Effect of Impact Angle on Slurry Erosion Behaviour and Mechanisms of Carburized AISI 5117 Steel

Abstract

The paper reports a study of slurry erosion of carburized AISI 5117 steel using whirling-arm rig. The study is mainly focused on studying the erosion wear resistance properties of AISI 5117 steel after carburizing at different impact angles. The mechanisms of erosion wear at different impact angles are presented using SEM examination of eroded samples. In addition, the SEM images of eroded samples at different stages are presented for better understanding of erosion mechanisms at different angles. The tests were carried out with particle concentration of 1 wt %, and the impact velocity of slurry stream was 15 m/s. Silica sand having a nominal size range of 250 – 355 μm was used as an erodent. The results showed that, carburizing process of steel increased the erosion resistance and hardness compared with untreated material for all impact angles. The erosion resistance of AISI 5117 steel increases by 70, 57, 60 and 36 % at an impact angle of 30o, 45o, 60o and 90o, respectively as result of carburizing, i.e. the effectiveness of carburizing was the highest at low impact angles. Treated and untreated specimens behave as ductile material, and the maximum mass loss appears at impact angle of 45o. Plough grooves and cutting lips appears for acute impact angle, but the material extrusions are for normal impact angles. The erosion traces are wider and deeper for untreated specimens comparing by the shallower and superficial ones for the carburized specimens.