JPS59118239A - Forging method - Google Patents

Abstract

PURPOSE:To improve the material flow of a hollow article and to eliminate the difference in the directivity of strength in an upsetting stage by specifying the relation of the extruding length at the front end thereby obtaining the hollow article. CONSTITUTION:A blank material 14 which is a solid round bar is disposed in a hollow die 11 in an upsetting stage and thereafter a punch 12 is advanced into the die 11 to upset the material 14 thereby forming a semielliptical hole 14a and forming a backward laterally drawn part 15b; at the same time, the front end of the material 14 is extruded to the extruding length thereof designated as l1. A punch 22 is advanced to form an intermediate hole 14b and to form a forward laterally drawn part 15a in a punching stage. The punch 22 is further advanced to form a deep hole 14c, and the front end part 14d of the material 14 of which the extruding length is designated as l3 is formed by the end face of the die 11, in a punching and extruding stage, wherein the relation of the extruding lengths l1, l3 is determined at l3/(l1+l3)<0.55. The front end part 14d is thereafter blanked in a blanking stage whereby a hollow article is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forging a hollow product suitable for obtaining a hollow product having a constricted portion by forging.

Conventionally, hollow products with a drawn part, for example, the front in the forging direction (
011 and a hollow product having a constricted portion on the rear side by forging, for example, as shown in FIGS.
The process was as shown in the figure.

In the figure, 1 is a hollow die having drawn portions 1a and 1b on the front side and rear side in the forging direction, respectively, and 2 is a punch disposed in the hollow die 1 so as to be movable back and forth, and has a stepped portion 2a. be.

First, as shown in FIG. 1, in the upsetting process, a solid round bar-shaped material 4 is charged into the hollow die 1, and then the punch 2 is advanced into the hollow die 1, and the material 4 is subjected to the upsetting process. Then, as shown in FIG. 1, a semi-elliptical hole 4a is formed, and a rear aperture portion 5b is formed.

Next, in the drilling step, another punch 21 without a stepped portion is further advanced into the hollow die 1 3 -2-10. , by page -1----------
As shown in FIG. 2, an intermediate hole 4b is formed and a front-side constricted portion 5a is formed.

Next, by further advancing the punch 21, the third
As shown in the figure, a deep hole 4C is formed and the front end 4
d on the end face of the hollow die 1, and then in the punching process, the front end 4d is punched,
As shown in FIG. 4, a hollow product 5 having a front constricted portion 5a, a rear constricted portion 5b, and a hollow hole 5C was manufactured.

This hollow article 5 (dl) is then suitably threaded in one or both of the portions 5d, 5e on the smaller diameter side than the two constricted portions 5a, 5b, and is used as a tool joint member or the like.

Indeed, in such conventional forging methods,
As shown in an enlarged view in FIG. 5, a bend (arrow A in FIG. 5) may occur in the material flow at a portion 5d of the hollow product 5 on the smaller diameter side than the front constricted portion 5a. When a portion is threaded, there is a problem in that the strength of the thread may vary.

JP-A-59-118239 (2) This invention was made to solve the above-mentioned conventional problems, and when obtaining a hollow product having a drawn portion on the front side in the forging direction by forging, Provided is a forging method capable of obtaining a hollow product in which the material flow of the product is good, the material flow is not curved so as not to follow the shape of the hollow product, and the strength does not locally vary. It is intended to.

The forging method according to the present invention uses a hollow die having a drawing part forming part on the front side in the forging direction, and a punch disposed in the hollow die so as to be able to move forward and backward. When forging a hollow product having a drawing part on the front side through the steps of upsetting, drilling, punching extrusion, and punching, a front end part is placed in the hollow die on the front side of the drawing part forming part. After charging the material in the position, the front end extrusion length is set to t in the upsetting process.
Then, in the punching step, the rear end of the material is punched and a constricted portion is formed, and in the next punching and extrusion step, the constricted portion is -1, town 11. -1-
The holes are drilled deeper than one page, and the front end extrusion length is set to t3, and the relationship between the extrusion lengths t□ and t3 is expressed as ta/(
Z-work + t8) <: 0.55, and then punching is performed to obtain a hollow product.

Next, embodiments of the present invention will be described based on the drawings.

FIGS. 6 to 9 are diagrams showing one embodiment of the present invention, and in the figures, reference numeral 11 indicates drawn portion forming portions 11a on the front side and the rear side in the forging direction, respectively.

11b is a hollow die, 12 is the hollow die 11;
This is a punch that is arranged to be movable forward and backward within the punch and has a stepped portion 12a.

In forging, first, as shown in FIG.
The side constriction forming portion 11a.

11b is also arranged with its front end and rear end located on the front side and the rear side, respectively, and then the punch 12 is advanced into the hollow die 11, and the material 14 is upset and processed in the same manner. As shown in FIG. 6 on page -1-=, ---, a semi-elliptical hole 14a is formed, and a rear constriction part 15b is formed, and at the same time, the front end extrusion length of the material 14 is adjusted to t□ extrude as

Next, in the hole punching step, as shown in FIG.
form a. Next, in the hole extrusion process, by further advancing the punch 22, as shown in FIG. The front end 14d is formed by the end face of the hollow die 11 with t3 set as By performing the hole punching process, as shown in FIG.
A hollow article having c is obtained.

