EROSION WEAR STUDIES OF MULTI-AXIALLY FORGED MARTENSITIC STAINLESS STEEL

Abstract

Owing to the attractive combination of high strength, hardness and corrosion resistance, martensitic stainless steels are used in several engineering applications such as bolts, nuts, bearings, seals, shafts, pumps, food and chemical processing equipment etc. Grain refinement of bulk metals using severe plastic deformation (SPD) is a popular approach to improve both strength and toughness. In the present work, focus has been on increasing the wear resistance of AISI 431 martensitic steel which has its applications particularly in areas where erosive wear occurs predominantly. The martensitic stainless steel is multi-axially forged (MAF) at 1150°C and subjected to tempering at 250, 400 and 650 T. The effect of forging and tempering on the performance of these steels in slurry erosion conditions is studied. In a given forging condition, least weight loss is observed in the samples tempered at 250 °C, while the highest weight loss is noted in samples tempered at 650 T. The least erosion wear is obtained in steels samples tempered at 250 °C after 6 passes of MAF, while the highest material loss is observed for the steel tempered at 650 °C after 3 passes of MAF. Micro cracking, carbide pull-out and pore formation, ploughing and lip formation are dominant wear mechanisms for the steels on the selected slurry erosion conditions. A correlation between microstructure, mechanical properties and slurry erosion wear behavior is highlighted.