Heat resistant steel castings are widely used for applications involving service temperatures exceeding 650°C. Mechanical strength at the elevated temperatures and type of aggressive environment are the main criteria by which these materials are selected.

Heat resistant steels maintain their mechanical strength and exhibit a suitable corrosion resistance over long periods of time. Iron-chromium-nickel heat resistant alloys have an austenitic matrix.

These alloys show superb strength and ductility at elevated temperatures. In addition, nickel-chromium-niobium (THR50/50) alloy will give improved resistance to attack by ash products of low grade fuel oils.

Moreover, it has superior creep rupture behavior in comparison to other heat resistant steels.