ASTM A789 Duplex Seamless Steel Tubing with High Strength
ASTM A789 Duplex Seamless Steel Tubing with High Strength
Description
ASTM A789/A789M is the premier standard specification for seamless and welded ferritic/austenitic (duplex) stainless steel tubing. Engineered specifically for applications requiring both high mechanical strength and exceptional corrosion resistance, it is the ultimate material choice for heat exchangers, condensers, and general industrial service.
Covering industry-leading grades such as Duplex S32205 (2205) and S31803, ASTM A789 tubing delivers outstanding protection against chloride stress corrosion cracking (SCC), pitting, and crevice corrosion. Unlike standard piping specifications, A789 mandates exceptionally tight dimensional tolerances for outside diameter and wall thickness, ensuring perfect fitment in critical thermal equipment. By combining the durability of ferritic phases with austenitic formability, our ASTM A789 seamless duplex tubes allow engineers to design with thinner walls, significantly reducing equipment weight and overall project costs. It is the most reliable, cost-effective tubing solution for the chemical processing, petrochemical, and marine industries.
| Item | Description | |
|---|---|---|
| Basic Information | Material Grade | S31803 , S32205 ( 2205 ) , S32750 ( 2507 ) , S32760 |
| Outer Diameter | OD 6.35mm - 114.3mm (1/4" to 4.5") | |
| Wall Thickness | 0.89mm - 12.7mm (BWG 20 to BWG 10) - Available in Average Wall or Minimum Wall | |
| Length | Random / Fixed Length, U-Bent Tubes available upon request. | |
| Standard | ASTM A790/A790M , ASME SA790/790M , ASTM A789/789M , ASME SA789/789M | |
| Process Method | Cold Drawn or Cold Rolled | |
| End Type | PE (Plain End - Cut Square and Deburred) | |
| Delivery condition | Annealed & Pickled (AP) / Solid Solution & Pickled / Bright Annealed (BA) | |
| Industry & Advantage | Application | a) Oil & Gas Transportation |
| b) Marine & Shipbuilding | ||
| c) Petrochemical & Chemical Process | ||
| d) Pulp and Paper Industry | ||
| e) Desalination Plants | ||
| f) Boiler & Heat exchanger | ||
| g) Food and Beverage | ||
| Advantages | a) Professional production ( Good Quality ) | |
| b) Fast lead time | ||
| c) Sufficient stock in warehouse | ||
| d) Perfect inspection method and inspection equipment | ||
| Terms & Conditions | Price Item | FOB , CFR , CIF , EXW , FCA or as negotiation |
| Payment | T/T, LC at sight or as negotiation | |
| Delivery Time | 20 - 40 working days after we receive your advanced payment ( Normally according to the actual order quantity ) | |
