JPS6023894B2 - Metal plate overhang processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overhang processing method for dramatically improving the overhang processing limit of a metal plate.

Generally, in the stretching process of a metal plate, as shown in the schematic cross-sectional view in FIG. The metal plate is formed into a predetermined shape by pushing a ball-head punch P into the plate S. However, the process of pushing the punch from only one side of the metal plate (on the other hand, the same-strength machining process) ), the overhang height (final overhang processing limit) of the metal plate until it breaks with the ball-head punch is determined by the properties of the metal plate itself, especially the work hardening system number n, so it is natural that there is a limit to it. It is well known.

Therefore, the same applicant previously filed
No. (hereinafter referred to as the prior invention), in order to improve the final elongation limit of the metal plate in the conventional unidirectional elongation processing of the metal plate as described above, a suitable method is applied to the metal plate prior to elongation processing of the metal plate. We proposed a method for overhanging metal sheets that consists of performing a pre-overhang process in the reverse direction of a large amount.

However, in the above-mentioned prior invention, the improvement rate △ days of the final overhang machining limit when the punch diameter for reverse direction pre-overhang processing and the punch diameter for final overhang processing are approximately the same size is (where ΔH = 3 Voice x10.

(%). Ratio: Final overhanging eye when overhanging is performed without performing reverse pre-overhanging,
H: The overhanging limit in the final overhanging process when the final overhanging process is performed after performing the most appropriate amount of reverse pre-overhanging process, respectively.

) For example, when the metal plate is a rolled steel plate, a pure aluminum plate, and a brass plate, it shows only about 14%, 18%, and 16%, respectively.

From the above-mentioned viewpoint, the inventors of the present invention have conducted research to further dramatically improve the overhang processing limit of metal plates.
Prior to stretching the metal plate, when performing an appropriate amount of reverse pre-stretching on the metal plate, the ratio of the diameter of the punch for final tensioning to the punch for forward and reverse pre-stretching is 0.6 or less. As a result, they came to the knowledge that the final overhanging limit of the metal plate was significantly improved.

Hereinafter, the present invention will be explained in detail by way of examples with reference to the drawings.

The present invention was applied to a cold-rolled steel plate with a thickness of 0.8 legs and a pure aluminum plate with a thickness of 0.6 willow, having the tensile properties and formability table** parameters n, y shown in Table 1, respectively. The overhang processing method was applied.

Table 1 In Table 1, n and y are each n=
~.

Mountain. Kipa Manibari 932y450 Calculated by.

That is, as shown in the schematic cross-sectional view in Fig. 2a, each plate material S having the characteristics shown in Table 1 is
After sandwiching between 7-rib wrinkle holding rings R, and R2 and applying a wrinkle holding force of 1 n/, press oil was used as a lubricant to prepare a 2-diameter rib for reverse pre-stretching. The upper ball-head punch P was advanced downward, and the plate material was subjected to various reverse pre-stretching processes within the range of 0 to 11 sides.

Next, as shown in FIG. 2b, the same machine was used to tighten the plate material that had been subjected to the reverse pre-stretching process to a diameter of 1.5 mm while applying the same wrinkle pressing force. The lower ball-head punch P2 for the final overhanging process was advanced upward, and the overhang process was performed until the plate material was broken, and the overhang height (final overhang process eye) was determined. That is, for cold-rolled steel sheets and pure aluminum plates having the properties shown in Table 1, the ratio of the diameter of the punch for reverse pre-stretching to the punch diameter for final stretching was varied in the amount of reverse pre-stretching of 5 skins. Changes in the improvement rate of the final overhang limit were measured when overhang processing was performed with different values.

The results are shown in Fig. 5 (cold-rolled steel plate) and Fig. 6 (pure aluminum plate). When the ratio exceeds 0.6, the improvement rate of the final overhang limit remains at a low, almost constant level;
．． It is clear that when it is 6 or less, the improvement rate of the final overhang processing limit increases dramatically.

As mentioned above, when performing an appropriate amount of reverse pre-stretching on the metal plate prior to stretching the metal plate, the ratio of the diameter of the punch for reverse pre-stretching to the punch diameter for final stretching (in addition, , a compound curved surface where the punch surface has two or more radii of curvature will have a punch surface that approximates a spherical surface) is set to 0.6 or less, the final stretching limit of the metal plate to be stretched is significantly improved. This brings about industrially useful effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the secondary bulging process, FIGS. 2 a and b are schematic sectional views showing the bulging process mode of the present invention, and FIGS. 3 and 4 are for a cold-rolled steel plate and a pure aluminum plate. , is a diagram showing the relationship between the improvement rate of the final overhang processing limit and the ratio of the punch diameter for reverse preliminary overhang processing to the punch diameter for final overhang processing. In the drawings, S... plate material, R,, R2...
・Wrinkle press ring, P... Ball head punch, P.・
...Punch for reverse direction pre-extension processing, P2...
...Punch for final overhang processing. Figure 1 Figure 2 (Figure 2 (.b) Figure 3 Figure 4

Claims (1)

[Claims] 1 In a metal plate stretching method in which an appropriate amount of reverse pre-stretching is performed on the metal plate prior to stretching the metal plate, (final stretching punch diameter)/(reverse pre-stretching punch diameter) A method for overhanging a metal plate, characterized in that the ratio of diameter) is 0.6 or less.