The invention discloses 420 stainless steel
powder for MIM and a water-gas combined atomization pulverizing method thereof, and belongs to the field of
alloy materials. The 420 stainless steel powdercomprises the following elements in percentage by weight: 0.5-0.6% of C, less than or equal to 1.0% of Si, 0.7-1.5% of Mn, 0.1-0.7% of N, 12.0-14.0% of Cr, 1.0-3.0% of Ni, 0.5-1.5% of Mo, 0.1-0.5% ofCo, 0.5-1.5% of Nb and the allowance Fe and impurities. The method comprises the steps of adopting a medium-frequency
induction furnace for
smelting, dumping the medium-frequency
induction furnace, and enabling
molten steel to flow into a
tundish and flow out of a leakage hole; enabling high-pressure water to be sprayed out from a
nozzle of the spraying disc and focused on the
molten steel flow tocrush the
molten steel into fine particles, and cooling the fine particles into
metal particles in the flying process; and conducting filtering,
vacuum drying and screening, and thus obtaining
fine powder of which the particle size is less than 400 meshes. The method has the beneficial effect that the
alloy powder prepared by the process has good degree of
sphericity. Due to the good degree of
sphericity, the
powder can obtain enough flowability in the process of being injected into a mold cavity in the MIM process, the mold cavity can be fully filled with the powder, an injection blank withhigh density is obtained, and size fluctuation is small.