JPS6238736A - Integral forging forming method for nozzle using composite punch - Google Patents

Abstract

PURPOSE:To increase the shape accuracy in a nozzle, etc. by forming a nozzle part with the composite punch composed of a pressing plate and punching part, then by extruding the punching part from the nozzle part in the state of removing the pressing plate. CONSTITUTION:The composite punch is formed by a pressing plate 5 and punch 2 and made freely connectable and separatable via a pin 6. The outer face curvature of the connecting part of the pressing plate 5 with the punch 2 is formed in the same shape as the inner face curvature of the nozzle to be formed. A main body member 1 is heated to the prescribed temp. by making a prepared hole in advance on the nozzle fitting part of the member 1. The main body member 1 is subjected to a rolling reduction with the composite punch and the rolling reduction is stopped in the state of constraining the member 1 by the pressing plate 5. The rolling reduction is then performed until the punch 2 only is removed from the nozzle forming part by drawing out a pin 6 and by removing the pressing plate 5. With this method the deflection and floating of the member 1 are prevented and the shape accuracy of the nozzle is improved as well.

Description

[Detailed Description of the Invention] <Object of the Invention> Industrial Field of Application The present invention relates to a nozzle integral forging method using a composite punch, and more specifically, a nozzle part is formed on a member to be used as a pressure vessel body together with a main body. It pertains to a forging method using a composite punch that forms an integral part.

Conventional Technology Many nozzles are attached to the main body of a pressure vessel such as a nuclear reactor, and the following two methods are usually used to attach nozzles. That is, (1) a method in which the nozzle is manufactured in a separate process from the main body and joined by welding; (2) a method in which the nozzle is formed from the main body member through either gas processing or machine cutting, or both.

In the case of method (1), periodic inspections are required for the welded joint between the nozzle and the main body from a safety perspective, and there are also drawbacks such as restrictions on the distance between the nozzles due to periodic inspections. There is.

In addition, in the case of method (2), in order to cut out the nozzle,
As shown in FIG. 4, it is necessary to increase the thickness of the main body member by the height of the nozzle, which is economically disadvantageous due to a decrease in yield and an increase in processing time.

*t:,/X)IAR”!tf!A C* 16 T
*@ m tf T $ , reduce the pressure by 1 inch and use so-called burring to form the pilot hole: Alternatively, as a method of forming the nozzle, the method shown in Fig. 5 or Fig. 6 shown in Japanese Patent Publication No. 57-2418 is used. There is a method, but when the size of the material to be formed is considered to be finite with respect to the nozzle diameter, if the punch 2 is pressed down by the method shown in Fig. 5, the main body member 1 will become as shown in Fig. 5 (b). As a result, the entire structure is greatly distorted and the phenomenon of lifting from the die is observed, and the curvature of the inner surface becomes large, making it difficult to obtain the desired nozzle shape. Furthermore, in the method not shown in FIG. 6, the deformation behavior of the main body member 1 during the punching process is almost the same as in the case of FIG. 5, and the above-mentioned problem is not solved.

Problems to be Solved by the Invention The present invention aims to solve the above-mentioned drawbacks. Specifically, when the main body member and the nozzle part of a pressure vessel are integrally molded, the main body member that is generated during the pressing down process of the punch. It is an object of the present invention to provide a method for correcting the lifting and distortion of the molding nozzle and for molding the inner surface shape of a molding nozzle into a desired shape.

<Structure of the Invention> Means for solving the problem and its operation, that is, the present invention provides a means for solving the problem and its operation. A pilot hole is made in the center of the main body member corresponding to the nozzle part of the body, and the nozzle part is integrally hot-forged through the pilot hole using a composite punch consisting of a punch part and a presser plate part, and a die. The feature is that the presser plate section is removed from the machine, and then the punch section is pushed down to push the punch section out of the nozzle section.

Hereinafter, the configuration and operation of the means of the present invention will be explained using the drawings.

Figures 1 (a) to (0) are explanatory diagrams showing step-by-step the nozzle forming method according to the present invention, and Figures 2 (a) and (b) are diagrams showing when the nozzle is squeezed out by the present invention method and the conventional method, respectively. Graphs showing the relationship between the Pontier length and the load ratio and the Pontier length and strain ellipse, Figures 3 (a) and (b) are longitudinal cross-sectional views showing the shapes of molded nozzles obtained by the conventional method and the method of the present invention. be.

The nozzle forming method according to the present invention will be explained based on FIG.

The main body member 1 is usually a forged steel product or a steel plate having a cylindrical or spherical shell shape, and only the nozzle mounting portion is shown in the figure. The main body member 1 is manufactured through an ingot and forging process or a rolling process, and may also undergo a heat treatment process or a machining process depending on the case. To attach the nozzle to the main body member 1, a pilot hole 9 smaller than the diameter of the punch 2 is made in advance by gas machining or machining, and before the nozzle is formed,
Either the entire body member 1 or the vicinity of the nozzle attachment portion is heated to an appropriate temperature using a heating furnace or other appropriate method.

Next, the forming jig will be explained. The punch 2 has a diameter slightly larger than the inner diameter of the nozzle to be molded, and its tip is spherical or conical.

The holding plate portion 5 has a shape in which the curvature of the outer surface of the connection portion with the punch 2 is equivalent to the inner curvature of the forming nozzle.

