JP6060714B2 - Manufacturing method of disk-shaped forged products - Google Patents

Description

  The present invention relates to a method for manufacturing a disk-shaped forged product, and more particularly, to a method for manufacturing a disk-shaped forged product capable of forging a large-diameter disk-shaped forged product using a press machine having a small capacity.

  Forging is a method in which a metal material is compressed between tools to be processed into a predetermined shape, and is roughly divided into free forging and die forging. Forging is roughly divided into hot forging and cold forging according to the forging temperature. Forging may be performed not only for plastic deformation of the material into a desired shape but also for the purpose of breaking the cast structure and refining crystal grains.

  In order to plastically deform the material, it is necessary to apply a load corresponding to the size of the material. On the other hand, the minimum stress required to plastically deform a material is generally smaller than the minimum stress required to refine crystal grains. Therefore, when the capacity of the press machine is constant, the larger the material, the smaller the maximum strain that can be applied to the material, and it becomes difficult to refine the crystal grains.

In order to solve this problem, various proposals have heretofore been made.
For example, Patent Document 1 discloses that Ni is a process in which the reduction rate per impact is 7% or more at the same location twice or more until the temperature of the Ni-base heat-resistant alloy falls below the recrystallization start temperature. A method for producing a base heat-resistant alloy is disclosed.
This document describes that when the processing is performed a plurality of times while at the recrystallization start temperature, the grain size can be made uniform and finer as the number of processing increases.

Patent Document 2 discloses a method in which a rod material made of a Ni-base alloy is heated at a temperature lower than the temperature at which crystal grain growth occurs and the rod material is rotationally forged.
This document describes that a material having a very uniform crystal grain size, high tensile strength, good ductility, and excellent stress rupture properties can be produced by using rotary forging.

Patent Document 3 discloses a method for forging a Ni-base superalloy under forging conditions that satisfy a relationship of heating temperature 950 ° C. to 1100 ° C., reduction ratio / (heating temperature−forging temperature) ≧ 0.3. Yes.
This document describes that a uniform fine recrystallized structure can be obtained after forging by such a method.

  Furthermore, Patent Document 4 discloses a method for forming a sputter target in which a preform formed from an ingot is forged in the rotational axis direction (oscillating forging).

A disk-shaped forged product can be produced by free forging a cylindrical material. Methods for forging a disk-shaped forged product include cross forging and radiation forging.
Cross forging uses an upper anvil with a length longer than the diameter of the forged product, which is the final product. The center of the upper anvil and the center of the work material are almost aligned, and the center of the work material is the axis of rotation. This is a forging method in which striking is repeated while intermittently rotating.
Radial forging is a forging method in which an upper anvil is disposed on the outer periphery of a material to be forged, and striking is repeated while the upper anvil is intermittently rotated about the center of the material to be forged.

  Cross forging is characterized by the fact that there is a small number of passes until the forging is completed because the entire forged material directly under the upper anvil is struck by a single stroke. However, in order to process a workpiece having a large diameter, an upper anvil than the forged product that is the final product is required. As a result, when the capacity of the press machine is constant, there is a limit to the size of workable material that can be processed.

On the other hand, the radial forging can be forged if there is an upper anvil having a length about the radius of the forged product that is the final product. Therefore, when the capacity of the press machine is the same, the radial forging can process a workpiece that is larger than the cross forging.
However, even in the case of radial forging, if the capacity of the press machine is constant, there is a limit to the size of the workable material that can be processed.

Japanese Patent Laid-Open No. 2008-200320 JP 2000-212709 A JP 07-138719 A Special table 2007-536431 gazette

  The problem to be solved by the present invention is to provide a method for producing a disk-shaped forged product in which the size of the work material that can be substantially forged is not limited even when the capacity of the press machine is constant. There is.

In order to solve the above-described problems, the gist of a method for manufacturing a disk-shaped forged product according to the present invention is as follows.
(1) The method of manufacturing the disk-shaped forged product is as follows:
An initial diameter D and an initial height H (≦ D) can be placed on a disk-shaped work material, and a lower anvil that can rotate around a single axis;
With respect to the to-be-worked material, it is possible to reduce the to-be-worked material by moving up and down on a single axis, and using an upper anvil that is movable in the center direction of the lower anvil,
A multiple radial forging process is performed in which radial forging is performed two or more times from the outer periphery to the center of the work material.

(2) The upper anvil is subjected to a corner dropping process at the corner of the striking surface.
(3) The multiple radiation forging process includes:
The apparent central direction length of the upper anvil is L,
The apparent width of the upper anvil is W (≦ L),
The effective value of the length of the upper anvil in the center direction (= L−the width of the corner dropping process × 2) is expressed as L _eff ,
The effective value of the width of the upper anvil (= W−the width of the corner dropping process × 2) is expressed as W _eff ,
The distance from the center of the work material to the position farthest from the center of the work material among the contact surfaces when the upper anvil and the work material contact each other, r,
The apparent width of the upper anvil at the position of distance r is W (r),
When the effective value of the width of the upper anvil at the position of the distance r (= W (r) −width of the corner dropping process × 2) is W _eff (r),
(A) The apparent central direction length (X) of the contact surface when the upper anvil and the work material contact each other satisfies X <L _eff ,
(B) The rotation angle (θ _k ) between the k-th (1 ≦ k ≦ n−1) hit and the (k + 1) -th hit of the lower anvil is
(W (r) −W _eff (r)) / 2 <rθ _k ≦ W _eff (r)
(C) The amount of movement (s) of the upper anvil toward the center of the work material is s <L _eff , and
In order to satisfy (L−L _eff ) / 2 <s <D / 4 + (L−L _eff ) / 2,
Radial forging is performed two or more times from the outer periphery to the center of the work material.

