Alloy 321 (UNS S32100) is a stabilized stainless steel pipe which offers as its main advantage an excellent resistance to intergranular corrosion following exposure to temperatures in the chromium carbide precipitation range from 800 to 1500°F (427 to 816°C). Alloy 321 stainless steel tubing is stabilized against chromium carbide formation by the addition of titanium.
Alloy 321 stainless steel tube is also advantageous for high temperature service because of its good mechanical properties. Alloy 321 stainless steel pipe offers higher creep and stress rupture properties than Alloy 304 and, particularly, Alloy 304L, which might also be considered for exposures where sensitization and intergranular corrosion are concerns.
General Properties
Chemical Composition
Resistance to Corrosion
Physical Properties
Mechanical Properties
Elevated Temperature Oxidation Resistance
Heat Treatment
Fabrication
321 Stainless Steel Tube | 321H Stainless Steel Pipe
304 | 304L | 304H| 316/316L| 316Ti| 317L| 321/321H | 309S | 310S | 347/347H| S32205/S31803| S32750| 904L
Physical Properties of 321/321H Alloys in the Annealed Condition at -20°F to +100°F
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Tensile Strength |
Yield Strength |
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| Alloy |
UNS Designation |
Spec. |
psi |
MPa |
ksi |
psi |
MPa |
ksi |
Elongation in 2 inches (min.) % |
Grain Size Req. |
Maximum Harndess |
Modulus of Elasticity (x106 psi) |
Mean Coefficient of Thermal Expansion (IN./IN./°F x 10-6) |
Thermal Conductivity (BTU-in/ft2-h-°F) |
| 321 |
S32100 |
— |
75,000 |
515 |
— |
30,000 |
205 |
— |
35 |
— |
— |
29.0 |
9.2 |
— |
| 321H |
S32109 |
— |
75,000 |
515 |
— |
30,000 |
205 |
— |
35 |
7 or coarser |
— |
29.0 |
9.2 |
— |
| Grade |
321 |
321H |
| UNS Designation |
S32100 |
S32109 |
| Carbon (C) Max. |
0.08 |
0.04–0.10 |
| Manganese (Mn) Max. |
2.00 |
2.00 |
| Phosphorous (P) Max. |
0.04 |
0.04 |
| Sulphur (S) Max. |
0.03 |
0.03 |
| Silicon (Si) Max. |
0.75 |
0.75 |
| Chromium (Cr) |
17.0–20.0 |
17.0–20.0 |
| Nickel (Ni) |
9.0–12.0 |
9.0–12.0 |
| Molybdenum (Mo) |
— |
— |
| Nitrogen (N) |
0.1 Max. |
0.1 Max. |
| Iron (Fe) |
Bal. |
Bal. |
| Other Elements |
Ti=5(C) to 0.70% |
Ti=4(C) to 0.60% |
321/321H Product Range
| Alloy |
UNS Designation |
Werkstoff NR. |
Specifications* |
| 321 |
S32100 |
1.4541 |
A269, A/SA249, A/SA312 |
| 321H |
S32109 |
— |
A/SA249, A/SA312 |
*Note: The specifications noted including ASTM, ASME, or other applicable authorities are correct at the time of publication. Other specifications may apply for use of these materials in different applications.
