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Introduction to the classification of thinning and drawing of packaging steel strip
by：Hongmei
2021-03-15
Introduction to the classification of thinning and drawing of packaging steel strip
Thinning and drawing can be divided into two ways:
(1) The wall thickness is thinner, and the inner diameter is not significantly reduced (the inner diameter of the blank is slightly larger, which facilitates the smooth insertion of the punch in the subsequent process). This is a method often used in production, and this is the focus of this chapter. This method uses ordinary drawing methods to make the inner diameter of the blank slightly larger than the inner diameter of the workpiece before the workpiece is thinned and drawn, and then the thinning is performed.
(2) The wall thickness becomes thinner and the inner diameter decreases. That is, in each thinning and drawing process, the inner diameter is reduced and the wall thickness is reduced at the same time as the thickness of the wall is reduced according to the specified degree of deformation, and finally the required shape and size are reached, because this method is deformed and stressed during the drawing process Complex and easy to cause the workpiece to break, so it is usually not used.
Compared with ordinary drawing, thinning drawing has the following characteristics:
(1) When thinning and drawing time, the deformation zone of the material is the metal in the tapered part of the die hole, and the force transmission zone is the side wall part of the thickness t1 that has been pulled out from the die hole And the bottom of the thickness t0.
(2) The metal in the deformation zone is mainly in a three-way stress state of axial tension and compression in the other two directions, that is, the axial tensile stress generated by the pressure of the punch, and the pair of materials between the punch and the die The radial compressive stress generated and the tangential compressive stress generated by the mutual extrusion of materials. The strain state is to produce elongation deformation in the axial direction, and compression deformation in the wall thickness direction and tangential direction.
(3) In the process of thinning and drawing, because the deformation of the material is under the three-dimensional stress state, the phenomenon of cold work hardening occurs, resulting in fine metal grains and increased strength.
(4) There is no wrinkle problem in thinning and drawing, so there is no need to use a blanking device, and deep drawing can be carried out on a single-action punch. The die structure is simple and the cost is low.
(5) In one stroke of the punching machine, if a multi-layer combined die is used for thinning and drawing delay, a greater degree of deformation can be obtained. In one stroke of the press, one ordinary drawing and two thinning drawing processes can be completed.
(6) Because of the serious friction during the drawing process, the requirements for lubrication and mold materials are high.
Thinning and drawing can be divided into two ways:
(1) The wall thickness is thinner, and the inner diameter is not significantly reduced (the inner diameter of the blank is slightly larger, which facilitates the smooth insertion of the punch in the subsequent process). This is a method often used in production, and this is the focus of this chapter. This method uses ordinary drawing methods to make the inner diameter of the blank slightly larger than the inner diameter of the workpiece before the workpiece is thinned and drawn, and then the thinning is performed.
(2) The wall thickness becomes thinner and the inner diameter decreases. That is, in each thinning and drawing process, the inner diameter is reduced and the wall thickness is reduced at the same time as the thickness of the wall is reduced according to the specified degree of deformation, and finally the required shape and size are reached, because this method is deformed and stressed during the drawing process Complex and easy to cause the workpiece to break, so it is usually not used.
Compared with ordinary drawing, thinning drawing has the following characteristics:
(1) When thinning and drawing time, the deformation zone of the material is the metal in the tapered part of the die hole, and the force transmission zone is the side wall part of the thickness t1 that has been pulled out from the die hole And the bottom of the thickness t0.
(2) The metal in the deformation zone is mainly in a three-way stress state of axial tension and compression in the other two directions, that is, the axial tensile stress generated by the pressure of the punch, and the pair of materials between the punch and the die The radial compressive stress generated and the tangential compressive stress generated by the mutual extrusion of materials. The strain state is to produce elongation deformation in the axial direction, and compression deformation in the wall thickness direction and tangential direction.
(3) In the process of thinning and drawing, because the deformation of the material is under the three-dimensional stress state, the phenomenon of cold work hardening occurs, resulting in fine metal grains and increased strength.
(4) There is no wrinkle problem in thinning and drawing, so there is no need to use a blanking device, and deep drawing can be carried out on a single-action punch. The die structure is simple and the cost is low.
(5) In one stroke of the punching machine, if a multi-layer combined die is used for thinning and drawing delay, a greater degree of deformation can be obtained. In one stroke of the press, one ordinary drawing and two thinning drawing processes can be completed.
(6) Because of the serious friction during the drawing process, the requirements for lubrication and mold materials are high.
