ASTM A312 / ASME SA-312
Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd., based in Ban Bueng, Chonburi, Thailand, produces stainless steel seamless pipes across the austenitic range for pressure piping, process lines and high-temperature plant. Our office is in Bang Phli, Samut Prakan. The range starts with UNS S30400 seamless pipe (EN 1.4301) and seamless WNR 1.4404 pipe for general and chloride service, then extends to heat-resisting, stabilized and high-alloy grades, each length pierced from solid billet without welding.
Stainless Steel seamless pipeASTM A312 / ASME SA-312
EN 10204 3.1 certificate / 3.2 on request
Order by outside diameter and wall, or by NPS and schedule, and name the grade by its alloy designation. The envelope below is common to every grade we produce, so a single inquiry can cover a complete line list across several alloys.
ASTM A312 / ASME SA-312 governs most of our austenitic production. It covers pipe for high-temperature and general corrosive service, requires seamless pipe to be made without welding at any stage, and calls for every length to be delivered heat treated. ASTM A999 adds the general requirements, including OD and wall tolerances, and ASME B36.19M sets the standard dimensions. We produce 309, 310 and 314, which sit outside the A312 grade tables, in their own chemistry to the same dimensions. For heat exchanger and instrumentation sizes, we make stainless steel seamless tubes.
Each ASME SA-312 seamless stainless steel pipe passes a hydrostatic test or a nondestructive electric test, each lot passes the tension and flattening tests A312 requires, and every heat is released with an EN 10204 3.1 (3.2 on request) material test certificate. We also provide raw material certificates, positive material identification (PMI) of every pipe, heat treatment charts, third-party inspection reports, surface roughness and size measurement, and a laboratory test certificate from a government-approved lab. Impact, flare, bend, hardness, intergranular corrosion, pitting corrosion, eddy current and ultrasonic results go on the manufacturer test certificate when ordered, with intergranular testing to ASTM A262 where your specification calls for it, and grain size is reported on the H grades.
Service conditions decide the grade: carbon level for welding, molybdenum for chlorides, chromium, nickel and silicon for heat, and stabilizing elements or controlled carbon for strength at temperature. Each austenitic stainless steel seamless pipe grade below links to its own page with full grade data and sizes. We also make 304H and SMO 654 seamless pipe to order.
304 is the basic chromium-nickel grade and the usual choice for general corrosive service in food and chemical plants. UNS S30400 seamless pipe welds by all fusion methods and stays tough at sub-zero temperatures, and drawings often call it seamless WNR 1.4301 pipe. In hot chlorides, seamless 1.4301 stainless steel pipe gives way to 316.
304L is the low-carbon version of 304. Lower carbon reduces sensitization and intergranular corrosion after welding, so UNS S30403 seamless pipe is preferred for heavy welded fabrications that will not be post-weld annealed. Unsensitized, seamless WNR 1.4307 pipe resists corrosion as well as 304.
309 carries more chromium and nickel than 304, which gives it strong oxidation resistance in non-cyclic high-temperature service and better behavior in some sulfur-bearing atmospheres. Boiler components, flue gas desulfurization systems and industrial furnaces all run in 309 seamless pipe, while strongly reducing sulfurizing atmospheres are best avoided.
310 is the higher-carbon member of the high-chromium, high-nickel family, chosen where strength at high temperature matters in furnaces, fluidized bed furnaces, sintering and cement plants and petroleum refining. Seamless stainless steel 310 pipe stays stable in carburizing and nitriding atmospheres and differs from low-carbon 310S in carbon level and high-temperature strength.
310H is the H-grade of 310S. Carbon is held in a controlled range and a coarse grain size is required, so SS 310H seamless pipe suits service where creep and stress rupture properties govern, such as furnace headers and superheater piping. It is not chosen for intergranular corrosion resistance in liquids.
310S is the low-carbon version of 310. Its lower carbon reduces the risk of sensitization during welding, which suits fabricated furnace parts, heat exchangers and boilers, thermal processing and petroleum refining. Like 310, 310S stainless steel seamless pipe is designed for oxidizing heat rather than aqueous chloride service.
310MoLN adds molybdenum and nitrogen to a very low-carbon, high-chromium, high-nickel base. It is known as the urea grade for its stability in urea plant service and its resistance to carbamate corrosion, and it also serves nitric acid duty. Stripper lines and high-pressure urea reactor piping are typical uses of seamless 310MoLN stainless steel pipe.
314 is a high-silicon heat-resisting grade. Silicon gives it resistance to oxidation, scaling and carburization, which suits furnace conveyor systems, muffles, retorts and heat treatment fixtures. The same silicon makes 314 seamless pipe harder to weld than 310, so thick multi-pass joints need controlled preheat and filler selection.
316 adds molybdenum to the chromium-nickel base, improving resistance to pitting and crevice corrosion in chloride-bearing media, and is often called the marine grade. UNS S31600 seamless pipe also offers good tensile and creep strength, and seamless WNR 1.4401 pipe is widely specified for chemical, petroleum and marine lines.