| Package | Iron case , Plywood box , Plywood frame , Knitted bag or as per customer's actual requirement. | |
| Quality Requirement | Mill Test Certificate will be supplied with shipment , Third Party Inspection is acceptable | |
| Quality | Test | NDT ( Ultrasonic test , Eddy Current test , Hydrostatic test ) |
| Mechanical Test ( Tensile Test , Flaring Test , Flattening Test , Flange Test , Hardness Test , Hydrostatic test , Intergranular Corrosion Test ) | ||
| Metal Test ( Metallographic Analysis , Austenitic / Ferritic & Duplex Stainless Steel ) | ||
| Chemical Analysis ( Spectrometer ) , PMI ( Portable chemical analyzer ) | ||
| Market | Main Market | Europe , Middle East , Southeast Asia , South America etc |
| UNS | C | Mn | P | S | Si | Ni | Cr | Mo | N | Cu | 其他(Others) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| S31200 | ≤0.030 | ≤2.00 | ≤0.045 | ≤0.030 | ≤1.00 | 5.5-6.5 | 24.0-26.0 | 1.20-2.00 | 0.14-0.20 | ... | ... |
| S31260 | ≤0.030 | ≤1.00 | ≤0.030 | ≤0.030 | ≤0.75 | 5.5-7.5 | 24.0-26.0 | 2.5-3.5 | 0.10-0.30 | 0.20-0.80 | W:0.10-0.50 |
| S31500 | ≤0.030 | 1.20-2.00 | ≤0.030 | ≤0.030 | 1.40-2.00 | 4.3-5.2 | 18.0-19.0 | 2.50-3.00 | 0.05-0.1 | ... | ... |
| S31803 | ≤0.030 | ≤2.00 | ≤0.030 | ≤0.020 | ≤1.00 | 4.5-6.5 | 21.0-23.0 | 2.5-3.5 | 0.08-0.20 | ... | ... |
| S32001 | ≤0.030 | 4.00-6.00 | ≤0.040 | ≤0.030 | ≤1.00 | 1.0-3.0 | 19.5-21.5 | ≤0.60 | 0.05-0.17 | ≤1.00 | ... |
| S32003 | ≤0.030 | ≤2.00 | ≤0.030 | ≤0.020 | ≤1.00 | 3.0-4.0 | 19.5-22.5 | 1.50-2.00 | 0.14-0.20 | ... | ... |
| S32101 | ≤0.040 | 4.0-6.0 | ≤0.040 | ≤0.030 | ≤1.00 | 1.35-1.70 | 21.0-22.0 | 0.10-0.80 | 0.20-0.25 | 0.10-0.80 | ... |
| S32202 | ≤0.030 | ≤2.00 | ≤0.040 | ≤0.010 | ≤1.00 | 1.00-2.80 | 21.5-24.0 | ≤0.45 | 0.18-0.26 | ... | ... |
| S32205 | ≤0.030 | ≤2.00 | ≤0.030 | ≤0.020 | ≤1.00 | 4.5-6.5 | 22.0-23.0 | 3.0-3.5 | 0.14-0.20 | ... | ... |
| S32304 | ≤0.030 | ≤2.50 | ≤0.040 | ≤0.040 | ≤1.00 | 3.0-5.5 | 21.5-24.5 | 0.05-0.60 | 0.05-0.20 | 0.05-0.60 | ... |
| S32506 | ≤0.030 | ≤1.00 | ≤0.040 | ≤0.015 | ≤0.90 | 5.5-7.2 | 24.0-26.0 | 3.0-3.5 | 0.08-0.20 | ... | W:0.05-0.30 |
| S32520 | ≤0.030 | ≤1.50 | ≤0.035 | ≤0.020 | ≤0.80 | 5.5-8.0 | 23.0-25.0 | 3.0-5.0 | 0.20-0.35 | 0.50-3.00 | ... |
| S32550 | ≤0.04 | ≤1.50 | ≤0.040 | ≤0.030 | ≤1.00 | 4.5-6.5 | 24.0-27.0 | 2.9-3.9 | 0.10-0.25 | 1.50-2.50 | ... |
| S32707 | ≤0.030 | ≤1.50 | ≤0.035 | ≤0.010 | ≤0.50 | 5.5-9.5 | 26.0-29.0 | 4.0-5.0 | 0.30-0.50 | ≤1.0 | Co:0.5-2.0 |
| S32750 | ≤0.030 | ≤1.20 | ≤0.035 | ≤0.020 | ≤0.80 | 6.0-8.0 | 24.0-26.0 | 3.0-5.0 | 0.24-0.32 | ≤0.50 | ... |
| S32760 | ≤0.030 | ≤1.00 | ≤0.030 | ≤0.010 | ≤1.00 | 6.0-8.0 | 24.0-26.0 | 3.0-4.0 | 0.20-0.30 | 0.50-1.00 | W:0.50-1.00 |
