420 stainless steel powder for MIM and water-gas combined atomization pulverizing method thereof

Abstract

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.

Description

technical field [0001] The invention relates to the field of alloy materials, in particular to a 420 stainless steel powder and a water-gas combined atomization powder making method thereof. Background technique [0002] 420 stainless steel belongs to martensitic stainless steel, which can be divided into 420J1 (national standard GB2Cr13) and 420J2 (national standard GB 3Cr13) according to different carbon content. 420J1 (2Cr13) does not meet the performance requirements of cutting tools due to its low hardness and tensile strength. The currently commonly used 420 generally refers to 420J2 (3Cr13). The characteristic of martensitic stainless steel is that the matrix is ​​martensite, which is magnetic, and its mechanical properties can be adjusted by heat treatment. The American Iron and Steel Institute marks martensitic stainless steel with numbers 410, 420, and 440. Martensite has an austenite structure at high temperature, and when cooled to room temperature at an appro...

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Problems solved by technology

[0015] Aiming at the problem that the 420 stainless steel powder prepared by the water atomization method in the prior art cannot meet the requirements of MIM manufacturing, the present invention provides a 420 stainless steel powder and its water-gas combined atomization powder making method, which will provide a new solution for the MIM manufacturing industry. Provide new 420 stainless steel powder with high hardness, high strength and high corrosion resistance suitable for MIM manufacturing process

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