JP2014240082A - Hot upset forging device and hot upset forging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot upset forging device and a hot upset forging method capable of preventing buckling even when using a long-size material to be worked in material difficult to be worked such as titanium alloy and capable of imparting high strain to a forged product.SOLUTION: A hot upset forging device includes a shaft-like pore part 6, an inside inclination surface 7 linked to the pore part 6 and a recessed part 5 having an upset part 8 linked to the inside inclination surface 7, and is composed of a lower die 2 in which a long-size material 20 to be worked is charged into the recessed part 5 and an upper die which presses down the material 20 to be worked. Therein, an inner diameter A of the pore part 6 is set as the diameter which is larger than the outer diameter C of a lower part of the material 20 to be worked and is 1.1 times of the outer diameter C or less, a height E of the pore part 6 is set as the height which is larger than 1/100 and 1/10 or less with respect to a shaft length L of the material 20 to be worked, an inner diameter B of the upset part 8 is set as the diameter which is larger than the outer diameter D on the upper part or the middle part of the material 20 to be worked and is 1.5 times of the outer diameter D or less and an inclination angle θ of the inside inclination surface 7 is set as the angle which is larger than 0° and 45° or less with respect to the axial center in the vertical direction of the recessed part 5.

Description

  The present invention relates to a hot upset forging device and a hot upset forging method for forging a long workpiece into a forged product having a recess.

In general, titanium alloys, nickel alloys, and stainless steels are used for structural members such as engine members or chassis of transportation equipment such as aircraft and vehicles because they have excellent mechanical properties and heat resistance.
A hot upset forging method using a hot upset forging device (die) is used as a method of forging the above-mentioned forged product using a workpiece such as a titanium alloy that is difficult to process. In the hot upset forging method, a heated work material is charged into a mold formed in advance to simulate the shape of the product, and the work material is kept in a high temperature state so as to conform to the shape of the mold. Forging while deforming so as to stretch. Using a hot upset forging method, a metal flow that conforms to the product shape can be obtained in the deformation during forging, so that it is more tenacious than other processing methods and has excellent mechanical properties such as impact fracture resistance. Can be obtained.

As a technique for performing hot upset forging, for example, there are those disclosed in Patent Documents 1 to 3.
In Patent Document 1, in a hot upset forging method in which a heated shaft-shaped material is pressed in the axial direction, and the central portion of the material is plastically deformed in a radially outward direction while being shortened in the length direction. A hot upset forging method is disclosed in which the axial length of the shaft-shaped material is prevented from being deformed in the radially outward direction so that the ratio of the axial length / outer diameter of the free deformation portion is 3 or less. ing.

  Further, in Patent Document 2, there is a first presser die that is a stamping portion at one end of a columnar material, a second presser die that is a stamping portion at the other end of the columnar material, and the presser die. A forging material manufacturing method for upsetting forging by a mold set including an intermediate mold having a columnar mold space, wherein a heated columnar material is inserted into the mold space of the intermediate mold, and the first presser A first upset forging step is performed in which a die is arranged downward, the second presser die is arranged upward, and the columnar material is axially pressed down by a predetermined length from the second presser die side, The mold set is turned upside down together with the columnar material, the second presser mold is disposed below, the first presser mold is disposed above, and the columnar material is axially moved from the first presser mold side. Discloses a method for producing a forging material for performing a second upsetting forging step in which the upsetting down is performed for a predetermined length. There.

  Further, Patent Document 3 is an upset method for processing a metal slag having a predetermined narrow aspect ratio, and has a cross section that is equal to the cross section of the housing in order to reduce the thin aspect ratio in preparation for forging operation. In order to obtain a cylindrical slag, the metal slag is arranged at least partially in the upset pot in the direction of the length of the metal slag with a cylindrical housing provided for upset purposes, An upset method is disclosed in which pressure is applied to the metal slug longitudinally using a punch until the entire cross section of the housing is filled.

JP 7-171650 A JP 2013-27925 A JP 2006-123007 A

In recent years, difficult-to-work materials such as titanium alloys, nickel alloys, and stainless steels are often formed into large forged products by hot upsetting forging. As the base material of this forged product, a long workpiece having an axial length / outer diameter ratio exceeding 3 is used.
However, when hot upset forging is performed using such a workpiece, the workpiece is long and may buckle. If the workpiece is in such a situation, it becomes difficult to obtain a desired forged product. In addition, large forged products are often used in harsh environments, and there is a demand for imparting high strain to the entire forged product and having excellent mechanical properties.

Here, when forming a long workpiece into a large forged product, it is considered to use the hot upset forging technique disclosed in Patent Documents 1 to 3.
In Patent Document 1, the workpiece is loaded into a cylindrical lower mold lower than the axial length of the workpiece, and the upper portion of the workpiece protruding from the lower mold is placed in a bulge shape in the radially outward direction. This is a method of forging.
However, according to the technique of Patent Document 1, as shown in FIG. 3 of the same document, the upper part of the columnar workpiece is greatly expanded with respect to the lower part, and the outer diameter dimension in the height direction of the workpiece. Will cause a difference. Therefore, when upset forging is performed multiple times, the difference between the outer diameter of the upper part and the outer diameter of the lower part of the workpiece is further increased, and the above-mentioned difference in outer diameter may be promoted. It is not preferable. In addition, since the amount that can be reduced by one upset forging is small, the number of upset forging steps increases, and the method cannot be applied at a site where a large forged product is efficiently manufactured.

  Patent Document 2 discloses an inner diameter that is provided between a pair of upper and lower cylindrical pressing dies, an upper pressing dies, and a lower pressing dies, and that is larger than a workpiece (billet) outer diameter. The work material is loaded into a hot upset forging device composed of a cylindrical holding mold having a length of This is a method in which the entire forging device is reversed and upset forging is performed again.

