Xi'an Dongmeng Group Co., Ltd. is one of the most reliable manufacturers and suppliers of aisi 321h / uns s32109 in China, also supports customized service. With abundant experience, we warmly welcome you to wholesale cheap products in stock here and get free sample from our factory. For price consultation, contact us.
AISI 321H stainless steel (UNS S32109) is a high-carbon titanium-stabilized austenitic stainless steel designed for high-temperature structural applications up to 850–900°C. It provides excellent resistance to intergranular corrosion, oxidation, and creep deformation in long-term heat exposure environments.
It is widely used in boilers, heat exchangers, refinery equipment, pressure vessels, and exhaust systems, especially in welded structures operating under high thermal stress.
As a professional stainless steel supplier, we provide 321H sheets, plates, coils, pipes, tubes, and custom fabrication services for global industrial projects.
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High Quality
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Advanced Equipment
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Professional Team
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Custom Service
WHAT IS AISI 321H STAINLESS STEEL?
AISI 321H is the high-carbon version of 321 stainless steel (UNS S32109).
It is stabilized with titanium (Ti) to prevent chromium carbide precipitation during welding.
Key composition:
Chromium (Cr): 17–19%
Nickel (Ni): 9–12%
Carbon (C): 0.04–0.10% (higher than 321)
Titanium (Ti): Stabilizing element
👉 The higher carbon content improves high-temperature strength and creep resistance
Why AISI 321H?
1. Increased Carbon = Higher Creep Strength
Compared with 321 (S32100), the higher carbon content in 321H significantly improves:
Creep resistance
Stress rupture performance
Strength at elevated temperatures
2. Titanium-Stabilized Structure
Ti stabilization prevents chromium carbide precipitation, enhancing:
Intergranular corrosion resistance
Weldability under high heat input
Long-term thermal stability
3. Oxidation Resistance Up to 900°C
321H maintains surface stability under extreme heat, suitable for:
Furnace components
Heater tubes
Exhaust assemblies
4. Excellent for Pressure Retaining Equipment
Meets ASME Boiler & Pressure Vessel (BPVC) requirements for elevated temperature service.
Project Case – Refinery Heat Exchanger System
Client Country: UAE
Industry: Oil & Gas Refining
Material Supplied:
321H Stainless Steel Tubes
Specification:
OD 25mm × WT 2.5mm
Requirement:
Continuous operation at 650–800°C
Resistance to thermal cycling
Long-term creep resistance
Our Solution:
Supplied ASTM A213 certified 321H tubes
Controlled titanium stabilization ratio
Full UT + PMI testing
Result:
Extended equipment service life by 28% under high-temperature operation.
High Temperature Performance
Continuous service: up to 850–900°C
Excellent oxidation resistance
Strong creep rupture resistance
Stable welded joint performance
321 vs 321H
| Property | 321 | 321H |
|---|---|---|
| Carbon Content | Lower | Higher (0.04–0.10%) |
| Creep Strength | Medium | High |
| High Temperature Performance | Good | Better |
| Application Focus | General heat service | Heavy-duty thermal systems |
👉 Conclusion:
321H is preferred for high-temperature pressure and long-term service applications.
Standards & Compliance
AISI 321H (UNS S32109) complies with:
ASTM A240 / A312 / A213
ASME SA240 / SA213
EN 1.4878
UNS S32109
Widely used in refinery, chemical, and power generation industries.
