High Quality Stainless Steel 321/321H Pipes & Tubes
Seamless • Welded • Durable & Precise
Get a QuoteWhat is 321 & 321H Stainless Steel?
321 stainless steel is a titanium-stabilized austenitic stainless steel with excellent high-temperature strength and intergranular corrosion resistance. 321H is the high-carbon variation of 321 stainless steel, offering improved high-temperature strength. These grades are particularly suitable for applications in the temperature range where sensitization and subsequent intergranular corrosion are concerns.
321 Stainless Steel
Chromium (Cr)
Nickel (Ni)
Carbon (C) Max
Manganese (Mn) Max
Silicon (Si) Max
Phosphorus (P) Max
Sulfur (S) Max
Titanium (Ti)
Iron (Fe)
321H Stainless Steel
Chromium (Cr)
Nickel (Ni)
Carbon (C)
Manganese (Mn) Max
Silicon (Si) Max
Phosphorus (P) Max
Sulfur (S) Max
Titanium (Ti)
Iron (Fe)
Types of Stainless Steel 321 & 321H Pipes & Tubes
As premier manufacturers in the industry, we specialize in producing both stainless steel 321/321H seamless pipes & tubes and stainless steel 321/321H welded pipes & tubes, offering comprehensive solutions for high-temperature and corrosive applications.
Manufactured from solid billets through an extrusion process, these pipes deliver superior strength and exceptional pressure resistance at elevated temperatures. Seamless construction eliminates weld seams, making them the preferred choice for critical high-temperature applications including heat exchangers, boilers, and aircraft exhaust systems where welding integrity is paramount.
These pipes provide an economical alternative with availability across a broader spectrum of sizes and dimensions. Welded pipes excel in high-temperature structural applications, furnace parts, and general corrosive service conditions where reliable welded joints are essential. Their cost-effectiveness makes them ideal for projects with budget constraints without compromising high-temperature performance.
Specification of Stainless Steel 321/321H Seamless & Welded Pipes And Tubes
| Specification | Details |
|---|---|
| Stainless Steel Pipe Specification | ASTM A312, A358 / ASME SA312, SA358 |
| SS Tube Specification | ASTM A213, A269, A249, A511, A554 / ASME SA213, SA269, SA249, SA511, SA554 |
| Pipe Size | 1/8” NB to 24” NB, 1/4” OD to 24” OD sizes |
| Tube Size | 1/2″ OD to 8″ OD |
| Thickness Range | 0.3mm – 50 mm, SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXS, SCH XS |
| Type | Seamless / ERW / Welded / Fabricated Pipes |
| Form | Round, Square, Rectangular, Oval, Hydraulic Etc |
| Length | Single Random, Double Random & Required Length |
| End | Plain End, Beveled End, Threaded |
| End Protection | Plastic Caps |
| Outside Finish | 2B, No.4, No.1, No.8 Mirror Finish for Stainless Steel Pipes, Finish as per customer Requirements |
| Delivery Condition | Annealed and Pickled, Polished, Bright Annealed, Cold Drawn |
| Inspection, Test Reports | Mill Test Certificates, EN 10204 3.1, Chemical Reports, Mechanical Reports, PMI Test Reports, Visual Inspection Reports, Third Party Inspection Reports, NABL Approved Lab Reports, Destructive Test Report, Non Destructive Test Reports |
| Packing | Packed in Wooden Boxes, Plastic Bags, Steel Strips Bundled, or as per Customers Requests |
| Specials | Sizes and Specifications other than above can be manufactured on request |
STAINLESS STEEL PIPE & TUBES SCHEDULE DIMENSIONS WALL THICKNESS, WT./MTR. (KG)
Click to expand ▼
Stainless Steel 321/321H Pipe Dimensions & Weight Chart
| OD (mm) | WT (mm) | NPS (dn) | Schedule | Weight (kg/m) |
|---|---|---|---|---|
| 13.72 | 1.65 | 1/4″ | 10S | 0.50 |
| 13.72 | 2.24 | 1/4″ | 40S | 0.64 |
| 13.72 | 3.02 | 1/4″ | 80S | 0.81 |
| 17.15 | 1.65 | 3/8″ | 10S | 0.64 |
| 17.15 | 2.31 | 3/8″ | 40S | 0.86 |