However, in Patent Document 2, the workpiece to be charged is cooled while the entire hot upset forging device is inverted while the workpiece is charged, and the forging is performed hot. It becomes difficult. In particular, when the workpiece is a difficult-to-work material such as a titanium alloy, the technique of Patent Document 2 is not suitable.
Further, Patent Document 3 discloses that a workpiece having an axial length / outer diameter ratio of more than 12 is provided in a cylindrical lower mold having an inner diameter of 1.35 times or less of the outer diameter of the workpiece and a protrusion on the bottom periphery. Is pressed down with a punch (upper die) having protrusions on the periphery of the pressed surface and repeatedly upset forged until the ratio of the axial length / outer diameter of the workpiece becomes about 3.

However, in Patent Document 3, a protrusion is provided on the bottom peripheral edge of the lower mold to try to position the workpiece at the center in the axial direction of the lower mold. It is difficult to securely hold the mold in the center in the axial direction, which may cause buckling.
In other words, a technology for obtaining a forged product excellent in mechanical properties by imparting high strain to the entire workpiece while preventing buckling during upsetting forging has not yet been developed.

  The present invention has been made in view of the above-mentioned problems. In difficult-to-work materials such as titanium alloys, buckling can be prevented even when a long work material is used, and high strain is exerted on the entire forged product. An object of the present invention is to provide a hot upsetting forging apparatus and a hot forging method capable of providing the above.

In order to solve the above-described problems, the present invention takes the following technical means.
The hot upsetting forging device of the present invention includes a shaft-shaped hole, an inner inclined surface connected to the upper portion of the hole, and an upset portion formed connected to the upper portion of the inner inclined surface. And a lower mold in which a long workpiece is inserted into the recess, and an upper mold for rolling down the long workpiece inserted in the lower mold from above In the hot upsetting forging apparatus used for hot upsetting forging, the inner diameter A of the hole of the lower mold is larger than the outer diameter C of the lower part of the workpiece and 1.1 times or less in diameter. The height E of the hole of the lower mold is set to a height greater than 1/100 and 1/10 or less with respect to the axial length L of the workpiece, and the recess of the lower mold is installed. The inner diameter B of the part is set to be 1.5 times or less larger than the outer diameter D of the upper part or the middle part of the workpiece, and the inclination angle θ of the inner inclined surface is the concave part. Against the axis oriented in the vertical direction, characterized in that it is set below 0 ° larger than 45 °.

Preferably, the inclination angle θ of the inner inclined surface is set to be larger than 10 ° and not larger than 45 ° with respect to the axial center of the concave portion.
Preferably, the inner wall surface of the upset portion of the recessed portion of the lower mold is inclined radially upward with respect to the axial center of the recessed portion in the vertical direction, and the inner wall surface of the upset portion Is preferably set to be larger than 0 ° and not larger than tan ⁻¹ [0.1 × D / L].

Preferably, a lower projecting portion that fits into an upper portion of the workpiece is formed on a peripheral edge of the pressure lower surface of the upper mold.
Preferably, the downward projecting portion is formed in a rectangular shape or a triangular shape in a sectional view.
Preferably, a convex portion protruding downward is formed at the center of the pressure surface of the upper mold.

Preferably, a convex portion projecting downward is formed at the center of the pressing surface of the upper mold, and an upward projecting portion projecting upward at the center of the bottom of the concave portion of the lower mold. Is good to be formed.
The hot upsetting forging method of the present invention is a hot upsetting forging method in which a long workpiece is upset forged, and includes a lower mold and a pressed surface provided in the hot upsetting forging apparatus of the present invention. Upward forging is repeatedly performed until the long workpiece becomes a workpiece having a predetermined size and shape using an upper mold having a lower protrusion formed on the periphery of Using the upset forging process, the lower mold provided in the hot upset forging apparatus of the present invention, and the upper mold in which a protruding convex portion is formed downward in the center of the pressed surface, In the central portion of the workpiece forged in the upset forging step, a hollow portion having a bottom thickness of 1/2 or less with respect to the axial length L of the workpiece is formed, and the whole And a hollow forging step for producing a forged product having a strain of 0.2 or more.

Preferably, in the upsetting forging step, the upsetting and forging of the workpiece may be reversed and the upsetting forging may be repeatedly performed hot.
Preferably, in the upsetting forging step, a plurality of upper molds and lower molds having different lengths provided in the hot upsetting forging apparatus of the present invention are prepared in accordance with the number of times of upsetting forging repeatedly. Then, each time upset forging, the upper mold and the lower mold are replaced with short ones, and the long workpiece is changed to a workpiece having a predetermined size and shape. It is good to perform upset forging until it becomes.

Preferably, in the hollow forging step, the forged product may be formed in a U shape in a sectional view.
Preferably, in the hollow forging step, the workpiece after the upsetting forging step is held without being released from the lower die, and is changed to an upper die included in the hot upsetting forging device of the present invention. Then, the forged product may be manufactured by hot upsetting.
Preferably, a drilling step is provided for penetrating a central portion facing the axial center direction of the forged product after the hollow forging step.

  Preferably, the forged product is formed into a shape in which the ratio of axial length L / outer diameter D is 3 or less.

  According to the hot upset forging device and the hot upset forging method of the present invention, in difficult-to-work materials such as titanium alloys, it is possible to prevent buckling even when using a long work material, and forging. High strain can be applied to the entire product.

It is the figure which showed the hot upset forging method of this invention. It is the figure which showed the hot upset forging apparatus of this invention, and the shape of a workpiece. In the hot upsetting forging method of this invention, it is a figure which shows the process in which a high distortion is provided to the forged product forged. It is the side view which showed an example of the forged product forged using the hot upsetting forging method of this invention.

Hereinafter, the hot upset forging device 1 and the hot upset forging method of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the hot upset forging device 1 of the present invention inserts a heated workpiece 20 (hereinafter referred to as wasteland) into a mold, and follows the shape of the mold. A forged product 21 having a desired shape is formed by deforming the wasteland 20 in a hot state. Specifically, this hot upsetting forging device 1 has a mold for forming a forged product 21, and this mold can be divided into two parts, upper and lower, and a wasteland 20 The lower mold 2 is loaded and placed, and the upper mold 3 that squeezes the waste land 20 placed on the lower mold 2 from above.

