Fracture of straight seam steel pipe, mechanical properties of hydraulic (pneumatic) parts are adopted in design, brittle fracture is also related to temperature of components.


It has been found that when the temperature is lower than a certain temperature, the information will be transformed into brittle state, and its shock absorption is significantly reduced. This phenomenon is called low stress brittle fracture in cold brittle and high strength metal materials. In this process, data organization is far heterogeneous, isotropic, there will be cracks, inclusions, pore defects, these defects can be seen as microcracks in materials. Therefore, the appropriate information of cold brittle transition temperature should be selected according to the working temperature of the components.


Generally speaking, assuming that the information is homogeneous and continuous isotropic, the analysis based on this method is considered to be a safety design, sometimes accidental rupture accident. Cold-rolled seamless steel tubes are made into cylinders due to cracks or other defects in hot-rolled tube blanks or high precision cold-drawn tubes. Fracture occurs in the course of service, almost no plastic deformation occurs, generally brittle fracture. Brittle fracture is caused by many reasons, such as precipitation at grain boundaries, whether its strength is stronger than the strength of matrix or weaker, which is the cause of crack; grain boundary segregation is also the cause of fracture; in addition, even if it is far less than the yield limit of alternating load, fatigue fracture will occur.