Types And Process Characteristics Of Pipe Bending Machine
Pipe bending machine can be roughly divided into CNC pipe bending machine, hydraulic pipe bender and so on. Pipe bending machine is mainly used in electric power construction, public railway construction, boilers, bridges, ships, furniture, decoration and other aspects of pipeline laying and building, with many functions, reasonable structure, simple operation and other advantages.
In addition to bending pipe function, the pipe can also be used as a hydraulic jack, compared with CNC pipe bending equipment has a cheap, easy to use characteristics, in the domestic pipe bending machine Market occupies the leading product location. Pipe bending machine is the same as bending the pipe and bending the sheet. In the case of pure bending, the outer diameter is D, and the pipe with a wall thickness of t is bent by the action of the external force moment M, the lateral tube wall of the neutral layer is subjected to tensile stress σ1, the pipe wall becomes thinner, the inner tube wall of the neutral layer is subjected to tensile stress σ1, and the pipe wall thickens.
Moreover, the shape of the cross section changes from circular to approximate elliptic due to the action of the combined F1 and F2, and when the deformation is too large, cracks will occur in the outer tube wall and wrinkles will appear in the inner wall. The degree of deformation of the pipe depends on the relative bending radius R/D and the relative thickness of the T/d value. The smaller the R/D and T/d values, indicates the greater the degree of deformation. In order to ensure the forming quality of pipe fittings, it is necessary to control the degree of deformation within the permitted range, and the bending forming limit of pipe depends not only on the mechanical properties and bending method of the material, but also on the use requirements of pipe fittings.
The forming limit of the pipe fittings should contain the following contents:
1) The maximum elongation deformation in the external tensile deformation zone of the neutral layer does not exceed the plastic allowable value of the material to produce rupture;
2) in the inner compression deformation zone of the neutral layer, the thin-walled structure part of the tangential compressive stress action does not exceed the instability and wrinkle;
3) If the pipe fittings have the requirement of ellipticity, control its section to produce distortion; 4) If the fittings have the strength requirements to withstand the internal pressure, control the forming limit of the wall thickness thinning.