The lower mold 2 (container) is formed to be connected to the shaft-shaped hole 6, the inner inclined surface 7 connected to the upper portion of the hole 6, and the upper portion of the inner inclined surface 7. It is comprised by the flange-shaped recessed part 5 which has the upsetting part 8, and the long rough ground 20 is inserted in this hole 6, the inner side inclined surface 7, and the upsetting part 8 (namely, recessed part 5). ing.
Specifically, as shown in FIG. 2 (a), a concave portion 5 having an inner diameter larger than the outer diameter of the rough ground 20 and having a flange shape is formed at the center in the width direction of the lower mold 2 and on the upper side. It is formed, and the wasteland 20 can be inserted into the recess 5 from the upper side to the lower side. The inner diameter B of the upsetting portion 8 of the recess 5 is set to be larger than the outer diameter D of the wasteland 20 and 1.5 times or less than the outer diameter D of the wasteland 20 (for example, the maximum outer diameter of the wasteland 20). (D <B ≦ 1.5D). Preferably, the inner diameter B of the upsetting portion 8 is set to be larger than 1 and larger than the outer diameter D of the wasteland 20 to 1.3 times or less with respect to the outer diameter D of the wasteland 20 (D <B ≦ 1.3D).

The reason why the inner diameter B of the upsetting portion 8 is set is that, for example, when the outer diameter D of the wasteland 20 is set larger than 1.5, the wasteland 20 buckles.
An inner inclined surface 7 is formed at the lower portion of the concave portion 5 so as to be connected to the shaft-shaped hole portion 6 so that the inner diameter gradually decreases (a shape that tapers downward). That is, the inner inclined surface 7 connects the lower part of the upsetting part 8 and the upper part of the hole part 6. The inclination angle θ of the inner inclined surface 7 is set to be greater than 0 ° and not more than 45 ° with respect to the axial center of the concave portion 5 (0 ° <θ ≦ 45 °). Preferably, the inclination angle θ of the inner inclined surface 7 is set to be larger than 10 ° and not larger than 45 ° with respect to the axial center of the concave portion 5 (10 ° <θ ≦ 45 °).

The reason for setting the inclination angle θ of the inner inclined surface 7 is that, for example, when the inclination angle θ of the inner inclined surface 7 is larger than 45 °, the concave portion of the wasteland 20 formed by the inner inclined surface 7 is the following. This is because when the wasteland 20 is reduced in the upsetting forging process, the wasteland 20 is folded into the inside of the wasteland 20 and may become a folding rod.
In this way, it is possible to prevent folding wrinkles by setting the inner inclined surface 7. Further, the joint portion between the inner inclined surface 7 and the hole 6 is rounded and chamfered (fillet processing), or the joint portion between the inner inclined surface 7 and the hole 6 is cut to a surface with an inclination angle of 30 ° or less. In this case, it is possible to further prevent folding wrinkles. Further, when the inner inclined surface 7 is brought into contact with the wasteland 20 during upsetting forging, a wedge-shaped region constrained by friction due to the concave portion 5 is increased, and a high strain is imparted to the forged product 21 correspondingly. It is also possible to do.

A shaft-shaped hole 6 having a diameter close to the outer diameter C of the lower portion of the waste land 20 is formed at the center in the width direction of the lower mold 2 and on the lower side. The hole 6 is a “fitting portion” into which the lower portion of the wasteland 20 inserted in the concave portion 5 is fitted.
The inner diameter A of the hole 6 is larger than the outer diameter C of the lower portion of the wasteland 20 and 1.1 times or less (C <A ≦ 1.1C). For example, the space (clearance) between the hole 6 and the wasteland 20 fitted in the hole 6 is about 2 mm to 5 mm. Therefore, the axial center of the wasteland 20 substantially coincides with the axial center of the recess 5 (the hole 6 and the upsetting portion 8).

  Further, the height E of the hole 6 is set to a height greater than 1/100 and 1/10 or less with respect to the axial length L of the wasteland 20 (L / 100 <E ≦ L / 10). For example, if the height of the wasteland 20 is 1 m, the height E of the hole 6 is about 100 mm or less. Therefore, it is possible to stably hold the wasteland 20 and widen the outer diameter of the wasteland 20 over a wide range (increase the outer diameter of the wasteland 20 and reduce the height). Moreover, it is preferable that the height E of the hole 6 is a value that can center the rough ground 20 while including chamfering and filleting (round chamfering) of corners of the rough ground 20.

The reason why the inner diameter A of the hole 6 is larger than the outer diameter C of the lower part of the wasteland 20 and 1.1 times or less is, for example, that the inner diameter A of the hole 6 is 1 with respect to the outer diameter C of the lower part of the wasteland 20 When the ratio exceeds 1.times, the effect of holding (centering) the wasteland 20 becomes small, and the wasteland 20 buckles during upsetting forging.
The reason why the height E of the hole 6 is 1/10 or less of the axial length of the wasteland 20 is, for example, that the height E of the hole 6 is greater than 1/10 with respect to the axial length of the wasteland 20. This is because the length in the axial direction of the portion where the outer diameter D of the wasteland 20 can be increased is shortened. Moreover, if the height E of the hole 6 is smaller than 1/100 (lower) than the axial length of the wasteland 20, the wasteland 20 will fall to the left and right, and the wasteland 20 will fall during upsetting forging. This is for buckling.

Thereby, the hole 6 is formed so that the wasteland 20 fits in, and the axis of the lower mold 2 (including the hole 6 and the recess 5) coincides with the axis of the long wasteland 20. It is like that. That is, the long wasteland 20 can be easily and quickly placed at the center of the lower mold 2, and can be stably held in an upright state.
In this way, by setting the inner diameter A of the hole 6 and the inner diameter B of the upsetting portion 8, the displacement of the axial center of the wasteland 20 during upsetting forging can be reduced. It is also possible to reduce the risk. In addition, the occurrence of wrinkles in the wasteland 20 can be suppressed. Moreover, by setting the inclination angle θ of the inner inclined surface 7, a high strain of 0.2 or more can be given to the forged product 21.

