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Effect of Liquid Content on Dimensional Stability and Sinter Properties of Liquid-Phase Sintered Low Alloyed Steels

  • : Bernardo, E1
  • : 1University Carlos III Madrid
  • : PDF Download
  • : 2012

Abstract

Dimensional control has become a crucial issue for the PM industry of liquid-phase sintered steels. The presence of a liquid phase activates densification of the steel, however it may cause swelling depending on the amount of liquid, wetting behavior and liquid composition. This study reports the effect of the liquid:solid ratio on the shape distortion when increasing amounts of Cu-Ni-Zn master alloy (3%, 6% and 9%) are added to plain iron powders along with 0.5wt.% graphite and 0.6wt% lubricant. Based on ThermoCalc calculations and thermal analysis, different sintering temperatures (above and below liquidus temperature of the master alloy) are proposed in order to evaluate the influence of liquid volume on densification and mechanical properties of the steel. Additional microstructural evolution reveals that optimization of the liquid volume provides with improved dimensional control and higher performance of the steel.
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