The item
Super Duplex seamless Tubes with an outside diameter of 21.3 mm and a wall thickness of 0.9 mm. Roughly equal austenite and ferrite. Around twice the yield strength of 316L.
This is a size we hold rather than one we have to roll. Roughly equal austenite and ferrite. Around twice the yield strength of 316L. Supplied with a mill test certificate to EN 10204 3.1 as standard.
Pitting resistance equivalent. Higher resists chlorides better.
Indexed to 304. Indicative, for specification triage.
Rajgranth Metal & Alloys stocks and supplies Super Duplex seamless Tubes, OD 21.3 mm × 0.9 mm wall from Mumbai, with the material, tests and documentation covered by our ISO 9001:2015 quality system. Rajgranth Metal & Alloys has been trading since 1980, is self-funded and debt-free, and despatches most orders from its Mumbai stockyard within two days.
Super Duplex seamless Tubes with an outside diameter of 21.3 mm and a wall thickness of 0.9 mm. Roughly equal austenite and ferrite. Around twice the yield strength of 316L.
Duplex and Super Duplex Stainless Steel, designated UNS S31803 / S32205 / S32550 / S32750 / S32760, EN 1.4462 / 1.4507 / 1.4501, AISI F51 / F60 / F53 / F55, JIS SUS329J3L, GB S22053 and Werkstoff X2CrNiMoN22-5-3 / X2CrNiMoCuWN25-7-4.
Standards include ASTM A213 / ASME SA-213, ASTM A269, ASTM A312 / ASME SA-312, ASTM A376 / ASME SA-376, ASTM A789 / ASME SA-789, ASTM A790 / ASME SA-790, ASTM A268 / ASME SA-268 and ASTM A511. Finishes and conditions include Bright Annealed (CFA), Solution Annealed (CFD), Electro Polished (EP), Polished (APP), Annealed and Pickled (AP), Mirror Polish, Matt Polish and Cold Drawn.
offshore and subsea piping, seawater cooling and desalination, chemical tankers and cargo systems, sour gas service and pressure vessels where weight matters. We supply across India and export to markets in the Middle East, Africa, Europe, Asia, North America and South America.
Send the quantity, standard and any special requirement and we will confirm availability. Material is supplied with documentation, tested in house across 18 listed testing facilities, and covered by our ISO 9001:2015 quality management system.
Cut to length on request
3.2 with third-party inspection on request
The full detail for this product as supplied from our Mumbai stockyard: sizes, grades, standards, tolerances, tests and applications.

Rajgranth Metals & Alloys is a leading manufacturer and exporter of SS seamless tubes made from Super Duplex stainless steel are among the most reliable options. Crafted to offer superior strength, durability, and corrosion resistance, these tubes are essential in demanding environments. Specifically, tubes with a diameter of 21.3 mm and a 0.9 mm wall thickness offer the right balance between size and performance for a wide range of applications.
Super Duplex stainless steel is a type of alloy that combines the best features of both austenitic and ferritic stainless steels. The result is a metal that delivers high corrosion resistance, incredible strength, and enhanced durability. It’s called "Super" Duplex because it has even greater properties than standard Duplex stainless steel, particularly in terms of resistance to stress corrosion cracking, making it an ideal choice for challenging environments.
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The production of seamless tubes begins with a solid steel billet, which is heated and pierced to create a hollow tube. The tube is then stretched and rolled to the desired dimensions. The lack of seams means there are no weak points, ensuring consistent strength throughout the tube's length.
The dimensions of SS seamless tubes play a significant role in determining their suitability for specific applications. A diameter of 21.3 mm is commonly used in systems where medium-sized flow is required, while a wall thickness of 0.9 mm provides enough strength without adding unnecessary weight.
This particular size is widely used because it fits well into both small and large-scale industrial systems. It’s flexible enough to be applied in compact spaces without compromising on flow capacity.
This size strikes a balance between capacity and compactness, ideal for use in various industrial processes where medium-level fluid or gas transport is necessary.
A tube wall thickness of 0.9 mm ensures that the tube remains light but durable, capable of withstanding moderate pressures while maintaining flexibility.
