Research on Pressing and Sintering Process of A100 Steel in Powder Metallurgy

A variable-temperature supersolidus liquid phase sintering (SLPS) process was employed to fabricate high-density A100 high-alloy steel through vacuum pressureless sintering, with systematic investigation of the sintering densification mechanisms. The effects of powder particle size, compaction parameters, and sintering conditions on the densification, microstructure, and mechanical properties of powder metallurgy A100 steel were analyzed using optical microscopy, scanning electron microscopy (SEM), tensile testing, and density/hardness measurements. The results indicated that the sintering densification rate increased with decreasing particle size, and the variable-temperature SLPS process significantly enhanced alloy densification. By utilizing powders with a particle size range of 7.3–20.8 μm, mixed with 0.7 wt.% styrene-butadiene rubber (SBR) binder, granulated through 40-mesh sieving, and uniaxially pressed, the specimens achieved a density of 99.4 % and tensile strength exceeding 1700 MPa after sintering at 1440 ℃ for 10 min followed by 1430 ℃ for 72 min. During sintering, the variable-temperature profile promoted rapid densification via viscous flow and particle rearrangement at the high-temperature stage, while the dissolution-reprecipitation mechanism at the low-temperature stage optimized particle morphology adaptation, collectively improving densification efficiency.