By Callum - Duplex stainless steel is a kind of stainless steel composed of ferrite and austenite
- Duplex stainless steel applications in various industries is introduced
Because of the high strength of duplex stainless steel, it can save material, such as reducing the wall thickness of the pipe.
Take SAF 2205 and SAF 2507 as examples.
SAF 2205 is suitable for chlorine-containing environment, and this material is suitable for oil refining or other process media.
SAF 2205 is especially suitable for heat exchanger with brackish water as a cooling medium. This material is also suitable for sulfuric acid solution and their mixture, e.g
- Oil pipe in oil and natural gas industry
- Crude oil desalting
- Sulfur-containing gas purification
- Wastewater treatment equipment in refinery
- Cooling system using brackish water or chlorine solution
Duplex Stainless Steel Applications
Duplex stainless steel applications are as follows
| NO | Equipment name | Medium condition | Materials and problems | Duplex stainless steel application |
| 1 | Oil field and oil well mouth pipeline | water/oil：91/10，H2S：2%，NaCL：9%，CO2：2%~3%，PH：4.5~6，115℃~140℃，7MPa | When the carbon steel lining is used for 3-9 months, SCC will be produced in 304 in a short time | Started in 1980 |
| 2 | Oil field air cooler | water/oil：91/10，H2S：2%，NaCI：9%，CO2：2-3%，PH：4.5~6，80℃~110℃，7MPa | ||
| 3 | Refinery distillate | water，28℃~45℃ | The pitting corrosion and SCC of carbon steel in service for 1 year and 321 for half | Started in 1985 |
| 4 | Refinery air cooling tower | 0.1 kPa ~1kPa | Carbon steel and 13% ~ 17% Cr ferritic stainless steel are easy to be damaged | Started in 1983 |
| 5 | Polyethylene product cooler | Tube side: polyethylene gas mixture，100℃，2MPa Shell side: including100×10-6C freshwater，Material temperature <100℃ | 304L tubesheet damaged due to SCC | Good condition after changing SAF2205 steel |
| 6 | Air cooler for offshore gas field | Tube side：CO2：25%，Wet natural gas with CI，90℃，13MPa | Started in 1980 | |
| 7 | Seawater heat exchanger for soda production | Tube side: seawater, inlet temperature12℃~31℃，outlet temperature40℃~60℃ Shell side：NH357%，CO233%，H2O10%，Oxygen free H2S | The welding seam of Ti welded pipe is damaged for 2-3 years, and Ti ground seam pipe is invalid after 7-8 years of service | Started in 1983 |
Duplex stainless steel also has many important applications in the processing industry.