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AISI 321H is an austenitic stainless steel for high-temperature service, stainless steel 321H is the modification of Grade321. 321H stainless steel is a widely used stainless steel, where parts are heated within carbide-precipitation temperature range (800°F-1500°F) and exposed to corrosive atmosphere. 321 stainless steel is similar to 304 stainless steel, but with higher nickel content and stabilized with titanium.
Titanium preferentially reacts with carbon in the steel and prevents precipitation of chromium carbides at the grain boundaries, thus preserving corrosion-resistant properties by preventing depletion of chromium near the grain boundaries during exposure within critical temperature range. This grade responds well to hardening by cold working.
321H, is a titanium stabilized austenitic stainless steel that is known for its general corrosion resistance. This higher carbon version of Type 321 stainless steel offers a wide variety of benefits including:
Excellent resistance oxidation to 1500°F (816°C).
Good low temperature toughness.
Comparable corrosion resistance and machinability to Type 304.
Readily welded by most standard processes.
Very ductile and forms easily.
Grade | C≤ | Mn≤ | P≤ | S≤ | Si≤ | Cr | Ni | Ti |
321H | 0.04-0.1 | 2.0 | 0.045 | 0.03 | 0.75 | 17.0-19.0 | 9.0-12.0 | 4*(C+N)-0.7 |
Tensile, min, ksi[MPa] | Yield, min, ksi[MPa] | Elongation, %(min) | Hardness, HB（max） |
75【515】 | 30【205】 | 40 | 217 |
| Property | Value | Conditions / Notes |
|---|---|---|
| Density | 7.92 g/cm³ (0.286 lb/in³) | At room temperature (20°C/68°F) |
| Melting Range | 1,400–1,450°C (2,552–2,642°F) | Typical for titanium-stabilized austenitic SS |
| Specific Heat Capacity | 500 J/kg·K (0.12 BTU/lb·°F) | At 20°C (68°F) |
| Thermal Conductivity | 16.2 W/m·K (9.4 BTU·in/hr·ft²·°F) | At 100°C (212°F) |
| Electrical Resistivity | 0.72 μΩ·m | At 20°C (68°F) |
Thermal Expansion Coefficient
Temperature Range | μm/m·°C | μin/in·°F |
20–100°C (68–212°F) | 16.6 | 9.2 |
20–300°C (68–572°F) | 17.5 | 9.7 |
20–500°C (68–932°F) | 18.0 | 10.0 |
20–800°C (68–1472°F) | 18.7 | 10.4 |
Thermal Conductivity vs. Temperature
Temperature (°C) | Thermal Conductivity (W/m·K) |
100 | 16.2 |
300 | 19.5 |
500 | 22.0 |
800 | 26.5 |
Electrical and Magnetic Properties
Property | Value |
Electrical Resistivity | 0.72 μΩ·m (20°C) |
Relative Permeability | 1.02 (Annealed) |
≤1.10 (Cold-worked) | |
Curie Temperature | Not applicable |
Structural and Elastic Properties
Property | Value | Conditions |
Elastic Modulus | 193 GPa (28 x 10⁶ psi) | At 20°C (68°F) |
179 GPa (26 x 10⁶ psi) | At 500°C (932°F) | |
152 GPa (22 x 10⁶ psi) | At 800°C (1472°F) | |
Shear Modulus | 77 GPa (11.2 x 10⁶ psi) | Estimated |
Poisson's Ratio | 0.28–0.30 | Typical for austenitic SS |
Crystal Structure | Face-Centered Cubic (FCC) | Austenitic, stable to 900°C+ |
Creep and Rupture Strength
Temperature | Stress for 1% Creep/10,000h (MPa) | Rupture Strength/100,000h (MPa) |
600°C (1112°F) | 95 | 110 |
700°C (1292°F) | 55 | 75 |
800°C (1472°F) | 25 | 40 |
STANDARD | WERKSTOFF NR. | UNS | JIS | EN |
321H | 1.4878 | S32109 | SUS 321H | X12CrNiTi18-9 |
| Products | Standards | Show |
| 321H Stainless Steel Pipe | ASTM A312 |  |
| 321H Stainless Steel Tube | ASTM A269, ASTM A213 |  |
| 321H Stainless Steel Plate/Sheet | ASTM A240 |  |
| 321H Stainless Steel Bars/Rods | ASTM A276/A479 |  |
| 321H Stainless Steel Forging/Flange | ASTM A182 |  |
| 321H Stainless Steel BW Fittings | ASTM A403 |  |
Chemical and Petrochemical processing
Pharmaceutical production
Waste treatment including thermal oxidizers
Equipment and storage units for Food processing
Aerospace applications
