Hastelloy C4 is a nickel-chromium-molybdenum alloy which has improved thermal stability. In this alloy, the tungsten was totally omitted and the iron content was reduced to approximately 1%. The alloy also contains approximately 0.3% Ti. Outstanding high-temperature stability; exhibits good ductility and corrosion resistance after long-time aging at 650 to 1040 °C (1200–1900 °F).