The Purpose Of Heat Treatment For Cold Drawn Precision Seamless Steel Pipes

The heat treatment of cold drawn tubes is an important step in the cold drawing process. Both the inter process heat treatment in the cold drawing process of raw tubes without cold drawing and the heat treatment of finished tubes after cold drawing have a significant impact on the drawing effect and the metallographic structure or physical performance indicators of the finished tubes after drawing. If the billet of cold drawn tube is not in the normalising and annealing state, it needs to undergo heat treatment to reduce its hardness and improve its structure to enhance its cold drawing effect. After cold drawing, the steel pipe undergoes plastic deformation and undergoes work hardening due to lattice distortion and grain fragmentation and elongation, resulting in an unstable microstructure. Its hardness, strength, and other performance indicators are significantly improved while its plasticity is significantly reduced.

The purpose of heat treatment between cold drawn tube processes is to eliminate internal stress, reduce hardness, improve material plasticity, and enhance the effectiveness of re cold drawing. Otherwise, during the re drawing process, the decrease in material plasticity will cause interruptions in the drawing process and damage to the mould. The heat treatment of finished cold drawn tubes mainly aims to eliminate internal stress and ensure their strength, hardness, and other physical performance indicators to meet the requirements of use.