ASME SA266 Gr.2N Tubesheet: Forged Carbon Steel Heat Exchanger Part

What is Tubesheet?

A tubesheet (or tube sheet) is a critical component in shell-and-tube heat exchangers, boilers, condensers, and other pressure vessel systems. It acts as a structural anchor and sealing barrier for the tubes that carry fluids through the equipment.

What Does a Tubesheet Do?

Structural Support:

Holds an array of tubes in a fixed, organized arrangement (tube bundle).

Maintains alignment and spacing between tubes to ensure efficient heat transfer.

Fluid Isolation:

Separates two distinct fluid streams:

Shell-side fluid: Flows around the outside of the tubes.

Tube-side fluid: Passes through the tubes.

Prevents cross-contamination between the two fluids.

Pressure Boundary:

Seals the ends of the tubes and withstands pressure differences between the shell and tube sides.

Introduction to ASME SA-266 Gr.2N Tubesheet

ASME SA-266 Gr.2N is a carbon steel forging specification widely used for manufacturing tubesheets in pressure vessels and heat exchangers. Tubesheets are critical components in shell-and-tube heat exchangers, boilers, and condensers, serving as structural elements that hold tubes in place while isolating shell-side and tube-side fluids. The selection of SA-266 Gr.2N ensures robustness under high-pressure, high-temperature (HPHT) conditions and compliance with stringent safety standards.

Key Features of SA-266 Gr.2N

Material Composition:

Carbon Steel: Balanced composition (typically 0.30% max carbon, 0.60–0.90% manganese) provides strength and weldability.

Normalized Heat Treatment: Enhances mechanical properties (uniform grain structure, improved toughness) by heating above the critical temperature and air-cooling.

Mechanical Properties:

Tensile Strength: 415–585 MPa

Yield Strength: 205 MPa min

Ductility: ~30% elongation (ensures resistance to deformation).

Compliance:

Governed by ASME Boiler and Pressure Vessel Code, Section II (Materials) and Section VIII (Pressure Vessels).

Applications

SA-266 Gr.2N tubesheets are ideal for:

Oil & Gas: Heat exchangers in refineries.

Chemical Processing: Reactors and condensers.

Power Generation: Boilers and steam generators.

Cryogenic Systems: Suitable for moderate low-temperature service.

Manufacturing Considerations

Forging Process: Provides superior integrity compared to rolled plates.

Machining & Drilling: Precision drilling for tube holes (requires stress-relieving post-machining).

Testing: Mandatory non-destructive testing (NDT) such as ultrasonic inspection and hydrostatic tests to detect flaws.

Advantages

Cost-Effective: Balances performance and affordability compared to high-alloy steels.

Weldability: Compatible with common welding techniques, though pre/post-weld heat treatment may be required.

Durability: Resists mechanical stress and cyclic loading in industrial environments.

Limitations

Corrosion Resistance: Limited in corrosive environments; often paired with protective coatings or clad materials.

Temperature Range: Best for temperatures between -30°C to 425°C; not suitable for extreme cryogenic or high-temp applications requiring alloys.

ASME SA-266 Gr.2N tubesheets offer a reliable solution for HPHT applications, combining strength, manufacturability, and code compliance. Their use ensures safety and longevity in critical industrial systems, making them a preferred choice for engineers prioritizing cost-performance balance, if you have any demand in those tubesheets, pls feel free to contact Yuhong's sales team.