Caterpillar Inc.

Kenneth W Burris

Leonid Chuzhoy

M Brad Beardsley

Thomas E Clements

Chuong Q Dam

Gregory G Hafner

Gary L Biltgen

Timothy Michael Nenne

Joseph E McVicker

John B Walenta

Phil J Shankwitz

A method and apparatus for characterizing a quench for producing desired hardness characteristics on a steel part. The characterization preferably includes a series of heat transfer coefficients versus temperature for the quench determined from information representative of known quenches and distinguishing part characteristics such as geometry, size and composition. The quench characterization determined using the present method and apparatus can be utilized in hardness prediction software programs, and for determining a suitable quench for producing the desired hardness characteristics on the part.

Method and apparatus for characterizing a quench

A component subjected to one or more of rolling, sliding, abrasion and bending contacts is disclosed. The component has a surface and functionally graded material (FGM) thermally sprayed on the surface to form an FGM coating. The FGM coating has a thickness and a plurality of material compositions. The FGM coating also has a plurality of elastic modulus profiles. Each elastic modulus profile consists of a plurality of elastic modulii at a plurality of corresponding points within that thickness. The elastic modulii are in the range from about 28 Mpsi to about 60 Mpsi. Optionally, there is also a plurality of carbon content profiles.

Component having a functionally graded material coating for improved

A method for applying a functionally gradient coating on a component, having a surface and subjected to one or more of rolling, sliding, abrasion and bending contacts, including the step of thermally spraying a functionally gradient material (FGM) on said surface that forms an FGM coating, said FGM coating having a thickness, a plurality of material compositions and a plurality of elastic modulus profiles. Each elastic modulus profile consists of a plurality of elastic modulii at a plurality of corresponding points within that thickness. The elastic modulii are in the range from about 28 Mpsi to about 60 Mpsi. Optionally, there is also a plurality of carbon content profiles.

Process for applying a functional gradient material coating to a

A steel article has a composition, by weight percent, including from 0.20 to 0.45 carbon, from 0.4 to 1.5 manganese, from 0.5 to 2.0 silicon, from 0.01 to 2.0 chromium, from 0.15 to 1.2 molybdenum, from 0.01 to 0.40 vanadium, from 0.01 to 0.25 titanium, from 0.005 to 0.05 aluminum, from 0.0001 to 0.010 boron, less than 0.002 oxygen, from 0.005 to about 0.017 nitrogen, and the balance essentially iron. The steel article is free of any detrimental aluminum nitride and has, after quenching and tempering, a fully martensitic microstructure and a controlled distribution of spaced apart micrometer size titanium nitride cuboids and nanometer size background carbonitride precipitates.

Hardness, strength, and fracture toughness steel

A process for improving fatigue resistance of a case hardened component having a case thickness 't', subjected to one or more of rolling, sliding, abrasion, bending and pitting includes determining the magnitude of fatigue strength at surface and at a plurality of pre-selected points along thickness 't' of a component. The applied fatigue stresses acting upon the component at the surface and at the plurality of pre-selected points along thickness 't' are also determined. Then, a compressive residual stress profile is tailored from the surface to thickness 't' of the component. The compressive residual stresses at the surface and at the plurality of the pre-selected points along thickness 't' respectively have a magnitude sufficient to attain a net resultant stress which is at least 25% lower than the fatigue strength at the surface and the corresponding plurality of pre-selected points.

Process for improving fatigue resistance of a component by tailoring

A bearing assembly comprising, an inner race, an outer race spaced apart from the inner race and a plurality of rolling elements disposed in the space between the inner race and the outer race. The rolling elements are in rolling contact with the inner and outer races. An abrasion resistant coating is deposited on at least one of the inner race and the outer race. The coating is selected from the group consisting of metallic nitrides, metallic carbonitrides, and mixtures thereof.

Bearing assembly having improved fretting and abrasion resistance

A coated wear resistant steel article has a basic carburized low silicon steel article of preselected properties including carbides isotropically exposed and having an elevation greater than material adjacent said carbides of said carburized surface and a coating material having a hardness greater than about 1200 Kg/mm covering the material adjacent said carbides of said carburized surface. In another aspect, the coating material is absent and the surface is modified by ion implantation.

Wear resistant coated steel article

A process for forming a low silicon rapid-carburizing wear resistant steel article includes selecting an article formed of a steel material having less than about 0.05% silicon by weight, and carburizing the article for a preselected time and temperature to form an austenitic surface and attain a carburized case depth which is at least 5% greater than the carburized case depth of a similar article formed from a steel material having a range of about 0.09% to about 0.25% silicon by weight and being carburized at substantially same conditions of time and temperature. After quenching, the as-carburized surface transforms into a microstructure of martensite and retained austenite, being substantially free of intergranular oxides. A low silicon rapid-carburizing wear resistant steel article formed according to the present invention is particularly useful for making gears, couplings, shafts, bearings, and similar articles subjected to a combination of high bending loads, surface wear and contact fatigue.

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Peoria, IL, United States of America

Kenneth W Burris