  As shown in FIG. 2B, the inner wall surface of the upsetting portion 8 of the concave portion 5 of the lower mold 2 is directed in the vertical direction of the concave portion 5 in order to improve the releasability of the rough ground 20 after upsetting forging. It is good to incline in a radial shape upward with respect to the axis. The upsetting portion 8 becomes a mortar-shaped cylindrical body by inclining so that the inner wall surface becomes lower (inner inclined surface 7 side) so that the inner diameter becomes smaller. Hereinafter, the inner wall surface of the inclined upsetting portion 8 is referred to as an upset inclined surface 11.

The inclination angle η of the upset inclined surface 11 is more preferably set to be larger than 0 ° and not larger than tan ⁻¹ [0.1 × D / L] (0 ° <η ≦ tan ⁻¹ [0. 1 × D / L]). By setting the inclination angle η of the upsetting inclined surface 11 to be tan ⁻¹ [0.1 × D / L] or less, it is possible to secure an expansion amount of the outer diameter D of the upset forging waste 20.
The reason why the inclination angle η of the upset inclined surface 11 is not more than tan ⁻¹ [0.1 × D / L] is that, for example, when the inclination angle η is increased, the wasteland 20 can be easily released. As described above, in order to prevent buckling, “the inner diameter B of the upset portion 8 of the lower mold 2 ÷ the outer diameter D ≦ 1.5 of the waste land 20” (D <B ≦ 1.5D) is set. Therefore, when the inclination angle η of the upset inclined surface 11 is set to tan ⁻¹ [0.25 × D / L] or more, “the inner diameter B of the upset portion 8 of the lower mold 2 ÷ the outer diameter D of the rough ground 20”. This is because “≦ 1.5” does not hold.

  On the other hand, below the hole 6, a knockout bar 12 for discharging the forged product 21 after upsetting forging and a cylinder mechanism (not shown) for moving the knockout bar 12 in the vertical direction are provided. . The knockout bar 12 is formed in a bolt shape in a cross-sectional view, and is provided at a position corresponding to the hole 6 of the lower mold 2 so as to be movable in the vertical direction. The knockout bar 12 is moved upward by the cylinder mechanism to push up the forged product 21 (the rough land 20 after forging). The forged product 21 is peeled off from the lower mold 2 by the knockout bar 12.

Further, a mold support mechanism (not shown) is provided on the lower side of the lower mold 2 so that the lower mold 2 can be supported on the floor surface or the like by the mold support mechanism.
A plurality of lower molds 2 according to the present embodiment are prepared in accordance with the number of repeated upsetting forgings, and each time the upsetting forging is performed, the lower die 2 is changed to one corresponding to the upset forged 20. Like to do. In addition, in order to form the lower hollow part of a cavity in the bottom part of the wasteland 20 after upset forging, the lower hollow part formation by which the upward protruding part of the shape which protruded upwards was formed in the center of the bottom part of the recessed part 5 was formed. A lower mold 2 may be prepared.

  The upper mold 3 is disposed above the lower mold 2 and is approached and separated from above with respect to the waste land 20 loaded (placed) on the lower mold 2. A punch 4 for lowering the wasteland 20 is formed at the center of the upper die 3. By lowering the upper die 3, the upper surface of the wasteland 20 and the pressure lower surface of the punch 4 are brought into surface contact. Thus, the wasteland 20 can be crushed from above.

The punch 4 has an outer diameter slightly smaller than the opening diameter on the upper side (the upsetting portion 8) of the recess 5 of the lower mold 2, and is lowered until the upper mold 3 abuts on the lower mold 2. At this time, the concave portion 5 is fitted from above, and the upper portion of the waste land 20 is pressed down from above.
As shown in FIG. 1, the upper die 3 of the present embodiment includes an upset forging upper die 3 a for performing upset forging hot and a center in the axial direction of a wasteland 20 performed after upsetting forging. A hollow portion forming upper mold 3b for forming a hollow portion 22 is prepared.

The upset forging upper die 3a is for upsetting the long wasteland 20 to the wasteland 20 having a predetermined shape and size, and the center of the pressure lower surface of the upset forging upper die 3a is formed substantially flat. ing. Moreover, the downward protrusion part 9 fitted to the upper part of the wasteland 20 is formed in the periphery of the pressing surface of the upset forging upper die 3a (upset forging punch 4a).
As shown in FIGS. 2C and 2D, the downward projecting portion 9 is formed in a triangular shape in a cross-sectional view, and the lower projecting portion 9 is in surface contact with the upper portion of the waste land 20. The wasteland 20 is held upright. That is, the upset forging upper die 3a having the downward projecting portion 9 has a pressing surface formed in a concave shape that is opposite in cross section.

In this way, by providing the downward projecting portion 9 at the peripheral edge of the pressure lower surface of the upset forging upper die 3a, the wasteland 20 during the upset forging can be stably held and the displacement of the axial center of the wasteland 20 can be reduced. Therefore, it is possible to prevent the occurrence of buckling during the reduction.
In addition, as long as the shape of the downward protrusion part 9 is a shape fitted to the upper part of the wasteland 20, what kind of shape may be sufficient as it. For example, the downward projecting portion 9 may be formed in a rectangular shape in sectional view.

On the other hand, the depression forming upper mold 3b is for forming a hollow depression 22 at the center in the axial direction of the rough ground 20 formed in a predetermined shape and size. At the center of the pressure-lower surface of the depression forming punch 4b), a protruding portion 10 that protrudes downward is formed.
As shown in FIG. 1, the convex part 10 is formed in the tip part (pen point) shape of the ball-point pen in a cross-sectional view. Specifically, the convex portion 10 has a drooping shape that inclines so that the outer diameter gradually tapers downward from the pressure lower surface of the depression forming punch 4b and then projects downward from a predetermined position. Yes. That is, the pen core protrudes from the cover provided on the pen tip. The height of the convex portion 10 in the vertical direction is larger than ½ of the height of the wasteland 20 after upset forging, and is formed so as not to exceed the height of the wasteland 20. In addition, you may make the convex part 10 into various shapes according to the shape of the forged product 21 requested | required.

