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Alloy 304 Rectangular Pipe
SS 304 rectangular pipe, UNS S30400 and EN 1.4301, contains 18.0–20.0% chromium and 8.0–10.5% nickel. It is widely specified for architectural framing, railings, furniture, shopfitting and general fabrication.
Stainless Steel Rectangular Pipes Manufacturer in India
MLTI Private Limited (Moonlight Tube Industries) manufactures, supplies and exports stainless steel rectangular pipe from Gujarat, India, with production operations since 2008 and an installed combined capacity of approximately 8,000 MT per year. A rectangular section has two unequal outside face widths and is cold-formed from a stainless steel strip before being closed through a longitudinal ERW seam. The section is then sized to achieve the specified dimensions and corner profile.
ASTM A554 covers welded stainless steel mechanical tubing for ornamental, structural and similar applications, produced by fusing the longitudinal strip edges without filler metal. Grades 304, 304L, 310, 316, 316L, 316Ti, 321, 321H, 347, 347H, and 904L are listed in the ASTM A554 grade table. For more demanding requirements, rectangular pipes can be supplied in grades such as 310, 316Ti, 321H, 347H and 904L against agreed chemistry and customer specifications. Sections range from 20 × 10 mm to 120 × 60 mm, with wall thicknesses from 0.8 to 3.0 mm and lengths up to 12 metres.
Grade 304 is widely used for general fabrication, while 316 and 904L are selected for more demanding corrosive environments. Grades 310, 321, 321H, 347 and 347H are selected for elevated-temperature applications. Our company holds ISO 14001 and ISO 45001 certifications. EN 10204 3.1 inspection certificates are available for applicable orders, and PMI, tensile and hardness testing are supported through our quality inspection system.
Specifications of Stainless Steel Rectangular Pipes
Grade, applicable standards, manufacturing route, section range, wall thickness and finish for our rectangular sections are given below.
| Parameter | Value |
|---|---|
| Grades | 304, 304L, 310, 316, 316L, 316Ti, 321, 321H, 347, 347H, 904L |
| Applicable standards | - ASTM A554: Standard Specification for Welded Stainless Steel Mechanical Tubing. Dimensional standards for round pipe, such as ASME B36.19M, do not apply to rectangular sections; rectangular sizes are supplied to the mill's rolling range and A554 tolerances. |
| Manufacturing process | ERW/welded |
| Section basis | Outside height H × outside width B, with wall thickness t |
| Section size | 20 × 10 mm to 120 × 60 mm |
| Wall thickness | 0.8 to 3.0 mm |
| Length | Up to 12 metres; cut lengths available |
| Corner profile | Radiused inside and outside corners |
| Weld seam | Longitudinal ERW seam, formed without filler metal |
| Finish | Mill finish; pickled and passivated to order |
Stainless Steel Rectangular Pipe Grades
Eleven austenitic grades are available across the rectangular pipe range. Grade selection depends on corrosion exposure, welding requirements, temperature and the required mechanical performance.
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Stainless Steel 304L Rectangular Pipe
SS 304L, UNS S30403 and EN 1.4307 are the low-carbon versions of 304. Its lower carbon limit reduces sensitisation risk after welding, making it suitable for fabricated frames with welded joints.
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310 SS Rectangular Pipe
SS 310 rectangular pipe, UNS S31000, contains approximately 24.0–26.0% chromium and 19.0–22.0% nickel. Its high-temperature oxidation resistance makes it suitable for furnace structures, heat-treatment equipment and elevated-temperature fabrication.
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SS 316 Rectangular Pipe
SS 316, UNS S31600 and EN 1.4401 contain 2.00–3.00% molybdenum in addition to chromium and nickel. This improves resistance to chloride-induced pitting in marine, coastal and chemical-processing environments.
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Alloy 316L Rectangular Pipe
SS 316L, UNS S31603 and EN 1.4404 combine molybdenum with a low carbon content. It is commonly selected for welded structures exposed to chlorides, chemical washdown and other corrosive service conditions.
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Stainless Steel 316Ti Rectangular Pipe
SS 316Ti, UNS S31635 and EN 1.4571, is titanium-stabilised to improve resistance to sensitisation during elevated-temperature exposure. It is used for fabricated structures and process equipment exposed to repeated heating.
