Effect of impact angle and velocity on erosion of API X42 pipeline steel under high abrasive feed rate

The cost of erosion attack to the global oil and gas industry has drawn significant attention amongst researchers in recent years. Erosion is a complex phenomenon and in order to recommend ways to mitigate its effect it is essential to have a full understanding of the tribo-mechanisms involved. In the present study erosion tests were conducted on API X42 steel using aluminum oxide as erodent. The extent of material degradation is a function of the properties of abrasive particle, target material, erodent velocity, abrasive feed rate, attack angle and environment. In this study, erosion tests were carried out under high mean abrasive feed rate of 160 g min−1. Particle velocities and attack angles employed were as follows: 36 m s−1, 47 m s−1, 56 m s−1 and 81 m s−1 at 30°, 45°, 60° and 90°, respectively. Similar to erosion at low abrasive feed rate, it is found that erosion rate decreases with increasing impact angle and increases with increasing particle velocity. However, under the present experimental conditions, it is found that the velocity exponent (n) in the erosion rate equation (E=kVn) decreases with increasing abrasive particle angle of incidence. Contrary to common understanding for low particle feed rate tests, this finding suggests that the “n” value is mechanism dependent. Several mechanisms are found to be responsible for the behavior of API X42 steel under the experimental conditions used in this work. Heavy plastic deformation and fracture, ploughing and metal cutting are identified as operative mechanisms during erosion of API X42 pipeline steel.