The relationship between fracture toughness and impact toughness of high-speed wheel steel at room temperature

The fracture toughness of high-speed wheel steel was measured at room temperature through compact tension(CT) specimens heat-treated with different procedures.Charpy V-notched impact specimens were made from the CT specimens with different fracture toughness,respectively.Impact tests were carried out on impact specimens at room temperature.The fracture toughness as well as the fracture surface and microstructure of impact specimens were observed and analyzed.Results show that the fracture toughness increases linearly with the increasing of impact toughness.The fracture modes of both CT specimens and impact specimens are mainly cleavage fractures.The inclusions in wheel steel mainly are Ti(C,N) which have little effect on the fracture toughness and impact toughness at room temperature.