Method of hot working metal with induction reheating

A process for producing a wrought billet of enhanced fineness and uniformity of grain size and formed of a metal having a predetermined optimum hot working temperature range, said process comprising

• initially heating the workpiece by conduction and radiation heating in a box furnace to a temperature within said optimum hot working temperature range;
• hot working the heated workpiece by deformation to reduce the workpiece diameter and to refine and homogenize the grain structure and until the outer portions of the workpiece become chilled to the minimum practical working temperature, thereby necessitating reheating prior to further hot working;
• and
• subjecting the chilled workpiece to electric induction heating at a frequency preselected to concentrate the induced heat in the chilled outer portions of the workpiece to rapidly return the workpiece to the optimum hot working temperature throughout so that continued hot working can be reinitiated before appreciable grain growth can occur.

A process for producing a wrought billet of enhanced fineness and uniformity of grain size and formed of a metal, such as a nickel base alloy, having a relatively narrow range of temperatures within which hot working can be carried out, said process comprising

• initially heating the workpiece to an optimum hot working temperature;
• hot working the heated workpiece by deformation to reduce the workpiece diameter and to refine and homogenize the grain structure and until the outer portions of the workpiece become chilled to the minimum practical working temperature, thereby necessitating reheating prior to further hot working;
• and
• directing the chilled workpiece to an electric induction heating coil and reciprocating the workpiece back and forth through the coil while applying electric current to the coil at a frequency within the range of 300 to 1000 Hz. and preselected to concentrate the induced heat in the chilled outer portions of the workpiece to rapidly return the workpiece to the optimum hot working temperature throughout so that continued hot working can be reinitiated before appreciable grain growth can occur.