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MLTI (Moonlight Tube Industries), based in Gujarat, has been manufacturing, supplying, and exporting 316L stainless steel tube since 2008 and now has a combined annual capacity close to 8,000 MT. Stainless steel 316L tube is a low-carbon, molybdenum-bearing austenitic grade, UNS S31603, ordered as ASTM A213 TP316L. Molybdenum enters at 2.00 to 3.00%, chromium at 16.0 to 18.0%, and nickel at 10.0 to 14.0%. That molybdenum is what raises pitting resistance in chloride-bearing water, brine and acid condensate well beyond 304L, though not to the level required for continuous seawater immersion.
Carbon content is 0.035% maximum under ASTM A213 / ASME SA-213 and 0.030% maximum under ASTM A249 / ASME SA-249, which leaves chromium available to the passive film after welding. Solution-treated material certifies to 485 MPa (70 ksi) tensile, 170 MPa (25 ksi) yield, and 35% elongation. Hardness is held to 90 HRB. We produce 316L stainless steel tubing on both routes. Seamless tube is made by the seamless process and finished hot or cold, so the wall carries no longitudinal joint, and it is certified to ASTM A213 / ASME SA-213. Welded and ERW tube is roll-formed from flat-rolled strip and closed by an automatic weld with no filler metal added, then cold-worked before the final solution anneal, to ASTM A249 / ASME SA-249. General-service material on either route follows ASTM A269. Round AISI 316L tube covers outside diameters of 12.7 mm to 101.6 mm, on seamless walls of 1.07 mm to 3.40 mm (19 BWG to 10 BWG) and ERW walls of 1.02 mm to 3.25 mm (19 SWG to 10 SWG), and we roll square and rectangular sections alongside it. We are an ISO 14001 and ISO 45001-certified firm approved by BIS, EIL, and IBR, with PED 2014/68/EU held for European pressure duty.
Governing standards, dimensional envelope, and condition appear in the table below. Two ordering decisions follow it: 316L against 316 and surface finish.
| Parameter | Value |
|---|---|
| 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 A554: Welded Stainless Steel Mechanical Tubing |
| Manufacturing route | Seamless (hot finished or cold finished); welded (ERW) |
| Section | Round, square, rectangular |
| Outside diameter, round | 12.7 mm to 101.6 mm (1/2" to 4") |
| Wall thickness, round | Seamless 1.07 mm to 3.40 mm (19 BWG to 10 BWG); ERW 1.02 mm to 3.25 mm (19 SWG to 10 SWG) |
| Square section | 12 x 12 mm to 100 x 100 mm, wall 1.0 mm to 6.0 mm |
| Rectangular section | 13 x 25 mm to 100 x 50 mm, wall 1.0 mm to 6.0 mm |
| Length | To 24 metres round; to 12 metres box section; cut to order |
| Delivery condition | Solution treated at 1040 °C minimum, rapidly cooled |
| Finish | Mill finish; pickled and passivated; polished to order |
| End type | Plain end, cut to specified length |
Molybdenum and carbon are the two elements that define this analysis commercially. Seamless 316L SS limits to ASTM A213 / ASME SA-213 are given in the table below.
| Element | Composition, % by mass |
|---|---|
| Carbon (C) | 0.035 max |
| Manganese (Mn) | 2.00 max |
| Phosphorus (P) | 0.045 max |
| Sulphur (S) | 0.030 max |
| Silicon (Si) | 1.00 max |
| Chromium (Cr) | 16.0 – 18.0 |
| Nickel (Ni) | 10.0 – 14.0 |
| Molybdenum (Mo) | 2.00 – 3.00 |
| Iron (Fe) | Balance |
Carbide precipitates at the grain boundaries between 425 °C and 815 °C. The chromium-depleted metal left beside it corrodes intergranularly. Carbon that is absent cannot feed that reaction, so a 316L weld zone stays passive without a post-weld anneal. Molybdenum supplies the chloride pitting resistance that 304L lacks. Above roughly 60 °C under tensile load, neither element prevents stress corrosion cracking, and duplex is specified instead.
The mechanical properties of 316L SS Tube are listed below along with its tensile strength, yield strength, elongation, and hardness.
| Property | Value |
|---|---|
| Tensile strength, min | 485 MPa (70 ksi) |
| Yield strength, 0.2% offset, min | 170 MPa (25 ksi) |
| Elongation in 50 mm, min | 35% |
| Hardness, max | 90 HRB (192 HBW / 200 HV) |
The tube is ordered unstraightened after the final heat treatment, certified at 35 MPa lower on yield, under a U suffix.
Eight national and international standards carry the material we roll as TP316L, and they are matched below.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | UNS S31603 |
| Europe (EN/W.Nr.) | 1.4404, X2CrNiMo17-12-2 |
| Japan (JIS) | SUS 316L, SUS 316LTB to JIS G 3463 |
| India (IS) | X02Cr17Ni12Mo2 to IS 6911 |
| China (GB) | 022Cr17Ni12Mo2 |
| UK (BS) | 316S11 |
| France (AFNOR) | Z3CND17-12-02 |
| Sweden (SS) | 2348 |
Construction route and section profile are specified independently of each other. Manufacturing routes come first, then the three profiles in which 316L stainless steel tubes are supplied.
