AISI 321 Stainless Steel Plate | 321 China steel mill-Direct Supply
What is AISI 321 Stainless Steel?
As a professional China steel mill-Direct Supply and stainless steel plate supplier, SHH STEEL is pleased to present AISI 321 Stainless Steel Plate.
AISI 321 (UNS S32100) is a titanium-stabilized austenitic stainless steel based on the classic 18% chromium – 10% nickel composition. Titanium is intentionally added to combine preferentially with carbon, forming stable titanium carbides. This stabilization effectively prevents chromium carbide precipitation at grain boundaries during welding or exposure to the sensitization temperature range (approximately 425–900°C), thereby providing excellent resistance to intergranular corrosion.
AISI 321 retains good general corrosion resistance, formability, toughness and non-magnetic properties in the annealed condition. It is widely used for welded constructions that operate at elevated temperatures, such as exhaust systems, heat exchangers, furnace components, expansion joints and chemical process equipment.
SHH STEEL supplies AISI 321 as true China steel mill-Direct Supply, sourcing directly from major Chinese stainless steel mills. This model delivers competitive mill pricing, consistent quality, complete heat traceability and reliable delivery. SHH STEEL offers AISI 321 in plate and sheet form across a practical range of thicknesses and surface finishes.
AISI 321 is frequently compared with a240 304, a240 304l, a240 316l, a240 316ti, a240 347 and a240 310s when selecting stabilized or high-temperature grades. SHH STEEL provides technical support to help customers choose the most appropriate material.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Grade | AISI 321 / UNS S32100 | Confirmed |
| Related Standards | ASTM A240, ASME SA240, JIS G4305 (SUS321), EN 1.4541 | Available |
| Product Form | Plate, Sheet | Available |
| Delivery Condition | Solution Annealed | Standard |
| Thickness Range | 0.5 mm – 100 mm (thicker available on request) | Custom sizes supported |
| Width | Up to 2000–3000 mm | Available |
| Length | Up to 12000 mm or cut-to-length | Available |
| Surface Finish | 2B, No.1, BA, No.4 | Available |
| Certification | EN 10204 3.1 / Mill Test Certificate | Available |
SHH STEEL can supply AISI 321 dual-certified to ASTM A240 / ASME SA240 when required by the project.
Chemical Composition
Typical Chemical Composition of AISI 321 (UNS S32100):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 17.00 – 19.00 |
| Nickel (Ni) | 9.00 – 12.00 |
| Titanium (Ti) | 5 × (C + N) min – 0.70 max |
| Nitrogen (N) | ≤ 0.10 |
| Iron (Fe) | Balance |
The intentional titanium addition is the key stabilizing element in AISI 321. Titanium combines with carbon and nitrogen to form stable titanium carbides/nitrides, preventing chromium depletion at grain boundaries. This provides excellent resistance to intergranular corrosion after welding or high-temperature exposure. SHH STEEL carefully controls the titanium-to-carbon ratio to ensure effective stabilization.
Mechanical Properties
Annealed Condition (typical values)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 515 MPa (75 ksi) |
| Yield Strength (0.2%) | ≥ 205 MPa (30 ksi) |
| Elongation (in 50 mm) | ≥ 40% |
| Hardness | ≤ 217 HB |
AISI 321 offers mechanical properties similar to standard 304, with good strength, excellent ductility and toughness. The titanium stabilization does not significantly affect room-temperature mechanical properties but provides important benefits after welding and in elevated-temperature service. SHH STEEL supplies material with consistent mechanical properties suitable for fabrication and welding.
Physical Properties Density is approximately 7.90–8.00 g/cm³. The grade is non-magnetic in the annealed condition. Melting range is approximately 1400–1425°C.
Material Comparison
| Grade | Stabilization | Mo (%) | Intergranular Corrosion Resistance | High-Temp Suitability | Typical Preference |
|---|---|---|---|---|---|
| AISI 304 | None | — | Moderate | Moderate | General purpose |
| AISI 304L | Low carbon | — | Excellent | Moderate | Heavy welded constructions |
| AISI 321 | Titanium | — | Excellent | Better | Stabilized high-temp welded service |
| AISI 347 | Niobium | — | Excellent | Better | Stabilized high-temp welded service |
| AISI 316Ti | Titanium | 2.0–3.0 | Excellent | Better | Stabilized high-temp chloride service |
| AISI 310S | Low carbon | — | Good | Excellent | Severe high-temperature oxidation |
AISI 321 is selected when resistance to intergranular corrosion after welding and good performance in the sensitization temperature range are required. Compared with a240 304l, it offers better high-temperature stability. Compared with a240 316ti, it lacks molybdenum and therefore has lower pitting resistance. For niobium stabilization, SHH STEEL also supplies a240 347.
Corrosion Resistance
AISI 321 offers good resistance to atmospheric corrosion, fresh water, food products and many mild to moderate chemical environments, similar to standard 304. The titanium stabilization provides excellent resistance to intergranular corrosion after welding or exposure to the sensitization temperature range.
In chloride-containing environments, AISI 321 can be susceptible to pitting and stress corrosion cracking. For improved pitting resistance, SHH STEEL recommends a240 316l or a240 316ti. For severe high-temperature oxidizing service, a240 310s is preferred.
Weldability
AISI 321 has excellent weldability due to titanium stabilization. Matching or 321/347-type filler metals are commonly used. The stabilization effectively prevents intergranular corrosion in the heat-affected zone, making post-weld annealing generally unnecessary for most applications.
SHH STEEL recommends proper welding procedures and post-weld cleaning to achieve optimum corrosion performance. This combination of good general corrosion resistance and as-welded intergranular corrosion resistance is the main advantage of AISI 321 for high-temperature welded service.
