Longitudinal welded pipe fracture:
It has been found that when the temperature is below a certain temperature, it is found that the data will be converted to a brittle state, and its impact absorption is significantly reduced. This phenomenon is called cold and brittle, high-strength metal of the low stress brittle fracture process, the data organization is far from uniform isotropic organization will have cracks, there will be inclusions, pores and other defects, these defects can be seen as micro-cracks in the material. Therefore, the design should also be based on the work of the component temperature to select the appropriate cold brittle transition temperature of the information.
In general, it is assumed that the information is uniform and continuous isotropic, according to this method analysis is considered safe design, and sometimes accidental fracture accident. As the hot-rolled tube billet cracks or other defects or high-precision cold-drawn tube was made after the cylinder, seamless steel pipe cold drawn. The use of the process of the fracture occurred, almost no plastic deformation occurs, are generally brittle fracture.
Brittle fracture is caused by a variety of reasons such as: grain boundary has precipitates, regardless of its strength stronger than the matrix strength or weak, are the cause of cracks; grain boundary segregation is also the reason for the fracture; in addition, even in the far less than the yield limit of the alternating load, it will cause fatigue fracture phenomenon.