| S32808 | ≤0.030 | ≤1.10 | ≤0.030 | ≤0.010 | ≤0.50 | 7.0-8.2 | 27.0-27.9 | 0.80-1.20 | 0.30-0.40 | ... | W:2.10-2.50 |
| S32900 | ≤0.08 | ≤1.00 | ≤0.040 | ≤0.030 | ≤0.75 | 2.5-5.0 | 23.0-28.0 | 1.00-2.00 | ... | ... | ... |
| S32906 | ≤0.030 | 0.80-1.50 | ≤0.030 | ≤0.030 | ≤0.80 | 5.8-7.5 | 28.0-30.0 | 1.50-2.60 | 0.30-0.40 | ≤0.80 | ... |
| S32950 | ≤0.030 | ≤2.00 | ≤0.035 | ≤0.010 | ≤0.60 | 3.5-5.2 | 26.0-29.0 | 1.00-2.50 | 0.15-0.35 | ... | ... |
| S33207 | ≤0.030 | ≤1.50 | ≤0.035 | ≤0.010 | ≤0.80 | 6.0-9.0 | 29.0-33.0 | 3.0-5.0 | 0.40-0.60 | ≤1.0 | ... |
| S39274 | ≤0.030 | ≤1.00 | ≤0.030 | ≤0.020 | ≤0.80 | 6.0-8.0 | 24.0-26.0 | 2.5-3.5 | 0.24-0.32 | 0.20-0.80 | W:1.50-2.50 |
| S39277 | ≤0.025 | ≤0.80 | ≤0.025 | ≤0.002 | ≤0.80 | 6.5-8.0 | 24.0-26.0 | 3.00-4.00 | 0.23-0.33 | 1.20-2.00 | W:0.80-1.21 |
| S82011 | ≤0.030 | 2.0-3.0 | ≤0.040 | ≤0.020 | ≤1.00 | 1.00-2.00 | 20.5-23.5 | 0.10-1.00 | 0.15-0.27 | ≤0.50 | ... |
| S82031 | ≤0.05 | ≤2.50 | ≤0.040 | ≤0.005 | ≤0.80 | 2.0-4.0 | 19.0-22.0 | 0.60-1.40 | 0.14-0.24 | ≤1.00 | ... |
| S82441 | ≤0.030 | 2.50-4.00 | ≤0.035 | ≤0.005 | ≤0.70 | 3.0-4.5 | 23.0-25.0 | 1.00-2.00 | 0.20-0.30 | 0.10-0.80 | ... |
| S83071 | ≤0.030 | 0.50-1.50 | ≤0.030 | ≤0.020 | ≤0.50 | 6.0-8.0 | 29.0-31.0 | 3.0-4.0 | 0.28-0.40 | ≤0.80 | ... |
| PREN Data | ||
|---|---|---|
| Steel Grade | Equation | Requirement |
| Duplex S31803 | PREN=%Cr+3.3x%Mo+16x%N | ≥35 |
| Duplex S32205 | PREN=%Cr+3.3x%Mo+16x%N | ≥35 |
| Super Duplex S32750 | PREN=%Cr+3.3x%Mo+16x%N | ≥41 |
| Super Duplex S32760 | PREN=%Cr+3.3x(%Mo+0.5x%W)+16x%N | ≥41 |
| Permissible Variations in Dimensions | ||||
|---|---|---|---|---|
| OD Range (mm) | OD Tolerance (mm) | Average Wall Tolerance (%) | Min Wall Tolerance (%) | Length Tolerance (mm) |
| <12.7 | ±0.13 | ±15 | +30%, 0 | +3, 0 |
| 12.7≤OD<38.1 | ±0.13 | ±10 | +20%, 0 | +3, 0 |
| 38.1≤OD<88.9 | ±0.25 | ±10 | +20%, 0 | +5, 0 |
| 88.9≤OD<139.7 | ±0.38 | ±10 | +20%, 0 | +5, 0 |
| 139.7≤OD≤203.2 | ±0.76 | ±10 | +20%, 0 | +5, 0 |
| Mechanical Properties and Hardness Requirement | |||||
|---|---|---|---|---|---|
| UNS Designation | Tensile Strength Mpa, min | Yield Strength Mpa, min | Elongation min%, 2in or 50mm | HBW, max | HRC, max |
| S31803 | 620 | 450 | 25 | 290 | 30 |
| S32205 | 655 | 485 | 25 | 290 | 30 |
| S32750 | 800 | 550 | 15 | 300 | 32 |
| S32760 | 750 | 550 | 25 | 310 | 32 |
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Typical Applications & Industries
1. Shell & Tube Heat Exchangers
Providing excellent thermal conductivity and corrosion resistance for critical cooling and heating systems.
