United Technologies Corporation

David A Haluck

Herbert A Chin

William P Ogden

Michael A Moulin

Sean P McCutchan

Leroy H Favrow

Roger W Bursey

Ronald I Holland

Anindya Ghoshal

Samuel S Owen

Ronald F Spitzer

James L Ambler

Allen V Keller

Lucy M Favrow, Legal Representative

William E Poole

John B Olinger, Jr

Sean Mccutchan

A method for cost effectively case hardening a component formed from a martensitic stainless steel material with a desired metallurgical condition for high temperature, high rolling contact fatigue, corrosion and spall initiation and propagation resistance bearing performance. The method describes a method to significantly reduce the carburization or carbo-nitriding process times for appreciable reduction in manufacturing cost. The Method includes the steps of: forming the component from a martensitic stainless steel material having an ASTM grain size of 9 or finer; and subjecting the component to one of a carburization and a carbo-nitriding treatment with significantly lower case hardening times for manufacturing cost-effectiveness.

Case hardening method for high performance long life martensitic stainless steel bearings

A method of treating bearing rolling elements or bearing rings after a hardening and temper heat treatment is disclosed. The method may include treating the bearing rolling elements in a tumbling treatment and then in a duplex hardening treatment. The method may include treating the bearing rings in a peening treatment and then in a duplex hardening treatment. The duplex hardening treatment may also include at least one sequential process segment consisting of subjecting the bearing rolling element & rings to a nitriding process to increase the surface hardness and compressive residual stress. The combined two-step process produces a deep surface/sub-surface residual stress greater than the depth of the maximum operating von-Mises shear stress along with an ultra-hard surface with high magnitude of compressive residual stress. In so doing, the bearing ring and rolling elements will have significantly enhanced rolling contact fatigue resistance and resistance to surface imperfections and debris.

Manufacturing process for aerospace bearing rolling elements

A method for testing ball bearings includes applying a Hertzian contact stress on a ball bearing to provide a fracture of the ball bearing that releases acoustic energy, establishing a signal representing the acoustic energy, and identifying occurrence of the fracture based upon the signal.

Acoustic method and apparatus for fracture detection of ball bearings

A carbo-nitriding process for forming a martensitic stainless steel, which is case hardened and superior corrosion resistance over carburized process, is provided. A process for forming a martensitic stainless steel which is case hardened is provided. The process comprises the steps of providing a material consisting essentially of from 8.0 to 18 wt % chromium, cobalt up to 16 wt %, vanadium up to 5.0 wt %, molybdenum up to 8.0 wt %, nickel up to 8.0 wt %, manganese up to 4.0 wt %, silicon up to 2.0 wt %, tungsten up to 6.0 wt %, titanium up to 2.0 wt %, niobium up to 4.0 wt % and the balance iron, and carbo-nitriding to prescribed levels of C+N, to form a hard, corrosion resistance case in a fracture tough stainless steel.

Carbo-nitrided case hardened martensitic stainless steels

A high performance rolling element bearing (5) which is particularly suitable for use in a cryogenically cooled environment, comprises a composite cage (45) formed from glass fibers disposed in a solid lubricant matrix of a fluorocarbon polymer. The cage includes inserts (50) formed from a mixture of a soft metal and a solid lubricant such as a fluorocarbon polymer.

High performance rolling element bearing

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Stuart, FL, United States of America

David A Haluck