Induction Heating Plant

an electrothermal installation for heating metal stock or parts by induction. Induction heating plants are most widely used for through-heating of metal stock before hot working and for surface hardening of steel parts. They usually consist of a generator, an induction heater, a capacitor battery, a transport mechanism for the articles being heated, a water cooling system, and protective and control systems.

Induction heating plants for through-heating of stock have multiturn, water-cooled lined induction heaters. Cold stock enters the heater from one side and, after heating, leaves from the other side. The feed mechanisms may have an electric-machine, pneumatic, or hydraulic drive. The heating is done at low or medium frequencies. Induction heating plants are used mainly for heating stock made of steel, copper, aluminum, molybdenum, tungsten, titanium, and zirconium and various alloys based on them. Induction heating plants are characterized by a high degree of automation and by low oxidation losses (less than 0.5 percent for steel).

The heaters of induction heating plants for surface hardening of steel parts are made without thermal insulation. The gap between the induction heater and the part being heated is 3–5 mm, which ensures high electrical efficiency of the process. Induction heaters most often have one turn; they are connected to a medium-frequency or high-frequency generator through a matching transformer. Water, oil, and various emulsions, which are fed onto the surface of the workpiece through openings provided in the induction heater or by special apparatus, are used as cooling liquids in hardening.