Line-up of the Next Generation Duplex Stainless Steel Replacing the SUS304/316 Series

― Rollout of duplex stainless steel NSSC®2351 with excellent weldability used under severe corrosive environments ―

NIPPON STEEL Stainless Steel Corporation (Address: Chiyoda-ku, Tokyo, Representative Director & President: Hitoshi Ito) has developed as a commemorative product of the merger the unique duplex stainless steel “NSSC®2351” (23Cr-5Ni-1Mo-N) which is the upper grade for SUS316/316L (hereinafter the “SUS316 series”) and able to replace the SUS316 series. NSSC®2351 can be used under severe corrosive environments including brackish water, and its higher strength can reduce steel volume that may lead to cost down. It is a brand-new product which can offer a new value to customers together with improved weldability..

The lineup of the next generation duplex stainless steel, including NSSC®2351 and NSSC®2120 (former NSSC 2120® announced in 2012 and currently obtaining high reputation) can be replaceable with generic austenite stainless steel SUS304 and SUS316 with better weldability.

1. Features of NSSC®2351

(1) Higher corrosion resistance

Under the environment of brackish water with higher temperature due to recent the global warming, sometimes the SUS316 series is not able to show satisfactory corrosion resistance. Corrosion resistance of the newly developed NSSC®2351 (23Cr-5Ni-1Mo-N) is better than the SUS316 series. Even in a case where the SUS316 series don’t work well on corrosion resistance, the choice of a grade with minimum cost increase can improve the life cycle cost.

(2) Excellent weldability

In the conventional duplex stainless steel, it is necessary to control welding heat. This deteriorates the welding efficiency, and the problem is that the quality of corrosion resistance at the weld area is greatly fluctuated depending on the welding conditions. NSSC®2351 allows for high heat-input welding because of the micro-alloying technology1 and the design technology of chemical composition to inhibit the deterioration at the weld area, which has been developed from NSSC®2120. The quality of the corrosion resistance by high heat-input welding is almost equivalent to the SUS316 series.

(3) Higher strength

The strength (0.2% yield strength) is about two-fold greater than the SUS316 series. Therefore, the steel volume is able to be reduced (up to 50% maximum: this is variable according to applications) by thinning of the design thickness. This also leads to compact size and light-weight of the equipment or system.

(4) Cost performance and resource saving

NSSC®2351 is a duplex stainless steel with reduced additives of nickel or molybdenum which are rare metals. Compared to the SUS316 series, it is excellent in resource saving and price stability. In this way, we are able to offer a more competitive price2 than the SUS316 series.


The duplex stainless steel has a microstructure with an almost equivalent ratio of the austenite phase and the ferrite phase. Compared to the austenitic stainless steel represented by SUS304 and SUS316, it has higher strength and corrosion resistance. It also shows excellent resistance to stress corrosion cracks under chloride environments.

2. Potential applications

NSSC®2351 covers the applications not only for foods, chemical tanks, etc. which the SUS316 series are used, but also for high corrosion resistance in infrastructure equipment such as the water gates in waterfront areas. It has excellent capability with reasonable cost. Also, NSSC®2351 is the steel equivalent to SUS329J1 and conformable for the boiler and pressure vessel code. We manufacture NSSC®2351 for both of sheets and plates for various applications for customers.

We will contribute to society by providing a new value in a wide range of demands through the solution of the next generation duplex stainless steel.

  1. Microalloying technology is a technology to improve the characteristics of steel material by adding trace elements (and optimizing steel production technology accordingly).
  2. Since sales price may vary depending on the material price, exchange rate, etc., please contact us for inquiries.

Contact information:

Products Development Div. Tel: +81-3 6841 5290
Corporate Planning Div. Tel: +81-3 6841 4919