Corrosive wear behaviour of various nitriding treatments on a low alloy steel

The corrosive wear behavior of three gas nitriding treatments (72h, 90h and 120h) on nitrided steel (BS 970-905M39) was investigated under erosion-corrosion conditions at two angles of submerged jet impingement i.e. 90o and 20o. The test solution was 3.5% NaCl. Experiments were conducted with and without the presence of a burden of suspended silica sand particles. It was demonstrated that all the nitriding treatments promoted excellent corrosion resistance in the, particle-free impinging liquid. In the presence of the sand particles, however, clear mass losses were recorded on the nitrided steel but at a lower rate for 20o impingement than at perpendicular incidence. A comprehensive surface examination was conducted and facilitated measurements of wear scar depths under the impingement jet. The outcome of this approach was to demonstrate that the wear scar depths are not directly linked to total mass losses for all materials and this trend is discussed in the paper.