Fracture of high frequency straight seam welded pipe, hydraulic (pneumatic) components are used to design mechanical properties, brittle fracture and temperature-related components.
 
The results show that when the temperature is lower than a certain value, the data will become brittle and the shock absorption energy will decrease significantly. This phenomenon is called cold brittleness. The isotropic structure with heterogeneous data of high strength metal materials occurring in the low temperature stress brittle fracture structure will produce cracks, inclusions and pore defects. These defects can be regarded as microcracks in materials. Grain. Therefore, the appropriate data of cold and brittle transition temperatures should be selected according to the working temperature of the components.
 
Usually, it is assumed that the data are homogeneous and continuous isotropic.  According to this method, the design is considered to be safe and unexpected damage may occur. Cylinder and cold-drawn seamless steel pipe are made because of cracks in hot-rolled pipe or high precision cold-drawn pipe. In the process of fracture, plastic deformation hardly occurs and brittle fracture generally occurs.
 
Brittle fracture is caused by a variety of reasons: grain boundary precipitates, whether their strength is greater than the strength of matrix, are the causes of cracks; grain boundary inclusion segregation is the cause of fracture; in addition, fatigue fracture will occur even if they are far less than the yield limit of alternating load.