Method for manufacturing a gear

A method for manufacturing a gear, comprising:

• forming a bi-material billet by:
• providing a steel cylinder having:
• a cylindrical wall with a cylindrical wall thickness;
• a first end closed with a first steel cap;
• and
• a second end distal to the first end wherein the second end is an open end;
• disposing a core material other than steel through the open end into the steel cylinder;
• welding a second steel cap onto the second end of the steel cylinder to form the bi-material billet;
• heating the cylindrical wall until a minimum temperature of a coolest portion of the cylindrical wall is at least about 1900 degrees F. and a maximum temperature of a hottest portion of the cylindrical wall is less than about 2300 degrees F.;
• performing a first forging blow on the heated billet or on a disk-shaped rough forging forged from the heated billet with a first closed blocker die driven by a press to produce a partial toothed preform;
• and
• performing a second forging blow on the partial toothed preform with a second closed blocker die driven by the press to produce a netshape gear wherein:
• the first closed blocker die has a die cavity including gear tooth forms;
• and
• the partial toothed preform includes a plurality of spaced gear teeth.