Alloy 21-6-9 • UNS S21900

21Cr-6Ni-9Mn is a high manganese nitrogen strengthened, austenitic stainless steel. It combines high strength in the annealed condition, excellent resistance to oxidation at high temperatures as well as good resistance to lead oxide and a high level of corrosion resistance at ambient temperatures. The alloy can be fabricated and formed much the same as type 304 and 316, and is readily wieldable. It remains nonmagnetic after severe cold work.

Available tube product forms

Typical Applications

Typical manufacturing specifications

  • AMS 5561
  • Also individual customer specifications.

Industries predominantly using this grade            

Technical Data

Mechanical Properties

Temper Annealed Cold-worked
Tensile Rm 95 ksi (min) 142 ksi (min)
Tensile Rm 655 MPa (min) 979 MPa (min)
R.p. 0.2% Yield 48 ksi (min) 120 ksi (min)
R.p. 0.2% Yield 330 MPa (min) 827 MPa (min)
Elongation (2” or 4D gl) 35 % (min) 20 % (min)


Physical Properties (Room Temperature)

Specific Heat (0-100°C) 500 J.kg-1.°K-1
Thermal Conductivity 14 W.m -1.°K-1
Thermal Expansion 16.7 mm/m/°C
Modulus Elasticity 19.6 GPa
Electrical Resistivity 73 μohm/cm
Density 7.83 g/cm3


Chemical Composition (% by weight)

Element Min Max
C - 0.08
Mn 8 10
Ni 5.5 7.5
Cr 19 21.5
Fe Balance
Mo 1.5 3
N 0.15 0.4
Si - 1
P - 0.06
S - 0.03
Request a quote