Duplex/ Super duplex butt weld fittings (ASTM A815)
The ASTM A815 specification covers duplex and super duplex butt weld fittings to match ASTM A790 and ASTM A928 pipes. These special grades of stainless steel are used for various chemical processes, piping, oilfield piping and heat exchangers, flue gas desulfurization processes.
Duplex stainless steel pipes
Duplex stainless steel has the following advantages over Series 300 standard SS:
1.Good general corrosion resistance and high strength
2.Higher resistance to chloride stress corrosion cracking
3.Resistance to chloride pitting and crevice corrosion
4.Good sulfide stress corrosion resistance
- Easy to weld and conform
UNS S31803, UNS S32205 Chemical Composition (Duplex)
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | Fe |
| S31803 | 0.030 max | 2.00 max | 1.00 max | 0.030 max | 0.020 max | 22.0 – 23.0 | 3.0 – 3.5 | 4.50 – 6.50 | 0.14 – 0.20 | 63.72 min |
| S32205 | 0.030 max | 2.00 max | 1.00 max | 0.030 max | 0.020 max | 21.0 – 23.0 | 2.50 – 3.50 | 4.50 – 6.50 | 0.8 – 0.20 | 63.54 min |
UNS S31803, UNS S32205 Mechanical Properties (Duplex)
| Grades | Density (g/cm 3) | Density (lb/in 3) | Melting Point (°C) | Melting Point (°F) |
| S31803 / S32205 | 7.805 | 0.285 | 1420 – 1465 | 2588 – 2669 |
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