The purpose is to reduce the hardness of steel pipes and improve cutting performance, mainly for high carbon steel.
Stress relief annealing: Also known as low-temperature annealing, the seamless steel pipe is heated to a lower temperature (such as 500 to 600 degrees), kept for a period of time, slowly cooled to a lower temperature (such as below 300 degrees) in the furnace, and then cooled at room temperature. The structure does not change during the annealing process, and the main purpose is to eliminate the internal stress of the steel pipe.