  As shown in FIGS. 1 and 2 (a), the wasteland 20 (workpiece) is a substantially cylindrical member that is elongated in the vertical direction, and the ratio of the axial length L / outer diameter D exceeds 3. Is. Moreover, the rough ground 20 used for the hot upsetting forging apparatus 1 and the hot upsetting forging method of the present invention is a difficult-to-work material such as titanium alloy, nickel alloy, and stainless steel. In the present embodiment, for example, a rough ground 20 of a titanium alloy such as Ti-17 (Ti-5Al-2Sn-2Zr-4Mo-4Cr) or Ti-6246 (Ti-6Al-2Sn-4Zr-6Mo) is used.

The upper and lower edges of the wasteland 20 are chamfered obliquely, and the chamfered portion of the upper part of the wasteland 20 and the lower protrusion 9 of the upset forging upper mold 3a described above come into surface contact with each other. Is held upright during upset forging. In addition, when the downward protrusion part 9 of the upset forging upper metal mold | die 3a is formed in the rectangular shape, you may make the upper part of the wasteland 20 into the shape according to a rectangular shape.
In this way, the outer diameter C of the lower portion of the waste land 20 is made to be along the inner diameter A of the hole 6 of the lower mold 2, and the shape of the upper portion of the waste land 20 is formed to correspond to the pressed surface of the upper mold 3. By doing so, the deviation of the axial center of the wasteland 20 can be reduced, and the occurrence of buckling during rolling down can be prevented.

Further, a glass lubricant (liquid glass and / or powder glass) for improving the lubricity and releasability with the lower mold 2 is applied (coated) to the surface of the waste land 20.
The glass lubricant increases the lubricity between the mold and the wasteland 20 during forging by covering the surface of the wasteland 20 (a difficult-to-work material such as a titanium alloy), and after the forging is completed, the glass lubricant or forging. The releasability when the product 21 is peeled off from the lower mold 2 is improved. In addition, the occurrence of seizure between the mold and the wasteland 20 during forging is suppressed, and cracks and wrinkles of the forged product 21 are prevented.

By the way, the forged product 21 manufactured by the hot upsetting forging apparatus 1 of the present invention is used for an engine member of a transportation device such as an aircraft or a vehicle, or a structural member such as a chassis. Stress) etc. Therefore, the forged product 21 is required to have high and stable mechanical properties such as high strength, ductility, toughness, and fatigue properties.
For example, titanium alloy forgings 21 (particularly α-β forging of Ti-64 alloy) used in aircraft and the like are added to the deformation (strain) applied in the finish forging process (in this embodiment, the hollow forging process). The strain applied in the upsetting forging process (billet forging process, wasteland forging process, etc.) performed before that also affects the characteristics (for example, tensile strength, proof stress, fatigue life, etc.) of the final forged product 21. For this reason, it is important to impart strain to the entire forged product 21 (the wasteland 20).

Therefore, the inventors of the present application use the hot upset forging device 1 described above to repeat upset forging to impart a high strain of 0.2 or more to almost the entire forged product 21, and to achieve a desired high level. A hot upset forging method for forging a forged product 21 having mechanical properties has been developed.
Next, a method for producing a forged product 21 having a high level of mechanical characteristics using the hot upsetting forging apparatus 1 described above, that is, a hot upsetting forging method of the present invention will be described with reference to the drawings. .

  As shown in FIG. 1, the hot extrusion forging method according to the present invention performs upset forging of a long waste land 20 (workpiece) having a ratio of axial length L / outer diameter D exceeding 3, and the inside is This is a method for manufacturing a forged product 21 having a U-shaped cross-sectional view in which a hollow recess 22 is formed. The hot extrusion forging method of the present invention uses hot upsetting forging device 1 described above to hot upset forging until long wasteland 20 becomes wasteland 20 having a predetermined size and shape. The hollow forging which manufactures the forging product 21 which formed the hollow part 22 in the axial center direction center part of the rough ground 20 forged in the upsetting forging process performed repeatedly and the upsetting forging process, and provided the high distortion to the whole whole. And a process.

In the upset forging process, the upset forging is repeatedly performed on the long wasteland 20 until the ratio of the axial length L / outer diameter D becomes 3 or less (FIGS. 1A to 1). d)).
In FIG. 1A, the long wasteland 20 is inserted into the recess 5 (the upsetting portion 8) of the lower mold 2, and the bottom portion of the wasteland 20 is fixed so as to be fitted into the hole 6. Then, hot forging is performed to produce a wasteland 20 having a predetermined size and shape.

Here, the lower mold 2 has a height slightly lower than the axial length L of the long wasteland 20, and the inner diameter B of the upsetting portion 8 is slightly larger than the outer diameter D of the long wasteland 20.
However, the inner diameter A of the hole 6 is larger than the outer diameter C of the lower part of the wasteland 20 and 1.1 times or less, and the height E of the hole 6 is 1/100 of the axial length L of the wasteland 20. The height is 1/10 or less. The inner diameter B of the upsetting portion 8 is larger than the outer diameter D of the wasteland 20 and is 1.5 times or less. The inclination angle θ of the inner inclined surface 7 is greater than 0 ° and less than or equal to 45 ° with respect to the axial center of the concave portion 5 that faces in the vertical direction.

The upset forging punch 4a of the upset forging upper die 3a here is elongated vertically and the diameter in the width direction is fitted into the recess 5. Further, the upset forging punch 4a is formed with a downward projecting portion 9 on the periphery of the pressed surface. And the wasteland 20 which finished the 1st upsetting forge process is what was squeezed by the axial length of about 1/4.
By the way, FIG. 3 is the figure which showed the process in which a high distortion | strain is provided to the forged product 21 forged in the hot upsetting forging method of this invention.

As shown in FIG. 3A corresponding to FIG. 1A, the high strain imparted to the wasteland 20 in the first upsetting forging process is slightly lower than the upper part of the wasteland 20 from the inner inclined surface 7. It is given during the period up to the upper side (the hatched portion with a wide interval). In addition, the low distortion part remains on the upper side of the wasteland 20 and the upper side of the inner inclined surface 7 (the hatched portion with a narrow interval).
Next, in FIG.1 (b), it changes to the upset forging upper metal mold | die 3a and the lower metal mold | die 2 corresponding to the rough land 20 upset forged in the 1st upset forging process first. And the upper part and the lower part of the rough ground 20 upset and forged in the first upset forging process are exchanged (inverted upside down) and inserted into the upset part 8 of the concave part 5, and the bottom part of the rough ground 20 is perforated. Fix so that it fits into the part 6. Then, hot forging is performed to produce a wasteland 20 having a predetermined size and shape.