| Stainless Steel Tubes Dimension – (S.S. Tubes) | 13 | 1 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wall thickness in mm. | 0.5 | 0.6 | 0.7 | 0.8 | 1 | 1.2 | 1.6 | 2 | 2.6 | 3 | 3.2 | 3.6 |
| O.D. in mm. | Weight in kg/meter | 12 | 1 | |||||||||
| 6 | 0.069 | 0.081 | 0.093 | 0.104 | 0.125 | 0.144 | 0.176 | – | – | – | – | – |
| 9.52 | 0.112 | 0.134 | 0.154 | 0.174 | 0.213 | 0.249 | 0.317 | – | – | – | – | – |
| 10 | 0.119 | 0.141 | 0.163 | 0.184 | 0.225 | 0.264 | 0.336 | – | – | – | – | – |
| 12.7 | 0.153 | 0.182 | 0.21 | 0.238 | 0.293 | 0.345 | 0.444 | – | – | – | – | – |
| 14 | 0.169 | 0.201 | 0.233 | 0.264 | 0.325 | 0.384 | 0.496 | – | – | – | – | – |
| 15.87 | 0.192 | 0.229 | 0.266 | 0.301 | 0.372 | 0.44 | 0.571 | 0.694 | – | – | – | – |
| 19 | 0.231 | 0.276 | 0.32 | 0.364 | 0.45 | 0.534 | 0.696 | 0.85 | 1.066 | 1.2 | 1.264 | – |
| 25 | 0.306 | 0.366 | 0.425 | 0.484 | 0.6 | 0.714 | 0.936 | 1.15 | 1.456 | 1.65 | 1.744 | 1.926 |
| 25.4 | 0.311 | 0.372 | 0.432 | 0.492 | 0.61 | 0.726 | 0.952 | 1.17 | 1.482 | 1.68 | 1.776 | 1.962 |
| 31.8 | – | – | – | – | – | 0.918 | 1.208 | 1.49 | 1.898 | 2.16 | 2.288 | 2.538 |
| 38 | – | – | – | – | – | 1.104 | 1.456 | 1.8 | 2.301 | 2.625 | 2.784 | 3.096 |
| 44.5 | – | – | – | – | – | 1.299 | 1.716 | 2.125 | 2.724 | 3.113 | 3.304 | 3.681 |
| 50.8 | – | – | – | – | – | 1.488 | 1.968 | 2.44 | 3.133 | 3.585 | 3.808 | 4.248 |
| 63.5 | – | – | – | – | – | – | 2.476 | 3.075 | 3.959 | 4.538 | 4.824 | 5.391 |
| 76.1 | – | – | – | – | – | – | 2.98 | 3.705 | 4.778 | 5.483 | 5.832 | 6.525 |
| 101.6 | – | – | – | – | – | – | 4 | 4.98 | 6 | 7 | 7,872 | 8.82 |
| CHEMICAL COMPOSITION ( IN PERCENTAGE ) | 11 | 1 | ||||||||
| Grade | C (Max) | Mn (Max) | P (Max) | S (Max) | Si (Max) | Cr | Ni | Mo | Nitrogen (Max) | Cu/ Others |
| 301 | 0.15 | 2 | 0.045 | 0.03 | 1 | 16.00 – 18.00 | 6.00 – 8.00 | – | 0.1 | – |
| 304 | 0.08 | 2 | 0.045 | 0.03 | 0.75 | 18.00 – 20.00 | 8.00- 10.50 | – | 0.1 | – |
| 304L | 0.03 | 2 | 0.045 | 0.03 | 0.75 | 18.00 – 20.00 | 8.00- 12.00 | – | 0.1 | – |
| 310S | 0.08 | 2 | 0.045 | 0.03 | 1.5 | 24.00- 26.00 | 19.00 – 22.00 | – | – | – |
| 316 | 0.08 | 2 | 0.045 | 0.03 | 0.75 | 16.00 – 18.00 | 10.00 – 14.00 | 2.00 – 3.00 | 0.1 | – |
| 316L | 0.03 | 2 | 0.045 | 0.03 | 0.75 | 16.00 – 18.00 | 10.00 – 14.00 | 2.00 – 3.00 | 0.1 | – |
| 317 | 0.08 | 2 | 0.045 | 0.03 | 0.75 | 18.00 – 20.00 | 11.00 – 14.00 | 3.00 – 4.00 | 0.1 | – |
| 317L | 0.03 | 2 | 0.045 | 0.03 | 0.75 | 18.00 – 20.00 | 11.00 – 15.00 | 3.00 – 4.00 | 0.1 | – |
| 321 | 0.08 | 2 | 0.045 | 0.03 | 0.75 | 17.00 – 19.00 | 9.00 – 12.00 | – | 0.1 | Ti5 ( C + N ) Min or 0.70 max |
| 347 | 0.08 | 2 | 0.045 | 0.03 | 0.75 | 17.00 – 19.00 | 9.00 – 13.00 | – | – | Cb= 10x ( C Min ) or 1.00 Max |
| 409 | 0.08 | 1 | 0.04 | 0.01 | 1 | 10.50 – 11.75 | 0.5 | – | – | Ti= 6x (C+ N ) Min or 0.70 Max |
| 409M | 0.03 | 0.81.2 | 0.03 | 0.03 | 0.40.75 | 11.00- 12.00 | 1.5 max. | – | – | Ti= 6x (C) Min or 0.70 Max |
| 410S | 0.08 | 1 | 0.04 | 0.03 | 1 | 11.50- 13.50 | 0.6 | – | – | – |
| 410 | 0.15 | 1 | 0.04 | 0.03 | 1 | 11.50- 13.50 | 0.75 | – | – | – |
| 420 | 0.35 | 0.5 | 0.035 | 0.015 | 0.5 | 12.00 – 13.00 | 0.20.3 | – | – | – |
| 430 | 0.12 | 1 | 0.04 | 0.03 | 1 | 16.00 – 18.00 | 0.75 | – | – | – |
| JSL AUS | 0.08 | 7.08.0 | 0.07 | 0.03 | 0.75 | 15.50 – 16.50 | 4.25 – 4.75 | – | – | 0.9 – 1.10 |
| JS- 203 | 0.08 | 9.2510.25 | 0.07 | 0.03 | 0.75 | 14.25 – 15.25 | 2.25 – 2.75 | – | – | 1.60- 2.0 |
| 301M | 0.1 | 4.55.5 | 0.06 | 0.03 | 0.75 | 14.50 – 15.50 | 6.0 – 7.0 | – | – | 1.70- 1.90 |
| * Thickness of 1.27mm & below will have elongation of 20% min. | 11 | 1 |
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Stainless steel seamless tubes, particularly those made from Grade 321, are used across a wide range of industries. Some of the most common applications include:
Our Stainless Steel Seamless Tube Used In Many Industries & Have Many Application
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