Introdution of Stainless Steel Pipe
We all know what is steel, it could be divided into carbon steel and stainless steel and so on.
Then pay attention to "Stainless steel". It can also be divided into Austenitic stainless steel, Martensitic stainless steel, Ferritic stainless steel, and so on.
TP304 stainless steel is the most universal steel material in the world, we can find the products around ourselves. It is typical one of Austenitic stainless steel for ordinary environment.
But when contacting directly to sea water, it would be complex environment that sea water will corrode pipes more quickly. So it need special stainless steel.
The duplex stainless steel pipe is the combination of Austenitic stainless steel and Ferritic stainless steel. UNS S32205 duplex stainless steel is typical one of it.
The performance of UNS S32205 also has both the advantages of Austenitic and Ferritic stainless steel. It has excellent mechanical properties, corrosion resistance, good weldability and good resistance to chloride stress corrosion cracking. So it is widely applied in petroleum and natural gas industry, marine engineering, chemical industry and other industries.
Also duplex have many other kinds of steel grade, performence of them are similar to UNS S32205. But some of them can be more perfact, such as UNS S32750, called super duplex stainless steel.
UNS S32750 super duplex stainless steel has strong strength and corrosion resistance, which is mainly used in chemical processing, petrochemical and subsea equipment. It has strong chloride corrosion resistance, high thermal conductivity and low coefficient of thermal expansion. It has high corrosion resistance of chromium and molybdenum.
As I concluded, duplex is really the best choice of pipe for most marine project, and other I mentioned above.