Satoshi Uenosono

Rolling Contact Fatigue Property of Sintered and Carburized Compacts Made of Molybdenum Hybrid-Alloyed Steel Powder

A new molybdenum hybrid-alloyed steel powder has been developed. The powder is based on a molybdenum prealloyed steel powder to which molybdenum powder particles have been diffusion bonded. The sintered compact made of the developed powder has a finer pore structure than that of the conventional molybdenum prealloyed steel powder, because the ferritic iron phase (α-phase) with a high diffusion coefficient is formed in the sintering necks where molybdenum is concentrated resulting in enhanced sintering. The rolling contact fatigue strength of the sintered and carburized compacts made of this powder improved by a factor of 3.6 compared with that of the conventional molybdenum prealloyed steel powder. The improvement in the rolling contact fatigue strength should result from the fine pore structure without coarse pores acting as stress concentration points.

Stronger necks and choked pores boost fatigue strength

Adding small amounts of molybdenum powder to molybdenum prealloyed steel can improve fatigue strength, researchers at Japans JFE Steel Corporation have found. They say that a finer pore structure is one of the contributors to improved properties…

Difference in Filling Property between Two Types of Binder Treated Powders Made of Atomized or Reduced Iron Powder

The filling property of the binder treated iron based powder made of atomized iron powder was compared with that of the one made of reduced iron powder. The latter one showed a better filling property than the former one, although the original reduced powder showed a worse flow rate. Changing the particle size distribution of the original atomized powder from wide to narrow like the original reduced iron powder, improved the filling property of the binder treated powder. As a result, the particle size distribution of the original iron powder was found to strongly affect the filling property of the binder treated powder.