321 Stainless Steel - AMS 5510, AMS 5645
321 stainless steel (UNS S32100) is a titanium-stabilized austenitic stainless steel that features improved resistance to intergranular corrosion. This grade is suitable for high-temperature applications up to 1500°F (815°C), where the addition of titanium stabilizes the material against chromium carbide formation. Since titanium has a stronger affinity for carbon than chromium, titanium carbide precipitates within the grain instead of forming at the grain boundaries. While corrosion resistance is similar to 304 and 304L in the annealed condition, it features higher creep and stress rupture properties. These properties make it ideal for pressure vessels and boiler applications. 321 stainless steel is non-magnetic and heat resistant for continuous service at elevated temperatures.
- Inventory & Specs
- Chemical Composition
- Physical Properties
- Mechanical Properties
- Datasheet
- Additional Info
Inventory Size Ranges for 321
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Working with grade 321 steel
321 stainless materials cannot be hardened through heat treatment, only cold working. It is easily welded by all standard methods, and post-weld annealing is not required. This product is ductile and can be formed with ease. While corrosion resistance is generally excellent, especially against dilute organic acids, 321 SS is not suitable for chloride solutions, where it is susceptible to pitting and crevice corrosion.
Machining 321 stainless
This alloy steel is prone to work hardening and can be difficult to machine due to the addition of titanium - recommend rigid, powerful machining with minimal vibration and a quality lubricant, with tools kept sharp at all times. Avoid interrupted cuts to prevent unnecessary work hardening.
Purchasing 321 stainless steel in sheet, coil, round bar, and hex bar
We are suppliers of 321 stainless steel sheet, coil, hex bar, and round bar stock in a variety of lengths and widths, and we can custom cut this material to your exact specifications. Our stainless steel coil can also be slit to your desired width.
Other industry standards we comply with:
- PWA-LCS
- GE Aircraft Engine (GT193)
- RR SABRe Edition 2
- DFARS Compliant
Common Trade Names
- ATI 321 (™ Allegheny Technologies)
- Alloy 321
- Type 321 steel
Industry Applications for 321
- Useful in the chromium carbide precipitation range (800-1500°F, 427-815°C)
- Aircraft exhaust stacks
- Manifolds
- Chemical processing equipment
- Welded equipment
- Jet engine parts
- Heat Exchangers
- Expansion joints
Chemical Composition
| Element | Min | Max | |
|---|---|---|---|
| C | Carbon | - | 8.00 |
| Mn | Manganese | - | 200.00 |
| P | Phosphorus | - | 4.50 |
| S | Sulfur | - | 0.03 |
| Si | Silicon | - | 75.00 |
| Cr | Chromium | 17.00 | 19.00 |
| Ni | Nickel | 9.00 | 12.00 |
| Ti | Titanium | 5x(C+N) | 0.70 |
| N | Nitrogen | - | 0.1 |
| Fe | Iron | - | Balance |
Physical Properties
- Magnetic Permeability: H/m Anneal 1.02 Max
| Grade | Density | Modulus of Elasticity in Tension | Melting Range | |||
|---|---|---|---|---|---|---|
| g/cm3 | lb/in3 | psi | GPa | °C | °F | |
| 321 | 7.92 | 0.286 | 28 x 106 | 193 | 1398-1446 | 2550-2635 |
| 347 | 7.96 | 0.288 | 28 x 106 | 193 | 1398-1446 | 2550-2635 |
| Temperature Range | Coefficients | ||
|---|---|---|---|
| °C | °F | cm/cm/°C | in/in/°F |
| 20-100 | 68-212 | 16.6 x 10-6 | 9.2 x 10-6 |
| 20-600 | 68-912 | 18.9 x 10-6 | 10.5 x 10-6 |
| 20-1000 | 68-1832 | 20.5 x 10-6 | 11.4 x 10-6 |
| Temperature Range | W/m·K | Btu · in / hr · ft2 · °F | |
|---|---|---|---|
| °C | °F | ||
| 20-100 | 68-212 | 16.3 | 112.5 |
| 20-500 | 68-932 | 21.4 | 147.7 |
| Temperature Range | J/kg K | Btu/lb · °F | |
|---|---|---|---|
| °C | °F | ||
| 0-100 | 32-212 | 500 | 0.12 |
| Temperature Range | microhm·cm | |
|---|---|---|
| °C | °F | |
| 20 | 68 | 72 |
| 100 | 213 | 78 |
| 200 | 392 | 86 |
| 400 | 752 | 100 |
| 600 | 1112 | 111 |
| 800 | 1472 | 121 |
| 900 | 1652 | 126 |
Mechanical Properties
| Property | Type 321 | Type 347 |
|---|---|---|
| Yield Strength 0.2% Offset, psi (MPa) | 30,000 (205) | 30.000 (205) |
| Ultimate Tensile Strength, psi (MPa) | 75,000 (515) | 75,000 (515) |
| % Elongation in 2 in. or 51 mm | 40.0 | 40.0 |
| Hardness Max., Brinell (Plate) | 217 | 201 |
| Hardness Max., RB (Sheet & Strip) | 95 | 92 |