Yuhong Group Co., Ltd. is a specialist manufacturer of shell-and-tube heat exchangers, pressure vessels, and air coolers, with integrated supply of replacement components including U-tubes, finned tubes, heat exchanger tubes, tubesheets, baffles, and channel heads. Our U-tube bundles are engineered as direct-fit replacements or custom-fabricated cores for new equipment, serving refineries, chemical plants, power generation facilities, and offshore platforms.
The U-tube bundle is a removable, single-tubesheet heat exchanger core consisting of seamless or welded tubes bent into a U-shape, with both tube ends terminating at the same tubesheet. Unlike fixed-tubesheet designs, the U-bend end of the bundle is free-floating within the shell, allowing each tube to expand and contract independently in response to thermal differentials.
This configuration eliminates the need for expansion joints and significantly reduces thermal stress—a critical advantage when shell-side and tube-side temperature differences exceed 60°C, with proven capability up to 120°C differential.
All bundles are designed and fabricated in accordance with ASME Section VIII Division 1 and TEMA Class R, C, or B standards, with U-Stamp certification available upon request.
| Component | Material Standard / Grade | Key Specifications |
|---|---|---|
| U-Tubes | ASME SA213 TP304, TP304L, TP316, TP316L; ASME SA789 S32205 (Duplex 2205); ASME SA790 UNS S31803 | OD: 12.7 mm - 51 mm (3/8″ - 2″); Wall: 1.2 mm - 3.5 mm; U-bend radius R ≥ 2 × tube OD |
| Tubesheet | ASME SA266 Gr.2 (forged carbon steel); ASME SA182 F304/316L (stainless); F51/60 (Duplex) | Forged construction for dense microstructure and high pressure resistance |
| Baffles | ASME SA516 Gr.70 carbon steel; or matching alloy | Segmental, disc-and-donut, helical, or rod-type |
| Tie Rods & Spacers | ASME SA193 B7 or matching alloy | Maintain baffle spacing and bundle rigidity |
| Sealing Strips | Carbon steel or alloy | Prevent shell-side fluid bypass |
Tube layouts are available in triangular or square pitch, with tube counts ranging from 10 to over 5,000 tubes depending on shell diameter and thermal duty requirements.
Every U-tube bundle undergoes a comprehensive inspection and testing protocol prior to release:
| Test / Inspection | Standard / Method | Acceptance Criteria |
|---|---|---|
| Material Verification | MTR (Material Test Reports) per ASME/ ASTM | Full chemical & mechanical compliance |
| Dimensional Inspection | Tube OD, ID, wall thickness, ovality per ASTM | Per specified tolerance |
| Eddy Current Testing (ECT) | 100% of tubes | Detects wall thinning, pitting, cracks |
| Hydrostatic Test | 1.5× design pressure per ASME Section VIII | No pressure drop; zero leakage |
| Liquid Penetrant Testing (PT) | Tube-to-tubesheet welds | No surface discontinuities |
| Radiographic Testing (RT) | Critical weld joints | Per ASME Code requirements |
Post-bending, all U-tubes are solution-annealed to eliminate residual stresses, then pickled and passivated to restore corrosion resistance.
U-tube bundles are specified across a wide range of process industries where thermal expansion management and tube-side cleaning access are critical:
Thermal Expansion Management - The free-floating U-bend design accommodates thermal differentials without inducing stress at tube-to-tubesheet joints. Each tube expands and contracts independently.
Removable Bundle Design - The entire bundle can be withdrawn from the shell as a modular unit, simplifying inspection, mechanical cleaning, and tube replacement. Shell-side cleaning remains accessible without disturbing tube-side connections.
High Pressure Capability - Single-tubesheet construction eliminates the second tubesheet found in fixed designs, reducing potential leak paths and enabling higher tube-side pressure ratings (up to 40 MPa / 5,800 psi).
A: Per TEMA RCB-2.31, the minimum centerline bend radius is typically 2 × tube outside diameter (OD) for stainless steels. Tighter radii may be achievable with specific alloys—consult our engineering team for application-specific guidance.
A: U-tube bundles are best suited for clean tube-side media due to limited access for mechanical cleaning inside the U-bend region. For heavily fouling services, floating-head designs with straight, pull-through tubes are recommended.
A: TEMA Class R is the most stringent, designed for petroleum and severe process services. Class C is for general commercial and moderate-duty applications, while Class B is for chemical process services. Our standard offering covers all three classes.
A: All U-tubes receive 100% eddy current testing after bending to detect any defects introduced during the forming process, followed by hydrostatic testing of the complete bundle.
For technical consultations, custom bundle drawings, material certification packages, or to request a quotation with full traceability, please reach out directly to our engineering and sales team:
Email: vladimir@steelseamlesspipe.com
