Fast induction heating of tantalum and tantalum alloys

Due to the high density of tantalum and its alloys, such as heating by a horizontally placed inductor, the surface of the blank will be coated when the inductor is moving.

Easily scratched by water-cooled rails. Generally, a straight sensor is used. According to the diathermy time and heating cycle of the blank, the number of stations of the sensor is determined. In order to ensure that the bad material is concentric with the inductor coil, the inclination of the end face of the blank should be ≤2mm. For a single station, it belongs to periodic induction heating.

Periodic induction heating is divided into uniform temperature heating and pulsation heating. The effective unit power of the uniform temperature heating surface is small, so that the heating time is long, and the billet is heated to lose more heat. In order to improve the thermal efficiency, the furnace lining wall thickness has to be increased. This in turn reduces the electrical efficiency and power factor.

Since the thermal conductivity of tantalum and its alloys is much higher than that of titanium, zirconium, nickel-based alloys, stainless steel, etc., in order to shorten the heating time, pulsation induction heating can be used.

Pulsating induction heating is to increase the effective unit surface power and use large road heating. When the surface temperature of the blank is close to the final temperature, reduce the power for uniform temperature and heat preservation. When the surface temperature drops to a certain value, increase the power to make the surface temperature close again. The final temperature. For example, if the temperature is raised several times-the temperature is equalized-the temperature is kept warm-the temperature is raised again, the pulsation heating can not only reduce the thermal stress generated in the billet due to the rapid heating, but also shorten the heating time and reduce the oxidation and gas pollution of the billet. The cyclically heated inductor can adopt a sealed design on the top and bottom, so that the blank is in a relatively closed environment in the inductor, which is beneficial to reduce oxidation and inhalation. When inert protective gas is passed, gas consumption can also be saved.