Influence of Microadditives of Different Nature on Powder Structure Formation of Carbon and Alloyed Steels during Sintering

摘要

The influence of additives of different nature on structure formation and properties of powder carbonand alloyed steels has been investigated. It has been shown that the introduction of high molecularcompound micro additives based on polypropylene glycol and alkali metal compounds leads toacceleration of carbon and alloying elements diffusion in iron, formation of fine-grained structure, increasein mechanical properties of carbon and alloyed powder steels due to redox reactions and refining of grainboundaries. Introduction of boron nitride in an amount of 0.5-1 wt. % leads to some increase in thestrength of carbon powder steels due to dispersed precipitates of carboborides, and also to a significantincrease in the strength of powder chromium steels due to the formation of liquid phase as eutectic alonggrain boundaries.