Velocity Measurements in a High Pressure Gas Quench Cell

Low pressure carburizing of automotive gears provides excellent control over case depth by ensuring that all parts are at the appropriate temperature before the carbon potential is introduced. For batch-processed loads of gears, however, uneven gas flow through the load in the high pressure gas quench cell can lead to distortion and variations in hardness. An ability to assess those flow patterns is needed.

This paper presents the development of an autonomous system to measure the flow pattern within a high pressure gas quench cell. The challenges of measuring velocities in an environment that includes a hard vacuum and pressures up to 20 bar is discussed. Also included in the paper is the approach used to incorporate the measurement system within the existing load of parts without presenting excessive obstruction to the flow field or displacing too much of the load. Sample data collected with the resulting device will be presented.