Sunday, August 25, 2019

(Super) Duplex Stainless Steel Tube

(Super) Duplex Stainless Steel Tube
Duplex stainless steel has a α+γ dual-phase structure, so its performance characteristics are characterized by austenitic stainless steel and ferritic stainless steel, and it is a kind of stainless steel with the best strength and corrosion resistance. Generally, in the case where C is low, the Cr content is 18% to 28%, and the Ni content is 3% to 10%. Some steels also contain alloying elements such as Mo, Cu, Nb, Ti, and N.
Compared with ferrite, it has higher plasticity, toughness, no room temperature brittleness, resistance to intergranular corrosion and weldability, and also maintains 475°C brittleness and high thermal conductivity of ferritic stainless steel, with superplasticity, etc. Features. Compared with austenitic stainless steel, the yield strength is significantly improved, and the resistance to intergranular corrosion, stress corrosion, corrosion fatigue and abrasion is significantly improved.
(Super) duplex stainless steel pipe main grades: S31803/S32250, S32750, S32760, S31500, S31500, 32001, S32003, S32304
(Super) duplex stainless steel pipe main components:
Common standards for (super) duplex stainless steel pipes:
ASTM A789 (ASME SA789)
General purpose seamless and welded ferritic/austenitic stainless steel pipe
ASTM A790 (ASME SA790)
Seamless and welded ferritic/austenitic stainless steel pipe
ASTM A928 (ASME SA928)
Standard Specification for Filled Metal Electrofusion Welded Ferritic/Austenitic (Duplex) Stainless Steel Tubing
GB/T 21832-2008
Austenitic-ferritic duplex stainless steel welded steel pipe
GB/T 21833-2008
Austenitic-ferritic duplex stainless steel seamless steel pipe
(Super) Duplex Stainless Steel Tube Performance Features:
1. Excellent resistance to general corrosion and local corrosion resistance, especially stress corrosion resistance, pitting corrosion resistance, crevice corrosion resistance, corrosion resistance, abrasion resistance, etc.
2. Good weldability
3. Good comprehensive mechanical properties
4. Good resistance to intergranular corrosion
5. High cost performance and long service life

Super austenitic stainless steel

Super austenitic stainless steel
When the pitting resistance equivalent value of chromium-nickel austenitic stainless steel (PREN=[Cr]+3.3[Mo]+16[N]) ≥40%, it can be called super austenitic stainless steel. Super austenitic stainless steel is mainly used to solve the problems of pitting corrosion and crevice corrosion resistance of the original high molybdenum (>4%) chromium-nickel austenitic stainless steel under the severe corrosion conditions containing Cl- and poor thermal stability of the structure. And developed.

Super austenitic stainless steel Main grades: N08904 (904L), N08367 (6Mo), S31254 (6Mo), S30432, S31042

 
Super austenitic stainless steel Main criteria (partial):

ASTM A312 Seamless and Welded Austenitic Stainless Steel Tube

ASTM A269 Seamless and welded austenitic stainless steel tubes for general equipment

ASTM B673, ASTM B674, ASTM B677, ASTM B675, ASTM B676, ASTM B690

 
Super austenitic stainless steel Performance characteristics:

1. Excellent resistance to pitting and crevice corrosion in harsh corrosive environments

2. Excellent mechanical properties and high yield strength

3. Good processability