Seamless steel pipe end crevasse processing

Oil drill pipe end threads using pipe, seamless steel pipe ends before threading usually after machining, including: cutting, car cylindrical, boring, chamfering and face processing. These processes are generally done on a dedicated machine once finished threading on both machines. In order to ensure compliance with regulatory requirements thread size. Various instruments required rigorous factory testing, test items include snails moment, tooth height, tooth, thread length, taper, tight moments. Ensure dimensional accuracy of machined steel, seamless steel pipe end sizing reduce ovality purposes. Mainly used for oil casing. After sizing sleeve ends after black buckle ends of the wire when the car (car left tainted threaded surface) small quantity, can improve the yield. Commonly used methods of sizing and expanding punch punch expanding and sizing ring compression two kinds. Reduced flaring punch when pipe ovality effect depends on the level of the pipe wall thickness uniformity on a large level. Severe than those of the wall thickness is not as hot tube rolling machine rolling cycle-type steel (see cycle-type rolling machine rolling) after expanding punch, seamless end sizing by cold deformation process. Deterioration in the quality of the appearance of the pipe end. Therefore, in order to eliminate the influence of uneven wall thickness and reduced pipe ovality, should be enlarged diameter punch and sizing ring compression method. Since the cold sizing, the pipe end is elastically deformed and also only a small amount of plastic deformation. After sizing, expanding and non-expanding transition zone, there may be different levels of residual stress, but may also occur due to internal and external appearance of punches and scratches caused by sizing the ring, leading to a slight stress corrosion. Therefore, it should enhance the dimensional accuracy of rolled steel, used to prevent the pipe end sizing method. Threaded throughout the local became the weak link in the pipe strength. In order to improve the strength of the local threaded connections, pipe end thickening mainly used in petroleum and geological steel pipes. After threading pipe ends due to wall thinning. Using the method of increasing the pipe end thickened pipe end wall thickness. In addition, drill (tube) multi-use tool butt end of the connecting tube, the weld and heat affected zone is weak link strength. To improve the strength of the weld zone, the pipe end is also used generally thickened. Tube end forms the thick thick, thick outer and internal and external thickened.