ASME SA240 Gr. 321 Stainless Steel Dished Heads are critical pressure-retaining components tailored for high-temperature service in shell and tube heat exchangers, reactors, and pressure vessels.

By incorporating titanium stabilization (minimum 5 × C+N%), SA240 Grade 321 prevents chromium carbide precipitation at grain boundaries during deep-drawing/spinning forming and subsequent circumferential seam welding, thereby preserving intergranular corrosion resistance in the Heat-Affected Zone (HAZ) without mandatory post-weld solution annealing.

Operating effectively within the sensitized temperature range of 427℃ to 816℃(800℉ to 1500℉), these dished ends exhibit higher creep-rupture strength and structural stability under sustained pressure compared to standard 304/316 austenitic grades, making them an optimal choice for cyclic thermal loads and aggressive process media.

To help engineers and procurement specialists design accurately, below are the standard dimensional parameters and calculation formulas for our ASME SA240 321 Torispherical Heads as shown in the schematic above:

• D₀: Outside Diameter
• D_i: Inside Diameter
• t: Nominal Wall Thickness
• SF: Straight Flange Height (≥ 3.5 × s)
• DH: Dished Depth / Internal Depth
• TH_i: Total Internal Height (TH_i = SF + DH)
• CR: Crown Radius (CR = D₀)
• KR: Knuckle Radius (KR = 0.1 × D₀)

• Internal Depth (DH): DH = 0.1935 × D₀ - 0.455 × t
• Total Inside Height (TH_i): TH_i = SF + DH

(Note: Custom dimensions, SF heights, and beveling options are available upon request.)

• Superior High-Temperature Performance: Titanium addition prevents chromium carbide precipitation during welding and service in the 427℃ - 816℃ range.
• ASME Code Compliance: Fully compliant with ASME Section VIII, Division 1 manufacturing standards.
• Precise Cold/Hot Pressing: Precision-formed via spinning or hydraulic pressing to maintain uniform wall thickness.
• Full Traceability: Provided with original Mill Test Certificates (MTC) compliant with EN 10204 3.1 (Third-party testing available with 3.2 certificate upon customer request.).