Enhancing the erosion-corrosion resistance of steel through friction stir processing

Erosion-corrosion is a critical problem in marine components and has huge economic impact. In the current study, friction stir processing was utilized for enhancing the erosion-corrosion resistance of SS316L steel, most widely used material for marine applications. Compared to the unprocessed alloy, the friction-stir processed specimen showed nearly 3.5 times and 5 times higher erosion and erosion-corrosion resistance respectively at oblique impingement. In contrast, erosion and erosion-corrosion resistance for processed alloy was 2 times higher at normal impingement. The unusual enhancement in erosion-corrosion resistance was attributed to surface strengthening through grain-size refinement and martensite phase formation. In addition, higher corrosion resistance due to stronger passivation also contributed towards superior performance of the processed alloy.