Furnace Muffles, Retorts and Radiant Heating
Radiant tubes, muffles, retorts and flame tubes inside industrial furnaces are made from 314 stainless steel seamless pipe, which endures continuous thermal cycling without cracking or losing its shape.
ASME B36 / UNS S31400 / W.Nr. 1.4841
Stainless Steel 314 Seamless Pipes Manufacturer in Thailand
Stainless steel 314 seamless pipes leave the Ban Bueng, Chonburi, Thailand mill of Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd. hot pierced, cold drawn or cold rolled and solution annealed, ready for furnace muffles, radiant heating and heat-treatment lines where scale and carburization limit service life. Designated UNS S31400 and W.Nr. 1.4841, this high-silicon grade is one of the heat-resisting members of our seamless stainless steel pipe range, while our sales team in Bang Phli, Samut Prakan handles quotations and order paperwork.
Stainless Steel 314 seamless pipeUNS S31400 / W.Nr. 1.4841
- 6 to 1016 mmOutside diameter
- 1 to 65 mmWall thickness
- Up to 18 mLength
- EN 10204 3.1Test certificate
EN 10204 3.1 certificate / 3.2 on request
Specifications of SS 314 Seamless Pipe
Our production range for SS 314 seamless pipe is set out below. Lines can be called up by pipe size and schedule or by outside diameter and wall, and every length is solution annealed before release.
- Grade
- Stainless Steel 314 (UNS S31400)
- Form
- Seamless
- WNR / EN Number
- 1.4841 (X15CrNiSi25-21)
- Outside Diameter
- 6 to 1016 mm
- Wall Thickness
- 1 to 65 mm
- Schedules
- Sch 5S to XXS
- Length
- Up to 18 mcut to length on request
- Dimensional Standards
- ASME B36.19M and ASME B36.10M
- End Type
- Plain endbeveled end; threads cut only on Sch 40S and heavier walls
- Surface Finish
- Pickled and passivatedbright annealed, polished, mirror, brushed
- Manufacturing Route
- 1Hollow shell hot pierced from billet
- 2Then cold drawn or cold rolled
- Heat Treatment
- Solution annealed at 1040 to 1150°C (1900 to 2100°F), rapid cool
- Test Certificate
- EN 10204 3.13.2 on request
ASME B36.19M governs Sch 5S through 80S, and ASME B36.10M governs the numbered Sch 40, 80 and 160 walls and XXS, so a 314 run fits the same isometric as the rest of a process line. ASTM A312 carries no 314 grade, which is why every seamless S31400 stainless steel pipe we make follows the UNS S31400 chemistry and annealed properties tabulated below. European drawings that identify the material only by number are answered with seamless WNR 1.4841 pipe, cross-referenced to UNS S31400.
For every heat we issue an EN 10204 3.1 (3.2 on request) material test certificate; a 100% PMI record, the heat treatment chart and the raw material certificate travel with it. The manufacturer test certificate can also carry flattening, flare, bend, impact, hardness, intergranular and pitting corrosion, grain size, ET, UT and hydrostatic (HT) results. A government-approved lab's test certificate, third-party inspection and measurement of surface roughness and size can be added on request.
Chemical Composition of Stainless Steel 314 (UNS S31400)
Silicon at 1.50 to 3.00% is what makes 314 a high-silicon grade, and together with 23.00 to 26.00% chromium it supports the oxidation resistance that furnace service depends on. The heat analysis on each material test certificate is checked against these limits.
- CrChromium, 23.00 to 26.00
- NiNickel, 19.00 to 22.00
- SiSilicon, 1.50 to 3.00
- MnManganese, 2.00 max
- CCarbon, 0.25 max
UNS S31400314
| Element | Stainless Steel 314 (%) |
|---|---|
| C (Carbon) | 0.25 max |
| Mn (Manganese) | 2.00 max |
| P (Phosphorus) | 0.045 max |
| S (Sulfur) | 0.030 max |
| Si (Silicon) | 1.50 to 3.00 |
| Cr (Chromium) | 23.00 to 26.00 |
| Ni (Nickel) | 19.00 to 22.00 |
314 Stainless Steel Seamless Pipe Mechanical Properties
Minimum values for 314 stainless steel seamless pipe hold in the annealed state, produced by a 1040 to 1150°C (1900 to 2100°F) solution anneal followed by rapid cooling. Mechanical and chemical results for each heat appear on the material test certificate.
| Property (annealed) | Minimum |
|---|---|
| Tensile Strength | 550 MPa (80 ksi) |
| Yield Strength | 205 MPa (30 ksi) |
| Elongation | 35% |
Equivalent Designations of Stainless Steel 314
Across national and international standards, Stainless Steel 314 appears under the names and numbers below, from UNS and AISI to EN, ISO, GB, JIS and GOST.
