Heat treatment process and purpose of GB/T 8163 20# seamless steel tube

The annealing process of GB/T 8163 20# seamless steel tube: the 20# steel tube intercepted forged steel parts are heated to 30 - 50℃ above the critical temperature, and heat preservation for a certain time, and then slowly cooled with the furnace (or buried in sand for cooling). The tempering is a heat treatment process that heat the steel to a certain temperature below AC1 after quenching the GB/T 8163 20# seamless steel tube workpiece to a certain temperature, which is kept warm for a certain time and then cooled to room temperature.

Tempering is usually followed by quenching. The purpose is to:
(a) eliminate residual stresses produced during quenching of steel tubes and prevent deformation and cracking.
(b) adjust the hardness, strength, plasticity and toughness of the workpiece to meet the performance requirements.
(c) stable organization and size, ensuring precision;
(d) improve processing performance. Tempering is the last important step in obtaining the desired properties of the workpiece.

Generally speaking, the main purpose of heat treatment for GB/T 8163 20# seamless steel tube is to refine the grain, even the organize, reduce the hardness and fully eliminate the internal stress.