- DUPLEX SS 31254
DUPLEX SS 31254
Duplex stainless steel 31254 is a super austenitic alloy with moderate mechanical strength, excellent ductility and corrosion resistance in various industrial environments.
The grade has full austenite microstructure, which provides higher overall strength–localized as well uniform corrosion resistance strength is better than standard austenitic steels. The grade is normally known as 6 Mo due to its 6% molybdenum content, which is comparatively higher than fellow grades. This provides higher resistance to pitting in severe conditions and is also positively used as an alternative to the 300 series.
The grade can provide double the strength of 3300 series under normal conditions. Normally, it has PREN (pitting resistance number) of about 43-44, which is fine enough to be used in environments having high pitting. But with it, it also provides fine crevice corrosion resistance.
The grade is normally delivered in an annealed condition that yields stress of about 300MPa. The yield stress provided by the grade is very low as compared to duplex steels and even lower when compared to super duplex stainless steels. The grade is not used at very high temperatures but it can be used in variable industrial conditions. Ductile to brittle transition in lower temperatures is zero to none whilst the notch ductility provided by the grade is exceptional, even at sub-zero temperatures. Due to its low carbon content, inter-granular corrosion is highly avoided. Carbide precipitation at the grain boundary of the heat affected zone during processes like welding is restricted. This grade can be machined conveniently and has its application in various forms and shapes.
It has a low magnetic permeability in the annealed condition, which might change after welding. It also has high impact strength at room temperature and conveniently retains its strength at sub-zero temperatures. It can be suitably worked under proper conditions. 31254 is also known to be cost-effective and possibly used as an alternative for high-cost titanium and nickel alloys providing similar characteristics. The grade can be appropriately hot worked as well as cold worked, forging and hot working operations are usually performed at a temperature of 980-1150°C. During these processes, the temperatures should be balanced properly, since higher temperatures would result in the reduction of toughness and ductility of the material. The grade can be hardened by proper cold reduction process.
CHEMICAL PROPERTIES
Grade | Ni | C | CR | Mn | Si | P | Fe | S | Mo | N | |
Duplex SS 31254 | Min | 17.5 | – | 19.5 | – | – | – | Bal | – | 6.0 | 0.18 |
Max | 18.5 | 0.02 | 20.5 | 1.00 | 0.08 | 0.03 | – | 0.01 | 6.5 | 0.22 |
Physical Properties:
Density kg/cm3) | 8 g/cm3 0.289 lb/in3 |
Melting Point | – |
Specific Heat 0-100°C ( J/kg.K) | 500 J.kg-1.°K-1 |
Thermal Conductivity at 20°C Btu/h ft ºF | 14 W/mK 97.2 BTU in/hr.ft².°F |
Elastic Modulus (GPa) | 195 Gpa 28300 Ksi |
Electrical resistivity [μΩ . cm] | 8.5 μohm/cm |
Poissons Ratio | 0.30 |
Shear Modulus | 75 Gpa 10900 Ksi |
General
Standard | 31254 |
UNS | S31254 |
WERKSTOFF NR. | 1.4547 |
EN | X1CrNiMoN20-18-7 |
US | ASTM A479/A473, /A240 S31254 F44 |
AFNOR | |
JIS |
Application areas:
Paper and pulp, Flue gas desulphurisation units in power plants, Desalination plant equipment, Pipework, flanges & manifolds, Seawater handling systems, Oil & Gas industry components, Pumps, Chemical processing, Valves, Control and instrumentation tubes, Process equipment in chemical industry, Components used in petroleum production, Tall oil distillation columns, Saltwater handling, Food processing equipment.