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Stainless Steel 304 Square Pipe
SS 304 square pipe, UNS S30400, contains 18.0–20.0% chromium and 8.0–11.0% nickel. It is widely used for railings, furniture, architectural structures, and general fabrication.
Stainless Steel Square Pipes Manufacturer in India
MLTI Private Limited (Moonlight Tube Industries) manufactures, supplies, and exports stainless steel square pipes from Gujarat, India, with production operations since 2008 and an installed capacity of approximately 8,000 MT per year. Our square sections are cold-formed from stainless steel strip and closed through a longitudinal ERW seam. ASTM A554 provides the primary dimensional and workmanship basis for welded stainless steel mechanical tubing in square, rectangular and special sections.
Our range covers 304, 304L, 310, 316, 316L, 316Ti, 321, 321H, 347, 347H and 904L, subject to grade and section availability. Grade 304 suits general fabrication, making 304 stainless steel square pipe a common choice for railings, furniture and architectural structures. Grades 310, 321, 321H, 347 and 347H are used where elevated-temperature resistance is required. A stainless steel welded ERW square pipe utilises longitudinal seams to deliver tight dimensional tolerances. Our square sections range from 12 × 12 mm to 120 × 120 mm, with wall thicknesses from 0.8 to 3.0 mm and lengths up to 12 metres. We hold ISO 14001 and 45001 certifications alongside EN 10204 3.1 certification, and PMI, tensile and hardness testing are available for applicable orders.
Specifications of Stainless Steel Square Pipes
The applicable standard, grades, manufacturing route, section range, wall thickness and finish for our stainless steel square pipe range 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. It covers welded stainless steel mechanical tubing in round, square, rectangular and special shapes. |
| Dimensional Basis | Outside face width A and wall thickness t, to ASTM A554 tolerances. ASME B36.19M does not apply to square sections. |
| Section Size | 12 × 12 mm to 120 × 120 mm |
| Manufacturing process | ERW, cold-formed from stainless steel strip |
| Section | Equal outside faces, A × A |
| 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 |
| End type | Plain end |
Stainless Steel Square Pipe Grades
Eleven austenitic grades are available across the range. Carbon level, alloying additions, stabilisation and temperature or corrosion exposure determine grade selection.
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Alloy 304L Square Pipe
SS 304L square pipe, UNS S30403, has a maximum carbon content of 0.035%. Its lower carbon level reduces sensitisation risk after welding, making it suitable for fabricated frames with unannealed joints.
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UNS S31000 Square Pipe
SS 310 square pipe, UNS S31000, contains 24.0–26.0% chromium and 19.0–22.0% nickel. Its resistance to oxidation at elevated temperatures makes it suitable for furnace structures and heated process equipment.
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Alloy 316 Square Pipe
SS 316 square pipe, UNS S31600, contains 2.00–3.00% molybdenum in addition to chromium and nickel. It offers improved resistance to chloride-induced pitting compared with 304.
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316L SS Square Pipe
SS 316L square pipe, UNS S31603, combines molybdenum with a maximum carbon content of 0.035%. It is commonly selected for welded structures exposed to chlorides, moisture and chemical washdown.
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SS 316Ti Square Pipe
SS 316Ti square pipe is titanium-stabilised to resist chromium carbide precipitation during elevated-temperature exposure. It is suitable for fabricated structures subject to repeated heating and cooling.
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Stainless Steel 321 Square Pipe
SS 321 square pipe, UNS S32100, is titanium-stabilised for elevated-temperature applications. The stabilisation improves resistance to sensitisation following exposure to temperatures that can affect unstabilised austenitic grades.
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Stainless Steel 321H Square Pipe
SS 321H square pipe, UNS S32109, has controlled higher carbon content for improved high-temperature strength. It is selected for structural and process applications involving sustained elevated temperatures.
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Alloy 347 Square Pipe
SS 347 square pipe, UNS S34700, uses niobium stabilisation to improve resistance to intergranular corrosion after heating. It is suitable for elevated-temperature fabrication and process equipment.
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347H SS Square Pipe
SS 347H square pipe, UNS S34709, combines niobium stabilisation with controlled higher carbon content. This provides improved creep and stress-rupture performance at elevated temperatures.
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SS 904L Square Pipe
SS 904L square pipe, UNS N08904, contains molybdenum and copper with higher nickel content. It is selected for aggressive chemical environments where conventional 304 or 316 may not provide sufficient corrosion resistance.
