污视频网站在线观看-日本a在线-av无码一区二区三区-中文字幕久久久久-女攻总攻大胸奶汁(高h)-精品无码一区二区三区的天堂-国产又粗又猛又黄又爽的视频-亚洲人天堂-亚洲视频免费播放-亚洲熟妇无码乱子av电影-日韩中文网-伊人手机在线视频-av福利片-亚洲综合色一区-白白色在线播放-九九色精品-男女视频一区-欧美性猛交xx乱大交-日韩欧美理论片-就去吻亚洲

     The so-called cold drawing is to use a cold drawing machine to draw the metal without heating. The advantage is that it does not need to be carried out at high temperatures. The disadvantage is that the residual stress is large and it cannot be drawn too long. Cold drawing can improve toughness and tensile strength and obtain better mechanical properties.   
     Cold drawn (rolled) seamless steel pipe process: round tube blank→heating→piercing→heading→annealing→pickling→oiling (copper plating)→multi-pass cold drawing (cold rolling)→ billet tube→heat treatment→straightening→hydraulic test (flaw detection)→marking→warehousing.
The difference between cold drawing and cold drawing:

• 

  Precision boring and rolling tube

• 

  Precision cold drawn steel pipe

• 

  Precision cold drawn tube

    
    Cold drawing and cold drawing are two different methods of metal cold processing, and they are not the same concept. Cold drawing refers to the method of applying pulling force to both ends of the metal material to cause the material to stretch and deform; cold drawing refers to the method of applying pulling force to one end of the material to pull the material out through a die hole. The hole diameter of the die should be smaller than the diameter of the material. Cold drawing processing causes the material to have extrusion deformation in addition to tensile deformation. Cold drawing processing is generally performed on a special cold drawing machine. The properties of cold drawn materials are better than those of cold drawn materials.