Solidification structure of C2.08Cr25.43Si1.19Mn0.43Fe70.87 powders fabricated by high pressure gas atomization

Powders of hypoeutectic high chromium white cast iron (C2.08Cr25.43Si1.19Mn0.43Fe70.87) were produced by high pressure gas atomization. The microstructure of the powders was characterized using light microscopy, scanning electron microscopy and X-ray diffraction. The results showed that the as-atomized powders were mainly composed of austenite and M7C3 (M = Fe, Cr) type carbide, and became ferrite and carbide after annealing. With the decrease of the powder diameter, the number of austenite grains, primary dendrite length and second dendrite arm spacing were decreased. The relationship between cooling rate and microstructure was also determined.