Heat Exchanger Tubesheet – Fixed / Floating / U‑Tube Types – Solid / Clad /

Yuhong Group is one of the earliest groups to export Chrome Moly Pipe in China, with approximately 30 years of experience in alloy steel pipe and tube supply. Products are manufactured according to ASME SA335 / ASTM A335 P1, P11, P12, P22, P5, P9, P91, P92 and ASME SA213 / ASTM A213 T1, T11, T12, T22, T5, T9, T91, T92. Alloy steel pipe and tube are widely used in petrochemical, oil refinery, power plant, and related high-temperature industries.

• Fixed Tubesheet (TEMA L / M / N) – Welded or bolted directly to the shell on both ends; tubes are fixed at both ends. Requires an expansion joint on the shell when the temperature differential (ΔT) between tube and shell exceeds limits (typically >60°C for carbon steel, >40°C for stainless steel). Suitable for clean shell‑side fluids, small ΔT, and non‑fouling service. Shell‑side cleaning is not possible without removing the entire bundle.
• Floating Tubesheet (TEMA P / S / T / W) – One tubesheet is fixed to the shell flange; the other is free to move (floating) to accommodate thermal expansion. The floating tubesheet is not welded to the shell, allowing axial movement of the bundle. Suitable for large ΔT (>60°C) and fouling service that requires bundle removal. Requires a floating head cover for sealing, which increases cost and maintenance complexity.
• U‑Tube Tubesheet (TEMA U) – A single tubesheet supports both ends of U‑shaped tubes. No differential thermal expansion occurs between tubes and shell because each tube expands independently. Suitable for high ΔT (up to 200°C), high‑pressure gas service, hydrogen service, and thermal shock. Tubes cannot be mechanically cleaned (only chemical cleaning); minimum U‑bend radius limits tube OD selection.

The tubesheet material is selected based on service conditions, corrosion resistance, and design pressure/temperature. Available materials include:

• Carbon Steel – SA105, SA266 Cl.2 / Cl.3 / Cl.4, SA516 Gr.60 / 65 / 70, SA350 LF1 / LF2
• Alloy Steel – SA182 F1, F5, F9, F11, F12, F22
• Stainless Steel – SA182 F304 / 304L / 304H, F316 / 316L / 316H / 316Ti, F317L, F321 / 321H, F347 / 347H
• Duplex / Super Duplex – SA182 F44, F45, F51, F53, F55, F60, F61
• Titanium – SB265 Gr.1 / Gr.2 (typically as cladding)
• Nickel Alloys – SB564 UNS N04400 (Monel), N06600 (Inconel 600), N06625 (Inconel 625), N08800 (Incoloy 800), N08825 (Incoloy 825), N10276 (Hastelloy C‑276)

For corrosive environments where solid alloy tubesheets are cost‑prohibitive, clad tubesheets are supplied with a metallurgically bonded corrosion‑resistant layer on a carbon steel or low‑alloy steel base:

• Explosion‑Bonded Cladding – Produces a solid‑state metallurgical bond via controlled detonation. Preferred for thick or large‑diameter components. Capable of bonding titanium to steel. Cladding thickness: 3 mm to 12 mm (minimum 3.5 mm typically). Typical combinations: Ti/Steel (SB265 Gr.1 / SA266 Gr.2 or SA516 Gr.70N), Ni‑alloy/Steel.
• Roll‑Bonded Cladding – Achieves metallurgical bond by high‑pressure rolling. Suitable for thinner cladding and smaller diameters.
• Weld Overlay – Corrosion‑resistant alloy deposited by SAW or GTAW. Flexible in material selection and thickness.

All clad tubesheets undergo bond integrity testing per ASME VIII‑1, including ultrasonic testing and shear strength verification.