SS Box Pipes Dimensions
Stainless steel square pipe dimensions are specified by outside face width and wall thickness. Our SS square pipe sizes range from 12 × 12 mm to 120 × 120 mm, subject to confirmed availability. Weights below are theoretical, calculated at a density of 7.93 g/cm³ and covering grades 304, 304L and 321; for 316 and 316L multiply each value by 1.0088.
| Size (mm) | Size (inch, approx.) | 0.8 mm | 1.0 mm | 1.2 mm | 1.5 mm | 2.0 mm | 2.5 mm | 3.0 mm |
|---|---|---|---|---|---|---|---|---|
| 12 × 12 | 0.47" × 0.47" | 0.271 | 0.328 | 0.382 | 0.454 | — | — | — |
| 15 × 15 | 0.59" × 0.59" | 0.347 | 0.424 | 0.496 | 0.596 | — | — | — |
| 16 × 16 | 0.63" × 0.63" | 0.373 | 0.455 | 0.534 | 0.644 | 0.806 | — | — |
| 19 × 19 | 0.75" × 0.75" | 0.449 | 0.551 | 0.648 | 0.787 | 0.997 | — | — |
| 20 × 20 | 0.79" × 0.79" | 0.474 | 0.582 | 0.686 | 0.834 | 1.060 | 1.260 | — |
| 25 × 25 | 0.98" × 0.98" | 0.601 | 0.741 | 0.877 | 1.072 | 1.377 | 1.657 | 1.910 |
| 30 × 30 | 1.18" × 1.18" | 0.728 | 0.899 | 1.067 | 1.310 | 1.695 | 2.053 | 2.386 |
| 38 × 38 | 1.50" × 1.50" | 0.931 | 1.153 | 1.371 | 1.691 | 2.202 | 2.688 | 3.147 |
| 40 × 40 | 1.57" × 1.57" | 0.982 | 1.217 | 1.447 | 1.786 | 2.329 | 2.846 | 3.337 |
| 50 × 50 | 1.97" × 1.97" | 1.235 | 1.534 | 1.828 | 2.262 | 2.963 | 3.639 | 4.289 |
| 60 × 60 | 2.36" × 2.36" | 1.489 | 1.851 | 2.209 | 2.737 | 3.598 | 4.432 | 5.240 |
| 70 × 70 | 2.76" × 2.76" | 1.743 | 2.168 | 2.589 | 3.213 | 4.232 | 5.225 | 6.192 |
| 75 × 75 | 2.95" × 2.95" | 1.870 | 2.327 | 2.780 | 3.451 | 4.549 | 5.622 | 6.668 |
| 80 × 80 | 3.15" × 3.15" | 1.997 | 2.485 | 2.970 | 3.689 | 4.867 | 6.018 | 7.144 |
| 90 × 90 | 3.54" × 3.54" | 2.250 | 2.803 | 3.351 | 4.165 | 5.501 | 6.811 | 8.095 |
| 100 × 100 | 3.94" × 3.94" | 2.504 | 3.120 | 3.731 | 4.641 | 6.135 | 7.604 | 9.047 |
| 120 × 120 | 4.72" × 4.72" | 3.012 | 3.754 | 4.493 | 5.592 | 7.404 | 9.190 | 10.950 |
Sections outside the listed range can be produced to a specified outside face width on enquiry. The product is also known as stainless steel box pipe, stainless steel box section or stainless steel pipe square.
Industrial Applications of Stainless Steel Square Pipes
Square sections are used where equal outside dimensions, fabrication flexibility and corrosion resistance are required. Major applications include architectural fabrication, food equipment, marine structures, machinery frames and industrial supports.
Railing and Architectural Fabrication
Railings, balustrades, gates, staircases and canopy frames commonly use 304 square sections. Flat faces simplify the installation of brackets, clamps and architectural fittings.
Food Processing and Dairy Equipment
Food and dairy facilities use 304L and 316L sections for equipment frames, platforms and guards exposed to frequent cleaning, hot water and chemical washdown.
Marine and Coastal Installations
316 square sections are preferred for coastal railings, walkways, pontoon structures and equipment supports where chloride exposure increases the risk of pitting in 304.
Structural Frames and Supports
Machine bases, skid frames, equipment supports, mezzanine structures and guarding use square sections where equal outside dimensions provide consistent stiffness about the principal axes.
Furniture and Shopfitting
304 square sections are used for display units, counters, laboratory furniture, retail fixtures and fabricated structures requiring corrosion resistance and a finished surface.
Shipping and Packaging of SS Box Pipes
Stainless Steel (SS) box pipes are securely packaged, clearly labelled, and shipped globally or across India from our Umbergaon works.
- Sections are bundled by grade and size, strapped and prepared for road or export transport.
- Plastic end caps and protective sleeving are supplied where required.
- Export orders can be arranged on FOB or CFR terms.
- Pan-India dispatch is arranged from the 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
Stainless Steel Square Pipe FAQs
The range includes 304, 304L, 310, 316, 316L, 316Ti, 321, 321H, 347, 347H and 904L, subject to section and order requirements.
ASTM A554 is the primary specification for welded stainless steel mechanical tubing in square, rectangular and special shapes. ASTM A312 / ASME SA-312 applies to circular austenitic pressure pipe rather than square mechanical sections.
Our square sections are welded. Stainless steel strip is cold formed into the required profile and closed with a longitudinal ERW seam without filler metal.
Grade 304 is generally suitable for indoor, architectural and general fabrication. Grade 316 is preferred where chloride exposure, coastal conditions or chemical washdown increases the risk of pitting.
Yes. We supply SS square pipe across India and arrange export consignments from Gujarat to international destinations according to the order and shipping terms.