- UNS (USA)S31400
- AISI (USA)314
- W.Nr. (Germany)1.4841
- EN 10095 (Europe)X15CrNiSi25-21
- ISOX15CrNiSi25-21
- GB (China), ISC / NameS38340 / 1Cr25Ni20Si2
- JIS (Japan)SUS314
- GOST (Russia)20Kh25N20S2
The number 1.4841 is also cross-referenced to grade 310H. When a European data sheet asks for seamless 1.4841 stainless steel pipe and the high-silicon chemistry is intended, add UNS S31400 to the order; that is the designation stenciled on every length.
NPS, Schedule and Length Range of Seamless Stainless Steel 314 Pipe
OD sizes of 6 to 1016 mm and walls of 1 to 65 mm are covered for seamless stainless steel 314 pipe, with each length running to a maximum of 18 m. The selection below lists nominal wall in mm for NPS 6 to 18:
| NPS | OD (mm) | Sch 5S | Sch 10S | Sch 40 | Sch 80 | Sch 160 |
|---|---|---|---|---|---|---|
| 6 | 168.3 | 2.77 | 3.40 | 7.11 | 10.97 | 18.26 |
| 10 | 273.1 | 3.40 | 4.19 | 9.27 | 15.09 | 28.58 |
| 12 | 323.9 | 3.96 | 4.57 | 10.31 | 17.48 | 33.32 |
| 16 | 406.4 | 4.19 | 4.78 | 12.70 | 21.44 | 40.49 |
| 18 | 457.2 | 4.19 | 4.78 | 14.27 | 23.83 | 45.24 |
Swipe sideways to see the full table.
Smaller bores down to 6 mm OD, sizes between the schedule series and OD and wall combinations taken from your drawing are produced within the same range. Heat exchanger and instrument work that is ordered by exact OD and wall goes to our stainless steel 314 seamless tubes instead.
Welding and Fabrication of UNS S31400 Seamless Pipe
The silicon that gives 314 its scaling resistance also reduces weldability compared with standard 310. On thick sections joined by multi-pass welds, plan the preheat and choose the filler metal with care to avoid hot cracking. Send the wall thickness and joint design with your inquiry, so the weld procedure is settled before each UNS S31400 seamless pipe reaches the shop. Lengths leave the mill beveled for butt welds or plain for socket joints, and small-bore lines are threaded only where the wall is Sch 40S or heavier, each length trimmed to your isometric.
Choosing Between 314, 310 and 309
Grade 314 is built on a 25Cr-20Ni base similar to grade 310 seamless pipe, and its added silicon is what supports its resistance to scaling and carburization in furnace atmospheres. With 19.00 to 22.00% nickel, it keeps an austenitic structure up to its highest service temperatures. Stainless steel 309 seamless pipes carry less nickel than either 25Cr-20Ni grade and are the lower-alloy option for heat-resisting furnace and boiler duty.
Furnace and Combustion Uses of Seamless 1.4841 Stainless Steel Pipe
Furnace atmosphere, scale growth and carburization decide how long a hot component lasts, and those are the duties that bring 314 onto a drawing.
Furnace Conveyor Systems
Conveyor rollers that move parts through industrial heat-treatment furnaces are cut from seamless grade 314 lengths, which hold up in the hot and sometimes corrosive furnace atmosphere around them.
Heat-Treatment Fixtures and Carburizing Boxes
Baskets, fixtures, racks and annealing or carburizing boxes are fabricated from SS 314 seamless pipe sections, where resistance to carburization protects them across repeated heat-treatment loads.
Waste Gas Incinerators
Waste gas incinerators and other sulfur-bearing combustion systems use 314 for hot gas service, where the silica-rich sub-layer helps the pipe resist sulfidation in oxidizing flue gas.
