Effects of Zr

Y and Ba-Ca modifier on microstructure and properties of 00Cr25Ni7Mo4N stainless steel were investigated.The results show that castablity and mechanical properties of the stainless steel are greatly improved with the modifier addition as a result of refining grain size by inhibiting grain growth.Y modifier exhibits the most desirable modification effects

where fracture macro-shape is apparently improved

and grain size in fracture position is refined by 91% of un-treated samples.Meanwhile

isolated γ phase in the microstructure of the modified steel is obviously spheroidized and refined

and inclusions are decreased

leading to the increase of liquid steel fluidity and improvement of properties and elimination of the related defects.Mechanical properties of the modified steel are obviously improved as a result of refinement of microstructure

where tensile strength and yield strength are increased by 16.1% and 41.2%

respectively

with the desirable elongation of 19%.