JP3208818B2 - Press mold and press method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press method for pressing a rod having a circular cross section made of a metal material to be a material of a seamless pipe to a predetermined diameter by pressing, and is suitable for use in carrying out the method. Press mold.

[0002]

2. Description of the Related Art As is well known, when a bar having a circular cross section made of a metal material such as a steel material or a stainless steel material is manufactured, a billet having a predetermined diameter, which is generally a material, is cast by a casting machine. Multi-pass rolling was performed with a large number of grooved rolls to gradually reduce the cross-section to obtain a bar having a desired diameter.

[0003] However, in such a case, the diameter of the billet cannot be made much larger than the diameter of the final product because the amount of reduction by the grooved roll cannot be so large. Needed to cast many types of billets having different diameters. In addition, it is necessary to prepare a large number of grooved rolls corresponding to the diameter of the product, and it is necessary to work while exchanging these grooved rolls. It took time and the work efficiency was not good. In addition, when a billet is formed by a grooved roll, a considerable amount of useless portions are produced at both ends of the product, resulting in poor yield, and furthermore, a center porosity (segregation) generated when the billet is cast. (Gap) may remain as it is inside the product.

For this reason, in recent years, instead of forming with a grooved roll, the cross section is reduced by pressing a billet with a pair of dies, that is, a bar having a predetermined diameter is formed by a sizing press. Are being considered. That is, as shown in FIGS. 7 (a) to 7 (c), the dies 1
Are used, and the billet 2 is individually and sequentially pressed vertically and horizontally by the two pairs of molds. In this case, as the mold 1 described above, for example, FIGS.
As shown in (a) to (c), the pressing groove 3 has a substantially semicircular cross-sectional shape, and the inner diameter of the pressing groove 3 is on the entry side (the side where the billet 2 to be pressed enters). Is formed with a tapered portion 4 which gradually expands.

[0005]

SUMMARY OF THE INVENTION The above-described molds 1 and 1
When a sizing press is performed according to 1, an extremely large rolling force and reduction amount can be obtained as compared with the case of multi-pass rolling with grooved rolls, so that the billet size can be consolidated and the trouble of replacing rolls can be omitted. Therefore, the production efficiency can be improved, and the improvement of the yield and the elimination of the center porosity can be realized. However, in the above case, the vertical press and the horizontal press using two pairs of dies are required. Since this is not always the case, the cross-sectional shape of the molded product may be deformed irregularly with respect to the circular shape, or large burrs may be generated. It had been.

[0006]

Means for Solving the Problems The invention according to claim 1 has a circular shape.
While feeding the bar of the cross section in the axial direction by a predetermined dimension,
Pressing in the radial direction while rotating it around a predetermined angle
Therefore, it is necessary to reduce the cross section to obtain a rod
A pair of pressing dies used in a pressing method,
The bottom of the pressing groove is formed in an arc shape, and the insertion of the pressing groove is performed.
Side, there is a tapered portion with an inner diameter
It is characterized by being formed in advance .

[0007] The invention according to claim 2 is the invention according to claim 1.
A press method using a press die, wherein the press
Pressing the bar at a predetermined position using a tool
Rotate by a predetermined angle around the line and a predetermined dimension in the axial direction
By sending the bar material by the method,
It is characterized by being pressed sequentially by the mold
It is assumed that .

[0008]

The press die of the present invention has a two-stage taper on the entry side.
Part is formed.
The parts that need to be pressed are pre-pressed,
Pressing is performed continuously and smoothly over the entire length.
Further, in the pressing method of the present invention, the pressing of a billet or the like is performed.
While rotating the elephant bar and intermittently feeding
Sizing press in the longitudinal direction by the above-mentioned mold.
Over the entire length and circumference of the bar
An equal press is performed under the same conditions.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 (a) and 1 (b) show an outline of a press device for carrying out the method of the present invention, wherein reference numeral 10 denotes a bar to be pressed such as a billet, and 11 and 11 denote a pair of gripping ends. , And 12 and 12 are a pair of molds. The above-mentioned manipulators 11 and 11 rotate the gripped bar 10 around its axis by a predetermined angle, for example, 90 °, and run intermittently by a predetermined dimension in the same direction in synchronization. Then, when the bar 10 is stopped and the predetermined location is pressed by the dies 12 and 12 to reduce the cross section, the bar 10 is rotated by a predetermined angle and the dies 12 and 12 are rotated by a predetermined dimension. As a result, the bar 10 is sequentially sized and pressed over its entire circumference and over its entire length to have a predetermined cross-sectional dimension.

