The 2205 duplex stainless steel is formed by reducing the nickel content to about 5% and adjusting the addition amount of manganese and nitrogen to form ferrite of about 40-50%. The chemical composition of 2205 duplex stainless steel is balanced, so that the austenitic phase and the ferrite phase have large and appropriate corrosion resistance. "Biphasic" refers to a microscopic arrangement having two phases of austenite/ferrite.

The addition of nitrogen content of 2205 duplex stainless steel and its fine grain microstructure make it have higher strength than common austenitic stainless steels such as 304L and 316L. Under solid solution annealing conditions, the 2205 duplex stainless steel has a yield strength that is approximately twice that of 316L stainless steel. Due to this higher strength, the allowable stress of 2205 duplex stainless steel can be much higher, depending on the design specifications chosen for process equipment manufacturing. In many applications, it is possible to reduce the wall thickness, then reduce the weight and save costs.

The higher chromium, molybdenum and nitrogen content of 2205 duplex stainless steel achieved significantly better pitting corrosion and crevice corrosion resistance than 316L stainless steel. The relative pitting resistance of stainless steel can be confirmed by measuring the temperature (critical pitting temperature) required for pitting corrosion in the 6% ferric chloride specification test solution. The critical pitting temperature of 2205 duplex stainless steel is between 316L stainless steel and 6% molybdenum super austenitic stainless steel.

The manufacturing of 2205 duplex stainless steel is similar to 316L in many respects, but there are still some important differences. For cold forming operations, it is necessary to take into account the higher strength and higher work hardening characteristics of duplex stainless steels. Forming equipment may require higher load capacity, and in forming operations, 2205 stainless steel will exhibit a higher rebound than the standard austenitic stainless steel trademark. The higher strength of 2205 duplex stainless steel makes it more difficult than 316L. Perform cutting work.

The welding of 2205 duplex stainless steel can be welded by 316L stainless steel. However, it is necessary to strictly control the heat input amount and the interlayer temperature, and the interlayer temperature should not exceed 150° in order to adhere to the desired austenite-ferrite phase fraction and prevent the separation of harmful intermetallic phases. The use of a small amount of nitrogen in the gas helps to prevent these problems. In the evaluation of duplex stainless steel welding process, the common method is to use a ferrite analyzer or metallographic examination to evaluate the austenite-ferrite ratio. In the typical case, the ASTM A923 experimental method is used to verify the presence of a hazardous intermetallic phase.

Duplex stainless steel such as 2205 has poor penetration and fluidity than 316L stainless steel, so the welding speed is slower. Since the 2205 duplex stainless steel has poor permeability, it is required to correct the shape of the joint. 2205 duplex stainless steel requires a wider groove view, larger root clearance, and smaller blunt edges than 316L stainless steel for a thoroughly penetrated weld.