The punch 2 is assembled into the holding plate part 5 as shown in FIG. 1(a), and is held by, for example, a bottle 6, and the punch 2 and the holding part 5 can be easily separated by the opening for removing the bottle 6. . The die 3 has an inner surface slightly larger than the outer surface of the nozzle so that a certain machining allowance can be given to the outer surface of the molding nozzle. During forming, a composite punch consisting of a punch 2 and a presser part 5 is attached to the upper anvil 4 of a free forging press by an appropriate method. The pilot hole 9 and die 3 of the main body member 1, which have been sufficiently heated by the attached composite punch and a heating furnace, are set concentrically in a free forging press, and the main body member 1 is pressed down at an appropriate speed with the composite punch. As shown in FIG. 1(b), the pressing is stopped and the load is removed while the main body member 1 is restrained by the presser plate portion 5. At this time, the main body member 1 is distorted as the pressure is lowered, but when the pressure is applied by the presser plate portion 5, the distortion is corrected and the nozzle inner surface shape is formed into a desired shape. At this stage, remove the bottle 6 (Fig. 1(C)), then lift the upper anvil 4 and the holding plate part 5 (Fig. 1(d)), and remove the holding plate part 5 as shown in Fig. 1(e).
), as shown in Figure 1 ([), restart the rolling with only the punch 2, and continue rolling until the punch 2 comes off from the nozzle molded part of the main body member 1, as shown in Figure 1 (F). . The shape of the nozzle that can be formed is determined at the stage shown in FIG. However, the main body member 1 also shrinks due to a decrease in temperature, and cannot be easily removed. Therefore, Fig. 1 (
cl~((Jl process is required. The rolling blade in Fig. 1(f) requires a minimum load sufficient to overcome the frictional force moving between the punch 2 and the forming nozzle part.The load level Since this is much smaller than the maximum forming force, the distortion of the main body member 1 due to this reduction can be almost ignored, and the punch 2 can be easily removed from the nozzle portion.

EXAMPLE Next, an example of nozzle molding by the method of the present invention will be described.

As the main body member, a forged material having a thickness of 100 mm that had undergone an ingot and forging process and a flat plate having a thickness of 70 mm that had been machined were used. The material is SFυQIA. The main body member was machined with a pilot hole of φ140 mm in the nozzle attachment part, and was heated and maintained at 1200-1250°C prior to molding. For comparison, two types of nozzle forming methods were used: a method according to the present invention and a conventional method shown in FIG.

In the case of the conventional method, the punch used for forming has a diameter of 280 mm.
The tip is spherical in shape. On the other hand, in the case of the method according to the present invention, the composite punch for forming is composed of a punch part and a presser plate part, and the presser plate part is ring-shaped and has an inner diameter of 240 mm and an outer diameter of 600 mm. The presser plate part has an outer surface shape connected to the punch part with a radius of curvature R of 130 ml, and smoothly connects to the punch part. The shape of the punch part is the same as the conventional method described above, but the fitting part of the presser plate part is φ23.
It is stepped to 5mm. Further, a round bar with a diameter of 15 mm was used as the bottle connecting the punch portion.

Figures 2 (a) and (b) show the maximum load (P
Load ratio, Pontier distance, and strain amount (distance 1111X shown in Figure 2 (b)) with ffIax) removed by forming force (Pl)
and Ponche degree, respectively.

The solid line in Figure 2 shows the results of the present invention method, and the chain line shows the results of the conventional method. , occurs during the process from FIG. 1(a) to FIG. 1(b).On the other hand, curve 1 D→E is the load required for shaping the inner curvature of the main body member by the presser plate portion, and occurs during the process shown in FIG. 1(C). Furthermore, looking at the distortion-punch process diagram shown in Fig. 2(b), the distortion that occurs during nozzle forming is limited to the initial stage of forming. The amount of distortion gradually decreases when the nozzle is formed, indicating that the distortion generated during the nozzle forming process can be corrected. Figures (a) and (b) show the cross-sectional shape of the molded nozzle obtained by the method shown in Figure 5. The curvature of the molded nozzle is gentle, and the desired nozzle shape is obtained. On the other hand, Fig. 3(b) shows the cross-sectional shape of the nozzle obtained by the method of the present invention, and the outer surface curvature of the nozzle mounting portion is almost the same as the outer surface curvature of the holding plate portion. When used, it became possible to obtain the desired nozzle shape.

Furthermore, the distortion of the entire main body member could be corrected to a much smaller degree than with conventional methods.

<Effects of the invention> 1
As explained in detail above, the present invention involves drilling a pilot hole in the center of the main body member corresponding to the nozzle portion, and heating the nozzle portion integrally through the pilot hole using a composite punch and die consisting of a punch portion and a holding plate portion. This is a nozzle integral forging method using a composite punch that performs inter-forging forming. Conventionally, when the main body member and nozzle part of a pressure vessel are integrally formed, the lifting of the main body member that occurs during the reduction process of the punch and the The distortion has been corrected, and the inner surface of the molding nozzle can now be molded into the desired shape.

[Brief explanation of the drawing]

Figures 1 (a) to (<1) are explanatory diagrams showing step-by-step the nozzle forming method according to the present invention, and Figures 2 (a) and (b) show nozzles being squeezed out by the present invention method and the conventional method.
, : Ponche degree ~ Load ratio and Ponche degree ~
Graphs showing the relationship of distortion, Figure 3 (a) and (bl
FIG. 4 is an explanatory diagram showing an example of the conventional nozzle forming method, and FIGS. FIG. 6 is an explanatory diagram showing an example of a method for forming a nozzle, and FIG. 6 is an explanatory diagram showing another example of burring processing.

Claims (1)

[Claims] When hot forging the main body member and nozzle part, which are provided as part of the pressure vessel main body, into one body, a pilot hole is made in the center of the main body member corresponding to the nozzle part, and a punch is inserted through this pilot hole. After the nozzle part is integrally hot forged with a die and a composite punch consisting of a part and a holding plate part, the holding plate part is removed from the composite punch, and then the punch part is pushed down to extrude the punch part from the nozzle part. A unique nozzle integral forging method using a composite punch.