Pages -, -7-, - In the forging process described above, as shown in FIG. The relationship was made with the portion 15 having a smaller diameter than the front constriction portion 15a.
This is to prevent bending (section A) in the material flow as shown in FIG. 5 at d. In this way, the front end extrusion length t□ of the material 14 is made relatively large in the upsetting process, and the front end extrusion length t3 of the material 14 is made relatively small in the punching and extrusion process, thereby preventing material flow bending. You will be able to reduce it. Also, the fold height of the material flow Lf)
can also be made smaller.

Next, examples will be described.

In the explanatory diagram shown in FIG. 10, D is the diameter of the material 14;
Do is the inlet diameter of the constricted part 15a, 1, and Lo is the constricted part 15a.
is the length of , and d is the diameter of the bunches 12 and 22.

t□ is the extrusion length in the upsetting process, t3 is the extrusion length in the punching and extrusion process, and LT is the total extrusion length = 1.
+13), and in this example, the combinations shown in the following table were used.

For items other than those shown in the table, see L. = 52.5
The test was conducted at tan eDo = 65.0 rope. Further, the bending angle θ is the angle shown in FIG.

-2-? As shown in the above table, it is clear that the material flow bending angle θ can be reduced by making the value of t3/(t□+t3) less than 0.55.

In addition, Fig. 11 (&) shows changes in the folding height (Lf),
FIG. 11(b) is a diagram showing changes in the material flow bending angle (θ), and by setting t37 (t□+z3) to less than 0°55, the fold height and material flow bending angle can be reduced. It is clear that it can be done.

Furthermore, when the material flow was directly observed, as shown in FIG.
5d, no bending of the material flow as shown in FIG. 5 was observed, and good results could be obtained.

As described above, according to the present invention, a hollow die having a drawing part forming portion on the front side in the forging direction and a punch disposed in the hollow die such that it can move forward and backward are used. Upsetting, drilling, and
After going through the perforation extrusion and hole punching steps, a hollow body with 9 front side pressure constrictions is formed...10.

When forging the product, after charging the material into the hollow die with the front end located on the front side of the drawing part forming part, in the upsetting step, extrude with the front end extrusion length tl, Next, in a perforation step, a hole is perforated at the rear end of the material and a constricted portion is formed, and in the next perforation and extrusion step, a hole is perforated deeper than the constricted portion and the front end is extruded with a front end extrusion length of t3, and the extrusion length is tl 1 The relationship of t3 is t3/(t1+t3)〈
0°55, and then, in the punching process, the front end is punched to obtain a hollow product.The method for forging a hollow product has a drawn part, so the material flow of the hollow product is good, and the hollow product is There will be no bending of the material flow that does not follow the shape of the material, and the strength will not vary locally.
It is possible to eliminate problems such as different directions of strength.

[Brief explanation of drawings]

Figures 1 to 4 show conventional examples, Figure 1 is a cross-sectional explanatory diagram showing the state before and after the upsetting process, Figure 2 is a cross-sectional explanatory diagram showing the state before and after the drilling process, and Figure 3 is on page - A cross-sectional explanatory diagram showing the state before and after the punching and extrusion process, FIG. 4 is a cross-sectional diagram of the hollow product after punching, FIG. 5 is a partially enlarged explanatory diagram showing the material flow of the hollow product in FIG. Fig. 9 shows one embodiment of the present invention, Fig. 6 is a cross-sectional explanatory view showing the state before and after the upsetting process, Fig. 7 is a cross-sectional explanatory view showing the state before and after the drilling process, and Fig. 8 is a perforation extrusion. A cross-sectional explanatory diagram showing the state before and after the process, FIG. 9 is a cross-sectional diagram of the hollow product after hole punching, and FIG. 10 is an explanatory diagram showing the change in dimensions due to forging.
11(a) and 11(b) are graphs showing the relationship between the extrusion length ratio and folding height, and the relationship between the extrusion length ratio and material flow bending angle, respectively. It is a partially enlarged explanatory diagram showing the material flow of the product. DESCRIPTION OF SYMBOLS 11...Hollow die, 11a, 11b...Aperture part forming part, 12.22...Punch, 14...Material, 14
d...Front end portion, 15...Hollow product, 15a...Front side constriction part, 15b...Backward side constriction part, 15C...Hollow hole, t□. t3...Extrusion length. Special opening U39-118239 (4) Japanese Patent Application Publication No. 59-1
18239 (6) JP-A-59-118239 (7) Figure 10

Claims (1)

[Claims] (1) Upsetting, After going through each process of drilling, punching and punching,
When forging a hollow convex metal having a drawing part on the front side, the material is charged into the hollow die with the front end located forward of the drawing part forming part, and then in the upsetting process, the front end is Extrusion is performed with the extrusion length set as tl, then, in the drilling step, the rear end of the material is punched and a constricted portion is formed, and in the next punching and extrusion step, the hole is punched deeper than the constricted portion, and the front end extrusion length is set as t3. extrusion, the relationship of the extrusion length 11.13 is set to t3/(t1+t3)<0.55, and then, in a punching step, the front end is punched to obtain a hollow product; -1-1, ---- Page forging method for hollow products.