EFFECT OF MICROSTRUCTURE ON MATERIAL WASTAGE IN A ROOM-TEMPERATURE FLUIDIZED-BED WEAR-TEST RIG

Rod-shaped 1018 steel specimens were prepared in four different micros tructure conditions, i.e. annealed, normalized, cold-drawn and as-quen ched. A unique laboratory-scale fluidized-bed erosion-wear test appara tus was operated at room temperature to study the influence of the mic rostructure of the steel specimens on metal wastage. 800 mum angular q uartz (SiO2) particles were used as the bed material. The mass and cir cumferential thickness change distributions of the specimen rods were determined. The morphologies of the specimens were examined by scannin g electron microscopy (SEM) and the microhardness of the surface of th e specimens was measured. It was determined that the harder and more h omogeneous the morphology of the steel, the lower the metal wastage. T here was a different relationship between the microstructure of the st eel and metal wastage from that which occurs in erosion tests using a blast nozzle tester at higher particle velocities, i.e. greater than o r equal to 10 m s-1. Testing in the nozzle tester at higher particle v elocities and resultant impact forces, the erosion metal wastage is re lated to the distribution of hard, brittle phases in a softer metal ma trix and is not related to its hardness. The thickness change profiles around the periphery of the four different treated 1018 steel rods we re very similar. The locations of maximum thickness losses were at 144 -degrees and 216-degrees from top center, 0-degrees. This distribution was independent of the microstructure of the specimens.