HIGH-TEMPERATURE EROSION OF HAYNES AND WASPALOY - EFFECT OF TEMPERATURE AND EROSION MECHANISMS

Erosion studies were performed on two heat-resistant alloys, Waspaloy and Haynes-lss. The variable studied was temperature which was changed in steps to 200, 400, 500, 650, and 800 degrees C. Erosion experiments were performed in a vertical sand-blast type of test rig which was capable of heating the incoming air and accelerating the particulate erodent material to a desired velocity. The test specimens were impacted with angular 150 mu m SiC particles accelerated by high pressure air to a velocity of 50 m s(-1). Erosion rate was found to increase continuously with the increase in temperature and it was not affected significantly by corrosion. Erosion mechanisms and morphological features of the eroded craters were analyzed by scanning electron microscopy. The test specimens of these alloys were also impacted by 3 mm balls at 50 m s(-1) impingement velocity and their deformation behavior at high temperatures when subjected to high velocity impacts was studied. The indentation depth and dynamic hardness were determined from these tests for various temperatures. The observations related to the erosion mechanisms, dynamic hardness, strength and ductility have been used to explain the high-temperature erosion behavior of these materials.