SAIL develops highly corrosion-resistant ‘Super Duplex Stainless Steel’

New Delhi: In a major technological breakthrough, state-run Maharatna Steel PSU Steel Authority of India Limited (SAIL) has developed highly corrosion-resistant 'Super Duplex Stainless Steel'. In a statement, the steel giant on Wednesday said that its Salem Steel Plant (SSP) has developed the capability to produce super duplex stainless steel in SS 32205 grade. Currently, SAIL is among the few Indian steelmakers who have developed this grade of steel. This grade of stainless steel is mainly imported so far.

Commenting on this achievement, SAIL’s Chairman Anil Kumar Chaudhary said, “Inspired by the government's clarion call for 'Atmanirbhar Bharat’ and ‘Vocal for Local’, SAIL is relentlessly making efforts in developing steels, which can play important roles in these missions. The development of this high-end grade is an effort in that direction. We are confident of actively partaking in “Making In India” and “Making For India” and supplying steel which is required in the expansion of infrastructure in the country.”

Characteristics of Super Duplex Stainless Steel 

The Super Duplex Stainless Steel has superior corrosion resistance with higher strength and formability. Due to these characteristics, it can be effectively used in various applications in corrosion-prone areas, mainly in chemical processing equipment (transport and storage, pressure vessels, tanks, piping and heat exhaust), oil & gas exploration (process equipment, pipes, tubing, marine & other high chloride environments), pulp & paper industries (digesters and bleaching equipment), food processing equipment and biofuel plants. All these applications require high corrosion resistance steel with strength, which can be met by Super Duplex Stainless Steel (SS 32205 grade) having 3% molybdenum.  Earlier, SAIL – SSP developed Duplex Stainless Steel (SS 32202 grade) having 0.4% molybdenum content and has already serviced the orders for it. With the new capability to produce Super Duplex Stainless Steel (SS 32205 grade), SAIL has enriched its product basket further and will be able to cater to high-end steel requirement in the country. 

The superior qualities of corrosion resistance, strength and formability in this new grade come through the presence of chromium, molybdenum and nitrogen in the steel. This stainless steel also has higher yield strength, almost twice that of standard austenitic steel providing flexibility to use the steel in thinner gauges for the same strength.

Salem Steel Plant 

SAIL’s Salem Steel Plant is a special plant of the Maharatna Company which specialises in the production of quality stainless steel. This new grade of steel developed by Salem Steel Plant has a metallurgical structure consisting of two phases ie austenitic and ferritic, roughly in equal proportions, and are designed to provide better chloride stress corrosion and chloride pitting corrosion. 

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