2. Seawater Desalination Plants (SWRO)
Highly resistant to chloride pitting and crevice corrosion, ensuring long service life in marine environments.
3. Chemical & Petrochemical Processing
Ideal for handling aggressive acids, chlorides, and high-temperature chemical reactions safely.
4. Offshore Oil & Gas Platforms
Delivering high mechanical strength for subsea equipment, umbilicals, and processing systems.
5. Pulp & Paper Industry
Widely used in digesters and bleaching equipment where standard austenitic stainless steel (like 316L) often fails.
Secure Packaging & Safe Global Shipping
Precision heat exchanger tubes require extreme care. We use premium packaging to ensure your ASTM A789 duplex tubes arrive with zero scratches, dents, or corrosion.
1. Plastic End Caps
Every single tube is tightly fitted with plastic caps. This keeps the inside of the tubes perfectly clean and strictly prevents moisture, dust, or insects from entering during transit.
2. Individual Plastic Sleeving
To protect the high-quality surface finish, tubes can be individually wrapped in plastic sleeves. This prevents metal-to-metal friction and scratches.
3. Seaworthy Wooden Cases
Unlike standard pipes that use bare bundles, our thin-wall A789 tubes and U-bent tubes are strictly packed in strong, fumigation-free plywood boxes to prevent any bending, crushing, or mechanical damage.
4. Advanced Moisture Protection
Ocean freight is harsh. We line the inside of the wooden cases with waterproof plastic film and include desiccant bags (干燥剂) to completely block out saltwater humidity and prevent chloride attacks.
5. Safe Lifting Design
All wooden cases are heavily reinforced with steel straps and designed with clear lifting points. This ensures safe and easy unloading with forklifts or cranes at your port or facility.
Why Partner With Us?
1. Professional Manufacturer
With decades of expertise in seamless stainless steel pipes, our advanced mill ensures precision engineering and top-tier industrial performance.
2. Full Certification
Our factory certified by Domestic and International institutions holding certificates such as TS ISO9001, AD2000, PED, CCS, DNV, ABS, Etc.
3. Large Stock & Fast Delivery
We maintain a massive inventory of raw materials and finished pipes. Our flexible production lines guarantee the shortest lead times in the industry.
4. Rigorous Quality Control
Zero defects is our goal. Professional inspectors, Every pipe undergoes strict Hydrostatic, Eddy Current, and PMI testing before leaving our company.
5. Secure Packaging & Shipping
From plastic end caps to seaworthy wooden cases, our professional packaging prevents any transit damage, ensuring your cargo arrives in perfect condition.
6. Reliable After-Sales Support
We stand behind our products. If any quality issues arise, our team provides a 24-hour rapid response and immediate technical solutions to protect your interests.
Frequently Asked Questions (ASTM A789/A789M) FAQ
Q1: What is the main difference between ASTM A789 and ASTM A790?
A: ASTM A789 is for tubing (used in heat exchangers and condensers) and requires much tighter dimensional tolerances. ASTM A790 is for piping (used for general fluid transportation). If you are building a heat exchanger, A789 is the correct standard.
Q2: Can you supply ASTM A789 in U-bent tubes?
A: Yes. We offer precision U-bending services for A789 duplex tubes. They are manufactured strictly to your drawings, stress-relieved, and ready for direct installation into your shell and tube heat exchangers.
Q3: Are your A789 tubes seamless or welded?
A: The A789 standard covers both. However, we highly recommend and supply 100% seamless duplex tubing for high-pressure and critical corrosive environments to ensure maximum safety and longer service life.
Q4: What non-destructive testing (NDT) do you perform?
A: Because heat exchanger tubes cannot leak, every single A789 tube undergoes 100% Eddy Current Testing (ECT) and Hydrostatic testing before delivery.
Q5: What is the maximum length you can produce for straight A789 tubes?
A: We can manufacture straight seamless tubes up to 24 meters (approx. 78 feet). This extra-long capacity helps eliminate the need for welding and splicing in large heat exchanger projects.
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