Which Boiler Tubes Need Heat Treatment?

Most low-temperature, medium-temperature, high-temperature, and ultra-high-temperature steel boiler tubes need heat treatment to improve their mechanical properties, heat resistance, and corrosion resistance.

Boiler tubes are one of the most important parts of boilers. They usually refer to a metal pipe used to manufacture and install boiler bodies and auxiliary equipment, and to transfer and convert heat energy. According to the production method, they can be divided into seamless steel pipes and welded steel pipes. As an important pipeline under high temperature and high pressure, the pressure resistance, wear resistance, toughness, and strength of boiler tubes need to be guaranteed.

In the process of processing and using boiler tubes, due to the effects of high temperature and high pressure, their structure and performance are prone to change, and they may also cause safety problems such as cracking and deformation of boiler tubes. In order to ensure the performance and safety of boiler tubes, they need to be modified and optimized through heat treatment technology.

Principle of heat treatment

Heat treatment is a thermal processing process for materials, which improves their performance by changing the organizational structure of materials. Common heat treatment processes include annealing, normalizing, quenching, and tempering. Among them, quenching can greatly improve the hardness and strength of steel, but it will increase brittleness and reduce its toughness. Tempering can restore the toughness and plasticity of the quenched material.

The role of heat treatment

1. Change the organizational structure of the material

Heat treatment can change the grain size and morphology of the material, and then change its mechanical properties and electrical properties. In the heat treatment process of the boiler tube, the grain size and morphology of the material can be changed by controlling parameters such as temperature and time, thereby improving the strength and pressure resistance of the pipeline.

2. Improve the hardness and strength of the material

In the heat treatment process of the boiler tube, quenching can greatly improve the hardness and strength of the pipeline, thereby improving its wear resistance and deformation resistance.

3. Restore the toughness and plasticity of the material

Although quenching can improve the hardness and strength of the material, it will cause its toughness and plasticity to decrease, which will cause brittle fracture problems. Tempering can restore the toughness and plasticity of the material after quenching, thereby improving the safety of the boiler tube.

Which boiler tubes need heat treatment

1. Low-temperature and medium-temperature steel boiler tubes

Low-temperature and medium-temperature steel boiler tubes are generally forged and heat treated to improve their wear resistance, hardness and strength, and have good weldability.

2. High-temperature and ultra-high-temperature steel boiler tubes

High-temperature and ultra-high-temperature steel boiler tubes are generally heat treated and hot pressed to improve their heat resistance and oxidation resistance, while reducing creep and fatigue damage.

3. Ferritic stainless steel boiler tubes

Ferritic stainless steel boiler tubes are generally solution treated to improve their corrosion resistance and heat resistance, and can maintain their good weldability.

4. Austenitic stainless steel boiler tubes

Austenitic stainless steel boiler tubes are generally stress relieved and quenched to improve their hardness and strength, and can improve their stability and corrosion resistance at high temperatures.

Summary

Heat treatment of boiler tubes is a necessary means to ensure their performance and safety, and can optimize their performance by changing the material's organizational structure and mechanical properties. Whether it is low temperature, medium temperature, high temperature or ultra-high temperature steel boiler tube, it needs to be heat treated to improve its mechanical properties, heat resistance and corrosion resistance. When using boiler tubes, it is also necessary to pay attention to their maintenance and care to extend their service life. During production and use, attention should be paid to controlling the heat treatment parameters and process to ensure the quality and safety of boiler tubes.