The influence of laser processing on the cavitation erosion of ductile
iron? a material employed extensively for components in marine applic
ations? including diesel-engine cylinder liners, valves and pumps, is
addressed here. Pearlitic ductile iron has only modest resistance to c
avitation erosion; the mean depth of penetration rate (MDPR) was 10-12
mu m h(-1) in distilled water. Ferritic ductile iron had consistantly
better resistance to erosion than pearlitic iron, particularly in cor
rosive media. The cavitation erosion rates in an aqueous slurry of 35
wt%. 220 grit SiC, Synthetic sea water (3.4 wt%) and centinormal dilut
e H2SO4 were 24, 40 and 86 mu m h(-1) respectively, whilst the corresp
onding rates were reduced to 3, 6 and 12 mu m h(-1) for laser-melted s
amples. The synergistic effect of corrosion and cavitation erosion was
more pronounced in the dilute acid than in the salt water. The cavita
tion erosion rates decreased linearly with increase in the pH value of
the cavitation bath. Laser treatment was very effective in bringing a
bout a nearly seven-fold enhancement of the erosion resistance of duct
ile iron in mild corrosive media. This has enabled the delineation of
the mechanism of cavitation erosion of ductile iron before and after l
aser processing, particularly in corrosive baths. A comprehensive revi
ew of published technical literature concerning the influence of laser
surface treatment on the cavitation erosion of selected steels and ca
st irons in different baths is included.