Development process and application industry of duplex stainless steel

The corrosion resistance of duplex
stainless steel and corrosion fatigue performance is outstanding, widely used
in equipment made of refining and chemical industry, salt industry and other
industries in the atmospheric vacuum distillation unit and catalytic cracking
and hydrocracking, continuous sulfate cooking or intermittent cooking device,
compressor cooler operation environment is very bad.

In spite of the late appearance of this
material, the development of the duplex stainless steel is very rapid. Because
of its both austenitic stainless steel and ferritic stainless steel advantages
in, and also make up the shortcomings of their respective, so the international
attaches great importance to the development and production of duplex stainless
steel, especially in the last century after 70s, with the advent of refining
equipment, began production of duplex stainless steel equipment based on ultra
low carbon n, the more broad road is prompted to enter the rapid development of
dual phase stainless steel. Now duplex stainless steel has been combined with
austenitic stainless steel, ferritic stainless steel and martensitic stainless
steel as an independent large class of steel. In Europe, America and other
countries, the development is very fast.

But our country began developing duplex
stainless steel in the middle of 70s of last century, and because of the
difficulty of production of duplex stainless steel, it developed slowly in
China at that time. Later, with the mass production of stainless steel used VOD
furnace, AOD furnace and large vacuum induction furnace, the domestic duplex
stainless steel has also developed rapidly.

Below is the application field of the lower
double phase stainless steel in China.

In the oil refining industry, used to make
the CDU duplex stainless steel, including the lining, tower components, often
air cooler, cut the top of wet air cooler and cut the top after the cold water
cooling tube; there is a catalytic cracking unit, including catalytic
absorption desorption tower tray, pipe lining, etc., gasoline reheat; there is
a hydrocracking unit, including air cooler, desulfurization reactor, water
cooler heat exchange tube.

In the petrochemical industry, double phase
stainless steel will be used to made of polyvinyl chloride (PVC) and stripper
heat exchanger; coil type oxygen chloride reactor, vinyl chloride vinyl
chloride in the reboiler; methanol synthesis reactor, material / effluent heat
exchanger, top condenser pressure flash tank; oxo alcohol pipe type loop
reactor; acetic acid and other organic acids (formaldehyde and formic acid)
production equipment and pipeline.

In land and offshore oil and gas industry,
duplex stainless steel is used for conveying pipes and collecting pipes,
offshore oil platform heat exchangers, water treatment and water supply
systems, fire fighting systems, sprinkler systems and water stabilizing
systems.

In the field of pulp and paper industry,
the continuous sulfuric acid cooking or batch cooking device is used, or
chlorine dioxide bleaching cartridge is mainly made of duplex stainless steel
with excellent mechanical properties, wear resistance, corrosion fatigue and
stress corrosion resistance.

The dual phase stainless steel is also used
in the chemical fertilizer industry, in which the urea industry, the compressor
cooler pipeline. Ammonium methylamine pump body. Stripper gas pipe, condensing
high-pressure condenser tube, high-pressure decomposition tower pipe and pipeline
decomposition. In the phosphoric fertilizer industry, it is used to reflect the
tank, slurry pump and slurry pipeline.

The last use is high strength structural
parts, mainly on the oil platform, such as the tensioning system of the
derrick, the submarine pipeline, and the steam turbine blades, barges and so
on.

Source: China Duplex Stainless Steel Pipe
Fittings Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)