Rectangular tube rectangular hole design

The need to produce several shaped tube, the use of strip dimensions and allow reunification (eg several fasting Gangchuang tube), only a set of forming rolls, and then in plastic rack (rack pipe sizing) on the roll change you can get different sections, so that the replacement of species is very simple, which can be a significant reduction in roll processing and reserves.

First forming a rectangular welded pipe production process consists of sizing stands complete molding, sizing mill is generally two-roll mill, which has horizontal racks and vertical roll racks. Currently rectangular hole design, there are two: one is horizontal rack at box-hole design, the first frame of oval holes, each frame of the other approximate rectangular holes, which pass by the arcs cross-section, and an arc Radius-by-frame increments, all pass phase at the sidewalls and bottom fillet radius equal to the product of the cross-section of the fillet radius. Rectangular tube total elongation factor of about 1.05, mainly distributed in the flat roller, a small amount of deformation of the vertical roll, which acts to hold down the short side of the rectangular tube. With this design, calculation is more complex, and the calculated value is not precise enough to be constantly revised hole perimeter. Another modification is the use of the design angle, from the tube can be viewed from a rectangular tube 90 ° to 180 ° to the bending deformation, the deformation angle θ corners accurately reflect the degree of deformation and edge. Design, considering the dimensional accuracy and hardening of the metal, usually deformation angle distribution, the beginning and bigger intermediate passes, and then gradually decreases. Intersecting arcs constitute the direct use of the pass, the tube can not be filled hole fillet portion, so pass tube circumference and perimeter range. In order to ensure dimensional accuracy, the need for correction calculation pass fillet portions. So this method than other methods with higher design accuracy. However, due to the large amount of iteration calculation, this method is more suitable for use computers pass design. If you use the horizontal and vertical directions simultaneously deformed universal rack deformation angle θ can be directly used for pass design.