Numerical simulation of steel pipe quenching process using medium frequency induction heating machine

The use of medium-frequency induction heating machines for induction heating of steel pipes has the advantages of short induction heating time, precise temperature control, and environmental friendliness. It has been widely used in the quenching and bending of steel pipes. Aiming at the quenching induction heating process of a typical type of seamless steel pipe, especially the different heating sections using different frequencies, a debriefing simulation was performed to obtain the change process of the temperature field of the steel pipe during the entire heating process. The model can be used to optimize the parameters of the induction heating process, thereby providing a reference for formulating the induction heating process for seamless steel pipe quenching.

Induction heating of seamless steel pipes using medium-frequency electromagnetic induction heating machines is already a relatively mature technology in developed countries in Europe and the United States, and has been widely used in the field of special pipe manufacturing, such as TIMKEN Company and Longstar Company in the United States. , Japan's Kawasaki Steel Company, etc. all have their own steel pipe induction heating companies. Japan's Kawasaki Steel Company and others have their own steel pipe induction heating heat treatment production lines. At present, the application of induction heating steel pipe technology in China has just started. For example, Wuxi's Simles In 2006, Shiyou Special Pipe Manufacturing Co., Ltd. built a special pipe induction heating heat treatment production line in China. Medium frequency induction heating equipment is used in the heating area to conduct induction heating of steel pipes. At the same time, electromagnetic induction heating is also widely used in diameter expansion and bending of steel pipes. Induction heating uses electricity as the energy source, which avoids the emission of carbon dioxide and other harmful gases, so it is environmentally friendly. At the same time, induction heating steel pipes heat up quickly, have high efficiency, precise temperature control, easy automation, and flexible and convenient production organization, which saves the time and consumption required for the furnace to heat up and cool down when heating steel pipes with gas. Therefore, the induction heating method is considered to be the most promising steel pipe heating method and has broad application prospects.

This paper takes the induction heating process of a typical 45 steel seamless steel pipe (outer diameter 88.9mm, wall thickness 6.45mm) as the research object. Based on the established digital model of three-dimensional magnetic field, temperature field and the coupling between them, using The finite element method calculates the changes in the temperature field inside the steel pipe during the induction heating process, providing a reference for formulating a reasonable induction heating process.

We draw conclusions and discussions using physical and mathematical simulation and solution methods.

1. By establishing a magnetic-thermal coupling model for quenching induction heating of seamless steel pipes, the instantaneous distribution of the temperature field of the steel pipe can be well predicted and the changes in the temperature field inside the steel pipe can be obtained. At the combined frequency of 300-1000HZ, the inner and outer surface temperatures of the steel pipe tend to be consistent. By comparing with the heating temperature of steel pipes in actual projects, it can be seen that the simulation results are credible.

2. Numerical simulation results can reflect the impact of magnetic transition temperature on heating efficiency. In order to ensure a reasonable heating speed, a reasonable combination of heating frequencies must be selected. Through simulation, it can be seen that the frequency combination for practical application is suitable.

3. Through the numerical simulation of induction heating of seamless steel pipes, the induction heating system for steel pipe quenching can be formulated in a targeted manner.