Alloy,article of manufacture,and process

Abstract

Abstract ARTICLES OF MANUFACTURE GENERALLY AND IN PARTICULAR TAPPETS FOR INTERNAL COMBUSTION ENGINES ARE MADE OF A HIGH CARBON HIGH CHROMIUM ALLOY CONTAINING FROM ABOUT 1.3% TO ABOUT 3.1% CARBON, FROM ABOUT 15% TO ABOUT 35% CHROMIUM WITH THE REMAINDER IRON, WITH OR WITHOUT UP TO ABOUT 3.25% SILICON, MANGANESE AND OTHER RESIDUALS. THE ALLOY IS CAST, COOLED SO QUICKLY THAT A RELATIVELY SMALL NUMBER OF RELATIVELY LARGE PRIMARY CHROMIUM CARBIDE PARTICELS ARE FORMED AND WIDELY DISPERSED IN A MATRIX OF AUSTENITE CONTAINING A SOLID SOLUTION OF CHROMIUM AND CARBON. THEN LARGE NUMBERS OF RELATIVELY SMALL PARTICLES OF CHROMIUM CARBIDES ARE PRECIPITATED FROM THE MATRIX AND DISTRIBUTED THROUGOUT THE SPACES BETWEEN THE LARGE PRIMARY CARBON PARTICLES LEAVING THE REMAINDER OF THE MATRIX CONTAINING CARBON AND SUSCEPTIBEL TO SUBSEQUENT HARDENING. THEN THE CASTING IS HARDENED BY HEATING AND SUBSEQUENT QUENCHING AT SUCH TEMPERATURE AND AT SUCH TIME THAT THE MATRIX IS SUBSTANTIALLY CONVERTED TO MARTENISTE WITHOUT SIGNIFICANTLY CHANGING THE CARBIDE PARTICLES.

Inventors

• 👤 Earl A Thompson

Bibliographic Details