DLSS Heat Exchanger Tubes U-Bend Heat Exchanger Tubes

U-Bend Heat Exchanger Tubes

Precision U-bend tubes for shell & tube heat exchangers, feedwater heaters, condensers and process heat-transfer equipment.

DLSS supplies U-bend heat exchanger tubes in stainless steel, duplex, super duplex, nickel alloy, titanium, copper alloys, carbon steel and selected alloy steel grades, manufactured according to project drawings with controlled bend geometry, wall thinning, ovality and inspection requirements.

Custom Bend Radius

Drawing-Based Geometry

Straight-Leg Length

Project-Specific Dimensions

Post-Bend Treatment

Where Required

Inspection Support

Dimensions · NDE · TPI

Precision U-Bend Tubes for Heat Exchanger Bundles

U-bend tubes form a continuous flow path through a controlled 180° bend and are widely used in U-tube heat exchanger bundles.

Their manufacture requires more control than straight tubing because the bending process can affect wall thickness, tube roundness, leg alignment and material condition in the bend area.

Critical purchasing requirements include:

Tube OD · Wall thickness · Developed length · Straight-leg length · Bend radius · Tube pitch · Wall thinning · Ovality · Bend-plane alignment · Surface condition · Post-bend heat treatment · Nondestructive examination

DLSS reviews the base-tube material standard, exchanger drawing, bend geometry and inspection requirements before production.

Bend Geometry

Radius · Length · Alignment

Wall Control

Thinning at Bend Area

Ovality Control

Roundness After Bending

Traceability

Base Tube to Finished U-Tube

U-Bend Heat Exchanger Tube Materials

Critical U-Bend Engineering Parameters

Bend Radius

Centerline radius according to exchanger drawing and tube layout.

Straight-Leg Length

Controlled tube-leg dimensions for accurate bundle assembly.

Developed Length

Total tube length confirmed before cutting and bending.

Wall Thinning

Bend-area wall thickness controlled to project requirements.

Ovality

Tube roundness checked after forming.

Bend Alignment

Parallel legs and bend-plane alignment for bundle installation.

U-Bend Tube Manufacturing Process

Specification Review

Grade · Standard · OD · WT · Radius

Base Tube Inspection

Dimensions · Surface · Traceability

Cutting & Identification

Developed Length · Tube Identification

Precision U-Bending

Controlled Radius · Geometry · Alignment

Post-Bend Treatment

Where Required by Specification

Final Inspection

Dimensions · NDE · Documentation · Packing

U-Bend Heat Exchanger Tube Specifications

For accurate quotation, please provide the exchanger drawing or U-bend schedule together with the tube specification.

Specification	Available Options
Materials	Stainless / Duplex / Nickel / Titanium / Copper Alloy / Carbon & Alloy Steel
Construction	Seamless / Welded
OD & Wall Thickness	Project-Specified
Developed Length	According to Drawing
Straight-Leg Length	Customized
Bend Radius / Tube Pitch	Drawing-Specified
Wall Thinning / Ovality	Project-Specified Limits
Heat Treatment	Where Required
Inspection	Dimensional / NDE / Hydro / PMI / TPI
Documentation	MTC / EN 10204 3.1 / 3.2 / Inspection Reports
Packing	Wooden Cases / Steel Frames / Bend Protection

Standards for U-Bend Heat Exchanger Tubes

The final U-bend tube specification should combine the applicable material standard with the exchanger drawing and project-specific bending, heat-treatment and inspection requirements.

01｜U-Bend Specific Standards

ASTM A688 / ASME SA688

Stainless Steel Feedwater Heater U-Tubes

ASTM B395 / B395M

Copper & Copper Alloy U-Bend Tubes

02｜Base Tube Standards by Material

Stainless Steel

ASTM A213 / ASME SA213

ASTM A249 / ASME SA249

Duplex & Super Duplex

ASTM A789 / ASME SA789

Nickel Alloy

ASTM B163 · B165 · B167 B423 · B444 · B622

Titanium

ASTM B338 / ASME SB338

Carbon Steel

ASTM A179 / ASME SA179

Copper & Copper Alloy

ASTM B111 / ASME SB111

Post-Bend Heat Treatment

U-bending introduces localized cold work in the bend area. Depending on the material grade, wall thickness, bend radius and project specification, additional heat treatment may be required.

Solution Annealing

For applicable stainless and special-alloy projects

Stress Relief

Where required for applicable steel grades

Local Bend Treatment

Where permitted by specification

As-Bent Condition

Where additional treatment is not required

U-Bend Heat Exchanger Tube Applications

Shell & Tube Heat Exchangers

U-tube bundles for thermal-expansion flexibility.

Oil, Gas & Petrochemical

U-tubes for process heat-transfer equipment.

Chemical Processing

Special-alloy U-tubes for corrosion-critical service.

Refineries

New exchanger bundles and replacement U-tube projects.

Feedwater Heaters

U-tube requirements for applicable power-generation heater designs.

U-Bend Inspection & Quality Control

Bend Geometry

Radius · Leg Length · Alignment

Wall Thinning

Bend-Area Wall Control

Ovality

Roundness After Bending

Surface Inspection

Bend Surface & Tube Condition

NDE

ET · UT

Third-Party Inspection

TPI according to project ITP

Project Documentation Support

Complete documentation for seamless approvals and traceability.

Why DLSS for U-Bend Heat Exchanger Tubes?

Drawing-Based Production

Radius · Length · Geometry

Bend Quality Control

Wall Thinning · Ovality

Wide Material Range

Carbon Steel to Titanium

Post-Bend Inspection

Dimensions · NDE · TPI

Project Documentation

Traceability · 3.1 / 3.2

FAQ

What materials are available for U-bend tubes?

DLSS can review U-bend tubes in stainless steel, duplex, nickel alloy, titanium, copper alloys, carbon steel and selected alloy steel grades.

What information is required for quotation?

Please provide grade, standard, OD × WT, developed length, straight-leg length, bend radius, quantity and drawing.

How are wall thinning and ovality controlled?

Both can be inspected after bending according to the applicable project drawing, specification or TDC.

Is heat treatment required after U-bending?

It depends on the material, bend radius, wall thickness and governing project specification.

What documentation can be provided?

Documentation can include MTC, dimensional reports, NDE reports, heat-treatment records, EN 10204 3.1 / 3.2 and TPI reports.

U-Bend Tube Technical Resources

U-Bend Wall Thinning

Understand wall reduction at the outside bend radius.

U-Bend Ovality

Understand tube deformation and bend-area roundness.

U-Bend Radius

Understand centerline radius and exchanger geometry.

Tube Length Tolerance

Length-control requirements for bundle fabrication.

ASTM A688 U-Tubes

Feedwater-heater U-tube standard guide.

U-Bend Heat Treatment

Understand when post-bend treatment may be required.