AMS 5645 specification covers a corrosion- and heat-resistant steel (321 Stainless Steel / UNS S32100) in the form of forgings, wire, bars, mechanical tubing, flash welded rings, and stock of any size for forging or flash welded rings. 321 stainless steel bar is a chromium-nickel stainless steel stabilized with titanium, resulting in an engineering material that offers excellent resistance to intergranular corrosion in the heat-affected zone (HAZ). 321 stainless steel bar is resistant to intergranular corrosion, and its general corrosion resistance is less than Type 302. Typical examples include jet engine components and afterburners. The alloy benefits from impressive mechanical properties and may be easily welded and formed. The suitable operating temperature range is 427°C to 816°C (800°F to 1500°F) .
Product Forms & Availability – 321 Stainless Steel (UNS S32100)Bar & Related Forms (AMS 5645)| Product Form | Size Range | Condition |
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| Round Bar | Φ3mm – 500mm | Annealed | | Hex Bar | Custom sizes | Annealed | | Flat Bar | Custom sizes | Annealed | | Square Bar | Custom sizes | Annealed | | Wire | Various gauges | Annealed | | Forgings | Custom configurations | Annealed |
Additional 321 Product Forms| Product Form | Specification | Availability |
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| Sheet | AMS 5510 | Available | | Strip | AMS 5510 | Available | | Plate | AMS 5510 | Available | | Seamless Tube | AMS 5570 | Available | | Welded Tube | AMS 5557, AMS 5576 | Available | | Thin Wall Tube | AMS 5559 | Available | | Foil (Shim) | Various thicknesses | Available |
View Foil Stock List, Sheet Stock List, Plate Stock List for all availability – contact Sales.
Specifications – 321 Stainless Steel| Specification | Product Form | Description |
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| AMS 5645 | Bars, wire, forgings, mechanical tubing, rings | Corrosion and heat resistant | | AMS 5510 | Sheet, strip, plate | Flat products | | AMS 5557 | Welded/seamless tube | Tubing | | AMS 5559 | Welded/thin wall tube | Thin wall tubing | | AMS 5570 | Seamless tube | Seamless tubing | | AMS 5576 | Welded tube | Welded tubing | | UNS S32100 | – | Unified numbering system | | ASTM A276 | Bar | Standard specification | | ASTM A479 | Bar for pressure service | Standard specification |
Chemical Composition| Chemical Composition (Weight %) | 321 Stainless Specification |
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| Chromium (Cr) | 17.0 - 19.0 | | Nickel (Ni) | 9.0 - 12.0 | | Titanium (Ti) | 5 × C min. - 0.70 max. | | Carbon (C) | 0.08 max. | | Manganese (Mn) | 2.00 max. | | Silicon (Si) | 0.75 max. | | Phosphorus (P) | 0.045 max. | | Sulfur (S) | 0.030 max. | | Iron (Fe) | Balance |
| Physical Properties | Metric | Imperial |
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| Density | 7.92 g/cm³ | 0.286 lb/in³ | | Melting Range | 1400 - 1425°C | 2550 - 2600°F | | Modulus of Elasticity | 193 GPa | 28.0 × 10⁶ psi | | Coefficient of Expansion (20-100°C) | 16.5 µm/m·°C | 9.2 µin/in·°F | | Thermal Conductivity | 16.1 W/m·K | 112 BTU·in/hr·ft²·°F | | Electrical Resistivity | 0.72 µΩ·m | 0.72 µΩ·m |
| Mechanical Properties (Bar – Annealed) | Metric | Imperial |
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| Tensile Strength (min.) | 515 MPa | 75 ksi | | Yield Strength (0.2% offset, min.) | 205 MPa | 30 ksi | | Elongation (min.) | 40% | 40% | | Hardness (Brinell) | 217 max. | 217 max. |
Heat Treatment | Process | Temperature | Cooling | Purpose |
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| Solution Annealing | 950-1120°C (1740-2050°F) | Rapid cool (water quench or air cool) | Dissolve carbides, optimize corrosion resistance | | Stabilizing Treatment (optional) | 870-900°C (1600-1650°F) × 1 hour per 25mm thickness | Air cool | Fully stabilize carbon as titanium carbide |
Operating Conditions & Selection Criteria321 stainless steel bar is specified when designers require an austenitic stainless steel with excellent resistance to intergranular corrosion after welding or elevated temperature exposure, particularly in the 427-816°C (800-1500°F) range. Service Temperature Range: Suitable for continuous service from cryogenic temperatures up to 816°C (1500°F); retains significant strength, toughness, and corrosion resistance at elevated temperatures Intergranular Corrosion Resistance: Titanium stabilization prevents chromium carbide precipitation in the HAZ during welding or service in the sensitization range (427-816°C / 800-1500°F) Cryogenic Performance: As an austenitic stainless steel grade, cryogenic performance is equally impressive — suitable for low-temperature applications in sub-sea environments General Corrosion Resistance: Comparable to 304 stainless; general corrosion resistance is less than Type 302 Weldability: May be easily welded using all standard fusion and resistance methods; no post-weld heat treatment required for corrosion resistance Formability: Easily formed using conventional methods
ApplicationsJet Engine Components: Afterburners, exhaust manifolds, tailpipes, engine hardware Aerospace: High-temperature ducting, heat exchangers, engine mounts Chemical Processing: Equipment requiring resistance to intergranular corrosion after welding Sub-Sea Environments: Low-temperature applications requiring cryogenic toughness Industrial: Expansion joints, bellows, furnace components, heat-treating fixtures
Contact ZYTC Alloy TodayRequest a quote for AMS 5645 / 321 Austenitic Stainless Steel Bar (UNS S32100) – Titanium Stabilized – Excellent Intergranular Corrosion Resistance – 800°F to 1500°F . Please provide: Diameter / size (round, hex, flat, square, wire) Length or weight required Product form (bar / wire / forging / tubing / ring / stock) Tolerance requirement Destination port Any special certification requirements
📧 Email: daisy@zytcsteel.com
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