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Bearing Steels

Image of various bearing types.

Various bearing types.                       Source: NTN Americas

High performance mechanical systems (bearings and gears) in advanced gas turbine engines are required to operate at ever increasing operating, speeds, temperatures and loads. The balance of properties needed for improved bearing steel performance and reliability are typically in conflict with metallurgy requirements. To remain cost-effective, an optimized heat treatment of existing bearing steel compositions is desired. However, premature failure by corrosion pitting is a major concern in aerospace systems especially with operation in marine environments such as an aircraft carrier at sea.

Image of a EIS test setup.

EIS Cell Setup

The Bearing Steels project aims to assess the corrosion resistance of candidate heat treatments using a rapid screening test. Electrochemical corrosion testing is performed to rank bearing steel corrosion resistance. Testing is performed on bearing steels with various surface and heat treatments.

Testing for this research utilizes electrochemical impedance spectroscopy (EIS) scans during 24-72 hour immersion in synthetic sea water to provide a way to rapidly screen the corrosion resistance. The primary aim is to determine the effect of surface treatment corrosion behavior of a set of bearing steels that are used in gas turbine engines.