What is ASME SA182 S31803 duplex stainless steel tubesheets for heat exchangers?
ASME SA182 S31803 duplex stainless steel heat exchanger tube sheets, as core components of duplex steel tubes, possess a balanced 50% ferrite + 50% austenite microstructure, fully complying with ASME SA182, ASME BPVC Section VIII, and NACE MR 0175/ISO 15156 standards. With a pitting resistance equivalent number (PREN) of 32-35, its resistance to pitting and crevice corrosion is more than 40% higher than that of 316L tube sheets. The corrosion rate in a 3.5% NaCl solution (150℃) is ≤0.07 mm/year, effectively resisting corrosion from the heat transfer medium.
In terms of mechanical properties, its yield strength is ≥450 MPa and tensile strength is ≥620 MPa, ensuring stable load-bearing capacity at heat exchanger operating pressures up to 15 MPa and temperatures ranging from -50℃ to 300℃. The tube sheets are manufactured using precision CNC drilling, resulting in high dimensional accuracy-hole diameter tolerance of ±0.02 mm, hole pitch tolerance of ±0.05 mm, and perpendicularity of ≤0.01 mm/m-ensuring a tight fit with S31803/S32205 tubes.
The welded joints between the tube sheet and tubes maintain a strength retention rate of ≥90% after heat treatment and undergo 100% ultrasonic testing to eliminate internal defects, extending the overall service life of the heat exchanger by more than 30% compared to traditional austenitic stainless steel tube sheets.
Exchanger Type
Select the type of heat exchanger.
U-Tube has only one tubesheet. The tubes are bent in the form of a "U." The bundle can removed for maintenance, but the inside of the tube is harder to clean because of the bend.
Fixed has two tubesheets that are fixed at each end of the exchanger and are connected to each other by straight tubes. Both the tubesheets are stationary, so differential thermal expansion can develop between the shell and the tubes. An expansion joint is sometimes required to absorb the thermal growth. You must select a fixed type of tubesheet exchanger to perform finite element analysis on expansion joints.
ASME SA240 S31803 Duplex Stainless Steel Tubesheets Specifications
| Specification | Description |
|---|---|
| Material Grade | S31803 (Duplex Stainless Steel) |
| Standard | ASME SA240 |
| Typical Tube Sheet Dimensions | - Thickness: 10–80 mm (depending on application) - Outer Diameter: 200 mm to 2000 mm (custom sizes available) - Bore Diameter: Custom as per tube size and arrangement - Holes: Typically, 8–10 mm diameter depending on tube size |
| Certification | ISO, SGS, BV (may vary based on supplier) |
Chemical Composition
| UNS S31803 | Percent By Weight | |
|---|---|---|
| Cr | Chromium | 22.0 - 23.0% |
| Ni | Nickel | 4.5 - 6.5% |
| Mn | Manganese | 2.0% max |
| Si | Silicon | 1.0% max |
| P | Phosphorous | 0.03% max |
| S | Sulfur | 0.02% max |
| C | Carbon | 0.03% max |
| N | Nitrogen | 0.1 - 0.2% |
| Mo | Molybdenum | 3.0 - 3.5% |
| Fe | Iron | Balance |
Physical properties
| Physical property | Value |
|---|---|
| Density: | 0.278 lb/in3 |
| Melting Range: | 2525-2630°F |
| Specific Heat Capacity at 212°F | 0.119 Btu/lb/°F |
| Thermal Conductivity at 212°F | 8.4 Btu/hr-ft-°F |
| Poisson's Ratio | 0.3 |
| Elastic Modulus at 72°F | 29 x 10 psi |
Mechanical properties
| Mechanical property | Value |
|---|---|
| 0.2% Yield Strength, ksi | 65 min |
| SA-240 S31803 Sheet & Plate Tensile Strength, ksi | 90 min |
| Elongation, % | 25 min |
| 22 Cr Duplex UNS S31803 Plate Hardness [HRC] | 293 max |
Tensile Properties
| Ultimate Tensile Strength, ksi Minimum | 2% Yield Strength, ksi Minimum | Hardness Max. |
|---|---|---|
| 95 | 65 | 31 Rockwell C |
Main Applications of ASME SA182 S31803 Tubesheets
Chemical and petrochemical industries: Various heat exchangers, condensers, and reactors used to handle corrosive media such as acids, alkalis, and salts.
Marine engineering: Seawater desalination plants, ship heat exchangers, and offshore platform cooling systems.
Pharmaceutical and food industries: Process equipment requiring extremely high material purity and corrosion resistance.
Nuclear power industry: Auxiliary cooling systems and heat exchange equipment for non-nuclear components.
Pulp and paper industry: Handling corrosive chemical solutions.
ASME SA182 S31803 Tubesheets are securely packaged in moisture-proof plastic wrapping, with additional protection provided by wooden crates or steel frames to prevent damage during shipping and ensure safe delivery.
