JPH0344855B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a forged elbow used in high-pressure piping.

(Prior Art) The manufacturing process of a conventional forged elbow is explained with reference to Fig. 1. First, the material is cut as shown in Fig. 1A, and then the material is preformed into a flat shape as shown in Fig. 2B. Then, as shown in Figure C, the product is forged with burrs, then the burr is removed by trimming as shown in Figure D, and finally machined as shown in Figure E. In addition to cutting the hole, the inner surface and end surface are finished.

Another method is to use a split mold that has an L-shaped molding space on the split surface, supply heated material into the molding space, and insert one molding shaft from the horizontal open end of the molding space. Insert the molding shaft so that its tip surface receives one side of the material, and in this state, insert the other molding shaft vertically into the molding space from above to press and deform the material, and then press and deform the material to deform the material around the tips of both molding shafts. Methods have also been developed to manufacture elbows by forcing material into the material.

(Problem to be Solved by the Invention) However, according to the former method, the burrs generated during forging are removed and the holes are formed by cutting, which wastes material and increases the number of processing steps. The cost is high, and the thickness of the burr changes even if the temperature conditions etc. change slightly, which tends to cause variations in the outer diameter accuracy.As a result, machining is difficult and there is a risk of uneven thickness.Furthermore, There are problems such as the need for a press with significantly greater capacity in order to forge something with a large diameter.

On the other hand, according to the latter method, when the molding shaft is inserted from above into the L-shaped molding space and pushed into the material, a part of the material is moved to one side of the molding space depending on the amount of pushing. However, one of the molding shafts is inserted into one side of the material and is in pressure contact with the side surface of the material, so the outer peripheral surface of the tip of this molding shaft and the inner peripheral surface of one side of the molding space. In order to completely fill part of the material into the elbow end molding space, the pushing force of the molding shaft must be extremely large, which may result in the material not filling evenly in the molding space. Particularly, in order to manufacture a large-diameter elbow, forging becomes difficult.

This is because the material must be molded while dividing the pushing force of one molding shaft vertically into the L-shaped molding space into a horizontal component. If one forming shaft exists on the force-component side, the material must be formed while being deformed against the material-receiving force of the forming shaft, which requires even stronger pushing force. This is to do so.

In view of the above conventional problems, the present invention provides a method for manufacturing a forged elbow that can easily manufacture a high-quality forged elbow without requiring much pressure even if the elbow has a large diameter.

(Means for Solving the Problems) For this reason, the present invention provides a pair of mold pieces in which a substantially L-shaped molding space is formed in the vertical dividing surface from the upper end surface to one side. A heated material is loaded into the molding space from above, and then a first inner mold for forming the inner surface is pushed into the molding space from the upper opening of the L-shaped molding space to form one half of the elbow into the material. At the same time as molding, a part of the material is extruded to one side of the L-shaped molding space, and then a second inner mold for molding the inner surface is pushed into the molding space from the open opening on one side, and the inside mold is pushed into the space. The other half of the elbow is formed into a part of the material being extruded by the inner mold, and then the molded elbow is ejected from below by the shaft after separating the pair of mold pieces. That is.

(Function) When the heating material loaded into the L-shaped molding space is press-molded by inserting the first inner mold from above, a second inner surface is formed on one side of the molding space. Since there is no internal mold, one half of the elbow can be molded without requiring too much force to push the material, and a portion of the material will be forced into one side of the molding space.

In this state, when the second inner mold for molding the inner surface is pushed into the molding space from the opening on one side, the material extruded in that part is pressed and deformed, filling the molding part, and the other half of the elbow parts are formed.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 2 to 7.

First, the schematic configuration of the manufacturing equipment will be explained with reference to FIGS. 3 to 6. 1 is a forging press, base 2 is
and an elevating body 3 that is driven up and down by an appropriate drive device 4.
It is equipped with

A split outer mold 6 is mounted and supported on the base 2 via a base plate 5. As shown in FIG. 6, this split outer mold 6 has a generally L-shape corresponding to the outer shape of the elbow to be formed, and has a molding space 7 that extends from both ends of the mold along the axis to the outer surface. The molding space 7 is vertically divided into a pair of mold pieces 10a and 10b by a dividing surface 9 located on an imaginary plane through which the central axis 8 of the L-shape of the molding space 7 passes.

This split outer mold 6 is arranged so that the split surface 9 is vertical and one end side of the L-shaped central axis 8 is facing upward in the vertical direction. The other mold piece 10a is attached to a movable block 12 that is slidable on the base plate 5, and can come into contact with and separate from the one mold piece 10b.

Reference numeral 13 denotes a pressing shaft connected to the movable block 12, which is held slidably in the axial direction by a guide cylinder 14 attached to the base 2, and this guide cylinder 14
It is driven by a ram 15 attached to.

Reference numeral 16 denotes a first inner mold for molding the inner surface which can be inserted into the molding space 7 of the split outer mold 6 from its upper opening, and is attached to the elevating body 3 with a mounting fixture 17.

Reference numeral 18 denotes a second inner mold for molding the inner surface which can be inserted into the molding space 7 through its lateral opening, and is attached to a pressurizing shaft 20 that is slidably supported by a guide tube 19 fixed to the base 2. , are pressed and driven by a ram 21 attached to the guide tube 19.

Each of the inner molds 16 and 18 is axially shaped, and has molded portions 16a and 18a formed at the tip thereof in a shape corresponding to the inner surface shape of the elbow, as shown in FIG. The molded part 18a is formed short so as not to interfere with the tip of the other molded part 16a. 22 is a hole through which a product ejection shaft (not shown) is passed.