The above mold 12 is shown in FIGS. 2 and 3 (a).
As shown in (c), the cross-sectional shape is substantially semicircular, that is, the pressing groove portion 13 having a cross-sectional shape having an arc-shaped bottom portion 13a and straight side portions 13b, 13b continuous in a tangential direction of the bottom portion 13a. The pressing groove 13
On the entry side of the first tapered portion 1 whose inner diameter dimension gradually increases
4 and a second tapered portion 15 continuous therewith are formed in two stages. Then, FIG.
As shown in FIG. 5, the inclination angle θ _{4 of} the first tapered portion 14 (the inclination angle of the mold 12 with respect to the axial direction) is preferably 10 ° or more, for example, about 15 °.
The inclination angle theta ₅ of the tapered portion 15 of the good to be an inclination angle theta greater set to, for example, about 25 ° than ₄ of the first tapered portion 14. The pressing groove 1 is provided in the mold 12.
A similar tapered portion 16 is also formed on the exit side of No. 3,
This is not necessarily provided, and even when provided, the inclination angle may be set appropriately.

As shown in FIG. 3C, the opening angles θ _{1 to} θ ₃ of the pressing grooves 13 of the mold 12 are 80 ° to 12 °.
It is preferable to set the angle to about 0 °, preferably in the range of 90 ° to 100 °. If the opening angles θ _{1 to} θ ₃ are out of the above range, large burrs may occur or sufficient pressing may not be performed, which is not preferable.

As described above, the two-stage tapered portion 14,
The sizing press is performed by using a pair of molds 12 having the taper portions 15, 15.
With 15, a preliminary press is performed on the portion to be pressed next time, and as a result, the press is continuously and smoothly performed over the entire length of the bar 10. Further, in the conventional case in which pressing is performed by only one pair of dies 12 and 12 by rotating the bar member 10 as described above, and pressing in the vertical direction and the left and right direction is individually performed by two pairs of dies. As a result, uniform pressing is performed over substantially the entire circumference of the bar 10 under substantially the same conditions. From the above, by performing the above-described press using the dies 12, 12, a molded article having a sufficiently circular cross-sectional shape by performing a highly accurate sizing press is obtained.

FIG. 4 shows the results of an experiment conducted to compare the cross-sectional shapes of a molded article obtained by the method of the present invention and a molded article obtained by the conventional method. The method according to the present invention is obtained by pressing the sample while rotating it by 90 ° by using the dies 12 and 12 shown in FIGS. 2 and 3, and the method according to the conventional method is shown in FIGS. 9 are obtained by pressing two pairs of the conventional molds 1 and 1 shown in FIG.
In each case, the diameter of the sample before pressing was 80 mm, and the gap between the dies was set at 2 between 58 mm and 62 mm. The feed amount of each sample was 12 mm.
As is apparent from FIG. 4, the conventional method has a cross-sectional shape close to a square and has large burrs, while the method according to the present invention has a sufficiently circular shape. It has become.

FIG. 5 and FIG. 6 show the same experiment with the gap set at 58 mm, 62 mm, and 66 mm, and the maximum and minimum values of the diameter of the molded product obtained from each were set. Is a graph in which is plotted. FIG. 5 shows an example in which the opening angles θ _{1 to} θ ₃ of the mold are 90 °, and FIG. 6 shows an example in which the opening angles θ _{1 to} θ ₃ are 100 °. In each case, the conventional method has a large difference between the maximum and minimum dimensions, whereas the method according to the present invention has almost the same maximum and minimum dimensions, and the molded article according to the conventional method It can be seen that the molded article according to the method of the present invention is formed in a shape close to a perfect circle, while being deformed into a shape.