316L is the low-carbon version of 316, and seamless 1.4404 stainless steel pipe combines molybdenum's pitting resistance with lower sensitization risk during welding. UNS S31603 seamless pipe is the usual choice for welded pharmaceutical, food, marine, offshore, desalination and chemical process piping.
316LN is low-carbon 316 with a nitrogen addition. Nitrogen strengthens the austenite and further lowers the tendency to sensitize, so the grade matches the strength of standard 316 while keeping low-carbon weldability. It stays tough at cryogenic temperatures, and seamless stainless steel 316LN pipe serves nuclear plant piping and cryogenic vessels.
316Ti is the titanium-stabilized version of 316. Titanium forms titanium carbides in place of chromium carbides in the sensitization range, so the molybdenum-bearing structure keeps its corrosion resistance after welding and during sustained high-temperature service. In European specifications, SS 316Ti seamless pipe is the standard stabilized molybdenum grade.
317 carries more molybdenum than 316, giving higher resistance to chlorides, halides and sulfurous media, as well as sulfuric, acetic and formic acids. It is chosen over 316 for flue gas desulfurization scrubbers, pulp and paper digesters and acid-bearing chemical lines, where seamless stainless steel 317 pipe handles the harsher media.
317L is the low-carbon version of 317 and the usual step up from 316L when pitting or general corrosion is the concern. It resists sulfuric and phosphoric acids and offers better creep and stress-rupture strength than 316L at moderately elevated temperatures. Condensers, desalination units and acid lines use 317L stainless steel seamless pipe.
321 is stabilized with titanium, which ties up carbon so chromium carbides do not form in the sensitization range. Welds in seamless 321 stainless steel pipe therefore keep their resistance to intergranular corrosion after high-temperature exposure. The grade is specified for aircraft exhaust manifolds, expansion joints, bellows, furnace parts and heat exchangers.
321H is the H-grade of 321, with controlled higher carbon, a coarse grain size requirement and a higher solution annealing temperature. These give creep strength for high-temperature pressure service in power generation, petrochemical and oil and gas plants. Marking of SS 321H seamless pipe includes the heat-treatment lot.
347 is stabilized with niobium (columbium) instead of titanium. Seamless stainless steel 347 pipe is preferred over 321 for long-term service in the sensitization range and has slightly better high-temperature strength, which makes it a common choice for power generation, aerospace, oil and gas and chemical lines.
347H is the H-grade of 347. A carbon minimum, a coarse grain size requirement and a higher solution annealing temperature give it improved creep strength, so 347H stainless steel seamless pipe carries sustained load at high temperature in power generation, petrochemical and marine plants.
904L is a non-stabilized high-alloy austenitic grade with high nickel and molybdenum plus a copper addition. Copper gives it resistance to sulfuric acid, while the alloy content handles chloride-bearing media in chemical, hydrometallurgy, waste treatment and pharmaceutical plants. ASTM A312 lists seamless 904L stainless steel pipe by its UNS number.
253MA is a heat-resisting grade alloyed with silicon, nitrogen and cerium, a rare earth element. Together they resist cyclic oxidation, carburization and combustion gases, so 253MA seamless pipe serves furnace components, cement and mineral equipment, petrochemical and refining plants, and power generation.
SMO 254 is a super austenitic grade with high molybdenum and nitrogen, and a clear step above 904L in chloride resistance. SMO 254 seamless pipe resists chloride stress corrosion cracking, pitting and crevice corrosion in seawater systems, pulp and paper bleaching, pollution control, fertilizer plants and refineries.
Seamless SS pipe in standard sizes follows ASME B36.19M, where NPS fixes the outside diameter and the schedule fixes the wall. OD and wall combinations from your drawing are produced to the same specification requirements.
Nominal wall thickness in mm for common sizes:
| NPS (in) | OD (mm) | Sch 5S | Sch 10S | Sch 40S | Sch 80S |
|---|---|---|---|---|---|
| 1/2 | 21.3 | 1.65 | 2.11 | 2.77 | 3.73 |
| 4 | 114.3 | 2.11 | 3.05 | 6.02 | 8.56 |
| 8 | 219.1 | 2.77 | 3.76 | 8.18 | 12.70 |
| 12 | 323.9 | 3.96 | 4.57 | 9.53 | 12.70 |
| 24 | 610 | 5.54 | 6.35 | 9.53 | 12.70 |
Swipe sideways to see the full table.
Schedules 5S and 10S are too thin for threading, so order 40S or heavier where threaded ends are needed.
