By means of finite element numerical simulation,the effect of three-way compressive stress and screwdown speed of die on the equivalent strain and the morphologic change of the hole before physical closure during plastic deformation of the forging were studied.The physical closure law was revealed by comparing the changes of the volume,long axis and short axis of the spherical hole in the preset interior.It is found that the equivalent strain around the preset hole during plastic deformation is obviously greater than that at other positions of the body.In case of the same deformation rate,the larger three-way compressive stress and the smaller screwdown speed are more conducive to the closure of the internal holes of the forge piece.The rapid reduction of the length of the long axis indicates the start of physical closing of the holes.The physical closing direction of the holes is consistent with the screwdown direction of the top die.
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