| 17.15 | 3.20 | 3/8″ | 80S | 1.12 |
| 21.34 | 2.11 | 1/2″ | 10S | 1.02 |
| 21.34 | 2.77 | 1/2″ | 40S | 1.29 |
| 21.34 | 3.73 | 1/2″ | 80S | 1.65 |
| 26.67 | 2.11 | 3/4″ | 10S | 1.30 |
| 26.67 | 2.87 | 3/4″ | 40S | 1.71 |
| 26.67 | 3.91 | 3/4″ | 80S | 2.23 |
| 33.40 | 2.77 | 1″ | 10S | 2.13 |
| 33.40 | 3.38 | 1″ | 40S | 2.54 |
| 33.40 | 4.55 | 1″ | 80S | 3.29 |
| 48.26 | 2.77 | 1.1/2″ | 10S | 3.16 |
| 48.26 | 3.68 | 1.1/2″ | 40S | 4.11 |
| 48.26 | 5.08 | 1.1/2″ | 80S | 5.49 |
| 60.33 | 2.77 | 2″ | 10S | 3.99 |
| 60.33 | 3.91 | 2″ | 40S | 5.52 |
| 60.33 | 5.54 | 2″ | 80S | 7.60 |
| 88.90 | 3.05 | 3″ | 10S | 6.56 |
| 88.90 | 5.49 | 3″ | 40S | 11.47 |
| 88.90 | 7.62 | 3″ | 80S | 15.51 |
Stainless Steel 321/321H Tube Size Chart
| Wall Thickness (in) | Available Sizes (in) |
|---|---|
| 0.028″ | 1/16″; 1/8″; 3/16″; 1/4″; 5/16″; 3/8″ |
| 0.035″ | 1/8″; 3/16″; 1/4″; 5/16″; 3/8″; 1/2″; 5/8″; 3/4″; 1″; 1-1/4″; 1-1/2″; 2″ |
| 0.049″ | 1/8″; 3/16″; 1/4″; 5/16″; 3/8″; 1/2″; 5/8″; 3/4″; 1″; 1-1/4″; 1-1/2″; 2″ |
| 0.065″ | 3/16″; 1/4″; 5/16″; 3/8″; 1/2″; 5/8″; 3/4″; 1″; 1-1/4″; 1-1/2″; 2″ |
| 0.083″ | 1/4″; 5/16″; 3/8″; 1/2″; 5/8″; 3/4″; 1″; 1-1/4″; 1-1/2″; 2″; 2-1/2″; 3″ |
| 0.095″ | 1/4″; 3/8″; 1/2″; 5/8″; 3/4″; 1″; 1-1/4″; 1-1/2″; 2″; 2-1/2″; 3″ |
| 0.120″ | 1/2″; 5/8″; 3/4″; 1″; 1-1/4″; 1-1/2″; 2″; 2-1/2″; 3″ |
Pressure Ratings for SS 321/321H Tubing (PSIG)
| OD (in) | WT 0.028″ | WT 0.035″ | WT 0.049″ | WT 0.065″ | WT 0.083″ | WT 0.095″ | WT 0.109″ | WT 0.120″ |
|---|---|---|---|---|---|---|---|---|
| 1/8″ | 7,900 | 10,100 | N/A | N/A | N/A | N/A | N/A | N/A |
| 1/4″ | 3,700 | 5,800 | 7,900 | 9,500 | N/A | N/A | N/A | N/A |
| 5/16″ | N/A | 3,700 | 5,400 | 7,300 | N/A | N/A | N/A | N/A |
| 3/8″ | N/A | 3,100 | 4,400 | 6,100 | N/A | N/A | N/A | N/A |
| 1/2″ | N/A | 2,300 | 3,200 | 4,400 | N/A | N/A | N/A | N/A |
| 3/4″ | N/A | N/A | 2,100 | 2,900 | 3,900 | 4,500 | N/A | N/A |
| 1″ | N/A | N/A | N/A | 2,200 | 2,900 | 3,400 | 3,900 | 4,300 |
Chemical Composition of Stainless Steel 321/321H Pipes and Tubes
| Element | 321 Stainless Steel (%) | 321H Stainless Steel (%) |
|---|---|---|
| Carbon (C) | 0.08 max | 0.04 – 0.10 |
| Manganese (Mn) | 2.00 max | 2.00 max |
| Phosphorus (P) | 0.045 max | 0.045 max |
| Sulfur (S) | 0.030 max | 0.030 max |
| Silicon (Si) | 0.75 max | 0.75 max |
| Chromium (Cr) | 17.00 – 19.00 | 17.00 – 19.00 |
| Nickel (Ni) | 9.00 – 12.00 | 9.00 – 12.00 |
| Titanium (Ti) | 5xC min | 4xC min |
| Nitrogen (N) | 0.10 max | 0.10 max |
| Iron (Fe) | Balance | Balance |
Mechanical Properties of Stainless Steel 321/321H Pipes and Tubes
| Grade | Tensile Strength (MPa) min | Yield Strength (0.2% Offset) (MPa) min | Elongation (% in 2″) min | Hardness |
|---|---|---|---|---|
| 321 | 515 | 205 | 40 | Rockwell B (95) max Brinell (217) max |
| 321H | 515 | 205 | 40 | Rockwell B (95) max Brinell (217) max |
Physical Properties of Stainless Steel 321/321H Pipes and Tubes
| Grade | Density (kg/m³) | Elastic Modulus (GPa) | Mean Coefficient of Thermal Expansion (μm/m°C) | Thermal Conductivity (W/m.K) | Specific Heat 0-100°C (J/kg.K) | Electrical Resistivity (nΩ.m) |
|---|---|---|---|---|---|---|
| 321/321H | 8020 | 193 | 16.6 (0-100°C) 17.5 (0-538°C) 18.6 (0-1000°C) |
16.3 (at 100°C) 22.2 (at 500°C) |
500 | 720 |
Equivalent Grades for Stainless Steel 321/321H Pipes and Tubes
| STANDARD | WERKSTOFF NR. | UNS | JIS | AFNOR | BS | GOST | EN |
|---|---|---|---|---|---|---|---|
| SS321 | 1.4541 | S32100 | SUS321 | Z6CNT18-10 | 321S31 | 08Ch18N10T | X6CrNiTi18-10 |
| SS321H | 1.4878 | S32109 | SUS321H | Z8CNT18-12 | 321S51 | 08Ch18N12T | X7CrNiTi18-10 |
💡 Practical Difference in Use
Use 321 when: high-temperature applications up to 900°C are required, with good intergranular corrosion resistance.
