Abstract
In order to improve compressibility and compactibility of Cr bearing low alloy steel powder, spherical powder with controlled amount of surface oxide layer were prepared by water atomization and reduced in hydrogen atmosphere so as to make the surface of particles porous. Influence of preparing conditions on properties of powder were examined. Results were summarized as follows.
1) For obtaining a good compressibility and compactibility, effective oxygen contents of as-atomized powder were of 1-3 wt %.
2) To make the surface of spherical particle porous and controll rattler's value below 3%, maximum reducing temperature of 0.5, 1 and 2% Cr steel powders under the constant time of 60 min was of 900, 950 and 1050°C respectively.
3) Oxygen contents of reduced powder were 0.12-0.25 wt % when the reduction temperature is higher than 800°C.
4) 0.5 and 2% Cr steel powder containing 20100 mesh particles of about 60% showed the green density of 7.1 and 7.0 g/cm3 respectively, when pressed at 5 ton/cm2.
