Effect of titanium modification on the fracture behavior of ultrahigh-strength low-alloy steel

The causes of instability of fracture toughness of ultrahigh-strength low-alloy medium-carbon steel 55KhN2MA-Sh are determined with the help of mechanical tests and scanning electron microscopy of fracture surfaces. It is shown that the fracture toughness changes due to a change in the concentration of titanium within the grade composition. When the concentration approaches the upper standardized limit, the ductility and the impact toughness of the specimens decrease due to excessive growth in the number of segregations of titanium carbosulfides.