Although the mold 12 in the above embodiment has two tapered portions 14 and 15 on the entry side, the tapered portion may be provided in more stages. In addition, the rotation angle and the feed amount per one time of the bar and the gap size between the dies may be appropriately set in consideration of the size and material of the bar to be pressed, the shape and the size of each part of the die, and the like. Needless to say.

[0016]

As described above, the invention of claim 1 is described.
Press dies have an inner diameter that gradually increases on the entry side of the pressing groove.
The larger taper is formed over two or more steps
When pressing, press the next time by these tapered parts.
Preliminary presses are made on the parts to be
As a result, the press is continuously and smoothly pressed over the entire length of the bar.
To obtain a molded product with a sufficiently circular cross section.
Can be. The pressing method according to the second aspect of the present invention is characterized in that
Rotate the material by a predetermined angle around the axis and
By sending the specified dimensions, the entire circumference and the entire length
Pressing sequentially with the above molds, so using two pairs of molds
In the conventional case where the press in the vertical direction and the horizontal direction are performed separately
In comparison, a uniform press
Press can be performed, and a high-precision press can be performed.

[Brief description of the drawings]

FIG. 1 shows an outline of a press device for carrying out the method of the present invention, wherein (a) is a side view and (b) is a front view of a mold.

FIG. 2 is a perspective view showing one embodiment of a mold according to the present invention.

3A and 3B show the shape of the mold, wherein FIG. 3A is a plan view, FIG. 3B is a side sectional view, and FIG. 3C is a front view.

FIG. 4 is a diagram showing a cross-sectional shape of a molded product obtained by the method of the present invention and a cross-sectional shape of a molded product obtained by a conventional method.

FIG. 5 is a diagram showing the distribution of the diameter of a molded article obtained by the method of the present invention and the distribution of the diameter of a molded article obtained by the conventional method when the opening angle of the mold is 90 °.

FIG. 6 is a diagram showing the distribution of the diameter of a molded article obtained by the method of the present invention and the distribution of the diameter of a molded article obtained by a conventional method when the opening angle of the mold is 100 °.

FIG. 7 is a diagram showing an outline of a conventional press device,
(A) is a side view, (b), (c) is a front view of a mold, respectively.

FIG. 8 is a perspective view showing an example of a conventional mold.

FIGS. 9A and 9B show the shape of the mold, wherein FIG. 9A is a plan view, FIG. 9B is a side sectional view, and FIG. 9C is a front view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Bar material 11 Manipulator 12 Die 13 Pressing groove part 14 1st taper part 15 2nd taper part

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshihiko Obata 1st Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Pref. JP-A-60-244436 (JP, A) JP-A-48-25650 (JP, A) JP-A-5-212486 (JP, A) JP-A-52-55933 (JP, A) 154640 (JP, U) Actually open 63-85345 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21J 1/00-13/14 B21J 17/00-19/04 B21K 1/00-31/00

Claims (2)

(57) [Claims] 1. A rod material having a circular cross section has a predetermined dimension in the axial direction.
Feeding and rotating a predetermined angle around the axis
Pressing to reduce the cross section to a specified diameter
Pair of presses used in the pressing method to obtain
Mold, and the bottom of the pressing groove is formed in an arc shape.
And a taper whose inner diameter dimension gradually increases on the entry side of the pressing groove portion.
It is characterized in that the taper part is formed over two or more steps
And press mold. 2. A press using the press die according to claim 1.
And a predetermined method of forming a bar by the press die.
After pressing the position, the bar is rotated a predetermined angle around the axis.
And by sending a predetermined dimension in the axial direction,
The bar is moved around the entire circumference and the entire length by the mold.
A pressing method characterized by sequentially pressing.