Abstract
Casting of austenitic stainless steels offers the possibility of directly producing large and/or
relatively complex structures, such as the first wall shield modules or the divertor cassette for
the ITER, which may lead to simpler component fabrication and major cost savings. Past
efforts to use cast steel for these large components were unsuccessful due to lower than
acceptable strength in the test components. To improve and validate cast stainless steel as a
substitute for wrought stainless steel for shield module applications, a series of test cast steels
based on the commercially available CF3M specification have been designed and fabricated.
These modifications utilize combinations of Mn and N, which result in significant increases
in strength, fracture toughness, and impact properties. These mechanical performance
improvements have been achieved without any loss of irradiation performance, corrosion
performance, or weldability.
