November 2022 Volume 4

EQUIPMENT & TECHNOLOGY

Photo above of an 1100 KW Ajax TOCCO PowerZone System. The induction system coils are independently powered and matched for frequency and power level to the job requirements. Integral water system saves space as well as a fully integrated control package. When running lower production rates, the induction systems coils may be shut off thus better matching the power requirement to the production rate needs and reducing scale.

5. At this point you may have realized that the greatest losses in an induction forging system occur in the induction coils. It is important to use the correct copper for the frequency required to heat the billet or bar diameter and that the coil itself be properly engineered. Using the proper copper wall thickness, coil winding spacing and the proper relation of the copper coil id to the load od is particularly important to minimize losses. The refractory itself must be capable of both withstanding thermal shock and radiating as much as possible the thermal energy back into the load.The proper thickness of the refractory is also important so that we maximize thermal efficiency with consideration to also balance the proper coupling of the winding to the load to maximize coupling of the energy into the load. On systems with multiple coils, it is important to keep the gap between the coils to a minimum to reduce radiated losses that occur in these gaps.

6. It is also especially important to use the proper diameter coil in relation to the OD of the billet. This often results in having two to three sizes of coils in stock and available to run the various range of diameters. A good rule of thumb for efficient heating is to multiply the coils largest design diameter by .7 and this will provide to you the smallest diameter that should run thru this coil. For example, a coil designed for 6-inch diameter billets (6” x .7= 4.2”) would result in a 4.2-inch diameter billet being the smallest for an induction coil designed for 6 inch diameter billets. 7. Selecting the proper frequency for the billet or bar diameter being heated is also particularly important. Using the incorrect frequency results in wasted energy andmany times the inability for the induction system to effectively heat the part.

Curie Temperature is 1418 degrees F (770 degrees C)

FIA MAGAZINE | NOVEMBER 2022 24