Dual-frequency heating pipe thickened end of the quenching and cooling method, refer to preheat quenching cold + head content. Tempered steel pipe after delivery to the cooling bed for air cooling.

In short, dual-frequency heating method can make the thickening of the induction quenching and tempering heat treatment continued. The production process can be arranged in a production line, with the preheating method to improve production efficiency and save floor space. Oil well casing on-line induction heating quenching and off-line tempering quenching and tempering work, the use of steel after hot rolling caliper residual heat, followed by induction heating method to warm the temperature to the quenching temperature, the average temperature spray quenching . After quenching the oil casing pipe into the furnace and then into the high-temperature tempering, air-cooled quenched and tempered finish oil well after the art.