ASME SA240 321 Stainless Steel Pressure Vessel Dished Head / Dish End for Shell & Tube Heat Exchanger
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.
ASME SA240 Gr. 321 Chemical Composition, %
| C |
Mn |
P |
S |
Si |
Cr |
Ni |
N |
Ti |
| ≤ 0.08 |
≤ 2.00 |
≤ 0.045 |
≤ 0.030 |
≤ 0.75 |
17.0 - 19.0 |
9.0 - 12.0 |
≤ 0.1 |
5×(C+N) - 0.70 |
International Grade Equivalents for ASME SA240 321
| Standard System |
Country / Region |
Standard Number |
Equivalent Grade / Designation |
| ASME / ASTM |
USA/ North America |
ASME SA240 / ASTM A240 |
Grade 321 (UNS S32100) |
| EN |
Europe Union |
EN 10028-7 |
1.4541 (X6CrNiTi18-10) |
| GB / GB/T |
China |
GB/T 713.7 (Old: GB/T 24511) |
06Cr18Ni11Ti (Old: 0Cr18Ni10Ti) |
| GOST/ ГОСТ |
Russia / CIS |
GOST 5632 / GOST 7350 |
12X18H10T/08Х18Н10Т |
Dimensional Specifications & Geometry Formulas
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:
Key Dimensional Legend:
- D0: Outside Diameter
- Di: Inside Diameter
- t: Nominal Wall Thickness
- SF: Straight Flange Height (≥ 3.5 × s)
- DH: Dished Depth / Internal Depth
- THi: Total Internal Height (THi = SF + DH)
- CR: Crown Radius (CR = D0)
- KR: Knuckle Radius (KR = 0.1 × D0)
Formula Calculations:
- Internal Depth (DH): DH = 0.1935 × D0 - 0.455 × t
- Total Inside Height (THi): THi = SF + DH
(Note: Custom dimensions, SF heights, and beveling options are available upon request.)
Key Features of ASME SA240 321 Dished Ends
- 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.).
Technical Specifications
| Parameter |
Specification Details |
| Material Standard |
ASME SA240 / ASTM A240 |
| Grade |
UNS S32100 (Type 321 Stainless Steel) |
| Head Types Available |
Torispherical (shown above), Ellipsoidal (2:1), Hemispherical, Flat Ends |
| Outside Diameter (D0) |
Customized according to client drawing |
| Thickness (t) |
Customized according to design pressure |
| Forming Method |
Cold Pressing / Hot Pressing / Spinning |
| Heat Treatment |
Solution Annealed (upon request for heavy deformation) |
| Testing & NDE |
PT (Liquid Penetration), RT (Radiographic Test), UT (Ultrasonic Test) |
| Applications |
Shell and Tube Heat Exchangers, Boilers, Reactors, Petroleum Storage |
