Method of manufacturing a vehicle frame assembly

摘要

A heat treatment process is carried out on a closed channel structural member 25 to facilitate the subsequent performance of a magnetic pulse welding process so as to manufacture a vehicle frame component or a portion of a vehicle frame assembly. The workpiece 25 is preferably formed from a closed channel structural member having a circular or box-shaped cross sectional shape. The workpiece 25 is subjected to a scanning heat treatment process, wherein the workpiece 25 is heat treated in a continuous and longitudinal manner from one end to the other. Preferably, the workpiece 25 is supported vertically during the scanning heat treatment process to prevent the shape thereof from becoming distorted. The scanning heat treatment process is preferably a retrogression heat treatment process, wherein the workpiece 25 is rapidly heated by an induction heating coil 21 to a sufficient temperature that provides for full or partial softening thereof, followed by relatively rapid cooling by a quenching ring 22. In a third step of the method, a deforming process is performed on the workpiece 25 during the period of time following the retrogression heat treatment process in which the workpiece retains the full or partial softening characteristics. In a fourth step of the method, a magnetic pulse welding operation is performed to secure two workpieces together so as to manufacture a vehicle frame component or a portion of a vehicle frame assembly. At least one of the two workpieces is subjected to the scanning heat treatment process to facilitate the magnetic pulse welding process. <IMAGE>