A preliminary assessment of high speed tool steels manufactured from powder for rolling bearing materials

High speed tool steels manufactured from powder were assessed under arduous conditions of rolling contact and compared with conventional materials using an accelerated service simulation test. Metallographic investigations revealed factors influencing performance. Material manufactured from powder was generally found to be inferior to vacuum-remelted material due to poor structure, porosity, high interstitial nitrogen content and other manufacturing variables. Sound homogeneous material with uniform fine carbide distribution and gas content comparable with those of conventionally cast material appears potentially suitable for rolling bearings. The improved performance at elevated temperature may be due to metallographic changes, deleterious interstitial nitrogen content being reduced by a precipitation process.