10D ASTM A234 Grade WPB 4 Inch 45 Degree Bend , Metal Pipe Bender Hot Rolled

ASTM A234 Grade WPB Carbon Steel Bend, Hot Rolled, 4IN, 45 Deg, 10D, Pipe Connection.

The pipe bender bends like the sheet metal. Under the condition of pure bending, when the pipe with outer diameter of D, wall thickness of t is bent by the action of external moment M, the outer wall of neutral layer is subjected to tensile stress σ1, and the inner wall of neutral layer is subjected to tensile stress. The wall becomes thicker. Moreover, the shape of the cross section changes from circle to approximate ellipse due to the action of force F1 and F2. When the deformation is too large, the outer wall will crack and the inner wall will wrinkle.
The degree of deformation of the pipe depends on the relative bending radius R/D and the relative thickness t/D The smaller the value, R/D and t/D, the greater the degree of deformation. In order to ensure the forming quality of pipe fittings, the degree of deformation must be controlled within the permitted range. The bending forming limit of pipe material depends not only on the mechanical properties and bending methods of the material, but also on the use requirements of pipe fittings. The forming limit of pipe fittings shall include the following:
(1) The maximum elongation deformation in the lateral tensile deformation zone of the neutral layer does not exceed the plastic allowable value of the material, resulting in rupture;
(2) In the inner compression deformation zone of the neutral layer, the thin-walled structure subjected to tangential compressive stress does not wrinkle beyond instability;
(3) Control the distortion of the pipe section if the pipe has the requirement of ellipticity;
(4) Control the forming limit of wall thickness thinning if the fittings have strength requirements to withstand internal pressure.