Composite high-temperature valve and method of making the same

Abstract

Abstract A valve head blank consisting of a briquette of water-atomized high-temperature-resistant metal powder, commonly called ''''superalloy powder'''' (FIGS. 1 to 5 inclusive) is compressed by the upper punch of a briquetting press in the cavity of a die containing a core rod to form a socket in the head, which is then sintered in a sintering furnace in a protective atmosphere at about 2,000* F. Meanwhile, a valve stem of ordinary steel has been cold-headed or machined at its upper end to form a slightly flared reduced-diameter nose thereon. This valve stem is placed in the die cavity of a press with its flared nose projecting upward into the die cavity. A trumpet-shaped lubricant sleeve of nonferrous metal, such a copper, is then placed in the die cavity, followed by the reheated sintered valve head with its socket telescoping with the flared nose of the valve stem. The upper punch of the press is then caused to compress and thin the valve head while at the same time to elongate and interlock the neck thereof with the flared nose of the valve stem by an extrusion action as the metal lubricant sleeve facilitates the deformation of the respective parts. Alternatively (FIGS. 6 to 9 inclusive), gas-atomized superalloy powder is molded into a valve head blank consisting of a preform in a mold also containing a core pin, this assembly being sintered in a sintering furnace as before. A flared-nose valve stem is again placed in the die cavity, followed by the lubricant metal sleeve and not sintered preform, whereupon the hot-forming, extruding and elongating operation is carried out as before.

Inventors

• 👤 John Haller

Bibliographic Details