JPS6225468B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a press molding die by overlaying a rough-processed base metal with a metal different from that of the base metal, in particular a press molding die having an approximately polygonal inner diameter profile. The present invention relates to a method for efficiently and easily producing a mold, and for obtaining an excellent mold.

Traditionally, this type of mold has been manufactured using arc welding, gas welding, etc., to overlay metal with excellent wear resistance, seizure resistance, or slipperiness on the surface of steel materials. In the case of gas welding, manual welding or automatic welding was used, and in the case of gas welding, overlay was performed exclusively by manual welding. Among these, when arc welding is used, the penetration in the welded part is large, so the dilution of the components between the base metal and the overlay metal becomes large.
Since the purity of the overlay metal is significantly reduced, its excellent properties such as wear resistance, seizure resistance, and sliding properties are impaired. In order to avoid this, it is necessary to gradually increase the purity of the overlay metal by performing multilayer overlay.
Even though the wear of the mold due to press working is extremely small, it is usually necessary to apply three to four layers of overlay. Therefore, the time required for overlaying is long, and in some cases, the original purpose of such molds, which is to obtain inexpensive and high-performance molds, cannot be achieved. In addition, in the case of gas welding, although it is possible to obtain high-quality build-up metal with small penetration in the weld, gas welding originally has the disadvantage that the amount of heat that can be input is small, so the welding speed is slow. .

Furthermore, dies whose inner diameter contour is an Oji polygon, such as dies for rectangular tube drawing, have a roundness called a corner radius at the intersection of each side of the polygon, and a material to be formed from the top surface of the die to the inner surface of the die during press forming. The die shoulder has a roundness called a dial for sliding, and the intersection of this corner radius and the dial forms a saddle shape. However, if the die inner diameter contour is a polygon with a recess, the intersection of the corner radius and the dial of the recess becomes a part of the spherical shape or the like.

When overlaying such parts by arc welding, the quality of the overlay metal cannot be stabilized with manual welding, and automatic welding requires the use of expensive equipment such as copying equipment and numerical control equipment. It was hot.

This invention was made in view of the drawbacks of the conventional method as described above. By using the reverse polarity soft plasma overlay method, only one layer of overlay is applied to the other parts except around the corner radius to connect the base material and the overlay. By performing welding with almost no dilution of the components of the plated metal, then forming a groove near the corner radius, and placing a separately prepared insert in the groove, we can quickly manufacture inexpensive and high-quality press forming dies. This provides a method to do so.

Examples of the present invention will be described below.
First, we will briefly explain the characteristics of the reverse polarity soft plasma build-up method. FIG. 1 compares the cross-sectional shapes of build-up beads in normal arc welding and reverse polarity soft plasma build-up. In the figure, 1 is an overlay, 2 is a penetration, and 3 is a base material. The dilution ratio expressed by the following formula is often used as a measure to express the characteristics of the built-up part.

Dilution rate (%) = Penetration cross-sectional area / Penetration cross-sectional area + Reinforcement cross-sectional area × 100 Figure a shows the case of normal arc welding, although the dilution rate is several tens of percent. In comparison, in the case of reverse polarity soft plasma overlay method (Figure b)
Dilution rates as low as 0.1% can be achieved. If this dilution rate is large, the overlay metal component will be diluted by the base metal and its properties will be significantly impaired, but this does not occur in the reverse polarity soft plasma overlay method. By the way, Figure 2 shows the thickness of a copper-aluminum alloy, which is commercially available as a mold material that exhibits excellent wear resistance, seizure resistance, and slip resistance, and is overlaid on SS41, which is an inexpensive and strong material. This shows the relationship between the Vickers hardness of the plated metal and the dilution rate. It can be seen that when the dilution rate increases even slightly, the hardness of the overlay metal decreases significantly.

In this way, metals with excellent properties as molds, such as the copper-aluminum alloys mentioned above, can be deposited on the surface of inexpensive and strong materials such as SS41 and S45C using the reverse polarity soft plasma deposition method. Once filled, it can be used as an excellent mold with just one layer of overlay.

This reverse polarity soft plasma build-up method has a much higher energy density than gas build-up, so it can build up with high efficiency, but automatic build-up is used to ensure stable and high-quality build-up. are doing.

It is an object of the present invention to use this reverse polarity soft plasma build-up method to perform build-up with high efficiency and to easily obtain an excellent mold without using expensive equipment.

Next, an embodiment of the present invention will be described with reference to the drawings. FIGS. 3 and 4 show the manufacturing procedure of the rectangular cylinder drawing die according to the present invention. Figure 3 shows the state in which the upper and inner surfaces of the base metal are overlaid with reverse polarity soft plasma, except for around the rounded corners of the inner diameter contour, where 11 is the base metal, 12 is the overlay metal on the top surface, and 13 is the overlay metal on the top surface. Shows the metal overlay on the inner surface.

