ASTM A789 UNS S31803 Duplex Stainless Steel Seamless Tube For Chemical Process Plant
ASME SA789 S31803 stainless steel tubing provides better pitting and crevice corrosion resistance than 316L or 317L austenitic stainless steel in almost all corrosive media. It also has high corrosion and erosion fatigue properties, as well as lower thermal expansion rates and higher thermal conductivity compared to austenitic stainless steels. The advantage of a duplex structure is that it combines the advantages of ferritic alloys, stress corrosion resistance, crack resistance, and high strength with the ease of manufacture and corrosion resistance of austenitic alloys.
Chemical Composition
Grade | C max | Si max | Mn max | P max | S max | Cr | Ni | Mo | N |
UNS S32750 | 0.030 | 0.8 | 1.2 | 0.030 | 0.015 | 24.0-26.0 | 6.0-8.0 | 3.0-5.0 | 0.24-0.32 |
UNS S31803 | 0.030 | 1.0 | 2.0 | 0.020 | 0.020 | 21.0-23.0 | 4.5-6.5 | 2.5-3.5 | 0.08-0.20 |
UNS S31500 | 0.030 | 1.0 | 1.2-2.0 | 0.030 | 0.030 | 18.0-19.0 | 4.5-5.5 | 2.5-3.5 | 0.05-0.10 |
Physical Properties
Grade | Y.S.MPa min | T.S.Mpa min | Elongation % | Hardness HRC |
UNS S32750 | 550 | 800 | 15 | 20 |
UNS S31803 | 450 | 620 | 25 | 20 |
UNS S31500 | 440 | 630 | 30 | 20 |
Heat Treatment Requirements
UNS
Designation | Temperature | Quench |
S31803 | 1870-2010 °F [1020-1100°C] | Rapid cooling in air or water |
S32205 | 1870-2010 °F [1020-1100°C] | Rapid cooling in air or water |
S31500 | 1800-1900 °F [980-1040°C] | Rapid cooling in air or water |
S32550 | 1900 °F [1040°C] min. | Rapid cooling in air or water |
S31200 | 1920-2010 °F [1050-1100°C] | Rapid cooling in water |
S31260 | 1870-2010 °F [1020-1100°C] | Rapid cooling in water |
S32001 | 1800-1950 °F [982-1066°C] | Rapid cooling in air or water |
S32304 | 1700-1920 °F [925-1050°C] | Rapid cooling in air or water |
S32750 | 1880-2060 °F [1025-1125°C] | Rapid cooling in air or water |
S32760 | 2010-2085 °F [1100-1140°C] | Rapid cooling in air or water |
S32950 | 1820-1880 °F [990-1025°C] | Rapid cooling in water |
S32520 | 1975-2050 °F [1080-1120°C] | Rapid cooling in air or water |
Duplex Stainless Steel Pipe Application
S31803 Tubes Ordering Information
Orders for product under this specification should in- clude the following, as required, to describe the desired material adequately: