Heterogeneity of Structure and Mechanical Properties Studied in Thickness up to 100 mm of Low-Alloy Shipbuilding Steel Sheets with a Yield Strength Not Less Than 420 MPa

Abstract—This paper presents a study of changes in the structure and properties in thickness of rolled sheets up to 100 mm of low-alloy shipbuilding steel with a yield point not less than 420 MPa. The fracture surface of samples after impact bending tests at low temperatures was investigated. It was found that the combination of the parameters of lath morphology bainite (fraction, areas average size and length) and the size of structural elements at given tolerance angles of 5° and 15° (indicating the presence or absence of a developed subgrain structure of deformation origin) determines the level of impact work at testing at low temperatures.