Induction heating offers significant advantages in welding applications, from preheating to post-weld heat treating (PWHT) and seam annealing. Its advantages over older methods include higher efficiency, more consistent heating and greater ease of use.
What is basic heat treatment?
Traditional industrial heating processes – such as furnaces, torches or salt baths – warm the workpiece through convection and thermal radiation. Induction heating for welding uses magnetic fields to induce eddy currents in the workpiece, exciting the molecules in the metal and generating heat. Because the heating occurs directly in the workpiece, no heat is lost in cables, blankets or wraps. The process also does not require any external cooling sources and operates at a much lower power level.
The induction system consists of an induction power supply that generates electromagnetic field to excite eddy currents in the workpiece, and an induction coil that generates the inductive current to heat it. The coil’s dimensions are chosen based on the workpiece’s size, shape and heating requirements. The induction system’s frequency is optimized to achieve a critical frequency at which the eddy currents from opposite sides of the workpiece impinge on each other and cancel out. The higher the frequency, the less effective the heating.
