Method for producing a family of forged ring rolling preforms and forging die therefor

A method for forging a series of ring rolling preforms, each preform of said series to be ring rolled into a ring shaped forging blank for precision forging into a near net ring gear forging of known outside diameter, toe diameter and total volume, at least one of said outside diameter, toe diameter and total volume of the near net ring gear forging to be produced by each member of said series of preforms being different than the outside diameter, toe diameter and total volume of the near net ring gear forging to be produced by the other members of said series of ring rolling preforms, said method comprising:

• providing a preform forging die having a die cavity comprising a substantially toroidal shaped portion of given volume and of given cross-sectional interior diameter, a disc shaped portion extending radially inwardly from said generally toroidal shaped portion and an overflow portion extending radially outwardly from said generally toroidal shaped portion, said overflow portion in cross-section being generally traingular shaped and defined by flat surfaces extending from said toroidal shaped portion radially outwardly and tangentially toward the parting surface of said die to define an included angle therebetween;
• and
• forging preforms utilizing said preform forging die if the volume of the near net ring gear forging to be produced therefrom is in the range of eighty percent (80%) to one hundred percent (100%) of the volume of said toroidal cavity portion.