Grade 304 is the 18/8 austenitic default, holding 18.0 to 20.0% chromium against 8.0 to 11.0% nickel. Stainless steel 304 tubes suit fresh water, steam and mild organic acids.
View Stainless Steel 304 TubeStainless Steel Tubes Manufacturer in India
Established in 2008, MLTI Private Limited (formerly Moonlight Tube Industries) operates as a leading stainless steel tube manufacturer in Gujarat, India, delivering an annual production capacity of nearly 8,000 MT.
A stainless steel tube is ordered by measured outside diameter and wall thickness, so the dimension on the drawing is the dimension delivered. Seamless output answers to ASTM A213 / ASME SA-213, welded and ERW output to ASTM A249 / ASME SA-249, general service to ASTM A269, hygienic work to ASTM A270, and mechanical section to ASTM A554. SS seamless tubes are extruded and pierced from solid billets, so the wall carries no longitudinal joint and holds pressure evenly under thermal cycling. Welded SS tubes are formed from strips and fusion-joined along one seam, giving more uniform wall tolerance and lower cost at equal grade. We provide the following grades: 304, 304L, 310, 316, 316L, 316Ti, 321, 321H, 347, 347H and 904L. Documentation calling up UNS S31600 or N08 is matched directly. Chromium from 16.0 to 26.0% and nickel from 8.0 to 28.0% set corrosion and temperature behaviour across the list. Certified minimums for 304, 316, 316Ti, 321, 321H, 347 and 347H are 515 MPa tensile strength, 205 MPa yield strength and 35% elongation. The low-carbon grades 304L and 316L are certified to 485 MPa tensile and 170 MPa yield, and 904L to 490 MPa tensile and 215 MPa yield, each at 35% elongation.
Round section covers 12.7 mm to 101.6 mm outside diameter on walls of 1.016 mm to 3.40 mm. Heat exchanger, boiler, dairy and chemical work take most of the tonnage. We hold ISO 14001 and ISO 45001 certifications, and every material we provide is BIS / ISI Mark, EIL, IBR, and PED 2014/68/EU approved, with release on an EN 10204 3.1 certificate.
Specifications of Stainless Steel Tubes
Grade coverage, standards, section, dimensional envelope, delivery condition and finish are collected in the specification table below.
| Parameter | Value |
|---|---|
| Grades | 304, 304L, 310, 316, 316L, 316Ti, 321, 321H, 347, 347H, 904L |
| Applicable standards | • ASTM A213 / ASME SA-213: Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes • ASTM A249 / ASME SA-249: Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes • ASTM A269: Seamless and welded austenitic stainless steel tubing for general service. • ASTM A270: Seamless and Welded Austenitic and Ferritic/Austenitic Stainless Steel Sanitary Tubing • ASTM A554: Welded and ERW stainless steel mechanical and ornamental tubing in round, square, rectangular and special shapes. |
| Manufacturing route | Seamless, welded (ERW) |
| Section | Round, square, rectangular |
| Outside diameter | 12.7 mm (1/2") to 101.6 mm (4") |
| Wall thickness | 1.016 mm (19 SWG) to 3.40 mm (10 BWG) |
| Length | Up to 24 metres; cut to ordered length |
| Delivery condition | Solution annealed and pickled |
| Finish | Mill finish; pickled and passivated; polished to order |
Stainless Steel Tube Grades
Eleven grades cover the range. All are austenitic chromium-nickel steels, and 904L is a high-alloy superaustenitic; service temperature and the corrosive medium decide between them.
02
SS 304L Tube
Carbon capped at 0.035% is the main difference, and it comes with a trade: certified minima fall to 485 MPa tensile and 170 MPa yield. That ceiling suppresses carbide precipitation during welding, so fabricated water and food lines left unannealed specify 304L.
View SS 304L TubeGrade 310 carries 24.0 to 26.0% chromium and 19.0 to 22.0% nickel, holding an adherent oxide film in furnace and radiant-tube work. For aqueous chloride duty, it isn't suitable.
View Type 310 TubeAn addition of 2.00 to 3.00% molybdenum stabilises the passive film against chloride attack. 316 stainless steel tubes go into seawater cooling, brine handling and acid condensate duty.
View 316 Stainless Steel Tube
05
SS 316L Tube
The low-carbon 316 keeps chromium in solution across a weld cycle. The certified tensile minimum drops to 485 MPa and yield to 170 MPa. Welding process lines specify it.
View SS 316L TubeTitanium stabilisation combines with carbon before chromium can, so 316Ti retains intergranular resistance through repeated hot cycling. Jacketed chemical vessels and expansion bellows draw on that behaviour.