Ore Roasting and Glass Furnaces
Rabble arms and conveyor components in roasting plants that process sulfide ore concentrates, and recuperators in glass tank furnaces carrying silicon-containing flue gas, are produced from seamless 314 lengths.
Packing and Dispatch of Seamless WNR 1.4841 Pipe
Packing
Woven-bag bundles, or wooden and plywood cases made seaworthy for export.
Marking
Grade, UNS S31400, heat number and size stenciled on each length, with color coding, barcode labels or your own marking on request.
End caps
Plain, beveled and threaded ends capped for the sea or road journey.
Preparation
Lengths cut and bevels machined at the mill.
Trade terms
FOB, CIF or CFR.
Dispatch
From stock lengths or a booked production slot, as the quotation specifies.
Price per kg of Seamless S31400 Stainless Steel Pipe
Indicatively, Stainless Steel 314 Seamless Pipes trade at about USD 6 to 10 per kg. Nickel sets the base rate, and because few mills make 314 seamless and lots are small, a specialist-grade premium applies on top. Share your size list with Thaida to receive a firm figure.
Indicative price, Stainless Steel 314 Seamless Pipes
USD 6 to 10 per kg
Indicative only. Send your sizes and specification to Thaida for a firm quotation.
- Outside diameter
- Nickel price
Our Factory and Export Markets
We roll and finish Stainless Steel 314 Seamless Pipes at our mill at 154 Moo.1 Map Phai, Ban Bueng, Chonburi 20170, Thailand, and inquiries are answered from 89/18 Moo.15 Enterprize Park, Bangna-Trad Road, Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand. Furnace builders and plant operators across Thailand receive it directly, and we ship to Singapore, Malaysia, Vietnam, Indonesia, the Philippines and India.
Factory154 Moo.1 Map Phai, Ban Bueng,
Chonburi 20170, Thailand
Chonburi 20170, Thailand
Office89/18 Moo.15 Enterprize Park, Bangna-Trad Road,
Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand
Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand
Exporting to
- Singapore
- Malaysia
- Vietnam
- Indonesia
- Philippines
- India
FAQ: Grade 314 Seamless Pipe
Is 314 seamless pipe an ASTM A312 grade?
No. ASTM A312 lists no 314 grade, so we supply UNS S31400 seamless pipe to the 314 chemistry and annealed properties in our tables, with dimensions to ASME B36.19M and ASME B36.10M. If your line specification names an A312 grade, send it with the inquiry so the grade is agreed before production.
What does the silicon in 314 do to its oxide scale?
It enriches the surface oxide, so the scale adheres better and grows at a lower rate than on silicon-free grades of similar chromium content. Less metal is lost when the furnace heats and cools repeatedly, so the wall lasts longer in cyclic thermal service.
Is grade 314 seamless pipe suited to coal ash or heavy oil firing?
Yes. The silica-reinforced oxide on 314 resists fluxing by alkali sulfate and vanadium pentoxide deposits better than chromium oxide alone, which makes it effective in coal ash and heavy oil combustion environments. Keep it out of reducing sulfur gases, and send the fuel type and deposit analysis with your inquiry.
When is grade 310 the better order than 314 for a hot line?
When thick sections must be joined by multi-pass welds and the gas carries no sulfur, since the silicon in 314 lowers weldability and slightly reduces ductility compared with 310. Where the furnace gas is both oxidizing and sulfur-bearing, 314 outperforms standard 310 and is the better order.
At NPS 12, is XXS the heaviest wall available in grade 314?
No. At NPS 12, Sch 160 gives 33.32 mm, well above the 25.40 mm XXS wall, while Sch 80 is 17.48 mm. For heavy-wall furnace runs, name the schedule or the exact wall on your inquiry; walls between schedules are made to drawing within 1 to 65 mm.
How is the silicon range of each 314 heat documented?
On the EN 10204 3.1 (3.2 on request) material test certificate, which reports the heat analysis against the UNS S31400 limits, including silicon at 1.50 to 3.00%, together with the tensile, yield and elongation results. Name any extra test your specification needs, such as intergranular corrosion or ultrasonic testing, and it is added to the same certificate.
Request a Quote for Stainless Steel 314 Seamless Pipes
or email sales@thaida.co.th