Super-Austenitic Stainless Steel has a corrosion resistance higher than the duplex grades because its alloy content is higher. It has a high PREN (pitting resistance equivalency number) for superior resistance to chloride pitting and stress corrosion cracking.
Super austenitic stainless steel is defined as Cr-Ni stainless steel with a Pitting Resistance Equivalent Number （PREN=[Cr]+3.3[Mo]+16[N]）≥40%. It has better resistance to chloride pitting and crevice corrosion than Cr-Ni austenitic stainless steel with Mo ＞4% in highly corrosive media containing Cl-
N08904（904L）, N08367（6Mo）, S31254（6Mo）, S30432, S31042
ASTM A312 Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes
ASTM A269 Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service
ASTM B673,ASTM B674,ASTM B677,ASTM B675,ASTM B676, ASTM B690
1.Superior resistance to chloride pitting, crevice corrosion in aggressive environment
2.Good mechanical properties with high yield strength
(Super) Duplex Stainless Steel
Duplex stainless steel (DSS) is featured with structure of two phases (α and γ) and has characteristics of both ferritic and austenitic stainless steel. It has good corrosion resistance and high strength. It is alloyed with 18%-28% Cr and 3%-10% Ni in the condition of low C. Some steels also contain the alloy elements such as Mo, Cu, Nb, Ti and N, etc.
Comparing with ferritic stainless, duplex stainless steel has higher plasticity, ductility and better intergranular corrosion resistance and weldability. It keeps same 475℃ brittleness with ferritic stainless and high thermal conductivity. Duplex has improved yield strength, resistance to intergranular corrosion, stress corrosion, corrosion fatigue and abrasion & corrosion compared with austenitic stainless steel.
Grades：S31803/S32205, S32750, S32760, S31500, 32001, S32003, S32304
ASTM A789 Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service
ASTM A790 (ASME SA790) Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe
ASTM A928 (ASME SA928) Standard Specification for Ferritic/Austenitic (Duplex) Stainless Steel Pipe Electric Fusion Welded with Addition of Filler Metal
GB/T 21832-2008 Austenitic--Ferritic(duplex) grade stainless steel welded tubes and pipes
GB/T 21833-2008 Austenitic-Ferritic (duplex) grade stainlee steel seamless tubes and pipes
1.Superior resistance to general and local corrosion, especially to stress corrosion, pitting corrosion, crevice corrosion, corrosion fatigue and abrasion & corrosion.
3.Good mechanical properties
4.Excellent intergranular corrosion resistance
5.High cost-effectiveness, long life time
Corrosion & high temperature resistant alloys include nickel alloy and ferrous alloy. They have high strength and corrosion resistance in temperature range of 650 ~ 1000 ℃ with good comprehensive performance.
N04400, N06600, N06601, N06617, N06625, N06690, N08800, N08810, N08811, N08825, N08020, N08367
N08028, N06985, N06022, N10276
ASME SB163 Standard Specification for Seamless Nickel and Nickel Alloy Condenser and Heat-Exchanger Tubes
ASME SB165 Standard Specification for Nickel-Copper Alloy (UNS N04400)* Seamless Pipe and Tube
ASME SB167 Standard Specification for Nickel-Chromium-Iron Alloys, Nickel-Chromium-Cobalt-Molybdenum Alloy (UNS N06617),and Nickel-Iron-Chromium-Tungsten Alloy (UNS N06674) Seamless Pipe and Tube
ASME SB407 Standard Specification for Nickel-Iron-Chromium Alloy Seamless Pipe and Tube
ASME SB423 Standard Specification for Nickel-Iron-Chromium-Molybdenum-Copper Alloy (UNS N08825, N08221, and N06845) Seamless Pipe and Tube
ASME SB444 Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloys (UNS N06625 and UNS N06852) and Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219) Pipe and Tube
ASME SB622 Standard Specification for Seamless Nickel and Nickel-Cobalt Alloy Pipe and Tube
ASME SB668 UNS N08028 Seamless Pipe and Tube
ASME SB690 Standard Specification for Iron-Nickel-Chromium-Molybdenum Alloys (UNS N08366 and UNS N08367) Seamless Pipe and Tube
ASME SB729 Standard Specification for seamless UNS N08020, UNS N08026, and UNS N08024 nickel alloy pipe and Tube
Features (depending on grades)：
1.Excellent resistance to stress, pitting corrosion, crevice corrosion and localized corrosion at room temperature
2.Superior mechanical properties at room temperature
3.Superior corrosion resistance at elevated temperature
4.Good mechanical properties at elevated temperature