The upper surface of the base metal 11 is rough-processed to remove an oxide film, etc., if necessary, and the inner diameter contour is cut out and rough-processed using simple and highly efficient cutting such as gas cutting. A metal having excellent wear resistance, seizure resistance, and slip properties is overlaid on the upper surface and inner surface of the base metal 11 rough-processed in this way, except for the vicinity of the rounded corners of the inner diameter contour of the base metal 11. Thereafter, as shown in FIG. 4, the surfaces of the build-up metals 12 and 13 are finished by cutting, and a groove is placed near the corner roundness of the base metal 11 to a depth equal to or equal to the depth of the dial portion after press-forming die processing. Groove 1 to a depth greater than
Process 4.

Then, a nest 15 is made to fit this groove 14 as shown in FIG. 5, and this is fitted into the groove 14 and fixed with a bolt pin or the like to complete a rectangular cylinder drawing die.

The base metal 11 may be made of inexpensive and strong steel such as SS41 or S45C.

Further, the overlay metals 12 and 13 are suitably made of a copper-aluminum alloy having excellent wear resistance, seizure resistance, or slipperiness. Copper-aluminum alloys not only have excellent properties as molds, but also have a lower melting point than steel materials, making it easy to apply high-quality overlays with a low dilution ratio, and they can be cut, making finishing processing easy. Further, the insert 15 as shown in FIG. 5 may be made of a mold material such as heat-treated steel or a copper-aluminum alloy.

In the above embodiment, a method for manufacturing a rectangular tube drawing die was described, but the present invention can be applied to any press forming die whose inner diameter contour is roughly polygonal, consisting of straight lines and rounded corners. Further, although the example of the overlay metal is a copper-aluminum alloy, any other metal may be used as long as it has excellent wear resistance, seizure resistance, or slipperiness. Furthermore, although the procedure of fitting the insert 15 into the corner portion after finishing the build-up metal is shown, the build-up metal may be finished after the insert 15 is fitted. Furthermore, the groove 14 and the insert 15 fitted therein may penetrate through the base metal 11 from the upper surface to the lower surface.

As described above, according to the present invention, when manufacturing a press-forming die with an inner contour of a substantially polygonal straight line and rounded corners, the corner Welding with only one layer of metal with excellent abrasion resistance, seizure resistance, and slipperiness using the reverse polarity soft plasma overlay method on other parts except for the area around the radius, with almost no dilution of the components of the base material and overlay metal. After that, a groove was machined near the corner radius, and a separately prepared insert was placed in the groove, so there was no need to use expensive equipment such as copying equipment or numerical control equipment for overlaying. Moreover, it is possible to manufacture press molding dies with excellent performance extremely efficiently.

[Brief explanation of the drawing]

Figure 1 is a diagram comparing the cross-sectional shape of the build-up bead between the conventional method and the reverse polarity soft plasma build-up method.
Fig. 19 is a cross-sectional view showing a build-up bead in the conventional method, Fig. 1b is a cross-sectional view showing a build-up bead in the reverse polarity soft plasma build-up method, and Fig. 2 is a cross-sectional view showing a build-up bead in the reverse polarity soft plasma build-up method. A diagram showing the relationship between the Bitkers hardness of the overlay metal and the dilution rate when overlaying on the surface of SS41 material, FIGS. 3 and 4 are front views showing an example of the manufacturing procedure of the pressing die in this invention, FIG. 5 is a perspective view of the insert placed in the corner portion. 1... Surplus, 2... Penetration, 3... Base material, 11
... Base metal, 12 ... Overlay metal on top surface, 13 ...
...Inner surface overlay metal, 14...Groove, 15...Insert.
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A press-forming die whose inner diameter contour consists of straight lines and rounded corners, and in which a metal different from the base metal is overlaid on the upper surface and inner surface of the roughly processed base metal near the inner diameter contour. In the method of manufacturing, the upper surface and inner surface of the base metal near the inner diameter contour, excluding the vicinity of the corner rounding, are overlaid using a reverse polarity soft plasma overlay method, and the die is overlaid from the upper surface to the inner surface near the corner rounding. A method of manufacturing a die for press molding, characterized in that a groove having a depth equal to or greater than the depth of a dial in a continuous die shoulder is formed, and a separately prepared insert is placed in the groove. 2. The method of manufacturing a press-forming die according to claim 1, wherein a copper-aluminum alloy is used as the overlay metal. 3. The method of manufacturing a press-forming die according to claim 1, characterized in that a metal having better wear resistance, seizure resistance, or slipperiness than the base metal is used as the overlay metal. 4. The method for manufacturing a press-forming die according to claim 1, characterized in that only one layer of overlay is applied to the base metal except near rounded corners.