Duplex stainless steel has the advantages of both ferritic stainless steel and austenitic stainless steel.It combines the excellent toughness and weld ability of austenitic stainless steel with the high strength and chloride stress corrosion resistance of ferritic stainless steel.It is these excellent properties that make duplex stainless steel a weldable structure.Material has developed rapidly,and has become a kind of steel juxtaposed with martensitic, austenitic and ferritic stainless steels since the 1980s.Duplex stainless steel has the following characteristics:

ASTM A312 TP304 welded steel pipes

• Duplex stainless steel containing molybdenum has good resistance to chloride stress corrosion under low stress. Generally,18-8 austenitic stainless steel is prone to stress corrosion cracking in neutral chloride solution above 60 degrees.Heat exchangers and evaporators made of this kind of stainless steel tend to produce stress corrosion cracking in industrial medium of trace chloride and hydrogen sulfide, while duplex stainless steel has good resistance power.
• Duplex stainless steel containing molybdenum has good pitting resistance.The critical pitting potential of duplex stainless steel is similar to that of austenitic stainless steel with the same equivalent value of pitting resistance (PRE=Cr%+3.3Mo%+16N%). The pitting corrosion resistance of duplex stainless steel and austenitic stainless steel is similar to that of AISI 316L. The pitting and crevice corrosion resistance of high chromium duplex stainless steel containing 25% Cr,especially nitrogen, is better than that of AISI316L.
• It has good corrosion fatigue and wear corrosion resistance.Under certain conditions of corrosive media, it is suitable for making pumps,valves and other power equipment.
• The comprehensive mechanical properties are good.It has high strength and fatigue strength,and its yield strength is twice that of 18-8 austenitic stainless steel.The elongation of solid solution reached 25%,and the toughness value of AK (V groove) was above 100 J.
• Excellent Weldability, generally no preheating before welding,no heat treatment after welding,can be dissimilar with 18-8 austenitic stainless steel or carbon steel welding.

Haihao Group manufacture seamless steel pipes,welded steel pipes,butt welding pipe fittings,forged pipe fittings,flanges with materials carbon steel,stainless steel,alloy steel.The stainless steel are ASTM A304 WP304/TP304/F304,WP304L/TP304L/F304L,WP316/TP316/F316,WP316L/TP316L/F316L,WP321/TP321/F321,etc.If you want to know more about our pipeline products,please email us:sales@haihaogroup.com