System for peripheral differential heat treatemnt to form dual-property workpiece
AssigneeWyman-Gordon Company
InventorWilford H. Couts, Jr.
Life of this patent
Estimating the term…
Abstract
A system for developing a metal workpiece in which the center and the periphery have different properties. The workpiece is processed to put it into a first metallurgical condition. Then, a portion of the periphery is dipped into a molten salt bath and the workpiece is rotated so that the periphery is converted to a second metallurgical condition by the heat of the salt bath.
Claims12
A method of heat treating each of a plurality of metal workpieces each having a central portion, an axis, and a peripheral portion having an outer surface, whereby the central portions and peripheral portions area put into different metallurgical states with peripherally and annularly uniform interface between them, comprising the steps of:
- (a) brining the workpiece to a first metallurgical state, using a first temperature range,
- (b) partially immersing the workpiece into a molten salt bath having a second chosen treatment temperature range, higher than said first temperature range, the bath having a well-defined surface,
- (c) controlling the height and angle of an axis of rotation of the workpiece with respect to said well-defined surface of the salt bath, and
- (d) rotating the workpiece about the axis to cause thermal contact between the salt bath and the outer surface of the peripheral portion at such speed and for such time as to cause the transformation of the peripheral portion to a changed metallurgical state.
An apparatus for forming a plurality of disc-shaped workpieces each workpiece having an axis and a central portion in one physical state having an annularly and peripherally uniform interface with a peripheral portion in a second physical state wherein the location and shape of the interface of each workpiece is substantially identical compared with each other such interface comprising,
- (a) a bath of molten salt having a uniform temperature near a well-defined surface,
- (b) an elevation driver and controller adapted to hold each workpiece at the axis, to set the axis orientation, and to move the periphery of the workpiece into and out of the bath,
- (c) a rotation driver and controller adapted to rotate the workpiece about the axis while it is held by the elevation driver, and
- (d) a temperature sensor and temperature controller for the salt bath.
Dependencies are inferred from the claim text.