Next, to explain the manufacturing method, first, as shown in Fig. 2A, the overall flow is to cut the material m so that the weight is exactly equal to the weight of the elbow after molding, and then to cut the material The manufacturing process is completed in three steps: using the manufacturing equipment described above, the material m is forged into an elbow shape as shown in Figure B, and finally finished by machining etc. as shown in Figure C. It is.

To explain the forging process using the manufacturing device described above with reference to FIG. 7, first, as shown in FIG. It is loaded into the molding space 7 of the mold 6 from above.

When material loading is completed, both mold pieces 10a and 10b of the divided outer mold 6 are strongly pressed together by a ram 15 with a force of, for example, about 260 tons to prevent the mold from opening due to the pressure during forging. .

In addition, the material m may be loaded with both mold pieces 10a and 10b slightly opened, and then both mold pieces 10a and 10b may be brought into pressure contact with each other by the ram 15. In this case, the material m can be easily inserted. Additionally, it can be loaded to a deep position, reducing mold wear due to the flow of material during forging.

Next, as shown in Figure b, the first inner mold 16 for forming the inner surface is pressed down by lowering the elevating body 3 with a force of about 250 tons using the drive device 4, and the first inner mold 16 is divided into parts. The material m is forged by entering the vertical portion of the molding space 7 of the outer die 6 from above.

At the descending end of the first inner mold 16, the molding of the vertical half of the elbow is almost completed in the molding section 16a, and the remaining material is extruded into the horizontal portion of the molding space 7.

Next, as shown in FIG. The second inner mold 18 is inserted into the molding space 7, and the remaining horizontally oriented portion of the elbow is molded using its molding portion 18a.

In this forming process, the elbow is forged mainly from the inner side, so the degree of forging is high, and an elbow with high strength and reliability is formed.

When the elbow molding is completed as described above, the first and second inner molds 16 and 18 are pulled out from the molding space 7 and returned to their original positions, and the ram 15 is contracted to convert the mold piece 10a into the mold piece 10b. The split outer mold 6 is opened, the molded elbow is pushed out from below with a product ejecting shaft (not shown), and the product is transported out by appropriate means.

Note that in the molded elbow, a thin part will remain between the molded part 16a of the first inner mold 16 and the molded part 18a of the second inner mold 18, but this will be removed by later machining etc. It is removed during finishing process to open the fluid passage.

(Effects of the Invention) As described above, according to the method for manufacturing a forged elbow of the present invention, a substantially L-shaped molding space is formed in the vertical dividing surface from the upper end surface to one side. The heated material is loaded from above into the molding space of the pair of mold pieces, and then the first inner mold for inner surface molding is pushed into the molding space from the upper opening of the L-shaped molding space, and the material is heated. At the same time as one half of the elbow is molded, a part of the material is extruded to one side of the L-shaped molding space, and then a second inner mold for molding the inner surface is inserted into the molding space from the opening on one side. Since the other half of the elbow is to be molded by this inner mold into a part of the material that has been pushed and extruded into the space, the first inner molding material is inserted into the L-shaped molding space from above. When the inner mold is pushed in, the heating material loaded in the molding space is not regulated in any way from one side of the molding space, so a part of it bulges out into the one side space. Therefore, one end of the elbow can be reliably molded by pushing the first inner mold for molding the inner surface into the material without requiring a large pressing force unlike the conventional method.

Furthermore, after the molding by the first inner mold for forming the inner surface, the second inner mold for forming the inner surface is pushed into the molding space from the opening on one side, so that one side of the molding space is pushed by this pushing force. It is possible to easily press and deform a part of the material being extruded into the mold, and to reliably fill the molding space between the inner mold and the molding space, so that there is no shortage of material and a large diameter and high height. It is possible to efficiently manufacture quality forged elbows.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the manufacturing process of a conventional forged elbow, Fig. 2 is an explanatory diagram of the manufacturing process of a forged elbow according to the method of the present invention, Fig. 3 is a partially longitudinal simplified front view of the manufacturing equipment, and Fig. 4 is a partial longitudinal side view of the same main part,
Fig. 5 is a plan view taken along the line A-A in Fig. 4, and Fig. 6 shows a divided outer mold, in which a is a front view of one mold piece seen from the dividing surface, and b is a front view of one mold piece from the dividing surface. The plan view and FIGS. 7a to 7c are partially sectional front views of the forging process seen from the dividing surface of the divided outer die. 1 is a forging press, 3 is an elevating body (pressing device), 6
1 is a divided outer mold, 7 is a molding space, 15 is a ram (mold clamping device), 16 is a first inner mold, 18 is a second inner mold, 2
1 is the ram (pressing device), m is the material.

Claims (1)

[Claims] 1. A heated material is loaded from above into the molding space of a pair of mold pieces formed by forming a generally L-shaped molding space penetrating from the upper end surface to one side in the vertical dividing surface, and then , a first inner mold for molding the inner surface is pushed into the molding space from the upper opening of the L-shaped molding space to mold one half of the elbow into the material, and at the same time a part of the material is transferred into the L-shaped molding space. Then, a second inner mold for molding the inner surface is pushed into the molding space from the opening on one side, and a part of the material being extruded into the space is injected into this inner mold. Next, mold the other half of the elbow, and then
A method for manufacturing a forged elbow, which comprises separating a pair of mold pieces and ejecting the formed elbow from below with a shaft.