Effect of inclusions on fracture behavior of cast and wrought 13% Cr-4% Ni martensitic stainless steels

Microstructures and inclusion characteristics of cast and wrought 13% Cr-4% Ni martensitic stainless steels were related to tensile, fracture toughness JIc, and Charpy V-notch absorbed energy. A lower volume fraction of inclusions, a larger number of inclusions smaller than 10 µm, and a more resistant inclusion type against rupture and against micro-void formation were the key parameters explaining why the wrought steel has better mechanical properties than the cast steel. It has been shown that TRIP effect occurs only in a small region of 6 mm length from the crack plane in JIc-test.