Here, the lower mold 2 (lower mold 2 after replacement) is shorter than the lower mold 2 before replacement and is slightly lower than the axial length L of the rough ground 20, and the inner diameter B of the upsetting portion 8 is long. It is a little larger than the outer diameter D of the rough waste land 20. However, the inner diameter A of the hole 6 is larger than the outer diameter C of the lower part of the wasteland 20 and 1.1 times or less, and the height E of the hole 6 is 1/100 of the axial length L of the wasteland 20. The height is 1/10 or less. The inner diameter B of the upsetting portion 8 is larger than the outer diameter D of the wasteland 20 and is 1.5 times or less. The inclination angle θ of the inner inclined surface 7 is greater than 0 ° and less than or equal to 45 ° with respect to the axial center of the concave portion 5 that faces in the vertical direction.

  Further, the upset forging punch 4a of the upset forging upper die 3a here is formed slightly shorter than the upset forging punch 4a of the upset forging upper die 3a used in the first upset forging step. The diameter in the width direction is fitted into the recess 5. Further, the upset forging punch 4a has a lower protruding portion 9 formed on the periphery of the pressed surface, and the inclined surface of the lower protruding portion 9 is below the upset forging upper die 3a used in the first upsetting forging step. It is formed longer than the inclined surface of the protrusion 9. And the wasteland 20 which finished the 2nd upsetting forge process is what was crushed by the axial length of about 1/4.

As shown in FIG. 3B corresponding to FIG. 1B, the high strain imparted to the wasteland 20 in the second upsetting forging process is slightly lower than the upper part of the wasteland 20 from the lower part of the wasteland 20. It is given until it reaches the upper side (shaded part with wide interval). In addition, the low distortion part remains in the upper part and the lower part of the wasteland 20 (the hatched part with a narrow space | interval).
In FIG.1 (c), it changes to the upset forging upper metal mold | die 3a and the lower metal mold | die 2 corresponding to the rough ground 20 upset forged by the 2nd upset forging process first. And the upper part and lower part of the rough ground 20 upset and forged in the second upset forging process are exchanged (inverted upside down) and inserted into the upset part 8 of the concave part 5, and the bottom part of the rough ground 20 is formed in the hole. Fix so that it fits into the part 6. Then, hot forging is performed to produce a wasteland 20 having a predetermined size and shape.

  Here, the lower mold 2 (the lower mold 2 after the replacement) is shorter than the lower mold 2 before the replacement and has almost the same height as the axial length L of the rough ground 20, and the inner diameter B of the upsetting portion 8 is long. It is a little larger than the outer diameter D of the rough waste land 20. However, the inner diameter A of the hole 6 is larger than the outer diameter C of the lower part of the wasteland 20 and 1.1 times or less, and the height E of the hole 6 is 1/100 of the axial length L of the wasteland 20. The height is 1/10 or less. The inner diameter B of the upsetting portion 8 is larger than the outer diameter D of the wasteland 20 and is 1.5 times or less. The inclination angle θ of the inner inclined surface 7 is greater than 0 ° and less than or equal to 45 ° with respect to the axial center of the concave portion 5 that faces in the vertical direction.

  The upset forging punch 4a of the upset forging upper die 3a here is formed slightly shorter than the upset forging punch 4a of the upset forging upper die 3a used in the second upset forging step. The diameter in the width direction is fitted into the recess 5. Further, the upset forging punch 4a has a lower protruding portion 9 formed on the periphery of the pressed surface, and the inclined surface of the lower protruding portion 9 is below the upset forging upper die 3a used in the second upsetting forging step. It is formed longer than the inclined surface of the protrusion 9. And the wasteland 20 which finished the 3rd upset forging process is what was squeezed by the axial length of about 1/4.

As shown in FIG. 3C corresponding to FIG. 1C, the high strain imparted to the wasteland 20 in the third upsetting forging process is slightly lower than the upper part of the wasteland 20 from the lower part of the wasteland 20. It is given until it reaches the upper side (shaded part with wide interval). In addition, the low distortion part remains in the upper part and the lower part of the wasteland 20 (the hatched part with a narrow space | interval).
In FIG.1 (d), it changes into the upset forging upper metal mold | die 3a and the lower metal mold | die 2 corresponding to the rough ground 20 upset forged by the 3rd upset forging process first. And the upper part and the lower part of the rough ground 20 upset and forged in the third upset forging step are exchanged (inverted upside down) and inserted into the recess 5 of the lower mold 2, and the bottom of the rough ground 20 is perforated. Fix so that it fits into the part 6. Then, hot forging is performed to produce a wasteland 20 having a predetermined size and shape.

Here, the lower mold 2 (lower mold 2 after replacement) is shorter than the lower mold 2 before replacement and is slightly lower than the axial length L of the rough ground 20, and the inner diameter B of the upsetting portion 8 is long. It is a little larger than the outer diameter D of the rough waste land 20. However, the inner diameter A of the hole 6 is larger than the outer diameter C of the lower part of the wasteland 20 and 1.1 times or less, and the height E of the hole 6 is 1/100 of the axial length L of the wasteland 20. The height is 1/10 or less. The inner diameter B of the upsetting portion 8 is larger than the outer diameter D of the wasteland 20 and is 1.5 times or less. The inclination angle θ of the inner inclined surface 7 is greater than 0 ° and less than or equal to 45 ° with respect to the axial center of the concave portion 5 that faces in the vertical direction.

The upset forging punch 4a of the upset forging upper die 3a here is formed slightly shorter than the upset forging punch 4a of the upset forging upper die 3a used in the third upset forging step. The diameter in the width direction is fitted into the recess 5. And the wasteland 20 which finished the 4th upsetting forging process is what was squeezed by the axial length of about 1/4.
As shown in FIG. 3D corresponding to FIG. 1D, the high strain applied to the wasteland 20 in the fourth upset forging step is caused by the upper center of the wasteland 20 and the lower center of the wasteland 20. Except for a wide range (shaded areas with wide intervals). That is, a low strain portion (shaded portion with a narrow interval) remains in the upper center and lower center of the wasteland 20, and a high strain is applied to the outer side in the radial direction (surface layer of the wasteland 20).