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321 SS Rectangular Pipe
SS 321, UNS S32100 and EN 1.4541 are titanium-stabilised for elevated-temperature service. The stabilisation improves resistance to intergranular corrosion following exposure to temperatures that can affect unstabilised austenitic grades.
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UNS S32109 Rectangular Pipe
SS 321H, UNS S32109, is a higher-carbon version of the 321 family developed for improved high-temperature strength. It is selected for structural and process applications operating at sustained elevated temperatures.
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SS 347 Rectangular Pipe
SS 347, UNS S34700 and EN 1.4550, use niobium stabilisation to improve resistance to intergranular corrosion following heating. It is suitable for elevated-temperature structures and process equipment.
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Alloy 347H Rectangular Pipe
SS 347H, UNS S34709, combines niobium stabilisation with controlled higher carbon content for improved high-temperature strength. It is selected for applications involving elevated-temperature stress and prolonged exposure.
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SS 904L Rectangular Pipe
SS 904L, UNS N08904 and EN 1.4539 contain elevated nickel, chromium, molybdenum and copper. It is selected for aggressive chemical environments where conventional 304 or 316 grades do not provide sufficient corrosion resistance.
Stainless Steel Rectangular Pipe Dimensions
A rectangular section is specified by two outside face dimensions and wall thickness, all stated in millimetres. The SS rectangular pipe size chart below covers the full range, with theoretical weight in kilogrammes per metre for each section and wall combination.
| Size (mm) | Size (inch, approx.) | Wall Thickness → Weight (kg/m) | ||||||
|---|---|---|---|---|---|---|---|---|
| H × B | H × B | 0.8 mm | 1.0 mm | 1.2 mm | 1.5 mm | 2.0 mm | 2.5 mm | 3.0 mm |
| 20 × 10 | 0.79" × 0.39" | 0.347 | 0.424 | 0.496 | — | — | — | — |
| 25 × 12 | 0.98" × 0.47" | 0.436 | 0.535 | 0.629 | 0.763 | — | — | — |
| 25 × 15 | 0.98" × 0.59" | 0.474 | 0.582 | 0.686 | 0.834 | — | — | — |
| 30 × 15 | 1.18" × 0.59" | 0.538 | 0.662 | 0.781 | 0.953 | — | — | — |
| 30 × 20 | 1.18" × 0.79" | 0.601 | 0.741 | 0.877 | 1.072 | 1.377 | 1.657 | — |
| 40 × 20 | 1.57" × 0.79" | 0.728 | 0.899 | 1.067 | 1.310 | 1.695 | 2.053 | — |
| 40 × 25 | 1.57" × 0.98" | 0.791 | 0.979 | 1.162 | 1.429 | 1.853 | 2.251 | 2.623 |
| 50 × 25 | 1.97" × 0.98" | 0.918 | 1.137 | 1.352 | 1.667 | 2.170 | 2.648 | 3.099 |
| 50 × 30 | 1.97" × 1.18" | 0.982 | 1.217 | 1.447 | 1.786 | 2.329 | 2.846 | 3.337 |
| 60 × 30 | 2.36" × 1.18" | 1.109 | 1.375 | 1.638 | 2.024 | 2.646 | 3.243 | 3.813 |
| 60 × 40 | 2.36" × 1.57" | 1.235 | 1.534 | 1.828 | 2.262 | 2.963 | 3.639 | 4.289 |
| 70 × 40 | 2.76" × 1.57" | 1.362 | 1.692 | 2.018 | 2.500 | 3.281 | 4.036 | 4.765 |
| 75 × 45 | 2.95" × 1.77" | 1.489 | 1.851 | 2.209 | 2.737 | 3.598 | 4.432 | 5.240 |
| 80 × 40 | 3.15" × 1.57" | 1.489 | 1.851 | 2.209 | 2.737 | 3.598 | 4.432 | 5.240 |
| 90 × 50 | 3.54" × 1.97" | 1.743 | 2.168 | 2.589 | 3.213 | 4.232 | 5.225 | 6.192 |
| 100 × 50 | 3.94" × 1.97" | 1.870 | 2.327 | 2.780 | 3.451 | 4.549 | 5.622 | 6.668 |
| 100 × 60 | 3.94" × 2.36" | 1.997 | 2.485 | 2.970 | 3.689 | 4.867 | 6.018 | 7.144 |
| 120 × 60 | 4.72" × 2.36" | 2.250 | 2.803 | 3.351 | 4.165 | 5.501 | 6.811 | 8.095 |
Inch dimensions convert directly into millimetres. For example, the 50 × 25 mm section corresponds to approximately 1.97 × 0.98 inch. All listed grades share the same dimensional envelope, so the table also serves as an SS 304 rectangular pipe size chart. Weights are calculated at a density of 7.93 g/cm³, covering grades 304, 304L and 321; for 316 and 316L multiply each value by 1.0088.
