Flat base truck rim forming system

A method of forming a flat base truck rim, said method comprising the steps of

• a. forming a flat strip of hot, rolled, rimmed, low carbon steel into a smooth cylinder welded together along abutting axial edges,
• b. heating one end of the cylinder to avoid degradation of the ductility and fatigue life of the cylinder and forming a rim gutter at the heated end of the cylinder in a gutter-forming die cavity wider than the starting thickness of the cylinder while applying a compressive axial load to the cylinder to increase the metal thickness in the rim gutter,
• c. forming a fixed flange at the other end of the cylinder by flaring the other end radially outwardly by a first surface of an expandable die in a first radial position,
• d. rough forming said fixed flange by a second surface of the same expandable die in a second radial position, and
• e. reducing the radial thickness of the flat base of the rim between the rim gutter and the fixed flange.

A method of forming a flat base truck rim from a flat strip of steel rolled into the form of a smooth cylinder and welded together along the abutting axial edges, said method comprising the steps of

• a. heating one end of the cylinder,
• b. advancing a plurality of dies located at opposite ends of the cylinder relatively toward each other in the direction of the cylinder axis to flare the other end of the cylinder radially outwardly while forming a rim gutter by applying a compressive axial load to the cylinder to force the heated end of the cylinder into a gutter-forming die cavity wider than the starting thickness of the cylinder,
• c. radially shifting the flaring die and again advancing said dies relatively toward each other in the direction of the cylinder axis to deform the outwardly flared portion of the cylinder to form a fixed flange at that end of the cylinder, and
• d. shear forming the flat base of the rim to reduce the radial thickness thereof in the low stress area between the gutter and the rim flange.