The item
321 seamless Tubes with an outside diameter of 15.8 mm and a wall thickness of 0.9 mm. 304 stabilised with titanium. Resists sensitisation in the 425–815 degrees C range.
This is a size we hold rather than one we have to roll. 304 stabilised with titanium. Resists sensitisation in the 425–815 degrees C range. 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 321 seamless Tubes, OD 15.8 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.
321 seamless Tubes with an outside diameter of 15.8 mm and a wall thickness of 0.9 mm. 304 stabilised with titanium. Resists sensitisation in the 425–815 degrees C range.
Stainless Steel 321 and 321H, designated UNS S32100 / S32109, EN 1.4541 / 1.4940, AISI 321 / 321H, JIS SUS321 / SUS321H, GB S32168 / S32169 and Werkstoff X6CrNiTi18-10 / X7CrNiTi18-10.
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.
exhaust manifolds and expansion joints, refinery heater and furnace components, aircraft and aerospace piping and high-temperature process vessels. 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.

Stainless steel seamless tubes have become essential components in a wide variety of industries, from construction to aerospace, thanks to their combination of durability, corrosion resistance, and high performance under extreme conditions. These tubes, especially in precision dimensions like 15.8 mm in diameter and 0.9 mm thickness, provide a perfect solution for applications requiring strength and stability in small-sized configurations.
But what makes stainless steel seamless tubes, specifically Grade 321, stand out? This article delves into the properties, uses, and benefits of Grade 321 SS seamless tubes, focusing on those with a diameter of 15.8 mm and a thickness of 0.9 mm.
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Grade 321 stainless steel is an austenitic stainless steel that contains titanium as a stabilizing element. This grade is well-known for its excellent resistance to intergranular corrosion, which occurs in environments where the material is exposed to high temperatures. The addition of titanium ensures that the material maintains its mechanical properties at elevated temperatures, making it suitable for heat-related applications.
In comparison to other grades like 304 or 316, Grade 321 offers superior resistance to scaling and stress rupture at temperatures up to 900 °C, making it ideal for use in environments with significant thermal stress.
Tubes with a diameter of 15.8 mm and a thickness of 0.9 mm are commonly used for specialized applications where precision and space efficiency are crucial. Small-diameter tubes like these are widely employed in heat exchangers, automotive parts, and instrumentation.
Seamless tubes are produced by heating a solid round billet of stainless steel and then piercing it to create a hollow tube. For Grade 321, additional titanium is included in the alloy to give the steel its unique properties. Unlike welded tubes, seamless tubes have no weak points or seams, which can be areas of vulnerability under pressure or corrosion.
This seamless construction provides a uniform structure, increasing its ability to resist high pressure and temperatures.
| 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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