Stainless Steel Welded Pipe & Tube
We supply stainless steel welded pipe and stainless steel welded tube, cut and finished in our own plant in Wuxi and backed by our own stock. ERW pipe & tube run 19–480 mm OD with walls of 1.5–8 mm. Large diameter longitudinally welded pipe runs 426–3,000 mm OD with walls of 3–12 mm.
ERW (high-frequency) welded in stock sizes; TIG welded to order; welded from plate for large diameters
Weld solution annealed on A312 pipe; full-length solution annealed for chemical, heat exchanger and sanitary tube
Laser cut, polished or brushed in our own plant; lead time 8–12 working days
Pickled TP304 and TP316L pipe on NPS sizes from 1/2" to 14"
3,000 tons of stainless pipe & tube in stock (out of 80,000 tons in total) in Wuxi
Why Order SS Welded Pipe & Tube From MTS
01
Bright Annealed Heat Exchanger Tube
Our 304, 316L and 2205 heat exchanger tube runs 8–88.9 mm OD with walls of 0.8–1.5 mm. It is bright annealed and tested length by length.
02
Annealed Where the Service Needs It
Stock ERW pipe & tube for decoration and low-pressure water are not solution annealed; the weld is ground smooth. A312 pipe for industrial fluid lines has the weld zone solution annealed. Tube for chemical, heat exchanger and food sanitary service is solution annealed full length, and the MTC states "Solution Annealed".
03
Mill Finish, Pickled or Sanitary
304 welded pipe & tube come in mill finish from 19 to 480 mm OD, as pickled TP304 and TP316L pipe from NPS 1/2" to 14", or as sanitary tube from 19 mm OD.
04
Large Sizes Without Seamless Prices
From 8" up, welded is often the only practical choice. Large diameter longitudinally welded pipe in 304, 316L and 201 runs from 426 to 3,000 mm OD, with walls of 3–12 mm, in single lengths up to 14 m.
05
Cut and Finished in Our Plant
Our tube laser cuts lengths, holes and slots in one pass, for OD 10–350 mm, walls up to 10 mm and lengths up to 9 m. We also polish pipe & tube inside and outside to Ra 0.8 µm, and brush to No.4 or HL.
06
Processed in Wuxi, Shipped From Three Ports
We process up to 100,000 tons a month and keep 3,000 tons of stainless pipe & tube in stock in 60,000 m² of warehouse space in Wuxi. Our own cranes load every container. Orders ship from Shanghai, Qingdao or Tianjin.
The Practical Choice for Most Lines
Welded pipe & tube are made by forming strip or plate into a round shell and fusing the seam. After annealing, the seam behaves like the rest of the material in most services.
That makes stainless steel welded pipe & tube the standard choice for low and medium pressure. Water, food, chemical and utility lines all use them. They cost less than seamless, have a more even wall, and come in much larger sizes.
Welded Pipe & Tube Range
TIG Welded Pipe & Tube
Autogenous TIG or plasma welded, annealed and pickled, to A312, A269 and A249. Made to order.
ERW Stainless Steel Pipe & Tube
High-frequency welded, our main route for regular sizes. ERW ss pipe runs 19–480 mm OD in 304 and 32–219 mm OD in 316L, including SS 304 ERW pipe for water and structural lines.
Sch 10S Welded Pipe
The most common wall for stainless process lines. Also listed as 10S pipe or Sch10S pipe. Our pickled TP304 and TP316L pipe has Sch 10S walls up to 6", and 4.0–5.0 mm walls from 8" to 14".
Thin Wall Welded Tube
Thin wall ss tubing from 0.8 mm wall for heat exchangers, sensors and light frames. Sch 5S thin wall pipe for low-pressure water and press-fit systems.
DOM Tubing
Welded, then cold drawn over a mandrel. DOM stainless steel tubing gives seamless-like tolerance at welded cost. Quoted on request.
A358 EFW Pipe
Fusion welded from plate, with filler, for large diameters. Classes 1 to 5 by X-ray and filler. Quoted on request.
A778 Unannealed Welded Pipe
As-welded pipe for low-temperature corrosive service, such as pulp and paper. Quoted on request.
Spiral Welded Pipe & Tube
Spiral stainless steel pipe and spiral tube for ducts and low-pressure mains. Quoted on request.
Specifications
| Item | Range |
|---|---|
| Grades | 304, 316L, 201, 310S; 2205 heat exchanger tube; other grades on request |
| Process | ERW (high-frequency) for stock sizes; TIG to order; large diameter welded from plate; DOM and EFW on request |
| Pipe | OD 19–480 mm, wall 1.5–8 mm; pickled NPS 1/2″–14″; large diameter OD 426–3,000 mm, wall 3–12 mm |
| Tube | Heat exchanger tube OD 8–88.9 mm, wall 0.8–1.5 mm; sanitary tube OD 19–480 mm, wall 1.5–5 mm |
| Annealing / finish | ERW stock: as welded, weld ground; A312: weld solution annealed; chemical, heat exchanger and sanitary: full-length solution annealed; also pickled, bright annealed, polished or brushed |
| Length | 6 m standard, 9 or 12 m; 14–18 m to order; large diameter up to 14 m |
| Tests | Heat exchanger tube tested length by length; other tests to the standard |
| Tests | ET or hydro; X-ray to A358 class; flattening, bend tests |
Buying Stainless Steel Welded Pipe & Tube: Process, Standards and Limits
How Welded Pipe & Tube Are Made
Coil is slit to width, formed into a round shell, and the seam is welded. For A312 pipe and A269 tube, no filler metal is used. TIG, plasma or laser fuses the edges.