Beveled ends on seamless stainless steel pipe suit butt-welded joints and flange connections, plain ends suit socket-weld and mechanically joined systems, and threaded ends suit small-bore screwed lines. Hot-finished pipe is normally pickled and passivated, cold-drawn pipe can be bright annealed, and polished, mirror or brushed surfaces suit hygienic lines. For welded fabrication without post-weld annealing, choose an L grade such as UNS S30403 seamless pipe or seamless 1.4404 stainless steel pipe, or a stabilized grade such as 321 or 347.
Each industry pairs its medium and temperature with a grade family: L grades and molybdenum grades for corrosive process lines, H grades and heat-resisting grades for fired and high-temperature service.
Refinery utility lines, cooling systems and sour gas service use molybdenum grades for chloride resistance. Seamless 1.4401 stainless steel pipe is the common baseline, with SMO 254 for severe brines and seawater.
Acid and process lines run in 316L, 317L and 904L, and seamless WNR 1.4404 pipe is the usual baseline for welded process piping. High-temperature petrochemical lines take 321H and 347H for creep strength.
Boiler, superheater and steam piping relies on the H grades, 310H, 321H and 347H, for creep strength. Grades 309 and 310S cover flue gas, furnace-side and boiler duty.
Product, CIP and utility lines need cleanable, weldable pipe. Seamless 1.4307 stainless steel pipe covers general duty, and UNS S31603 seamless pipe takes chloride-bearing cleaning chemicals and brine processing.
Sugar mills carry raw juice, clarified juice, syrup and molasses through seamless stainless steel pipe, which also forms components for vacuum crystallizers. Low-carbon grades suit the welded runs between process vessels.
Bleach plant and liquor lines use seamless WNR 1.4401 pipe, 317 and 317L, with SMO 254 where bleaching chlorides are severe. Seamless 1.4301 stainless steel pipe serves milder water and utility circuits.
Exhaust manifolds, expansion joints and bellows use stabilized 321 and 347 to resist intergranular attack after heating. Seamless WNR 1.4301 pipe covers structural and fluid lines in vehicles.
Packing
Bundles with protective wrapping and woven bags, or wooden and plywood cases, with seaworthy packing for export.
Marking
Grade, specification, size, heat number and seamless marking stenciled on each length; color coding, barcode labels and customer marking on request.
End protection
End caps on plain, beveled and threaded ends.
Preparation
Cut-to-length and beveling completed before dispatch.
Trade terms
FOB, CIF or CFR.
Destinations
Delivery across Thailand and export to Singapore, Malaysia, Vietnam, Indonesia, the Philippines and India.
Our factory at 154 Moo.1 Map Phai, Ban Bueng, Chonburi 20170, Thailand, produces every grade above, from UNS S31603 seamless pipe for process lines to H grades for creep service. Our office is at 89/18 Moo.15 Enterprize Park, Bangna-Trad Road, Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand. Delivery is from stock or to production schedule, confirmed with the quotation.
Start with 316L for most chloride-bearing process water and coastal lines, because molybdenum improves pitting and crevice resistance over 304. UNS S31600 seamless pipe suits the same duty where welding is limited. Move to 317L when 316L is marginal, to 904L where sulfuric acid is also present, and to SMO 254 for seawater and severe chlorides.
Specify the L grade when the pipe will be welded and not solution annealed afterwards. Low carbon reduces sensitization and intergranular corrosion in the heat-affected zone, which is why seamless WNR 1.4307 pipe is preferred for heavy welded fabrication. Standard grades such as seamless 1.4401 stainless steel pipe suit lines with limited welding.
Choose by the main risk. Molybdenum-bearing grades such as 316L, 317L and 904L resist chloride pitting and crevice corrosion, while stabilized 321 and 347 keep welds resistant to intergranular corrosion after high-temperature exposure. 316Ti combines molybdenum with titanium stabilization. Where neither risk applies, seamless 1.4307 stainless steel pipe covers welded general service.
Stabilized grades (316Ti, 321, 347) add titanium or niobium so that chromium carbides do not form, which protects against intergranular corrosion after welding. H grades (310H, 321H, 347H) hold carbon in a controlled higher range with a coarse grain requirement for creep and stress rupture strength. 321H and 347H combine both features.
Choose from 309, 310, 310S, 314 and 253MA. 309 suits non-cyclic service, 310 and 310S handle higher heat, 314 adds silicon against scaling and carburization, and 253MA resists cyclic oxidation. Where the pipe carries pressure under sustained load at temperature, specify an H grade instead.
We make OD 6 to 1016 mm, wall 1 to 65 mm and lengths up to 18 m, ordered by NPS and schedule to ASME B36.19M or by OD and wall from your drawing. Schedules 5S and 10S suit thin-wall lines; choose 40S or heavier for threaded ends.
Every length passes a hydrostatic test or a nondestructive electric test after solution annealing and straightening, and each lot is tension and flattening tested. Each ASME SA-312 seamless stainless steel pipe also gets PMI, and the heat is released with an EN 10204 3.1 (3.2 on request) certificate. Intergranular testing to ASTM A262 is added when specified.
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