Some properties of powder forged steel based on chromium prealloyed powders of high oxygen content

The reduction annealing of the Fe–0.7Mn–1Cr–0.5Mo with 0.52% oxygen content was carried out in cracked ammonia and hydrogen with addition of natural gas in the temperature range of 900–1150 °C. High temperature sintering at 1200–1300 °C of compacts prepared from the starting powder with addition of different amounts of graphite provided necessary decrease of oxygen content in the samples. By this way prepared sintered preforms were powder forged (PF), and the mechanical properties were estimated. The rolling contact fatigue endurance of PF samples was compared with those prepared from the Cr-alloyed powder with starting low oxygen content, from Fe2Ni0.5Mo powder and from wrought bearing steel. The production of Fe–1Cr–0.7Mn–0.2Mo powders of low oxygen content by water atomisation with additions of special inhibitors was demonstrated.