Duplex Alloy
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by: Abbey smith
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Word Count: 342
Date: Thu, 5 Jan 2012 Time: 10:00 PM
A very popular form of alloy is duplex, which is made up of equal amounts of ferrite and austenite. It is renowned for its strength and resistance to corrosion. They are also twice as strong as singular austenitic steel. Usually the mix is 50/50, but you also find mixes of up to 60/40.
The Properties of Duplex Steel
It can be used at temperatures as low as -50 degrees without becoming brittle. 300 degrees is the maximum temperature it can withstand. This alloy is resistance to stress corrosion cracking. It performs better than type 316 stainless steel in chloride solutions.
It is resistant not only to cracking, but to pitting, crevices and stress corrosion cracking. Its oxide layer makes it almost self healing. Most Duplex stainless steel is tougher than ferritic stainless steel in some cases up to twice as strong. In certain applications, like buildings, where appearance is important duplex steel is used for its good looks as much as anything.
It cannot be hardened by super heating. However, it can be easily worked in a hardened state. One of the drawbacks of this alloy is that it is quite difficult to machine it. However, it is very easy to weld its relatively low thermal expansion reduces distortion and residual stresses after welding. It is also worth mentioning that this alloy is magnetic.
There are several kinds of Duplex stainless steel. The most popular is 2205, which is 22% Chromium, 5% Nickel. 2507 is 25% Chromium and 7% Nickel and is also known as SuperDuplex due to its far higher corrosion resistance. It is widely used in the petro-chemical and gas industries for their pipelines.
Applications for Duplex Steel
This marvellous alloy is used by a wide range of industries including the aerospace, chemical, gas, petro-chemical, transport and marine industries. In transport it is used for tanks to move chemicals and gases. The marine industry uses it for engine components. It is also used in pollution control equipment.
Duplex steel is sold in numerous forms including sheets, bars, pipes and wire. It is also available in a wide range of fittings and flanges.
About the Author
SPM sells a big range of duplexsteels to many industries across the globe.
