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     inCold drawn seamless pipeDuring the production process, there are cold work hardening and hydrogen embrittlement phenomena, which are the main reasons for the cracking of cold drawn seamless pipes. This article analyzes the two phenomena and proposes some measures to prevent cracking of cold-drawn small-diameter seamless steel pipes. Analysis of Burst Phenomenon Cold-drawn seamless pipes are formed by reducing the diameter of seamless steel pipes with smaller diameters through a drawing die. The process route is generally annealing, pickling, and drawing. During the drawing process, cold-drawn small-diameter seamless steel pipes sometimes crack rapidly from beginning to end like splitting bamboo poles. We call this phenomenon unified as cracking.   
   (1) Work hardening; The effect of work hardening is that the steel pipe produces a large amount of plastic deformation during cold drawing, causing obvious lattice distortion, which increases the lattice energy and the internal energy of the metal, resulting in uneven internal stress in the metal and generating residual internal stress. This increases the hardness of the metal and decreases its toughness. The higher the hardness of the metal, the greater the residual internal stress during cold drawing, and the more obvious the work hardening phenomenon. When the residual stress reaches a certain value, the metal will tear along a certain row of grain interfaces, causing cracks in the steel pipe.
  (2) Hydrogen embrittlement phenomenon. Influence of hydrogen embrittlement phenomenon: During the process of removing scale with acid solution, sulfuric acid reacts with iron to release hydrogen gas. Hydrogen penetrates into the steel in the form of atoms or ions, forming a solid solution. The influence of hydrogen on the mechanical properties of steel is typically manifested in the phenomenon of hydrogen embrittlement.