Method of making one-piece tubular axle blanks and the produced axle blanks
AssigneeVallourec
InventorsJean-Jacques Delfino, Maurice Prevot
Life of this patent
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Abstract
A method for the economical manufacture of one-piece tubular axle blanks of the type having a center portion with journals at both ends. The method involves quenching a length of a preheated steel tube followed by tempering and then swaging at both ends by forging or hammering. The areas of transition between the center portion and the respective journals are thickened by upsetting, and the ends of the axle blank are subsequently locally heat treated by annealing.
Claims12
Method of making one-piece tubular wheel axle blanks composed of a center portion having journals at both ends, wherein a preheated steel tube is subjected to quenching particularly in water over its whole length followed by tempering, the tube ends being then swaged while the transition area between the center portion and the journal is, moreover, thickened by upsetting, whereupon both ends of the axle blank are locally heat treated by annealing.
Method according to one of the preceding claims, wherein swaging and upsetting are performed in a single operation by heating the corresponding end portion of the tube that has been quenched and tempered and cut beforehand, rapidly and scale-free particularly by induction, and forging it over an internal mandrel while exerting an axial thrust upon the end of the inserted tube which is rotated axially.
Method according to one of the preceding claims, wherein the annealing operation is at least partially performed by induction.
Method according to one of the preceding claims, wherein the starting tube is made of a weldable structural steel hardenable particularly in water.
One-piece tubular wheel axle blank produced by the method according to one of the preceding claims.
Dependencies are inferred from the claim text.