Sintered steel bar is atomized iron powder mixed with 0.90% graphite, pressing, sintering, density of 6 ~ 7.1g / cm3. In 870 DEG C in a neutral atmosphere austenitic 30min after the water quenching. From the quenching end every 2.5mm measuring point on the iron base powder metallurgical materials, in addition to the above the influence of porosity on material hardenability, added to the material of alloy elements, such as copper, nickel, molybdenum, also affect the material hardenability.
The hardness and depth of the curve is the relationship between HRA hardness scales made. End quenching depth refers to the sample from the quenching hardness value than 65HRA end to the depth ( each 1.6mm interval ( 1 / 16 inch ) take a hardness readings ). Quenching data are apparent hardness determination, therefore, the results of determination also includes the influence of density.