Cu-Enrichment Characteristics at Grain Boundaries and Susceptibility to Surface Hot Shortness in Recycled Steels Containing Cu

摘要

The depth and number of Cu-enriched phase, which forms at austenite grain boundary during high-temperature oxidation, increase with copper content, while they decrease with increasing contents of Si, P and Ni. The susceptibility to surface hot shortness has a tendency to rise as the depth and number of Cu-enriched phase increase. However, this tendency toward increase is strongly dependent on the type of steel. The dependence seems to be attributed to the difference in the capability of steel for plastic deformation. As a consequence, the susceptibility can be evaluated by the multiple regression equation in which the maximum depth and number density of Cu-enriched phase as the chemical factor and the Vickers hardness as the mechanical factor are used as the independent variable.