Microstructure and wear resistance of spray formed high chromium white cast iron

A 2.9% C–22% Cr white cast iron was processed by spray forming (SF) aiming to investigate the resulting microstructure and the wear resistance of this alloy. Two gas to metal flow rate ratios (GMR) of 0.12 and 0.23 were used. The samples were characterized by wear resistance tests, X-ray diffraction (XRD), optical microscopy and scanning electron microscopy (SEM), in both as-sprayed condition and after heat treatments. The as-sprayed microstructure showed M7C3 carbides embedded in a matrix of austenite and martensite and after heat treatments the matrix became a mixture of pearlite and austenite, which presented a better performance in dry sand/rubber wheel wear resistance tests, particularly when associated with a fine distribution of carbides at the higher GMR.