Heating nonmagnetic metal workpieces
AssigneePark-Ohio Industries, Inc.
InventorNorbert R. Balzer
Life of this patent
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Abstract
Method and apparatus for heating a billet of nonmagnetic metal material to forging temperature by first preheating the billet in a high efficiency slot-type electric radiant heat furnace to a preheat temperature a substantial level below the forging temperature, and then conveying the preheated billet from the furnace immediately into an inductive heating coil and energizing the coil to inductively post-heat the billet to the forging temperature.
Claims11
The method of heating a workpiece of nonmagnetic metal material having an initial temperature to a selective elevated processing temperature comprising the steps of:
- (a) first preheating the said workpiece in a high efficiency electric radiant heat furnace to a preheat temperature elevated above said initial temperature by more than one half the difference between said initial temperature and said processing temperature and said preheat temperature being substantially below said processing temperature of the workpiece so as not to cause undesired surface degradation and grain coarsening thereof, and
- (b) then transferring the said preheated workpiece from said furnace immediately into and post-heating said preheated workpiece inductively in an induction heating coil to said selective processing temperature.
Apparatus for heating a workpiece of nonmagnetic metal having an initial temperature to a selective processing temperature comprising a slot-type high efficiency electric radiant heat furnace for preheating the workpiece to a preheat temperature elevated above said initial temperature by more than one half the difference between said initial temperature and said processing temperature and said preheat temperature being below said selective processing temperature, conveyor means associated with said furnace for conveying the said workpiece therethrough to a discharge position therein at which the workpiece is at said preheat temperature, an induction heating coil located adjacent said furnace and having a workpiece receiving coil passageway therethrough, transfer means cooperating with both said furnace and said induction heating coil for transferring the said preheated workpiece from the said discharge position thereof in said furnace substantially immediately into and through the said passageway of said induction heating coil, and a high frequency electrical power supply for energizing said induction heating coil, while the said preheated workpiece is moved through said coil passageway, to inductively post-heat said preheated workpiece to the said selective processing temperature.
Dependencies are inferred from the claim text.