In the seamless steel pipe production, the role of the perforation process is to wear a solid hollow tube capillary. As a first step of perforated metal deformation, wear thick pipe wall thickness, length is shorter, poorer quality of inner and outer surfaces, so called capillary. If there are some defects in the capillary tube, through the subsequent steps, which is difficult to eliminate or reduce. So perforated plays an important role steel production process. Today the production of seamless steel tubes piercing process is more reasonable and perforation process automated.
Perforated whole process can be divided into three stages
The first unstable process – gradually filled metal tube deformation zones front stage, that came into contact with the roller tube with (a bite) to the front metal deformation zone, at this stage, and the presence of a secondary bite biting. Stabilization process – this is the main stage of the perforation process, full metal deformation zone from the tube to the front end of the metal tube began to leave until the deformation zone. The second unstable process – to the end of the metal tube to the metal deformation zone gradually leave all leave the rolls so far. Stable and unstable process is a clear difference between the process, it is easy to observe in production. As the beginning and end of a capillary, and an intermediate size have a difference in size, the capillary tip diameter is generally large and small diameter end, and an intermediate portion is the same. Head and tail size deviation process is one of the big features of instability. The reason causing a large diameter head portion is: In the front end of the metal gradually filled in the deformation zone, the friction roller contacting the metal surface with a gradual increase of the deformation zone is completely filled before it reaches the maximum value, especially when the front end of the plug shell When met, the head of the resistance due to axial metal subjected to axial elongation resistance, so that the axial extension deformation decreases, while the lateral deformation increases, with no restrictions outer end, resulting in a large tip diameter. A small-diameter end, is because the trailing end of the head tube starts to penetrate, plug resistance decreased, the deformation is easy to extend, while the lateral rolling show small, small diameter. Appearing before the card production, post card is also one of the characteristics of instability, although three processes differ, but they are in the same deformation zone implementation. Deformation zone is composed of rollers, head, guide plate (guide plate). The deformation region is a more complex geometry, generally considered, the cross section is elliptical, the intermediate stage has an annular head deformation zone. Two small end of the cone in contact with the longitudinal cross section, with the interposition of an arcuate head. Determines the shape of the deformation zone deformation process perforation change the shape of the deformation zone (determined with the tools to design and mill adjustment) will lead to changes in the deformation process of perforation.
Post time: Sep-11-2019