Research and development concerning direct iron making by utilizing high temperature reducing gas

The research and development of direct iron making technology by utilizing high temperature reducing gas were carried out as one of the large scale national projects from fiscal 1973 to fiscal 1980. This project aimed at the development of a utilization system, high temperature heat exchangers, heat resistant super-alloys and others when direct iron making is carried out by using the high temperature reducing gas obtained by the utilization of nuclear thermal energy in high temperature gas-cooled reactors. The National Research Institute for Metals engaged in the development of heat resistant super-alloys, and carried out the property confirmation test on the candidate alloys developed by private enterprises in a neutral position. The corrosion behavior in helium at 1000 deg C, in reducing gas at 900 deg C and in steam at 800 deg C was examined, and the creep rupture characteristics in the atmosphere and in helium at 1000 deg C and in reducing gas at 900 deg C were tested. Two Ni-Cr-W alloys, 113 MA and KSN, were very promising in achieving the target of more than 1 kgf/mm2 of creep rupture strength in helium at 1000 deg C for 50,000 hours. (Kako, I.)