ASME SA336 F5N Tubesheet – Forged Chrome-Moly Tube Sheet for Shell-and-Tube Heat Exchangers

The ASME SA336 F5N tubesheet is a forged chrome-molybdenum-vanadium steel component designed for shell-and-tube heat exchangers, pressure vessels, and reactors operating in high-temperature, high-pressure (HPHT), and corrosive service environments. The tubesheet serves as a structural anchor that secures the tube bundle in fixed alignment while maintaining positive separation between shell-side and tube-side fluids.

Manufactured as a forging rather than rolled plate, the SA336 F5N tubesheet offers a refined grain structure and improved mechanical property consistency—particularly critical when the component must withstand differential thermal expansion between tubes and shell, cyclic pressure loading, and aggressive process media.

ASME SA336 F5N is a normalized and tempered 5% chromium-molybdenum-vanadium steel forging, compliant with ASME Boiler and Pressure Vessel Code (BPVC) Section II.

Source: ASME SA336 / SA336M

The 4.0-6.0% chromium content provides oxidation and corrosion resistance at elevated temperatures, while molybdenum (0.45-0.65%) enhances creep strength and resistance to hydrogen attack. The low carbon content (≤0.15%) improves weldability compared to standard F5 grade.

Source: ASME SA336 / SA336M

Heat Treatment: SA336 F5N undergoes normalization (heated to 900-980°C) followed by tempering (650-750°C) to achieve a uniform fine-grained bainite/martensite microstructure with balanced strength, ductility, and resistance to hydrogen-induced cracking (HIC).

Each ASME SA336 F5N tubesheet is subject to inspection and testing protocols per ASME Section VIII and TEMA requirements:

Source: ASME Section VIII Div.1, TEMA standards

3.2 inspection certificates can be issued by TPI (Third-Party Inspection) upon request.

ASME SA336 F5N tubesheets are specified for shell-and-tube heat exchangers, waste heat boilers, steam generators, and pressure vessels across the following industries:

• Petroleum Refining: Hydrocracking reactors, hydrodesulfurization (HDS) units, hydrotreating reactors, and catalytic reforming units
• Power Generation: High-pressure steam generators, feedwater heaters, condensers, and boilers
• Chemical Processing: Synthetic ammonia plants, hydrogen processing units, and high-temperature/high-pressure heat exchanger systems
• Hydrogen Service: Equipment handling high-pressure hydrogen, H₂S, or sour gas environments

• High-Temperature Strength: Retains mechanical properties under prolonged exposure to 500-565°C, with service capability up to 600°C (1112°F).
• Hydrogen Resistance: Resists hydrogen embrittlement and blistering in sour (H₂S) or high-pressure hydrogen environments—critical for refinery hydrocracker and hydrotreater service.
• Creep Resistance: Suitable for long-term cyclic thermal loads, such as those encountered in refinery hydrocrackers.
• Weldability: Compatible with shielded metal arc welding (SMAW) and submerged arc welding (SAW) with proper preheat (200-300°C) and post-weld heat treatment (PWHT). Requires low-hydrogen electrodes (e.g., E8018-B2).
• Customization: Available in diameters up to 8 meters with CNC-drilled hole patterns per customer drawings and TEMA standards.