Fabrication,Microstructure,and Cavitation Erosion Resistance of a Grey Iron Laser Surface Alloyed with 22%Cr

A flake graphite grey cast iron has been laser surface alloyed with 22%Cr, and the cavitation erosion of the coating in distilled and 3%NaCl waters has been investigated at 50°C using a 20 kHz vibratory apparatus with an amplitude of 15 μm. Except for a few pores, limited cracking, and an occasional undissolved particle of chromium, the coatings were relatively uniform in thickness (∼ 0.5 mm), composition, and microstructure, and had a high integrity ana continuity with the substrate. The microstructure consisted mainly of an austenite and ferrite mixture. The coating reduced the steady state erosion rate of cast iron in distilled and salt waters to 0·04 and 0·11 of the uncoated level respectively.