Manufacturing Capability
10+ years stainless steel export experience
Hot & cold rolling production lines
Precision tube & plate manufacturing
OEM engineering supply capability
Why 321H Performs Better at High Temperature
321H improves performance through:
1️⃣ Higher Carbon Content
Enhances creep strength
Improves long-term load resistance
2️⃣ Titanium Stabilization
Prevents chromium carbide formation
Eliminates intergranular corrosion after welding
👉 This makes it ideal for welded high-temperature pressure systems
Chemical Composition (Typical)
| Element | % |
|---|---|
| C | 0.04 – 0.10 |
| Mn | ≤ 2.00 |
| Si | ≤ 0.75 |
| P | ≤ 0.045 |
| S | ≤ 0.030 |
| Cr | 17.0 – 19.0 |
| Ni | 9.0 – 12.0 |
| Ti | ≥ 5 × C% |
| Fe | Balance |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥ 515 MPa |
| Yield Strength | ≥ 205 MPa |
| Elongation | ≥ 40% |
| Hardness | ≤ 95 HRB |
Specifications (Metric & Imperial)
Plates / Sheets / Coils
| Parameter | Metric | Imperial |
|---|---|---|
| Thickness | 0.3–80 mm | 0.012–3.15 in |
| Width | 1000 / 1219 / 1500 / 2000 mm | 40–78 in |
| Length | 2000–6000 mm (custom) | 78–236 in |
Pipes & Tubes
| Parameter | Metric | Imperial |
|---|---|---|
| Outside Diameter | 6–630 mm | 0.24–24.8 in |
| Wall Thickness | 0.5–40 mm | 0.02–1.57 in |
| Length | 1–12 m | 3–40 ft |
Bars / Rods
| Diameter | Length |
|---|---|
| 6–300 mm | 1–6 m |
| 0.24–12 in | 3–20 ft |
Dimensional Tolerances
Plate tolerances: ASTM A480
Pipe tolerances: ASTM A999 / A530
Bar tolerances: ASTM A484
Custom precision machining available
Key Features
High-carbon version for enhanced high-temperature strength
Titanium-stabilized to prevent carbide precipitation
Excellent creep & stress rupture resistance
Superior oxidation and thermal fatigue performance
Good weldability in heavy-section components
Reliable for long-term service at 538–900°C
Products Applications
AISI 321H is widely used in industries requiring continuous high-temperature service:
Petrochemical & Refinery
Heater tubes
Reformer tubes
Cracker tubes
Furnace parts
Power Generation
Superheater & reheater tubing
Boiler tubes
High-temperature steam piping
Industrial Thermal Systems
Thermal oxidizers
Heat exchangers
Incineration components
Automotive / Exhaust
High-temp exhaust manifolds
Turbocharger components
Inspection & Quality Assurance
PMI chemical verification
UT / ET / RT non-destructive testing
Hardness & tensile testing
Surface roughness measurement
Dimensional inspection with calibrated tools
MTC EN 10204 3.1 provided
SGS / BV / TUV third-party inspection available
Product Delivery Standards
Seaworthy export packaging
Waterproof film + kraft paper + steel pallet
Pipes with end caps + bundled packing
Reinforced container loading
Delivery terms: FOB / CFR / CIF / DDP available
Short lead times for custom orders
We supply stainless steel sheets, plates, coils, pipes, tubes, bars, and custom fabrication for global industrial buyers. Contact us for quotes, samples, or technical support.
Our address
Room 4107, Runfeng Building, Sanqiao New Street, Weiyang District, Xi'an City, Shaanxi Province
Phone Number
+86 15769214734
office@dongmjd.com
FAQ
Q1: What is the difference between 321 and 321H stainless steel?
A1: 321H contains higher carbon (0.04–0.10%), which improves high-temperature strength, creep resistance, and stress rupture performance compared to 321.
Q2: What is the maximum service temperature for 321H?
A2: 321H is suitable for continuous service up to 900°C (1650°F) with excellent oxidation and thermal fatigue resistance.
Q3: Can 321H be used in pressure vessels and boilers?
A3: Yes, it meets ASME BPVC requirements for elevated temperature pressure-retaining applications.
Q4: Do you provide MTC and third-party inspection?
A4: Yes. EN 10204 3.1 MTC is included, and SGS / BV / TUV inspections are available on request.
Q5: What product forms are available for 321H?
A5: Sheets, plates, coils, pipes, tubes, bars, and custom-fabricated components.
Q6: Can 321H be welded without sensitization?
A6: Yes. Titanium stabilization prevents carbide precipitation, allowing safe welding in high-temperature applications.
Q7: Do you provide customized sizes or machining services?
A7: Yes. Cutting, bending, polishing, beveling, welding, and CNC machining services are available.
Q8: What are the typical packaging and delivery options?
A8: Export-ready packing includes waterproof film, kraft paper, steel pallets, pipe end caps, and reinforced container loading.
AISI 321H (UNS S32109) is a high-carbon titanium-stabilized austenitic stainless steel designed for superior creep resistance, high-temperature strength, and long-term stability in boiler, refinery, and heat exchanger applications.
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