AMS 5645 SS 321 Stainless Steel Round Bar supplier, contact us to get free quote and sample!
AMS 5645 SS 321 Stainless Steel Round Bar has high temperature resistance of 870°C (1600°F) and corrosion resistance, and is widely used in industries such as aerospace industry, chemical processing, and oil and gas industry.
Why Engineers Specify AMS 5645 (SS 321)
Immunity to Sensitization: The titanium content bonds preferentially with carbon to form stable titanium carbides. This prevents chromium depletion along grain boundaries during welding or prolonged high-temperature exposure.
Elevated Creep Rupture Strength: Grade 321 exhibits superior long-term creep and stress rupture properties compared to standard 304 or 304L alloys at temperatures exceeding 500°C.
Excellent Fabrication Profile: It can be readily welded using standard fusion techniques and exhibits exceptional toughness down to cryogenic temperatures.
Chemical Composition (AMS 5645 / UNS S32100)
The chemical limits of AMS 5645 are tightly regulated, requiring a specific ratio of titanium to carbon to secure structural stabilization:
| Element | Percentage (%) | Engineering Purpose |
| Chromium (Cr) | 17.00 – 19.00 | Core corrosion resistance and high-temperature scale prevention |
| Nickel (Ni) | 9.00 – 12.00 | Stabilizes the resilient austenitic crystalline matrix |
| Titanium (Ti) | 5xC min - 0.70max | Fixed carbon binder that stops intergranular carbide precipitation |
| Carbon (C) | 0.08 max | Controlled base element; kept low to minimize excessive carbide load |
| Manganese (Mn) | 2.00 max | Enhances deoxidation and high-temperature workability |
| Silicon (Si) | 1.00 max | Improves oxidation resistance in severe thermal environments |
| Phosphorus (P) | 0.045 max | Kept low to ensure weld soundness and structural integrity |
| Sulfur (S) | 0.030 max | Regulated to prevent hot-shortness during forging |
Mechanical & Physical Properties
Mechanical Performance (Annealed Round Bar)
Tensile Strength: Minimum 515 MPa (75 ksi)
Yield Strength (0.2% Offset): Minimum 205 MPa (30 ksi)
Elongation in 2 inches: Minimum 40%
Reduction of Area: Minimum 50%
Brinell Hardness: Maximum 255 HBW
Key Physical Attributes
Density: 7.92 g/cm³ (0.286 lb/in³)
Thermal Conductivity (at 100°C): 16.1 W/m·K
Modulus of Elasticity: 193 GPa
Critical High-Temperature Applications
Thanks to its stabilization profile, AMS 5645 round bars are heavily utilized across demanding manufacturing domains:
Aerospace & Defense: Jet engine exhaust manifolds, piston engine stack assemblies, firewall fasteners, and gas turbine components.
Chemical Processing: High-temperature chemical reactors, pressure vessel internal fasteners, and heat exchanger tie rods.
Oil & Gas Refining: Thermal oxidizers, flare stacks, and refinery piping support elements handling hot hydrocarbon streams.
Power Generation: Boiler superheaters, steam tubes, and heavy-duty industrial exhaust systems.
Supply Range and Processing Capabilities at HT PIPE
We provide comprehensive value-added processing for AMS 5645 material to match your precise blueprint specifications:
Surface Finishes: Black hot-rolled, peeled & turned, cold-drawn centerless ground, and smooth h9/h10/h11 tolerance bright finishes.
Size Profiles: Diameters from 3mm up to 500mm, cut to custom lengths via precision band saws.
Dual Certification: Our stock regularly carries multi-certification meeting AMS 5645, ASTM A276, ASME SA276, and EN 10204 3.1 mill test reports to satisfy global defense and commercial audits.
321 Stainless Steel High Temperature Resistance:
- Continuous working temperature: SS S32100 can usually maintain good strength and oxidation resistance at high temperatures of 870°C (1600°F), suitable for long-term exposure to high temperature environments.
- Short-term working temperature: In short-term exposure, SS 321 can withstand higher temperatures, generally up to about 900°C (1650°F).
AMS 5645 Standards
- AMS5645: Corrosion Resistant Steel 18 Chromium - 8 Nickel (Weldable)
- AMS 5645T (latest version): Corrosion Resistant and Heat Resistant Steels, Bars, Wire, Forgings, Mechanical Tubing, Rings and Forging Stocks 18Cr - 10Ni - 0.40Ti (321) Solution Heat Treated
Request a Factory Quote for AMS 5645 Round Bars
Are you working with a strict aerospace or industrial Bill of Materials (BOM)?
Contact HT PIPE today for direct factory pricing, custom sizing options, and expedited global shipping.
