Retracted: Analysis on Low Temperature Impact Toughness and Fracture Appearance of Q420 Angle Steel

The impact absorbed energies of Q420 angle steels at the temperature range of -60~20 oC were determined by conducting series temperature impact tests, and the impact properties of Q420 angle steel at different temperatures were investigated. The microscopic fracture morphologies at different temperatures were observed by SEM. The results show that Charpy impact energies reduce as the temperature decreases, and the ductile-brittle transition temperature of Q420C angle steel is lower than Q420B, which are respectively -46.9 oC and -22.5 oC when the impact energy is equal to 21J. The primary fracture type at room temperature is ductile fracture. With the decreasing test temperature, the fracture type is a mixture of dimple fracture and quasi cleavage fracture. When the temperature decreases to -40 oC, the fracture type turns into the brittle fracture. Under the same temperature, the amount of the dimple and tearing ridge of Q420C angle steel exceeds Q420B.