Abstract
Gas Nitriding is a common industry process which can improve the hardness, wear resistance, and fatigue strength of steel components. Proper surface activation is reported to be critical in achieving a uniform and repeatable nitriding response, but little data is available to compare various activation techniques for common nitriding alloys. This paper reports the early hour compound layer formation for six activation techniques on both a low alloy steel and a specialized nitriding steel. Both grades of steel showed the best performance when a multi-stage nitride washer was used to prepare the surfaces. Two other processes, namely nitric acid etching and a neutral wash and rinse cycle, were also shown to provide acceptable early hour performance for both alloys under the test conditions in this study.
