418 (Greek Ascoloy) is a chromium-nickel-tungsten martensitic alloy. 418 is a deep hardening grade used for application where high resistance to tempering and stress-corrosion cracking are needed. Greek Ascoloy is engineered for use in high-stress components up to 649 C. Typical heat treatment at 980C -1010C, followed by air or oil quenching (depending on material thickness) and 2-hour tempering twice at minimum 620C gives this material a superior creep strength and resistance to stress-corrosion cracking and tempering. Strength at the higher temperature is superior to that of the standard 12Cr type steel. 418 (Greek Ascoloy) is often used for Compressor Components, Turbine Blades, Steam Turbine Buckets, and Elevated Temperature Bolts. (UNS S41800)
