Alloys in this group address the need for castings where the corrosion resistance of austenitic stainless steels is needed but higher strength levels are required. Balancing of Cr, Ni and Mo levels are done to achieve varying amounts of ferrite and austenite. Cu is added to the base matrix to provide a precipitation constituent for strengthening purposes. The proper balancing of all the elements to achieve proper properties is critical.
Melting characteristics are generally good. Precautions must be taken to avoid C pickup from any source and nitrogen pickup from the atmosphere while melting. Heat treatment is necessary to achieve full property development. The castings are generally supplied in a solution treated condition and then subsequently hardened by a precipitation treatment (aging) after machining by the customer.
Applications for alloys in this group include pump parts where corrosion and abrasion resistance is important.