View Stainless Steel 316Ti Tube
07
321 SS Tube
Grade 321 is titanium-stabilised 18/8, with 17.0 to 19.0% chromium and 9.0 to 12.0% nickel. Exhaust collectors and hot gas ducting are its usual destinations.
View 321 SS TubeCarbon held between 0.04 and 0.10% lifts creep-rupture strength above plain 321. Superheater and reheater elements running above 550°C are where higher creep and stress-rupture strength is required.
View Type 321H Tube
09
347 Tube
Niobium replaces titanium as the stabiliser in grade 347, giving cleaner weld metal than 321 in heavy sections. Refinery reformer circuits and catalytic cracking units take it.
View 347 Tube
10
347H SS Tube
Controlled carbon of 0.04 to 0.10% gives 347H creep-rupture strength that plain 347 doesn't carry. Steam headers and superheater outlet legs in a power plant use it.
View 347H SS Tube904L is a high-alloy austenitic: 4.0 to 5.0% molybdenum and 1.00 to 2.00% copper over a 23.0 to 28.0% nickel base. Dilute sulphuric acid service justifies the cost.
View 904L Stainless Steel TubeStainless Steel Tube Forms and Types
Construction route and cross-section are separate ordering decisions. Seamless and welded (ERW) cover the first; round, square and rectangular cover the second.
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Seamless Stainless Steel Tubes
Seamless stainless steel tubes are pierced from a solid billet and drawn over a mandrel, so no longitudinal joint exists. ASTM A213 / ASME SA-213 governs the route and normally covers walls of 0.4 mm to 12.7 mm.
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Welded Stainless Steel Tubes (ERW)
Welded stainless steel tubes are roll-formed from steel strip and seam-joined. This includes ERW options, which use electric current to forge the seam closed under pressure without any filler metal.
03
Round Stainless Steel Tubes
Stainless steel round tubes are the highest-volume section, rolled from 12.7 mm to 101.6 mm outside diameter across six wall gauges per route: six BWG for seamless and six SWG for ERW. Heat transfer bundles, instrumentation runs and hydraulic circuits take a round section.
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Square Stainless Steel Tubes
Stainless steel square tubes are welded box sections made to ASTM A554, a specification that permits round, square, rectangular and special shapes formed without filler metal. Balustrades and shopfront framing are the usual outlets.
05
Rectangular Stainless Steel Tubes
Stainless steel rectangular tubes carry load about one axis, so fabricators specify them for spans and framing members. The section is welded to ASTM A554 and finished to the ordered appearance grade.
Stainless Steel Tubes Size
Size, outside diameter and weight per metre for each wall gauge are given in the stainless steel tube size charts below. Seamless tube is listed to BWG and ERW tube to SWG.
Seamless SS Tubes Size Chart
| Size | OD (mm) | 10 BWG (3.40 mm) Weight/MTR | 12 BWG (2.77 mm) Weight/MTR | 14 BWG (2.11 mm) Weight/MTR | 16 BWG (1.65 mm) Weight/MTR | 18 BWG (1.25 mm) Weight/MTR | 19 BWG (1.07 mm) Weight/MTR |
|---|---|---|---|---|---|---|---|
| 1/2" | 12.7 | 0.78 | 0.68 | 0.55 | 0.45 | 0.35 | 0.31 |
| 5/8" | 15.875 | 1.05 | 0.89 | 0.72 | 0.58 | 0.45 | 0.39 |
| 3/4" | 19.05 | 1.31 | 1.11 | 0.88 | 0.71 | 0.55 | 0.47 |
| 1" | 25.4 | 1.85 | 1.55 | 1.21 | 0.97 | 0.74 | 0.64 |
| 1 1/4" | 31.75 | 2.38 | 1.98 | 1.54 | 1.23 | 0.92 | 0.81 |
| 1 1/2" | 38.1 | 2.91 | 2.41 | 1.87 | 1.48 | 1.13 | 0.97 |
| 2" | 50.8 | 3.98 | 3.28 | 2.53 | 2.00 | 1.52 | 1.31 |
| 2 1/2" | 63.5 | 5.04 | 4.15 | 3.19 | 2.52 | 1.91 | 1.64 |
| 3" | 76.2 | 6.11 | 5.01 | 3.85 | 3.04 | 2.30 | 1.98 |
| 3 1/2" | 88.9 | 7.18 | 5.88 | 4.51 | 3.55 | 2.69 | 2.31 |
| 4" | 101.6 | 8.24 | 6.75 | 5.17 | 4.07 | 3.08 | 2.65 |
