Fixed tube sheet ASME SA266 Gr.2N for Heat Exchangers
Yuhong Group Co., Ltd. is a leading Chinese enterprise specializing in the manufacture of heat exchange equipment and components, including shell-and-tube heat exchangers, air-cooled heat exchangers (ACHE), pressure vessels, as well as tube bundles, U-tubes, heat exchange finned tubes, flanges, baffles and covers.
General product description
The Tubesheet is the most critical component of a shell-and-tube heat exchanger or condenser. It is designed to securely fasten the heat exchange tubes within the tube bundle, withstand mechanical loads, and provide a leak-tight separation between the tube side and shell side fluid spaces.
The Fixed Tubesheet is welded to the equipment shell. The supplied tube sheet is forged from carbon steel ASME SA266 Grade 2N (normalized), complying with the requirements of ASME BPVC Section VIII Divisions 1 and 12 for high-pressure vessels. Normalization (the "N" in Grade 2N designation) relieves internal residual stresses generated after forging, refines grain structure, and guarantees uniform stable mechanical properties across the entire cross-section.
Main Components, Materials and Compliance with ASME Standards
| Element |
Material / Specification |
Note |
| Fixed Tubesheet |
ASME SA266 Gr.2N (forging) |
Normalized condition |
| Sealing surface |
ASME SA266 Gr.2N or cladding upon request |
As per customer drawing |
| Tube holes |
Drilling in accordance with TEMA R/CB standards |
Tolerances in accordance with standard |
Chemical Composition (ASME SA266 Gr.2N): C ≤ 0,25 %; Mn 0,60-1,35 %; P ≤ 0,025 %; S ≤ 0,025 %; Si 0,15-0,35 %.
Mechanical properties (in normalized condition): tensile strength 485–620 MPa; yield strength (minimum) 260 MPa; elongation (minimum) 21%; Brinell hardness ≤ 187 HB.
Testing and Quality Control
Each tube sheet is supplied with a complete documentation package, including a heat treatment report and Mill Test Report (MTR) containing chemical composition and mechanical property data. The standard scope of non-destructive testing is listed in the table.
| Type of Inspection (NDT) |
Standard / Scope |
Purpose of Inspection |
| UT (Ultrasonic Testing) |
ASME Sec.V Art.5 |
Detection of internal forging defects |
| PT (Penetrant Testing) |
ASME Sec.V Art.6 |
Inspection of surfaces, grooves and holes |
| Positive Material Identification (PMI) |
Upon request |
Verification of alloy grade |
All procedures are carried out under the supervision of third-party inspection bodies (BV, DNV, LR, ABS).
Application Fields of the Equipment
Main applications: medium- and heavy-duty equipment for oil refineries, heat exchangers used in hydrocracking and reforming processes, steam turbine condensers, high-pressure feedwater heaters, fired heaters, multi-effect distillation (MED) desalination plant evaporators, as well as auxiliary equipment for nuclear power plants (feedwater heaters).
Technological Advantages, Design Parameters and Services
Technical limitations and medium compatibility: Technical limitations and medium compatibility: Recommended for operation in non-corrosive and mildly corrosive media (water, steam, air, petroleum products with moderate H₂S content). For hydrogen sulfide-containing sour service environments, anti-corrosion coating or stainless steel overlay/cladding is required. This product is not designed for direct service with strong acids, chlorides (Cl⁻) and seawater. For such media, SA182 F304/F316 or bimetallic tube sheets are recommended.
Operating medium parameters: Operating temperature: -29°C to +425°C; material SA350 LF2 is required for temperatures below -29°C. Maximum design pressure: up to 5 MPa, subject to design configuration and thickness.
Technological Advantages
- Normalizing tempering delivers high ductility and resistance to cyclic loads during unit start-up and shutdown cycles.
- Excellent machinability on CNC machine tools (milling, tube hole drilling to TEMA standards).
- Reliable weldability with carbon steel shells and barrel sections (AWS E7018 welding electrodes are recommended; preheating is required for heavy wall thicknesses).
- Full traceability from melt certificate through to finished component.
Yuhong Group Engineering Services: Manufacturing according to customer-supplied finished drawings, structural design with strength calculation complying with ASME Section VIII, full scope of NDT (UT, PT, PMI), coordination with third-party inspection bodies (TÜV, BV, DNV), anti-corrosion treatment, or supply of welded clad blanks.
Frequently Asked Questions (FAQ)
Question: What is the difference between SA266 Gr.2N and SA266 Gr.2?
Answer: The suffix "N" indicates the material has undergone normalizing treatment after forging. It features finer grain structure and superior impact toughness compared to Gr.2 without such heat treatment.
Question: Can SA266 Gr.2N be used for hydrogen or hydrogen sulfide sour service (H₂S service)?
Answer: This grade is not recommended for such service in its bare state due to the risk of sulfide stress cracking (SSC). For projects complying with NACE MR0175/ISO 15156, either special incoming inspection for HIC/SSC is required, or cladding with SA240 316L followed by post-weld heat treatment (PWHT) shall be adopted.
Question: What types of tube-to-tubesheet joints are available?
Answer: Mechanical rolling, seal welding, or a combination of rolling plus welding (to eliminate crevice corrosion).
Question: What quality guarantees do you offer?
Answer: Every tubesheet undergoes ultrasonic testing of the forging and 100% inspection of all holes. We supply EN 10204 3.1 certification (MTR), including heat treatment verification documents.
For material selection consultation or quotation requests, please contact the specialists of Yuhong Group Co., Ltd. via email.: vladimir@steelseamlesspipe.com