• Forging or Plate Rolling – Smaller diameters and higher pressures use forged discs (SA266 or SA182); larger diameters use rolled plates (SA516 or equivalent).
• CNC Drilling – Hole pattern is drilled with CNC equipment to achieve precise hole diameter, pitch, and positional tolerances. Deep‑hole drilling used for thick plates.
• Hole Finishing – Reaming or boring to specified surface finish (Ra ≤1.6 µm for expanded joints, ≤3.2 µm for welded joints).
• Grooving – Tube holes may be grooved or serrated to improve mechanical strength of expanded joints. Number and depth of grooves per TEMA RCB‑4.3.

The minimum required thickness of a tube sheet is calculated per ASME VIII-1 Appendix A or TEMA RCB-4.3. Simplified formulas for preliminary sizing:

• t = F * (P * D) / (2 * S * E – 0.2 * P) * C (correction for tube hole ligament efficiency)
• Where: F = design factor (typically 1.0 – 1.5 depending on tube-to-tubesheet joint type), P = design pressure (higher of tube side or shell side, or differential), D = tube sheet diameter, S = allowable stress at design temp, E = ligament efficiency (area of ligament / total pitch area)
• Ligament efficiency η = (p – d) / p (for triangular pitch), where p = pitch, d = hole diameter

• t = d * sqrt(C * P / S * E)
• Where: d = tube sheet diameter (for circular plates), C = edge constraint factor (0.3 – 0.5 depending on support condition)

• For expanded tube joints: Minimum tube sheet thickness ≥ 1.5* tube OD or ≥ tube OD + 20mm (whichever is greater)
• For welded tube joints: Minimum thickness ≥ 1.0* tube OD or ≥ 20mm (whichever is greater)
• For combined (weld + expand): Minimum thickness ≥ tube OD + 15mm

Chemical Composition (Typical for Carbon Steel SA266 Gr.2)

Mechanical Properties (SA266 Gr.2)

• Material test certificates (EN 10204 3.1 or 3.2) – base plate, cladding material, filler materials
• ASME U-stamp data report (if applicable) – including design calculations
• TEMA datasheet (Class R/B/C) – if applicable
• Dimensional inspection report (hole diameter, pitch, ligament deviation, flatness, thickness)
• NDE reports – UT (lamination), UT (clad bond), PT (surface), borescope
• Cladding bond shear strength test report (if clad – explosion-bonded or roll-bonded)
• Tube hole surface finish report (profilometer records – sample 5% holes)
• Weld procedure specification (WPS) and qualification record (PQR) – if clad weld overlay or tube sheet-to-shell welds applied
• Post-weld heat treatment (PWHT) chart – if performed (time-temperature recording)
• Drawing (as-built) – with hole pattern coordinates, pitch, and dimensions

When ordering a tube sheet (new, replacement, or spare), provide:

• Tube sheet type – Fixed / Floating / U-tube
• Shell ID and channel ID – determines tube sheet diameter
• Tube count and tube layout pattern – Triangular / Square / Rotated square
• Tube OD and wall thickness – determines hole diameter and pitch
• Tube pitch (center-to-center distance) – per TEMA or GB/T 151
• Tube hole diameter – H11 tolerance per ISO 286
• Tube-to-tubesheet joint type – Expanded / Welded / Combined / Full penetration
• Tube sheet thickness – per ASME VIII-1 Appendix A or TEMA RCB-4.3
• Tube sheet material – CS / SS / Duplex / Ti / Alloy (solid or clad)
• Cladding requirement (if any) – material, thickness, method (explosion-bonded / roll-bonded / weld overlay)
• Design pressure – tube side and shell side (also specify differential pressure)
• Design temperature – tube side and shell side
• Flange connection type – RF (raised face) or RTJ (ring-type joint) – if tube sheet is flanged
• Flange drilling standard – ASME B16.5 / B16.47 or HG/T 20615
• PWHT requirement – based on material thickness and service (per UCS-56)
• NDE requirement – per ASME VIII-1 or project specification
• Surface treatment (if required) – pickling / passivation / coating / electropolish