ERW SS Tube Size Chart
| Size | OD (mm) | 10 SWG (3.25 mm) Weight/Mtr | 12 SWG (2.64 mm) Weight/Mtr | 14 SWG (2.03 mm) Weight/Mtr | 16 SWG (1.63 mm) Weight/Mtr | 18 SWG (1.22 mm) Weight/Mtr | 19 SWG (1.02 mm) Weight/Mtr |
|---|---|---|---|---|---|---|---|
| 1/2" | 12.7 | 0.75 | 0.65 | 0.55 | 0.45 | 0.34 | 0.29 |
| 5/8" | 15.875 | 1.01 | 0.86 | 0.72 | 0.58 | 0.44 | 0.37 |
| 3/4" | 19.05 | 1.26 | 1.06 | 0.88 | 0.71 | 0.53 | 0.45 |
| 1" | 25.4 | 1.76 | 1.47 | 1.21 | 0.97 | 0.72 | 0.61 |
| 1 1/4" | 31.75 | 2.27 | 1.88 | 1.54 | 1.23 | 0.91 | 0.76 |
| 1 1/2" | 38.1 | 2.77 | 2.29 | 1.88 | 1.49 | 1.10 | 0.92 |
| 2" | 50.8 | 3.78 | 3.11 | 2.54 | 2.01 | 1.48 | 1.24 |
| 2 1/2" | 63.5 | 4.79 | 3.93 | 3.20 | 2.53 | 1.85 | 1.55 |
| 3" | 76.2 | 5.79 | 4.75 | 3.86 | 3.05 | 2.23 | 1.87 |
| 3 1/2" | 88.9 | 6.80 | 5.57 | 4.52 | 3.57 | 2.61 | 2.18 |
| 4" | 101.6 | 7.81 | 6.39 | 5.18 | 4.09 | 2.99 | 2.50 |
Stainless Steel Tubes: Industrial Application
High-performance stainless steel tubing powers critical systems, from boiler superheaters and chemical reactor coils to sanitary dairy transfer lines across 6 major industrial sectors.
Heat Transfer Equipment Manufacturing
ASTM A249 names condenser service in its own title, and shell-and-tube exchangers draw on the same material. Stainless steel heat exchanger tubes form the bundle, with the grade chosen against both media.
Power Generation
Economiser coils, superheater elements and reheater loops run at metal temperatures where creep governs. Stabilised 321H and 347H hold rupture strength there, and our IBR approval covers stainless steel boiler tubes.
Dairy, Food and Beverage Processing
Dairies, breweries and edible oil plants clean product lines with caustic and acid daily, and the passive film reforms after each cycle. The hygienic section to ASTM A270 is bore-finished.
Chemical and Pharmaceutical Processing
Reactor coils, dosing lines and transfer runs select grade by medium. 316L covers most organic and mild mineral acid duty; 904L handles dilute sulphuric acid that 316L can't.
Water Treatment and Desalination
Chloride load sets the grade on dosing skids, filter internals and reverse osmosis frames. Treated fresh water runs in 304; saline feed and reject streams need 316 or higher molybdenum.
Architectural and Structural Fabrication
Handrails, balustrades and cladding supports take square and rectangular sections to ASTM A554. Appearance governs here as much as strength, so polish is agreed upon at the order stage.
Shipping and Packaging
As a leading stainless steel tube supplier, we ensure export-grade packaging, complete traceability, and reliable global shipping.
- Round tubes are bundled by diameter and gauge, strapped, and timber-cased where the destination requires it.
- End caps and protective sleeving are fitted to order.
- Marking carries the heat number, grade, specification, diameter and wall.
- Release documentation is an EN 10204 3.1 mill test certificate per lot.
- Overseas orders ship FOB or CFR to Brazil, Vietnam, Turkey and Europe.
- Cut lengths are prepared in-house.
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
01
IBR & EIL Approved
02
Why
Choose Us
03
Wide Range of Grades & Sizes
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Timely Global Delivery
FAQs about SS Tubes
A seamless tube is pierced from solid and carries no joint. ERW tube is roll-formed from strip and resistance welded, so it costs less per metre.
Specify 316 wherever chlorides reach the metal, because its molybdenum resists pitting that 304 cannot. For fresh water and steam, 304 does the same work for less.
Each lot is released on an EN 10204 3.1 mill test certificate with the heat number. Our laboratory runs PMI, tensile, hardness and dimensional inspection.