A stainless steel coil tube isn't a different alloy. It's a different answer to a question every instrumentation engineer eventually runs into: how many joints does this run actually need? Every fitting and union in a control line is a potential leak path, and a continuous coil replaces dozens of them with exactly two connection points, one at each end. USA Piping Solution supplies stainless steel coil tubes and coiled tubing to ASTM A269, A213, and A249, in grades from 304 and 304L and 316 and 316L through duplex and 904L, in continuous lengths reaching 2,000 metres with no intermediate welds. For the same grades in straight lengths, see our Stainless Steel Pipes and Tubes range.
Why a Coil Instead of Straight Lengths
- Fewer leak paths: a 500-metre instrument run in 6-metre straight lengths needs over 80 joints; the same run from a coil needs 2.
- Faster installation: no cutting, deburring, and fitting-up at every joint; the coil pays out along the route and terminates once at each end.
- Lower lifetime cost: every fitting eliminated is a part not bought, a connection not made, and a future inspection point removed.
- Bendable in place: supplied annealed, coil tubing routes around obstructions by hand-bending or with simple benders, no elbows required.
Choosing the Grade
The coil form is available across the stainless family. What changes by grade is the corrosion resistance, and picking the cheapest grade that survives your environment is where the real money is saved:
| Grade | Best For | Step Up When |
|---|---|---|
| 304 and 304L | General-purpose instrument air, water, and mild chemical service, the workhorse and lowest-cost option | Chlorides are present, marine air, coastal plants, brackish water |
| 316 and 316L | Chloride-bearing service, marine and coastal installations, most chemical plants, the most common coil grade | Higher chloride concentration or temperature pushes past 316's pitting limits |
| 317L | More aggressive chemical service than 316L handles, higher molybdenum | Severe chloride or acidic conditions warrant duplex or super-austenitic |
| 321 | Elevated-temperature service where 304 would sensitize, titanium-stabilized | Not specified |
| Duplex S31803 and S32205 | High-chloride, high-pressure service, offshore control and hydraulic lines, roughly double the strength of 316 | Not specified |
| 904L | Sulfuric and phosphoric acid service beyond what standard austenitics survive | Not specified |
For deeper detail on the high-performance end, see our Duplex Steel Pipes and Tubes and Stainless Steel 904L Pipes and Tubes pages. Unsure where your service chemistry lands? Send it over and we'll help narrow the grade with your engineer.
Seamless or Welded Coil
Seamless coil, drawn from a pierced billet with no weld seam, is the default for critical instrumentation and high-pressure control lines, and the only construction some project specs will accept. Welded-and-drawn coil costs less and performs well in general service; the weld is worked and annealed until it's nearly indistinguishable from parent metal. If the project spec is silent, pressure and criticality decide it. See our Stainless Steel Seamless Pipes and Tubes page for the seamless family in straight lengths.
Send Us Your Size, Grade and Run Length
Applications
- Instrumentation and Impulse Lines: pressure, flow, and level instrument connections across process plants, the form's defining use.
- Control and Chemical Injection Lines: downhole and surface control lines, including encapsulated lines, in oil and gas production.
- Heat-Transfer Coils: immersion and heat-exchanger coils in process vessels; see our Heat Exchanger Tubes and Pipes page for the wider heat-transfer range.
- Hydraulic and Pneumatic Lines: continuous runs in marine, offshore, and mobile equipment.
- Pre-Insulated and Steam-Traced Bundles: coil tubing as the core of heated instrument bundles.
- CNG and Gas Distribution: continuous small-bore gas lines where joint integrity is safety-critical.
Testing, Certification and Availability
Coil tubing is 100 percent tested, hydrostatic or eddy-current per the governing standard, with mill test certification and full heat traceability on every order; see our Quality Policy page for the full program. Standard coil sizes in 304 and 304L and 316 and 316L typically ship fastest; duplex, 904L, and non-standard sizes are confirmed against mill schedules. Send us your grade, OD, wall, and run length for current availability.
Related Products
- Stainless Steel Pipes and Tubes
- Stainless Steel Seamless Pipes and Tubes
- Heat Exchanger Tubes and Pipes
- Condenser Tubes
- Duplex Steel Pipes and Tubes
- Stainless Steel 904L Pipes and Tubes
Frequently Asked Questions
Is this the same as oil and gas coiled tubing used for well intervention?
No. Well-intervention coiled tubing is a large spooled carbon-steel string, typically 1 to 3.25 inch OD to API 5ST, run into wells for intervention and workover operations. This page covers stainless steel instrumentation, control line, and process coil tubing to ASTM A269, A213, and A249, small-bore tubing supplied in continuous coils to eliminate joints in surface and downhole control systems.
What's the longest continuous coil you can supply without a weld?
Up to 2,000 metres in a single length for smaller diameters; the achievable maximum shortens as OD and wall increase. Tell us your size and required run length and we'll confirm the longest single piece available.
Which grade should I pick for coastal or offshore instrument lines?
316 and 316L is the standard starting point for chloride exposure. For high-chloride, high-pressure offshore control lines, duplex S31803 and S32205 roughly doubles the strength and significantly improves pitting resistance; see our Duplex Steel Pipes and Tubes page.
Can coil tubing be bent on site without fittings?
Yes. It's supplied annealed specifically so it can be routed by hand or with simple benders, which is a large part of the installation-speed advantage over jointed straight lengths.
Do you supply welded as well as seamless coil tubing?
Yes, seamless to ASTM A269 and A213 and welded to A269 and A249. Seamless is the default for critical and high-pressure service; welded-and-drawn offers a lower cost for general applications.