Do you know key points of annealing and normalizing of seamless steel tube

Annealing of seamless steel tube:
Operation method: after heating the seamless steel tube to the temperature of AC3 + 30 ~ 50 ℃ or AC1 + 30 ~ 50 ℃ or below AC1, it is generally cooled slowly with furnace temperature.

Application points: 1. It is suitable for forging and welding parts of alloy structural steel, carbon tool steel, alloy tool steel and high speed steel, as well as raw materials with unqualified supply status; 2. Annealing is generally carried out in the blank state.

Normalizing of seamless steel tube:
Operation method: the seamless steel tube is heated to 30 ~ 50 ℃ above AC3 or ACCM, and then cooled at a cooling rate slightly higher than that of annealing.

Application points: normalizing is usually used as the pre heat treatment process of forgings, weldments and carburized parts. It can also be used as final heat treatment for low carbon and medium carbon carbon structural steel and low alloy seamless steel tube with low performance requirements. For general medium and high alloy steels, air cooling can lead to complete or partial quenching, so it can not be used as the final heat treatment process.

The purpose of annealing and normalizing of seamless steel tube: 1. Reduce the hardness, improve the plasticity, improve the cutting and pressure processing performance; 2. Refine the grain size and improve the mechanical properties to prepare for the next process; 3. Eliminate the internal stress produced by cold and hot working.