ASTM A790/ ASME SA790 duplex steel pipe is a metal alloy pipes that is made out of steel with different alloying elements. The name comes from the dual nature of the material. The duplex material contains both the austenitic and ferrite structures in the metallurgy of the material. These properties bring the material the best of both ferritic and austenitic steel types. The pipes could be hot rolled or cold drawn. The hot rolled ones are stronger and the cold drawn ones are seamless and accurate in dimensions. The duplex seamless pipe is used in applications with high precision requirements. The ASTM A790 duplex welded pipes are an example of welded duplex pipe. There are different grades of duplex pipes with different mechanical properties. There are duplex, super duplex and lean categories in the duplex pipes varieties. The seamless duplex pipes are both strong and is highly corrosion resistant.
Duplex stainless steel are considered resistant to stress corrosion cracking, they are not as resistant to this form of attack as ferritic stainless steel. However, the corrosion resistance of the least resistant duplex stainless steel is greater than that for the most commonly used grades of stainless steel, i.e. 304 and 316. Duplex stainless steel are also magnetic, a property that can be used to easily differentiate them from common austenitic grades of stainless.
Duplex 2205 stainless steel (both ferritic and austenitic) is used extensively in applications that require good corrosion resistance and strength. The UNS S31803 grade stainless steel has undergone a number of modifications resulting in UNS S32205. This grade offers higher resistance to corrosion. At temperatures above 300°C, the brittle micro-constituents of this grade undergo precipitation, and at temperatures below -50°C the micro-constituents undergo ductile-to-brittle transition; hence this grade of stainless steel is not suitable for use at these ttemperaures.
Equivalent Grades Of ASTM A790 Seamless Tube
PIPE STANDARD | WERKSTOFF NR. |
Duplex 2205 Pipe | 1.4462 / 1.4462 |
Specifications
Schedule | ASTM A790 ASME SA790 |
|---|---|
Ranging in size from | 1/2"- 12 “NB IN |
Pipes Schedules | SCH20, SCH30, SCH40, STD, SCH80, SCH120 Manufacturer and supplier in India |
Available Forms | Round, Hydraulic Etc |
Lengths | Cut to size |
Pipes End Finish | Plain End, PBE, POE, BOE, BSE, BBE, BLE, BOE, TOE, BE, TBE, Beveled End, Treaded |
Marking |
|
Test Certificate |
|
Pipe O.D. | Wall Thickness Of Pipe (Inches) | |||||||
|---|---|---|---|---|---|---|---|---|
.028 | .035 | .049 | .065 | .083 | .095 | .109 | .120 | |
Working Pressure (Psig) | ||||||||
1/8 | 7900 | 10100 | ||||||
1/4 | 3700 | 4800 | 7000 | 9500 | ||||
5/16 | 3700 | 5400 | 7300 | |||||
3/8 | 3100 | 4400 | 6100 | |||||
1/2 | 2300 | 3200 | 4400 | |||||
3/4 | 2200 | 3000 | 4000 | 4600 | ||||
1 | 2200 | 2900 | 3400 | 3900 | 4300 | |||
Roughness of Duplex Steel Welded Pipe
Outside surface roughnes | Inside surface roughness |
RA 20 defect level max. 50 μm | RA 20 defect level max. 20 μm |
Pipe Density | Pipe Melting Point | Yield Strength (0.2%Offset) | 2205 Duplex SS Pipe Tensile Strength | Elongation |
7.8 g/cm3 | 1350 °C (2460 °F) | Psi - 80000 , MPa - 550 | Psi - 116000 , MPa - 800 | 15 % |
C | N | P | Si | Mn | Mo | Fe | Cr | S | Ni |
1.0 | 0.03 | 0.02 | 2.0 | 3.0 - 3.5 | 22.0 - 23.0 | 0.03 | 4.5 - 6.5 | 0.14 - 0.2 | Bal |
Physical Properties
Grade | Density | Elastic | Mean Co-eff of Thermal | Thermal | Specific | Electrical | |||
(kg/m3) | Modulus | Expansion | Conductivity | Heat | Resistivity | ||||
|
| 0-100°C | 0-315°C | 0-538°C | at 100°C | at 500°C | 0-100°C | (nΩ.m) | |
UNS S32205 / 2205 | 782 | 190 | 13.7 | 14.2 | - | 19 | - | 418 | 850 |
Application
Chemical Processing, Transport and Storage
Oil and Gas Exploration and Offshore Rigs
Mil and Gas Refining
Marine Environments
Pollution Control Equipment
Pulp & Paper Manufacturing
Chemical Process Plant