And the wasteland 20 which finished the upsetting forging process is sent to a hollow forging process.
In the hollow forging process, a forged product 21 in which a hollow portion 22 is formed in the central portion in the axial center direction of the wasteland 20 forged in the upset forging process is manufactured (see FIG. 1E).
In FIG.1 (e), the waste land 20 which finished the 4th upset forging process is hold | maintained as it is, without releasing from the lower metal mold | die 2. FIG. And it changes into the hollow part formation upper metal mold | die 3b which has the hollow part formation punch 4b in which the convex-shaped convex part 10 was formed in the center of a pressing surface downward, and hot upsetting forging was performed, and the wasteland 20 A forged product 21 having a U-shaped (cup shape) in sectional view, which is formed so as to have a bottom thickness equal to or less than ½ of the height (axial length direction) of and a uniform thickness. In addition, when the bottom thickness of the forged product 21 exceeds 1/2, a portion (low strained portion) that is not subjected to strain other than the central portion of the forged product 21 is likely to be generated. Is ½ or less.

Here, the convex portion 10 of the depression forming upper mold 3b is formed in the shape of a tip of a ball-point pen (pen tip) in a cross-sectional view, and the convex portion 10 does not penetrate the rough ground 20. . Further, the diameter in the width direction of the depression forming punch 4b of the depression forming upper mold 3b is the same as the diameter of the upsetting forging punch 4a of the upsetting forging upper mold 3a used in the fourth upsetting forging process. It is.
And the forged product 21 which finished the hollow forging process is shape | molded in U shape by the cross sectional view by which ratio of axial length L / outer diameter D was 3 or less. In addition, since the center part of the axial center direction of the forged product 21 is crushed and the hollow part 22 is formed, it is slightly higher than the height (axial length L) of the waste land 20 in the fourth upsetting forging process.

  As shown in FIG. 3 (e), a high strain of 0.2 or more applied to the forged product 21 in the hollow forging process is applied to the whole except for the lower center of the wasteland 20 (a hatched portion with a wide interval). In other words, a low strain portion (having a narrow hatched portion with a small interval) of less than 0.2 remains only slightly in the lower center of the wasteland 20, and the main body portion of the wasteland 20 (the portion where strain is required). A high strain of 0.2 or more is applied.

As shown in FIGS. 1 (f) and 3 (f), the forged product 21 is peeled off from the lower mold 2 by the knockout bar 12 provided below the lower mold 2 (hole 6). To be discharged.
After that, the forged product 21 that has finished the hollow forging process is sent to the drilling process, and the center part facing the axial direction of the forged product 21 is punched (pierced) by punching forging / shearing or the like, and the forged product 21. The low strain part remaining in the substrate is removed. FIG. 4 shows an example of a cross section of the forged product 21 (final forged product) from which the low strain portion is removed and the center portion is penetrated. Note that the bottom of the forged product 21 having a U-shaped cross-sectional view may be penetrated by machining or the like.

As described above, the hot upsetting forging device 1 and the hot forging method of the present invention prevent buckling even in the case of using a long rough land 20 (workpiece) in difficult-to-work materials such as titanium alloys. The forged product 21 is formed into a forged product 21 having a U-shaped (cup shape) in cross-section and having a bottom thickness less than or equal to 1/2 of the height of the wasteland 20 (axial length direction). A high strain of 0.2 or more can be imparted to the portion excluding the central portion (substantially the entire forging 21). Moreover, the outer diameter D of the wasteland 20 can be expanded over a wide range over the axial length direction of the wasteland 20 by reversing the wasteland 20 and repeatedly performing upsetting forging. Moreover, the hot upsetting forging apparatus 1 and the hot forging method of the present invention set the inner diameter A of the hole 6 and the inner diameter B of the upsetting portion 8 of the lower mold 2 so that the upsetting forging is performed. Since the displacement of the axial center of the wasteland 20 can be reduced, the risk of buckling during pressurization can also be reduced. In addition, the occurrence of wrinkles in the wasteland 20 can be suppressed. Moreover, by setting the inclination angle θ of the inner inclined surface 7, a high strain can be imparted to the forged product 21, and stable mechanical characteristics can be obtained at a high level.

Specifically, the diameter A of the hole 6 of the lower mold 2 is larger than the outer diameter D of the lower portion of the wasteland 20 and 1.1 times or less (the wasteland 20 is fitted in the hole 6). The height E of the hole 6 is greater than 1/100 and less than or equal to 1/10 with respect to the axial direction of the wasteland 20.
The inner diameter B of the upsetting portion 8 of the lower mold 2 is set to be larger than the outer diameter D of the waste land 20 and 1.5 times or less, and the inclination angle θ of the inner inclined surface 7 connected to the upsetting portion 8 is 5 is set to be larger than 0 ° and not more than 45 ° with respect to the axis oriented in the up-and-down direction of 5, thereby preventing buckling of the forged product 21 and the wasteland 20 generated during upsetting forging and imparting high strain. Is possible. Preferably, the inclination angle θ of the inner inclined surface 7 is set to be larger than 10 ° and not larger than 45 ° with respect to the axial center of the concave portion 5 facing the vertical direction.

Further, the inner wall surface of the upsetting portion 8 of the recess 5 is inclined radially upward with respect to the axial center of the recess 5 and the inclination angle η of the inner wall surface is larger than 0 °. By setting it to tan ⁻¹ [0.1 × D / L] or less, the forged product 21 and the rough land 20 after the forging can be easily released from the lower mold 2. In addition, a rectangular or triangular downward projecting portion 9 is provided on the periphery of the pressure lower surface (upsetting forging punch 4a) of the upset forging upper die 3a so as to fit in the upper portion of the wasteland 20 in a sectional view. Thus, the wasteland 20 during upsetting forging can be stably held upright at the center of the upsetting forging upper die 3a, and the occurrence of buckling during reduction can be suppressed.

