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|Material Type:||UNS S32750||Tube Production:||COLD DRAWN|
|Outside Diameter:||1/4'' - 4''||Wall Thickness:||0.035'' - 0.120''|
|Finish Type:||SOLUTION ANNEALED||Standards:||ASTM A789/789M|
UNS S32750 Super Duplex Stainless Steel Pipe Seamless Round Tube ASTM A789 Descaled
Characteristic of Super Duplex Seamless Stainless Steel Tubing:
1. Good to very good resistance to uniform corrosion
2. Good to very good resistance to pitting and crevice corrosion
3. High resistance to stress corrosion cracking and corrosion fatigue
4. High mechanical strength
5. Good abrasion and erosion resistance
6. Good fatigue resistance
7. High energy absorption
8. Low thermal expansion
9. Good weldability
Typical values (Weight %)
|Ultimate Tensile Strength, ksi||116 min.|
|0.2% Offset Yield Strength 0.2%, ksi||80 min.|
|0.1% Offset Yield Strength 0.2%, ksi||91 min.|
|Elongation in 2 inches, %||15 min.|
|Hardness Rockwell C||32 max.|
|Impact Energy, ft.-lbs.||74 min.|
Super Duplex Seamless Stainless Steel Tubing are extremely corrosion resistant. They have high resistance to intergranular corrosion. Even in chloride and sulphide environments, duplex stainless steels exhibit very high resistance to stress corrosion cracking.
The super duplex grades are even more resistant to corrosion.
The high chromium content of duplex and super duplex seamless stainless steel tubing that protects against corrosion, causes embrittlement at temperatures over about 300°C.
At low temperatures duplex stainless steels have better ductility than the ferritic and martensitic grades. Duplex grades can readily be used down to at least -50°C.
Although machinable, the high strengths of duplex stainless steels makes machining difficult. As an example, machining of 2205 is around 20% slower than for 304.
Machining can be enhanced by using the following rules:
Cutting edges must be kept sharp. Dull edges cause excess work hardening.
Cuts should be light but deep enough to prevent work hardening by riding on the surface of the material.
Chip breakers should be employed to assist in ensuring swarf remains clear of the work
Low thermal conductivity of austenitic alloys results in heat concentrating at the cutting edges. This means coolants and lubricants are necessary and must be used in large quantities.
Duplex stainless steels cannot be hardened by heat treatment. They can however be work hardened.
Solution treatment or annealing can be done by rapid cooling after heating to around 1100°C.
Duplex stainless steels have good weldability. All standard welding processes can be used. They are not quite as easily welded as the austenitic grades but low thermal expansion in duplex grades reduces distortion and residual stresses after welding. The recommended filler material for 2205 stainless steel is 2209.
Applications of :
Pulp and paper industry
Cargo tanks and pipe systems in chemical tankers
Firewalls and blast walls on offshore platforms
Components for structural design
Rotors, impellers and shafts
Reinforcing bars for concrete structures