Spring back (Springback)
In the figuration exercise that is in any curving to produce permanent metabolic work, metallic neutral line the metal of two side, compress or a side is out of shape by drawing plasticity (see a picture 2) . In a side of neuter line, plasticity stress remain is in through stretch limit (yield point) inside the spare parts of material. Additional, in neuter line two side are put in stretch stress. The stretch stress of these remain causes spring back. Be out of shape the trend of metallic component replies its savagery.
Graph 2
Because the stretch limit of cold working material rises;
Plasticity meet an emergency rises (as a result of deflection of the plasticity in workpiece rise) ;
The board that gives ply when passes a radius very old point of view undertakes bending, embedded plasticity meet an emergency measures the ply that relies on workpiece and radius of bend, is not total angle of bend degree. Because this is become of radius of bend and plate thickness rate increase, volume of spring back of every degrees of bent rises.
Spring back can be passed reduce pressure head radius or a few curve control too.
Radius of bend
Right with any metals, figuration and it is the smallest radius of bend without what the smallest radius of craze says. The smallest radius of bend increases in proportion according to the addition of armor plate or metal strip ply almost.
Soft to quite a few metal or plasticity steel, resemble anneal stainless steel, it is likely that zero diameter curves figuration. When juncture place 180 ° bend, figuration of the ministry side along two pieces of armor plate joins a department jointly. Be used curving tool brim is not acerb, otherwise it is met when figuration cut armor plate.
Normally, to anneal material, radius of bend (R) be equal to material ply (T) when need of can contented major project. Cold working material, need big radius of bend, be like 1/4H material R=1~1.5T, 3/4H material R=3~6T. The choice of radius of bend must consider the order and degree that steel plants, be like double photograph stainless steel, need big radius.