316L seamless tube comes from a solid billet, pierced and then hot finished or cold drawn to size, so the wall carries no longitudinal joint. ASTM A213 / ASME SA-213 covers the route, and 316L seamless tubing serves boiler and heat-exchanger duty.
Slit strip feeds the welded route, roll-formed and closed by a resistance-welded seam. The weld is then cold worked before the final anneal, as ASTM A249 / ASME SA-249 requires, and the tube is solution treated to that specification. 316L SS tubing manufactured this way has a lower per-metre cost.
The round section makes up the bulk of the 316L stainless steel tubes we despatch, covering eleven diameters from 12.7 mm up to 101.6 mm. Exchanger bundles and instrumentation runs use it, and general-service material follows ASTM A269.
A square box section is welded to ASTM A554, 12 x 12 mm through 100 x 100 mm, on walls between 1.0 mm and 6.0 mm. Balustrades and frames take 316L square tubing.
The rectangular 316L tube spans 13 x 25 mm up to 100 x 50 mm on the same wall range, in lengths up to 12 metres. Fabricators call for the profile where a flat face simplifies bolting.
Stainless steel 316L tube sizes cover eleven round diameters from 12.7 mm to 101.6 mm. Each size is quoted as a measured outside diameter with its wall thickness, as tabulated below.
| 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 |
| Size | OD (mm) | 10 SWG (3.25 mm) Weight/m | 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 |
The ordering specification sets wall tolerance, not the grade. ASTM A213 tube is ordered on a minimum-wall basis by default, so thickness runs over the stated minimum only; average wall may be specified instead, in which case a cold-formed tube carries ±10%. ASTM A249 works to a nominal wall thickness throughout at ±10%. Cut lengths are fixed on the order.
Most of the 316L tubing produced goes to six sectors, each with its own equipment list beneath.
Reactor coils, dosing lines and scrubber circuits on sulphuric, phosphoric and organic acid duty run on 316L SS tubes. Site-welded assemblies enter service without a fabrication anneal.
Deck hardware, splash-zone fittings and offshore hydraulic lines take 316L stainless tube because salt spray attacks lower-alloyed austenitic grades first. For continuously immersed seawater duty, we point buyers to a 6% molybdenum or duplex grade instead, as 316L is not rated for full seawater immersion.
Exchanger and condenser bundles take 316L tube through the tube-side circuit, ordered to ASTM A213 or ASTM A249. A thin wall transfers heat efficiently, and tubesheet joints survive welding intact.
Product-contact runs in dairy, brewing, bioprocess, and pharmaceutical plants use 316L tubing, where orbital welds require no heat treatment afterwards. The surface also tolerates chlorinated detergent residue.
Impulse lines, chemical injection circuits, and umbilical runs take small-bore 316L stainless steel tube, where working pressure follows outside diameter, wall thickness, and the allowable stress of the grade. Chloride resistance covers coastal terminals, offshore platforms and gas-processing skids.
Bleach liquor circuits, white water lines and aeration headers use 316L stainless tubing against chloride-bearing process water. Numerous welded attachments justify the low-carbon analysis.
Stainless steel 316L tubes and sections are packed for export with care to protect quality during transit. Each shipment is prepared to meet destination and handling requirements, with clear marking and documentation for traceability.
We quote stainless steel 316L tube per kilogram, ranging from ₹350 to ₹500 per kg and
US$3.68–$5.26 per kg. Prices are at the current rate, since nickel and molybdenum inputs are repriced weekly. Seven factors then adjust that figure: wall gauge, outside diameter, section, construction route, length, finish, and order size.
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.
Stainless steel 316L tube is a low-carbon austenitic tube with 2.00 to 3.00% molybdenum, registered as UNS S31603.
Seamless 316L tube is certified to ASTM A213 / ASME SA-213, welded tube to ASTM A249 / ASME SA-249, and general-service 316L tubing to ASTM A269.
Carbon separates them. ASTM A213 allows 0.08% in TP316 against 0.035% in TP316L, so 316L remains free of intergranular attack after welding.
Round 316L tube covers 12.7 mm to 101.6 mm outside diameter, on walls from 1.02 mm to 3.25 mm (19 SWG to 10 SWG) in ERW and 1.07 mm to 3.40 mm (19 BWG to 10 BWG) in seamless. Square and rectangular sections run alongside.
Molybdenum gives 316L tubes sound pitting and crevice resistance in chloride-bearing process water, though it does not stop stress corrosion cracking in hot chloride solution. For continuously immersed seawater duty, we recommend a 6% molybdenum or duplex grade instead.
Welded joints in 316L SS tubes enter service in the as-welded condition in most duties, because carbon at 0.035% maximum keeps the heat-affected zone free of carbides.
Square and rectangular 316L SS tubes are welded to ASTM A554 in square sections from 12 x 12 mm to 100 x 100 mm and rectangular sections from 13 x 25 mm to 100 x 50 mm.
Mill finish is standard; pickled and passivated material covers scale-free duty, and we will polish the 316L tube to the ordered grit.