Production of wear-resistant iron-based powder materials by hot forging porous blanks in the presence of liquid phase of Ni - B eutectic

摘要

Alloys, containing Ni - B eutectic, possess high thermodynamic stability of the structure. These alloys retain high hardness and wear resistance at high temperatures. In the present work a nickel-based powder, containing Ni - B eutectic, was used as the fusible additive to the iron-based powder. Porous cold-pressed preforms were heated to various temperatures and subjected to hot forging. Heat treatment of samples was performed after hot forging. The influence of the content of low-melting ad-ditive and the modes of hot forging on the mechanical properties and wear resistance of the obtained material was studied. The possibility of cracking during hot forging has been determined. The probabil-ity of cracking is reduced by prolonging the heating prior to deformation. As this takes place, a liquid phase seeps along the grain boundaries inside the iron powder particles, resulting in fragmentation and reducing thickness of eutectic film and sizes of the precipitates of borides. The optimum values of process conditions, which provide obtaining powder material with high wear resistance and satisfacto-ry mechanical properties, have been determined.