Duplex Stainless Steel
Ultra-strong and corrosion-resistant stainless steel, comprising a duplex structure of austenite and ferrite and fabricated by adding an appropriate amount of nickel to high chromium. In terms of corrosion resistance and price, the scope varies widely from general-use to super stainless steel classes, which can be manufactured by adding molybdenum or nitrogen.
Technical Data
Chemical composition, etc. (examples)
| Class | Standard/UNS | Main chemical components |
|---|---|---|
| Lean-duplex stainless steel | SUS821L1 | 21Cr - 2Ni - 3Mn - 1Cu - 0.17N |
| SUS323L | 23Cr - 4Ni - 0.15N | |
| General-use duplex stainless steel | SUS329J3L | 22Cr - 5Ni - 3Mo - 0.15N |
| S31803 | 22Cr - 5Ni - 3Mo - 0.15N | |
| S32205 | 22.5Cr - 5.5Ni - 3.3Mo - 0.17N | |
| SUS329J4L | 25Cr - 6Ni - 3Mo - 0.15N | |
| Super-duplex stainless steel | SUS327L1/S32750 | 25Cr - 7Ni - 4Mo - 0.28N |
Mechanical Characteristics, etc. (examples)
| Class | Standard/UNS | 0.2% yield strength | Tensile strength | Elongation | Hardness | |
|---|---|---|---|---|---|---|
| （N／mm²） | （N／mm²） | （％） | HB | HRC | ||
| Lean-duplex stainless steel | SUS821L1 | ≧400 | ≧600 | ≧25 | ≦290 | ≦32 |
| SUS323L | ≧400 | ≧600 | ≧25 | ≦290 | ≦32 | |
| General-use duplex stainless steel | SUS329J3L | ≧450 | ≧620 | ≧18 | ≦302 | ≦32 |
| S31803 | ≧450 | ≧620 | ≧25 | ≦293 | ≦31 | |
| S32205 | ≧450 | ≧655 | ≧25 | ≦293 | ≦31 | |
| SUS329J4L | ≧450 | ≧620 | ≧18 | ≦302 | ≦32 | |
| Super-duplex stainless steel | SUS327L1/S32750 | ≧550 | ≧795 | ≧15 | ≦310 | ≦32 |
Features of Duplex Stainless Steel
- High strengthApproximately twice as strong as SUS304 and SUS316 (comparison in 0.2% yield strength), which allows for a slimmer and lightweight design.
- Pitting corrosion resistanceShows superior stress corrosion cracking resistance compared to general-use austenite stainless steel, as well as good pitting corrosion resistance.
- Price stabilityContains less nickel and molybdenum than in general-use austenite stainless steel, reducing the risk of raw material price fluctuations.
Main Uses
Petrochemical plants, chemical tankers, environment plants (exhaust gas desulfurization equipment, etc.), seawater desalination plants, etc.
Sizes in Stock
Hot-rolling steel plate
Steel type： SUS821L1, SUS323L, S32750（SUS327L1)
| Finish | Thickness (mm) |
Width (mm) |
Length (mm) |
|---|---|---|---|
| NO.1 | 6 | 2000 | 6100 |
| NO.1 | 8 | 2438 | 8000 |
| NO.1 | 9 | 2000 | 6100 |
| NO.1 | 10 | 2438 | 6100 |
| NO.1 | 12 | 2438 | 6100 |
| NO.1 | 16 | 2438 | 6100 |
| NO.1 | 20 | 2438 | 6100 |
| NO.1 | 25 | 2438 | 6100 |
| NO.1 | 30 | 2438 | 6100 |
* Thickness of 14t is available for SUS323L.
Cold-rolling steel plate
Steel type： SUS821L1
| Finish | Thickness (mm) |
Width (mm) |
Length (mm) |
|---|---|---|---|
| 2B | 0.8 | 1219 | 2438 |
| 2B | 1.0 | 1219 | 2438 |
| 2B | 1.2 | 1219 | 2438 |
| 2B | 1.5 | 1219 | 2438 |
| 2B | 2 | 1219 | 2438 |
| 2B | 3 | 1219 | 6096 |
| 2B | 3 | 1524 | 3048 |
| 2B | 3 | 1524 | 6096 |
| 2B | 4 | 1524 | 3048 |
Steel bar
Steel type： S31803／S32205(DUAL spec.), S32750
| Dia． (mm) |
Length (mm) |
Finish |
|---|---|---|
| 80 | 4～6ｍ | PM |
| 100 | 4～6ｍ | PM |
| 110 | 4～6ｍ | PM |
| 120 | 4～6ｍ | PM |
| 130 | 4～6ｍ | PM |
| 140 | 4～6ｍ | PM |
| 150 | 4～6ｍ | PM |
| 160 | 4～6ｍ | PM |
| 170 | 4～6ｍ | TM |
| 180 | 4～6ｍ | TM |
| 190 | 4～6ｍ | TM |
| 200 | 4～6ｍ | TM |
Duplex stainless steel, sanitary BA
Pipe/elbow/ferule
Steel type: S32750
| Nominal size |
|---|
| 1.5S |
| 2S |
| 3S |
| 4S |