Heat Treatment
AISI 321 is normally supplied in the solution-annealed condition by SHH STEEL.
Recommended solution annealing temperature range is 950–1120°C (often 1000–1100°C), followed by rapid cooling. Proper annealing ensures that titanium is available for effective stabilization and optimizes both room-temperature ductility and high-temperature performance. SHH STEEL controls heat treatment to ensure consistent quality.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| 2B | Cold-rolled, annealed, pickled, skin-passed | AISI 321 2B – most common for general fabrication |
| No.1 | Hot-rolled, annealed and pickled | AISI 321 No.1 – industrial plate |
| BA | Bright Annealed | AISI 321 BA – cleaner surface applications |
| No.4 | Brushed finish | AISI 321 No.4 – architectural surfaces |
SHH STEEL regularly supplies AISI 321 in 2B and No.1 finishes, and can provide other finishes according to project requirements.
Tolerances
Dimensional tolerances for AISI 321 Stainless Steel Plate supplied by SHH STEEL generally conform to ASTM A480 practices.
Typical available size range is thickness 0.5 mm – 100 mm, width up to 2000–3000 mm, and length up to 12000 mm or cut-to-length. SHH STEEL provides precise dimensional control and can support tighter tolerances when required.
Equivalent Material Grades
| Grade / Designation | Standard / Region | Notes |
|---|---|---|
| AISI 321 | — | — |
| UNS S32100 | Unified Numbering System | — |
| ASTM A240 Type 321 | ASTM A240 | When dual certified |
| 1.4541 / X6CrNiTi18-10 | EN (Europe) | European equivalent |
| SUS321 | JIS G4305 (Japan) | Japanese equivalent |
| 06Cr18Ni11Ti / 0Cr18Ni10Ti | GB/T (China) | Chinese equivalents |
| Related 321H / 347 | Multiple | High-carbon / Nb-stabilized variants |
Related grades for comparison include a240 304, a240 304l, a240 316l, a240 316ti, a240 347 and a240 310s.
Applications
AISI 321 is selected for welded constructions that operate in the sensitization temperature range or require resistance to intergranular corrosion after welding. Typical applications of AISI 321 include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Exhaust Systems & Automotive | AISI 321 exhaust manifolds, pipes and high-temperature components |
| Heat Exchangers & Boilers | AISI 321 heat exchanger tubesheets, shells and components |
| Chemical & Process Industry | AISI 321 tanks, vessels, piping and process equipment |
| Furnace & Heat Treatment | AISI 321 furnace components, fixtures and supports |
| Expansion Joints & Bellows | AISI 321 expansion joints and flexible components |
| Power Generation | AISI 321 high-temperature ducting and structural parts |
| General High-Temperature Service | AISI 321 welded structures operating at elevated temperature |
SHH STEEL supplies AISI 321 for these elevated-temperature welded applications with consistent quality. For related industry solutions, see our energy industry, petrochemical industry and equipment manufacturing pages. Supporting services include steel cutting services and steel welding services.
Why Choose SHH STEEL
SHH STEEL is a China steel mill-Direct Supply specializing in stainless steel plate and sheet. By working directly with major Chinese stainless steel mills, SHH STEEL supplies AISI 321 with the following advantages:
- Genuine China steel mill-Direct Supply pricing
- Consistent quality and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1)
- Titanium-stabilized material optimized for welded high-temperature service
- Flexible dimensions and surface finishes (including AISI 321 2B and AISI 321 No.1)
- Technical support for selection among 304L, 321, 347, 316Ti and high-temperature grades
- Value-added services including steel cutting services, steel welding services and worldwide shipping service
For more information about our company and full product range, please visit China steel Mill Agent-SHH STEEL.
FAQ
- What is the main advantage of AISI 321 over AISI 304 or 304L?The titanium stabilization provides excellent resistance to intergranular corrosion after welding and better performance in the sensitization temperature range (approx. 425–900°C). SHH STEEL recommends 321 for welded constructions that will operate at elevated temperatures.
- What is the difference between AISI 321 and AISI 347?Both are stabilized grades. 321 uses titanium, while 347 uses niobium (columbium). Performance is similar in many applications; 347 is sometimes preferred for certain high-temperature or welding conditions. SHH STEEL can supply both grades.
- How does AISI 321 compare with AISI 316Ti?Both are titanium-stabilized. 316Ti contains molybdenum and therefore offers better resistance to pitting and crevice corrosion. SHH STEEL recommends 316Ti when chloride resistance is also required.
- Is AISI 321 magnetic?Non-magnetic in the annealed condition. It may become slightly magnetic after heavy cold working. SHH STEEL supplies fully annealed material as standard.
- What is the density of AISI 321?Approximately 7.90–8.00 g/cm³. SHH STEEL provides material certificates confirming physical and mechanical properties.
- Can AISI 321 be used in chloride environments?It has limited resistance to pitting in chlorides. For better performance, SHH STEEL recommends a240 316l or a240 316ti.
- Does SHH STEEL supply dual-certified ASTM A240 / AISI 321 material?Yes, SHH STEEL commonly supplies dual-certified material upon request.
Conclusion
AISI 321 Stainless Steel Plate is a titanium-stabilized austenitic grade that offers excellent resistance to intergranular corrosion after welding and reliable performance in the sensitization temperature range. It is the classic choice for welded exhaust systems, heat exchangers, furnace components, expansion joints and chemical process equipment operating at elevated temperatures.
As a professional China steel mill-Direct Supply, SHH STEEL provides high-quality AISI 321 Stainless Steel Plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including AISI 321 2B and AISI 321 No.1), or a competitive quotation.
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