Hardening and corrosion behaviour of copper added SUS 304H austenitic steels subjected to thermal cycling

This research was aimed at determining optimum Cu content for the alloy design of SUS 304H austenitic steels having enhanced heat and corrosion resistance. Samples of the steel containing 1, 3, and 5 wt.% Cu were subjected to repeated heating and cooling to a temperature of 760°C and to a maximum of 15 cycles. Hardness measurement and the corrosion behaviour in 1M NaCl solution were evaluated. The hardness increases with an increase in the number of heating cycles for the three compositions. The hardening response to the thermal cycles is however higher for the 1 wt.% Cu composition and decreases with an increase in the Cu wt.%. The SUS 304H steel containing 3 wt.% Cu exhibited the least susceptibility to corrosion in the 1M NaCl solution irrespective of the number of heating cycles. The SUS 304H steel containing 1 wt.% Cu was found to exhibit the highest susceptibility to corrosion for all heating cycles compared.