NGF project within FIMECC DEMAPP Program has created deep fundamental knowledge in high-chromium ferritic stainless steels to all partners in cooperation. Based on this, novel corrosion resistant and deep drawable nickel-free steels have been developed.
Nearly 50 pcs laboratory scale melts have been made since 2009 at the Outokumpu Tornio Research Centre’s pilot plant (TRC). Metallurgical studies have been conducted at TRC, University of Oulu and Aalto University. In addition, close co-operation with other DEMAPP projects has been carried out (FABRICS/Exhaust applications, formability; X-WELD/welding). According to the findings, high chromium (21% Cr) ferritic stainless steel can be produced in full production scale having excellent product properties, especially improved corrosion resistance and formability.
High and fluctuating price of Nickel has been the pain of steel industry both manufacturers and end users. There is a global trend and need to increase the use of ferritic stainless steels, as they are affordable and cost-stable. Furthermore, future ferritic grades aimed for more demanding applications require enhanced corrosion performance and thus higher chromium contents.
Outokumpu can now expand into new area of ferritic steels, where it has not been before. The 4622 is the 1st high-chromium ferritic stainless steel in Outokumpu’s product portfolio. Full scale production trials and pilot material deliveries globally were started in 2012. This new 21%Cr grade fulfills ASTM UNS S44330 specification and was registered as EN number 1.4622 in 2013. Further EN standardization work is ongoing.
The new ferritic grade is a competitive alternative to traditional austenitic stainless steels and can be used in a broad range of applications such as home appliances, exhaust systems, process equipment, elevators and cladding panels – enabling new customers and business opportunities for Outokumpu. For the end user the 4622 is cost-stable and competitive alternative to austenitic 304/304L grades with similar corrosion resistance and enhanced deep-drawability – providing cost-efficiency, wide usability and high performance.
Positive feedback has been received from Outokumpu 4622 material performance globally. The work done in DEMAPP NGF together with Outokumpu’s own parallel development work has shortened the time to market and forms a basis for wider product portfolio development in this area.
Juha Kela, Outokumpu
Outokumpu, University of Oulu, Aalto University