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Home / All / Stainless Steel / Heat Exchanger Steel Tube (U-Bend / Straight, ASTM A213 304 / 316L / 321 / 310S)

Heat Exchanger Steel Tube (U-Bend / Straight, ASTM A213 304 / 316L / 321 / 310S)

ASTM A213 stainless heat exchanger tubes in 304, 316L, 321 and 310S. U-bend and straight, bright annealed, eddy-current tested.

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Categories	Stainless Steel
Brand	MESCO: Trusted Steel Wholesale Manufacturer
Model	MESCO-HX-TUBE
Material	Stainless Steel (Austenitic)
Grade	ASTM A213 / A249 / A269 — 304, 304L, 316, 316L, 321, 310S
Form	Round Tube (Straight / U-Bend)
OD	6 – 50 mm
Wall	0.5 – 5.0 mm
U-Bend Radius	1.5 × OD (typical)
Finish	Bright Annealed / Pickled
Test	Eddy-Current + Hydrostatic per ASTM A213

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Detail Information

Heat Exchanger Steel Tube (U-Bend / Straight, ASTM A213 304 / 316L / 321 / 310S)

High-performance stainless heat exchanger tubes — U-bend and straight, ASTM A213 / A249 / A269 compliant, with bright annealed finish and 100% eddy-current testing.

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MESCO supplies stainless steel heat exchanger tubes in 304, 304L, 316, 316L, 321 and 310S grades under ASTM A213 / A249 / A269 standards. Outside diameter ranges from 6 to 50 mm with wall 0.5 to 5.0 mm, available in straight lengths or precision U-bends with bend radius typically 1.5 × OD. Each tube is bright annealed, pickled and eddy-current tested to ensure leak-tight performance in shell-and-tube heat exchangers, condensers, boilers and chemical reactors.

Stainless steel U-bend heat exchanger tubes arranged in bundles in MESCO workshop

Specifications & Capabilities

ASTM A213 Grades & Differences

304 / 304L — general service, good corrosion resistance
316 / 316L — chloride-rich service, superior pitting resistance
321 — stabilized with Ti for elevated temperature (up to 870 °C)
310S — high Cr-Ni for very high temperature (up to 1100 °C)

U-Bend vs Straight Tube

Straight tube — for fixed tube-sheet and floating head exchangers
U-bend tube — for U-tube heat exchangers; bends expand freely
U-bend radius typically 1.5 × OD, max 3 × OD on request
All bends hydroformed and stress-relieved to prevent cracking

Size, Wall & Pressure Rating

OD 6 – 50 mm standard, 60+ mm on request
Wall 0.5 – 5.0 mm, tolerance ±10% per A213
Pressure rating depends on OD and wall; refer to ASME B31.3
Common sizes: 19.05 × 1.65 / 25.4 × 2.11 / 31.8 × 2.77 mm

Cleaning, Pickling & Bright Annealing

Bright annealing under protective atmosphere → oxide-free surface
Pickling in nitric-hydrofluoric bath → uniform matte finish
Optional passivation per ASTM A967 for enhanced corrosion resistance
100% eddy-current test for surface defects per ASTM E213

Typical Grade & Size Range

Parameter	Value
Material	Stainless Steel (304 / 304L / 316 / 316L / 430)
Standard	ASTM A240 / A480 / A312 / A213 (per product family)
Finish	2B / BA / No.4 / HL / 8K / Mill / Polished
Thickness / OD	Custom range per family (see attributes table)
MOQ	1 ton (or as agreed)

Frequently Asked Questions

When should I choose 321 vs 316L for heat exchangers?

Choose 321 for elevated temperature service (500-870 °C) where intergranular corrosion is a risk during thermal cycling, as Ti stabilization prevents chromium carbide precipitation. Choose 316L for chloride-rich wet service where pitting resistance matters more than high-temperature strength.

What is the typical U-bend radius?

Standard U-bend radius is 1.5 × OD for most heat exchanger designs. For thinner walls (less than 1.5 mm) the minimum is 2 × OD. We also offer 2.5 × and 3 × OD on request. Each bend is hydroformed and stress-relieved.

Are the tubes eddy-current tested?

Yes. 100% eddy-current testing per ASTM E213 is included as standard. Hydrostatic testing per ASTM A213 is also available on request. Both straight tubes and U-bends are individually tested and marked before packing.

What is the maximum service temperature for 310S?

310S (25Cr-20Ni) is designed for very high temperature service up to approximately 1100 °C in intermittent use and 1050 °C in continuous service. Above 600 °C it provides excellent oxidation resistance but lower strength compared to Inconel alloys.