As described above, the forged product 21 manufactured by the hot upsetting forging apparatus 1 and the hot forging method of the present invention is an engine member or chassis of a transport device such as an aircraft or a vehicle used in a harsh environment. It is most suitable for structural members such as.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive.

  In the present embodiment, the wasteland 20 (workpiece) is manufactured using a long cylindrical member, but may be manufactured using a cylindrical bar. In the hollow forging process, both the upper mold 3 and the lower mold 2 may be changed. For example, the upper die 3 is changed to a shape in which a convex portion 10 projecting downward is formed in the center of the pressing surface, and the lower die 2 is projected upward in the center of the bottom portion of the concave portion 5. You may change to what the upper protrusion part of is formed. The forged product 21 manufactured with the upper mold 3 and the lower mold 2 is formed into an H shape in a cross-sectional view. In the present embodiment, upset forging is performed using the columnar wasteland 20 (workpiece), but upset forging may be performed using the cylindrical wasteland 20.

In addition, the lower die 2 and the upper metal used in the upset forging process (pre-process of the hollow forging process) after upsetting the ratio of the axial length L / outer diameter D of the forged product 21 and the wasteland 20 to 3 or less About the type | mold 3, the thing of this embodiment may be used and another thing may be used (for example, the metal mold | die used at the upset forging process applicable to FIG.1 (d)).
In particular, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. Instead, values that can be easily assumed by those skilled in the art are employed.

DESCRIPTION OF SYMBOLS 1 Hot upsetting forging device 2 Lower die 3 Upper die 3a Upset forging upper die 3b Dimple formation upper die 4 Punch 4a Upset forging punch 4b Dimple formation punch 5 Recess 6 Hole (Fitting part) )
7 Inner inclined surface 8 Upset portion 9 Downward protruding portion 10 Convex portion 11 Upset inclined surface 12 Knockout stick 20 Work material (waste ground)
21 Forged product 22 Recessed part

Claims (14)

A shaft-shaped hole, an inner inclined surface formed to be connected to the upper portion of the hole, and a recess having an upset portion formed to be connected to the upper portion of the inner inclined surface. Heat used for hot upsetting forging consisting of a lower mold into which a long workpiece is charged and an upper mold that squeezes the long workpiece loaded into the lower mold from above In the upsetting forging machine,
The inner diameter A of the hole of the lower mold is set to be 1.1 times or less larger than the outer diameter C of the lower part of the workpiece,
The height E of the hole of the lower mold is set to a height greater than 1/100 and 1/10 or less with respect to the axial length L of the workpiece.
The inner diameter B of the upset portion of the concave portion of the lower mold is set to be 1.5 times or less larger than the outer diameter D of the upper part or midway part of the workpiece,
The hot upset forging device, wherein an inclination angle θ of the inner inclined surface is set to be larger than 0 ° and not larger than 45 ° with respect to an axial center facing the up-down direction of the concave portion.   2. The hot upsetting according to claim 1, wherein an inclination angle θ of the inner inclined surface is set to be greater than 10 ° and equal to or less than 45 ° with respect to an axial center of the concave portion. Forging equipment. The inner wall surface of the upset portion of the recessed portion of the lower mold is inclined radially upward with respect to the axial center of the recessed portion in the vertical direction,
2. The hot upsetting according to claim 1, wherein an inclination angle η of the inner wall surface of the upsetting portion is set to be greater than 0 ° and equal to or less than tan ⁻¹ [0.1 × D / L]. Forging equipment.   The hot upsetting according to any one of claims 1 to 3, wherein a lower projecting portion that fits into an upper portion of the workpiece is formed on a peripheral edge of the pressure lower surface of the upper mold. Forging equipment.   The hot upset forging device according to claim 4, wherein the downward projecting portion is formed in a rectangular shape or a triangular shape in a sectional view.   The hot upsetting forging device according to any one of claims 1 to 3, wherein a convex portion protruding downward is formed at the center of the pressure surface of the upper die.   A convex part projecting downward is formed at the center of the pressing surface of the upper mold, and an upward projecting part projecting upward is formed at the center of the bottom of the concave part of the lower mold. The hot upsetting forging device according to claim 1, wherein the hot upsetting forging device is provided. A hot upsetting forging method for upsetting a long workpiece,
Using the hot upsetting forging device according to any one of claims 1 to 5, the long work material is hot upset to a work material having a predetermined size and shape. Upsetting forging process for repeated forging,
Using the hot upset forging device according to claim 6 or 7, the axial length center portion of the work material forged in the upset forging process is arranged with respect to the axial length L of the work material. And a hollow forging process for producing a forged product having a bottom thickness of 1/2 or less and a strain having a strain of 0.2 or more applied to the whole. Forging method.   The hot upset forging method according to claim 8, wherein the upset forging step repeats hot upset forging by reversing an upper portion and a bottom portion of the workpiece. In the upsetting forging step, according to the number of times that upsetting forging is repeated hot, the upper mold and the lower die provided in the hot upsetting forging apparatus according to any one of claims 1 to 4 are provided. Prepare several molds,
Each time upset forging is performed, the upper mold and the lower mold are replaced with short ones, and the long work material is installed until the work material has a predetermined size and shape. The hot upset forging method according to claim 8 or 9, wherein the upset forging is performed.   The hot upset forging method according to any one of claims 8 to 10, wherein in the hollow forging step, the forged product is formed into a U shape in a sectional view.   The said hollow forging process hold | maintains the workpiece which finished the said upset forging process, without releasing from the said lower mold, The upper mold with which the hot upset forging apparatus described in Claim 5 is equipped. The hot upset forging method according to any one of claims 8 to 11, wherein the forged product is manufactured by performing upset forging while hot.   The hot upset forging method according to any one of claims 8 to 12, further comprising a drilling step of passing through a central portion facing the axial direction of the forged product after the hollow forging step. The hot upset forging method according to any one of claims 8 to 13, wherein the forged product is formed into a shape having a ratio of axial length L / outer diameter D of 3 or less.

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