ERW joins the edges with high-frequency current and pressure. It is fast and cheap, but the market uses the term loosely. Some “ERW stainless steel pipe” is actually TIG welded. Ask how the seam is made if it matters.
DOM tubing is welded, then drawn over a mandrel to size. Large pipe is rolled from plate and welded with filler, to A358. Spiral pipe & tube wind strip in a helix for large, low-pressure ducts.
For A312 pipe and A269 tube, the material is solution annealed and pickled after welding. This restores corrosion resistance in the weld zone. Decorative and low-pressure water tube is often left unannealed, with the weld only ground. Ask whether annealing is bright, in-line or in a furnace.
A312, A358 or A778 for Welded Pipe?
Schedule pipe has three welded standards.
A312 is the default for welded pipe up to about 12″. It requires annealing and a test on every length.
A358 covers EFW pipe, usually from 8″ up. Its Class sets filler use and how much weld is X-rayed. Class 1 is double welded and fully radiographed; Classes 3 and 5 use less X-ray. An “A358 pipe” order without a class cannot be quoted correctly.
A778 pipe is not annealed after welding. It suits low-temperature corrosive service, such as pulp, paper and wastewater. It costs less, but don’t use it hot or in severe corrosion. A778 pipe also uses L grades only.
For welded tube, A269 covers general service and A249 covers boilers and heat exchangers.
Sch 10S and Sch 5S for Pipe
Stainless needs no corrosion allowance in many services, so it runs thinner walls than carbon steel. Sch 10 stainless steel pipe is the most common wall in process plants.
For a 2″ Sch 10 pipe, the wall is 2.77 mm. A 4″ Sch 10 stainless steel pipe is 3.05 mm, and 6″ Sch 10 pipe is 3.40 mm. Sizes like 3″ Sch 10 stainless pipe and 8″ Sch 10 pipe are almost always welded.
Many buyers write “sch 10 pipe” or “sch10 pipe” without a grade. Carbon steel uses Sch 10 too. Always add the grade and “S”, as in “Sch 10S 316L.”
Sch 5S goes thinner still, 1.65 mm at 2″. It suits low-pressure water and press-fit systems.
Thin Wall Tube
Thin wall stainless steel tube is sold by OD × wall. Our heat exchanger tube runs walls from 0.8 mm, and capillary tube goes down to 0.05 mm. Ultra thin wall stainless steel tubing goes into sensors, medical parts and heat exchangers.
Thin wall tubing is easy to dent and cannot be threaded. Order it in wooden cases or with spacers. For very small OD, see Capillary Tube Stainless Steel.
Lengths and Large Diameters
Regular welded pipe & tube come in 6 m, 9 m or 12 m, with 6 m the most common. We can make single lengths up to 12 m, and 14–18 m to order. Long lengths cost more, because straightness is harder to hold.
Large diameter pipe up to 1,600 mm OD comes in single lengths of 6–12 m, at most 14 m. 12 m is the usual limit for road transport. From 1,600 to 2,000 mm OD, each shell is usually 3–6 m long, and up to 8 m with extra-wide plate at a clearly higher cost. From 2,000 to 3,000 mm OD, plate width limits each shell to 2–3 m. The shells are joined on site with girth welds into longer tanks or towers, so a 12 m length at 3 m OD cannot be made in one piece.
When Welded Is Enough, and When It Isn't
For most low and medium pressure lines, annealed welded pipe & tube perform like seamless. The wall is more even, since it comes from flat coil. It is cheaper, and available in sizes seamless cannot reach.
Choose seamless instead when:
- Your code applies a weld joint factor, and the pressure is high.
- Your spec bans welded material in hazardous or cyclic service.
- You need walls of Sch 80S or heavier.
For those cases, see Seamless Stainless Steel Pipe & Tube.
Frequently Asked Questions
Is ERW SS pipe the same as TIG welded pipe?
Not quite. ERW uses high-frequency current and pressure, with no arc. TIG uses an arc and inert gas. Both make A312 pipe when annealed and tested. TIG is more common for stainless process pipe & tube.
What is 10S pipe?
10S pipe is stainless pipe with Schedule 10S wall, from ASME B36.19. The "S" marks stainless dimensions. In many sizes, Sch 10S equals Sch 10, but not in all. Use Sch 10S on stainless orders.
Do welded pipe & tube need X-ray testing?
A312 pipe and A269 tube do not require X-ray. They are tested by hydro or eddy current on every length. A358 pipe uses radiography by Class. You can add X-ray as a supplementary requirement.
Can welded pipe & tube carry high pressure?
Yes, within code limits. Annealed welded material has the same minimum strength as seamless under A312. Some codes apply a joint factor, such as 0.85, to welded pipe. That only matters near the wall's pressure limit.
What welded sizes do you stock?
We keep 3,000 tons of stainless pipe & tube in our Wuxi warehouses. Welded sizes run 19–480 mm OD in 304, pickled TP304 and TP316L pipe from NPS 1/2" to 14", and heat exchanger tube from 8 to 88.9 mm OD. Lead time is usually 8–12 working days. Large diameter pipe is made to order.
Are stainless steel welded tubes cheaper than seamless?
Usually yes. The gap is widest in thin walls and large sizes. For heavy walls in small sizes, prices can be close. Send your size list and we will quote both within 2–4 working hours.
Request a Quote
We reply within 2–4 working hours with a price per ton, valid for 3 days.