Skew rolling flaring

Skew rolling flaring wall-expanding process, extending coefficient of 1. In the event of the main deformation, inevitably be some extra additional deformation. Additional deformation of the metal will result in shortage tube defects, and increase energy magazine. Additional deformation of the metal include additional torsional deformation, additional axial shear deformation, additional circumferential shear deformation. Causes annex deformation, deformation, with two tapered roller roll rotary piercing machine with feeding angle and Roll angle, rolling machine process basically the same. However, due to the ramp-rolling pipe expansion pipe expansion plug cone angle is relatively large, coupled with the use of the fixed guide rather than proactive guide plate, the length of the roll is relatively short. Therefore, the size distribution and the degree of skew rolling three additional deformation in the deformation of the expander produced there are differences with the two-roll rotary piercing machine and pipe rolling mill technology, namely small additional torsional deformation, additional axial shear relatively Great. Flaring skew rolling in the structure and the two-roll stretching machine is basically the same, flaring process and deformation characteristics are the two-roll cross rolling machine similar. The difference between the two is: the latter wish blank tube wall deformation in the event of reduction, the deformation of the metal occurs mainly axially extending, and controlling the amount of its wide exhibition; the former is required when wall-blank tube deformation, deformation of metallic silver and control its axial extension, extension coefficient of 1 or less than 1, that the blank tube diameter expanded but the same length or shorter main laterally broadened. So plug expander cone angle will be great, and Roll angle and feed angle is relatively large.

Skew rolling flaring defects: mother pipe wall thickness uneven surface cracks and scratches, rolled off, and within a helical spiral track, inside pits and the like. Since expanding the amount of skew rolling tube is large, a higher risk of mother pipe surface cracking. In addition, the skew rolling flaring, the surface of the spiral track more serious. For this reason, during the pass design can be considered appropriate longer length of the roll and to design appropriate both wall area. In both wall area, the normal distance between the surface of the roll surface plug between equal. At the same time, appropriate to reduce the amount of beneficial to expanding mother pipe wall thickness to improve accuracy. Although it is possible to reduce the shortage of pipe wall thickness of oblique rolling and uneven surface when the spiral track by a roll-shaped design and adjustment, but after rolling the amount of deformation of large and flaring roll length is short. System expansion by skew rolling mother pipe wall thickness remains uneven and varying degrees of spiral track. For this reason, after diagonal rolling tube expansion process during skew rolling reeling, mother pipe wall thickness accuracy will be significantly improved.