For operating temperatures of up to approx. 820 °C: ferritic SiMo cast irons, e.g. GJS-SiMo 40-6  At higher temperatures to a maximum of 950 °C: austenitic cast irons, e.g. GJSA-XNiSiCr35-5-2, also known as D5S   In the range up to 1,000 °C and slightly above: high-alloy, austenitic heat-resistant steels, e.g. 1.4849 up to 1,100 °C, or nickel-based alloys, e.g. Inconel 625 up to 1,050 °C