Influence of rolling conditions and aging process on mechanical properties of high manganese steels

Three laboratory cast and rolled high manganese steels with different Mn (in the range of 24–28 wt%), C (in the interval of 0.2–1.2 wt%) and Al (from 2.3 wt% to 12 wt%) contents has been investigated. Differences in chemical compositions, rolling conditions and followed by aging process at the temperature of 500 °C and four different aging dwells (in the range of 6 min to 60 min) have led to various k-carbides precipitation. The k-carbides have been responsible for the mechanical properties. The intragranular type of nano-size has increased the strength, respectively hardness level whereas the k-carbides nucleated in the intergranular form have reached size of micrometre and in lower volume fraction have not been importantly able to increase the matrix hardness, especially in case of lower C portion. Balanced Mn, C and Al contents for optimised k-carbides precipitation have been also discussed. The materials were hot rolled to strips of 1.9 mm in thickness from the heating temperature of 1100 °C using the rolling mill Tandem.