Five types of cast duplex stainless steels (A890 1B and a modification thereof, 4A, 5A, 6A) were characterized as to their corrosion, toughness and weldability performance and assessed microstructurally. These materials span the current range of alloys in commercial use. The solution-treated cast materials were compared to their wrought ‘equivalents’ in accord with ASTM A923. The cast duplex stainless steel materials were found to exhibit performance characteristics equivalent and, in some cases, superior to their wrought counterparts. The full range of testing strongly indicates that the cast materials can be evaluated in accordance with the A923 specification, which currently covers only limited wrought products.

The effect of welding on pitting performance was defined for both the cast and wrought materials. This evaluation revealed that a very strong potential for degradation of pitting resistance exists, upon autogenous welding, for both the wrought and cast materials. This potential should be addressed when selecting the type of duplex stainless steel for a particular service.