Dimensional control covers outside face width, height, wall thickness, squareness, twist, corner radius and straightness. Radiused corners are normal on cold-formed sections, along with a small weld bead that may remain on one internal face.
Industrial Applications of Stainless Steel Rectangular Pipes
Rectangular stainless steel pipe is selected where unequal face dimensions provide directional stiffness together with corrosion resistance. Major applications include architectural structures, transport fabrication, food equipment, marine installations and industrial frames.
Building and Architectural Framing
Curtain-wall framing, canopy structures, staircase components, gates and architectural frames use 304 rectangular sections where corrosion resistance and clean external geometry are required. The flat faces also simplify attachment of brackets and panels.
Transport and Bus Body Fabrication
Bus frames, luggage racks, trailer sub-frames and vehicle components use rectangular sections where directional stiffness and controlled weight are important. Stainless construction also reduces dependence on painted protective coatings.
Marine and Coastal Infrastructure
High performance stainless steel rectangular pipe, particularly in SS 316, is used for jetty handrails, pontoon frames, walkways and coastal equipment supports.
Food, Dairy and Pharmaceutical Plant
Equipment frames, conveyor supports, platforms and guards in washdown areas commonly use 304L or 316L. The flat faces provide convenient mounting surfaces for panels, brackets, and hygienic equipment components.
Furniture and Shopfitting
304 rectangular sections are used for display counters, retail fixtures, laboratory furniture, medical furniture and other fabricated structures. Smaller sections can be supplied cut to the required lengths.
Shipping and Packaging of SS Rectangular Pipes
Our secure shipping and packaging procedures provide physical protection and reliable transport for both domestic and global destinations.
- Sections are bundled according to grade and size, strapped securely, and prepared for road or export transportation.
- Plastic end caps and protective sleeving are supplied where required.
- Export orders can be arranged on FOB or CFR terms for Brazil, Vietnam, Turkey, and Europe.
- Pan-India dispatch is arranged by road from our Gujarat facility.
Why Choose MLTI Private Limited?
Buyers return to Moonlight Tubes for certified material, approved grades and stock that ships on schedule. Every order is backed by documented quality, a wide size range and delivery commitments we hold to.
Quality Certification
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IBR & EIL Approved
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Why
Choose Us
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Wide Range of Grades & Sizes
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Timely Global Delivery
FAQs for Stainless Steel Rectangular Pipes
Stainless steel rectangular pipes are available in outer cross-sections from 20 × 10 mm to 120 × 60 mm, with wall thicknesses from 0.8 mm to 3.0 mm and standard or custom cut lengths up to 12 metres.
Available material grades include 304, 304L, 310, 316, 316L, 316Ti, 321, 321H, 347, 347H, and 904L, tailored for architectural framing, structural support, elevated-temperature duties, or aggressive chemical processing environments.
Rectangular sections are cold-formed and roll-shaped from annealed stainless steel strip. The longitudinal seam is produced using continuous automated welding without filler metal before undergoing final calibration, sizing, and straightening.
Grade 304 is standard for indoor architectural frameworks, structural bracing, and general fabrication. Grade 316 contains 2.00–3.00% molybdenum, providing superior resistance against pitting in marine environments and chemical washdown applications.
Rectangular pipes feature flat faces and unequal axes engineered for structural bending resistance and architectural fabrication. Circular pipes distribute internal hoop stress uniformly, making them the standard geometry for pressurised fluid and gas transport.