Hastelloy S (UNS N06635)

Hastelloy S alloy (UNS N06635) is a nickel-base, high-temperature alloy with a unique combination of properties. It has excellent thermal stability, low thermal expansion and excellent oxidation resistance to 1093℃. In addition, the alloy has good high-temperature and thermal fatigue strength. S alloy retains its strength and ductility after aging at temperatures of 427 to 871℃.

Equivalent Grades

Hastelloy SHastelloy SN06635

Chemical Composition, %

Hastelloy S≤0.020.20-0.750.30-1.00≤0.025≤0.01014.5-17.0Bal≤2.0014.0-16.5≤1.00.1-0.5≤0.35≤0.0150.01-0.10≤3.0

Typical Physical and Mechanical Properties (RT, Annealed)

Density, g/cm3Melting Point, ℃Tensile Strength, MPaYield Strength, MPaELongation, %Hardness, HRB

Available Products and Specifications

Rod, Bar, Wire and Forgings
Plate, Sheet and Strip
Pipe and Tube
Welding Product


  • Excellent thermal stability
  • Low thermal expansion and excellent oxidation resistance to 1093℃
  • High temperature and thermal fatigue strength


Hastelloy S is mainly developed for applications involving severely cyclical heating conditions where components must be capable of retaining strength, ductility, and metallurgical integrity after long time exposure and are extensively used as seal rings in gas turbine engines where its low thermal expansion coefficients is also important.