AISI Type S21904 (Alloy 21-6-9) Stainless Steel, 30% final cold reduction, stress relieving heat treatment 540°C (1000°F) for 2 hours, air cooled

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. % C Max 0.04   Cr 20   Fe 64

Component    Wt. % Mn 9   N 0.23   Ni 6

Component    Wt. % P Max 0.06   S Max 0.03   Si Max 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 Properties	Metric	English	Comments
Density	7.83 g/cc	0.283 lb/in³
Mechanical Properties
Hardness, Brinell	360	360	Converted from Rockwell C hardness.
Hardness, Knoop	392	392	Converted from Rockwell C hardness.
Hardness, Rockwell C	39	39
Hardness, Vickers	378	378	Converted from Rockwell C hardness.
Tensile Strength, Ultimate	1235 MPa	179000 psi
Tensile Strength, Yield	1115 MPa	162000 psi	at 0.2% offset
Elongation at Break	28 %	28 %	in 50 mm
Modulus of Elasticity	200 GPa	29000 ksi	Typical for stainless steel
Machinability	30 %	30 %	Based on 100% machinability for AISI 1212 steel.
Electrical Properties
Electrical Resistivity	7.3e-005 ohm-cm	7.3e-005 ohm-cm
Thermal Properties
CTE, linear 20°C	16.7 µm/m-°C	9.28 µin/in-°F	at 25-95°C, 17.3 µm/m°C at 25-205°C. Annealed
CTE, linear 250°C	18.2 µm/m-°C	10.1 µin/in-°F	at 25-315°C. Annealed
CTE, linear 500°C	19.1 µm/m-°C	10.6 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 Capacity	0.48 J/g-°C	0.115 BTU/lb-°F	Typical value for stainless steel.
Thermal Conductivity	13.8 W/m-K	95.8 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.