AISI Type S21904 (Alloy 21-6-9) Stainless Steel, sheet and strip 30% cold reduction, tested at RT, stress relieved at 480°C (900°F) for 1 hour


Subcategory: Ferrous Metal; Heat Resisting; Metal; Stainless Steel; T S20000 Series Stainless Steel

Close Analogs: AISI Type S21900

Key Words: UNS S21904, AMS 5595, AMS 5656, ASME SA412, ASTM A269 (XM-11), ASTM A276 (XM-11), ASTM A314 (XM-11), ASTM A412 (XM-11), ASTM A473 (XM-11), ASTM A580 (XM-11)

Component   Wt. %
CMax 0.04 
Cr20 
Fe64 
Component   Wt. %
Mn9 
N 0.23 
Ni6 
Component   Wt. %
PMax 0.06 
SMax 0.03 
SiMax 1 

Material Notes:
Austenitic, high strength, excellent corrosion resistance, and low magnetic permeability. Applications include aircraft applications such as ducting and bellows systems, tail pipes and exhaust systems, clamps, fasteners, flanges, and hydraulic tubing.

Physical PropertiesMetricEnglishComments
Density7.83 g/cc0.283 lb/in³ 

Mechanical Properties
Hardness, Brinell389389 Converted from Rockwell C hardness.
Hardness, Knoop426426 Converted from Rockwell C hardness.
Hardness, Rockwell C4242 
Hardness, Vickers410410 Converted from Rockwell C hardness.
Tensile Strength, Ultimate1278 MPa185000 psi 
Tensile Strength, Yield1229 MPa178000 psi at 0.2% offset
Elongation at Break11 %11 % in 50 mm
Modulus of Elasticity200 GPa29000 ksi Typical for stainless steel
Machinability30 %30 % Based on 100% machinability for AISI 1212 steel.

Electrical Properties
Electrical Resistivity7.3e-005 ohm-cm7.3e-005 ohm-cm 

Thermal Properties
CTE, linear 20°C16.7 µm/m-°C9.28 µin/in-°F at 25-95°C, 17.3 µm/m°C at 25-205°C. Annealed
CTE, linear 250°C18.2 µm/m-°C10.1 µin/in-°F at 25-315°C. Annealed
CTE, linear 500°C19.1 µm/m-°C10.6 µin/in-°F at 25-540°C, 20.0 µm/m-°C at 25-760°C, 20.0 µm/m-°C at 25-870°C, 20.5 µm/m-°C at 25-980°C. Annealed
Specific Heat Capacity0.48 J/g-°C0.115 BTU/lb-°F Typical value for stainless steel.
Thermal Conductivity13.8 W/m-K95.8 BTU-in/hr-ft²-°F 13.8 at 95°C, 7.8 W/m°C at -180°C, 10.9 W/m°C at -73°C, 16.1 W/m°C at 205°C, 18.2 W/m°C at 315°C, 20.2 W/m°C at 425°C, 22.5 W/m°C at 540°C, 24.7 W/m°C at 650°C, 26.8 W/m°C at 760°C, 28.9 W/m°C at 870°C

References for this datasheet.


Some of the values displayed above may have been converted from their original units and/or rounded in order to display the information in a consistant format. Users requiring more precise data for scientific or engineering calculations can click on the property value to see the original value as well as raw conversions to equivalent units. We advise that you only use the original value or one of its raw conversions in your calculations to minimize rounding error. We also ask that you refer to MatWeb's disclaimer and terms of use regarding this information. MatWeb data and tools provided by MatWeb, LLC.