Heat treatment method in boiler pipeline

　　Heat treatment is a method to change the physical properties of high pressure boiler tubes by heating and cooling. Heat treatment can improve the microstructure of high pressure boiler tubes, so as to meet the physical requirements. Toughness, hardness and wear resistance were obtained by heat treatment. In order to obtain these properties, quenching, annealing, tempering and surface hardening must be used.

　　A. Quench

　　Hardening, also known as quenching, refers to heating the ASME Carbon Seamless Steel High Pressure Boiler Pipe evenly to a suitable temperature, then rapidly immersing in water or oil for rapid cooling, and then cooling in the air or freezing area. The required hardness of high pressure boiler pipe can be obtained.

　　B. tempering

　　ASME Carbon Seamless Steel High Pressure Boiler Pipe will become brittle after hardening. The stress caused by quenching will lead to the thread fracture of high pressure boiler pipe. The tempering method can be used to eliminate brittleness. Although the hardness of high-pressure boiler tube is reduced, its toughness can be increased to reduce brittleness.

　　C. annealing

　　Annealing is a method to eliminate the internal stress of ASME Carbon Seamless Steel High Pressure Boiler Pipe. The annealing method is to heat the steel parts to critical temperature, and then put them into dry ash, lime, asbestos or closed in the furnace, and then make them slowly cool.