The fracture of high frequency longitudinal
welded steel pipe, hydraulic (pneumatic) components are used to design mechanical properties, brittle fracture and the use of temperature dependent components.
It is found that when the temperature is lower than a certain temperature, it is found that the data will become brittle and the impact absorption work decreases obviously. This phenomenon is called the cold brittleness. The high strength metal materials occur at the low temperature stress brittle fracture tissue, and the isotropic tissue will produce cracks, and there will be inclusions, pores and so on. These defects can be regarded as micro cracks in materials. Therefore, the appropriate cold and brittle transition temperature data should be selected according to the working temperature of components.
Generally speaking, the data is assumed to be homogeneous and continuous isotropic. According to this method, the design is considered to be safe, and there may be accidental breakage. The cold drawn seamless steel tube is made by the defect of hot rolled pipe and the high-precision cold drawn steel tube after cold drawing. In the process of fracture, almost no plastic deformation occurs, usually brittle fracture.
Brittle fracture is caused by a variety of reasons, such as grain boundary precipitation, whether its strength is stronger than strength or strength or not, it is the cause of crack, and the segregation of grain boundary inclusions is the cause of fracture. In addition, even if it is far less than the yield limit of alternating load, it will cause the occurrence of fatigue failure.
