Patent ID: 6651477
Filing Date: 2003-11-25
Classification: B21D,B62D

Abstract:
A process of producing from an elongate tube a tubular structural support component having a first longitudinal section integrally connected to a second longitudinal section, the second section being located at the end of the tube and being of a desired cross-sectional shape and size, the cross-sectional size of the second section being greater than that of the first section, the process including an elongate tube formed from steel selecting a mandrel having a cross-sectional shape and size corresponding to the second section, relatively axially feeding said end of the tube over the mandrel with the tube or mandrel being held in a static condition in order to form said second section, the choice of the size of mandrel and the rate of feed and the axial pressure applied to said tube being controlled such that the wall thickness of the second section is on average at least 70 percent of the average wall thickness of the first wall section. the control of said feeding of the tube and the selection of the size of mandrel also being such that material flow in the tube forming the second section produces a neutral or negative strain in the axial direction of the tube and a neutral or positive strain in the circumferential direction of the tube with the strain values being less than the yield strength of the steel from which the tube is formed.