The Role of Some Precipitants in the Controlled Rolling of Low Carbon Micro-Alloyed Steels,

摘要

A series of low carbon steels with various micro-allowing additions has been processed using two reverse rolling schedules, a continuous schedule and an interrupted schedule. The results indicate that a continuous schedule is always to be preferred if good impact properties are to be obtained. However,instead of the expected strengthening which might have been expected from a nitrogen addition, a loss in strength resulted when 0.012wt% nitrogen was added to a low carbon-niobium steel. This is thought to be due to the increased N:C ratio resulting in a decrease in the solubility of the carbonitride at any given austenitising temperature resulting in earlier coarser precipitation. However,the addition of aluminium to a 0.08wt.% Nb. 0.012wt.% N2steel resulted in improved impact properties,but failed to restore strength levels to those found in the N2-free steels.