→ Example: aircraft exhaust systems, heat exchangers, furnace parts.
Use 321H when: superior high-temperature strength and creep resistance are needed above 500°C. → Example: superheater tubes, boiler components, high-temperature pressure vessels.
Uses of 321/321H Stainless Steel Pipes
The uses are defined by its excellent high-temperature strength, oxidation resistance, and resistance to intergranular corrosion. Pipes are used in high-temperature and corrosive environments.
- High-Temperature Process Piping: This is its primary function. It’s used for moving hot gases, steam, and process fluids in elevated temperature applications.
- Heat Exchanger and Boiler Tubes: 321/321H pipes are extensively used in heat exchangers, superheaters, and boiler systems where thermal stability is critical.
- Exhaust and Emission Systems: Excellent for aircraft exhaust systems, automotive exhaust components, and industrial emission control systems.
When to Choose 321H vs. 321?
This is a critical question for high-temperature applications. 321 is suitable for most high-temperature services, while 321H offers enhanced strength at elevated temperatures.
Choose 321 when:
- Applications require stabilization against chromium carbide precipitation during welding.
- Service temperatures typically range from 400°C to 900°C.
- Good general corrosion resistance with titanium stabilization is sufficient.
Upgrade to 321H when:
- Superior high-temperature strength and creep resistance are required above 500°C.
- Applications involve prolonged exposure to temperatures between 500°C and 815°C.
- Higher carbon content for improved high-temperature mechanical properties is needed.
Industries That Use 321/321H Stainless Steel Pipes
Virtually every industry that requires high-temperature and corrosion-resistant piping uses 321/321H. Here are the most prominent ones:
This is a major consumer of 321 pipes due to its excellent high-temperature performance and weight considerations.
Uses
Aircraft exhaust systems, engine components, afterburner parts, and high-temperature hydraulic lines.
Why 321/321H?
Superior oxidation resistance and strength retention at high temperatures. Titanium stabilization prevents sensitization during welding.
This industry demands materials that can withstand extreme temperatures and pressures.
Uses
Superheater tubes, boiler components, heat exchanger tubes, and high-temperature steam lines in thermal power plants.
Why 321H?
Enhanced creep strength and oxidation resistance at temperatures up to 815°C make it ideal for power plant applications.
For handling corrosive chemicals at elevated temperatures in process equipment.
Uses
Catalyst tubes in reformers, furnace tubes, heat exchanger tubing, and high-temperature process piping.
Why 321/321H?
Excellent resistance to intergranular corrosion and good general corrosion resistance at high temperatures.
Used in high-temperature exhaust and emission control systems.
Uses
Exhaust manifolds, turbocharger housings, catalytic converter shells, and high-performance exhaust systems.
Why 321?
Good thermal fatigue resistance and ability to withstand cyclic heating and cooling in exhaust applications.
Essential for furnace components and high-temperature processing equipment.
Uses
Radiant tubes, muffles, retorts, annealing covers, and furnace structural components.
Why 321H?
Superior high-temperature strength and resistance to thermal cycling make it suitable for continuous furnace operation.
Critical for high-temperature processing units in oil refineries.
Uses
Transfer lines in fluid catalytic cracking units, heater tubes, and high-temperature piping systems.
Why 321/321H?
Resistance to sensitization and good mechanical properties at refinery operating temperatures.
Used in high-temperature sterilization and process systems.
Uses
Sterilizer piping, autoclave systems, and high-temperature process lines requiring cleanability.
Why 321?
Good corrosion resistance to sterilizing agents and ability to withstand repeated thermal cycles.
Used in high-temperature cooking and processing equipment.
Uses
Retort systems, high-temperature processing lines, and thermal fluid heating systems.
Why 321?
Non-contaminating properties combined with good high-temperature performance for food processing applications.
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