欧美黑吊大战白妞欧美大片-日批视频免费-超碰视屏-欧美一级特黄aaaaaa-日本午夜精品理论片a级app发布-人人干人人澡-午夜精品久久久久久久99黑人-男人与雌宠物交h-日韩成人免费在线-天天射夜夜爽-九一亚色-香蕉视频首页-一区二区三区视频免费在线观看-欧美日韩亚洲国产一区-久久这里有-我不卡av-婷婷综合在线视频-久久在线视频精品-国产蜜臀在线-午夜欧美成人

     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.