Tungsten carbide coated piston rings

Abstract

Abstract PISTON RINGS, INCLUDING COMPRESSION AND OIL CONTROL RINGS, FOR INTERNAL COMBUSTION ENGINE PISTONS, HAIVNG A BEARING FACE OF AN ALLOY IS COMPOSED OF REFRACTORY A PLASMA JET STREAM. THE ALLOY IS COMPOSED OF REFRACTORY METAL CARGIDES SUCH AS TUNGSTEN CARBIDE IN SOLID SOLUTION WITH ANOTHER METAL, SUCH AS COBALT, TO PROVIDE A HARD WEAR PHASE WITH THE CARBIDE PARTICLES RELATIVELY FREE FROM SHARP EDGES AND CORNERS AND A SOMEWHAT SOFTER MATRIX PHASE COMPOSED OF METALS SUCH AS NICKEL, CHROMIUM, BORON, AND ALUMINUM. THE ALUMINUM SHOULD BE PRESENT IN A MINOR AMOUNT SUCH THAT EVER MINOR SCUFFING OF ENGINE CYLINDERS IS AVOIDED. THE COATING IS VERY HARD AND REFRACTOR, POSSESSES A HIGHER TENSILE STRENGTH THAN HERETOFORE USED PISTON RING FACINGS, DOES NOT SCUFF, HAS IMPROVED ABRASIVE WEAR RESISTANCE, AND OPERATES COMPATIBLY WITH THE ENGINE CYLINDERS. THE CARBIDES IN THE COATING WILL NOT PULL OUT IN OPERATION OF THE RING BECAUSE THEY ARE IN SOLID SOLUTION AND DO NOT HAVE A SHARP PARTICULATE FORM. THE NICKEL, CHROMIUM AND BORON IN THE ALLOY PROVIDE BINDERS IMPROVING THE MECHANICAL STRENGTH OF THE COATING AND THE HARDNESS OF THE MATRIX.

Inventors

• 👤 Harold E Mccormick

Bibliographic Details