  The manufacturing method of the disk-shaped forged product according to the present invention may further include a cross forging step of cross forging the unprocessed portion remaining in the central portion of the work material after the multiple radiation forging step.

  When radiation forging is performed two or more times from the outer periphery to the center of the disk-shaped work material, a relatively large disk-shaped forged product can be manufactured with a relatively small upper metallization. Moreover, even if the capacity | capacitance of a press machine is constant, there is no restriction | limiting in the magnitude | size of the workable material which can be processed. Furthermore, not only can a large work material be plastically processed, but also a strain sufficient to recrystallize the work material can be imparted to the work material.

It is a schematic diagram of a disk-shaped work material and an upper anvil used for the forging. It is a schematic diagram for demonstrating cross forging, radiation forging, and multiple radiation forging. It is a figure which shows the relationship between the number of pass | passes, and a rolling load when manufacturing a forge goods with a diameter of 1900mm by multiple radiation forging and normal radiation forging. It is a figure which shows the particle size distribution of the forged goods of diameter 1900mm manufactured by the multiple radiation forging.

Hereinafter, an embodiment of the present invention will be described in detail.
[1. Manufacturing method of disk-shaped forged product]
The manufacturing method of a disk-shaped forged product according to the present invention includes a multiple radiation forging process, a cross forging process, and a solution treatment process.

[1.1. Multiple radiation forging process]
The multiple radiation forging process
An initial diameter D and an initial height H (≦ D) can be placed on a disk-shaped work material, and a lower anvil that can rotate around a single axis;
With respect to the to-be-worked material, it is possible to reduce the to-be-worked material by moving up and down on a single axis, and using an upper anvil that is movable in the center direction of the lower anvil,
It is a step of performing radiation forging two or more times from the outer periphery to the center of the work material.

[1.1.1. Workable material]
The work material has a disk shape having an initial diameter D and an initial height H (≦ D). Although the absolute values of D and H are not particularly limited, the method according to the present invention can be applied even to a large work material and is substantially limited to the size of the work material. There is no.
Specifically, the present invention is applied to a work material having an initial diameter D = 550 mm or more and an initial height H = 400 mm or more, or an initial diameter D = 900 mm or more and an initial height H = 630 mm or more. Can be applied.

In the present invention, the material of the work material is not particularly limited, and the present invention can be applied to any metal material.
In particular, an austenitic material is suitable for the work material. Moreover, the Ni-based alloy is suitable for the work material among austenitic materials. Furthermore, the Ni-based superalloy is suitable as the work material among the Ni-based alloys.
Here, the “Ni-based alloy” refers to an alloy in which Ni is the largest among the contained elements.
The “Ni-base superalloy” refers to a Ni-base alloy to which Al, Ti, and other alloy elements are added for the purpose of improving heat resistance and corrosion resistance.

Ni-base superalloys are especially
15.0 ≦ Cr ≦ 17.0 mass%, 28.0 ≦ Fe ≦ 44.0 mass%,
2.8 ≦ Nb ≦ 3.3 mass%, 1.4 ≦ Ti ≦ 2.2 mass%,
0.1 ≦ Al ≦ 0.4 mass%, C ≦ 0.06 mass%, Cu ≦ 0.3 mass%,
Mn ≦ 0.35 mass%, Si ≦ 0.35 mass%, S ≦ 0.015 mass%,
P ≦ 0.02 mass%, B ≦ 0.006 mass%, and Co ≦ 1.0 mass%
In which the balance is made of Ni (equivalent to Inconel (registered trademark) 706) is preferable.

Austenitic materials (particularly Ni-based alloys) have high deformation resistance. On the other hand, when the forging / reheating temperature is raised to lower the deformation resistance, the crystal grains increase.
On the other hand, when the present invention is applied to hot forging of austenitic materials, the forging / reheating temperature can be lowered. Therefore, even when the deformation resistance is increased, a relatively large strain can be applied to the material to be forged. Further, even when a large forged product (for example, a disk-shaped forged product having a diameter of 1500 mm or more) is manufactured, plastic deformation and crystal grain refinement can be performed using a press machine having a small capacity.

[1.1.2. Lower anvil]
The lower anvil is made of a material on which a disk-shaped work material having an initial diameter D and an initial height H (≦ D) can be placed and is rotatable about a single axis. The lower anvil may be larger than the size on which the final product, forged product, can be placed.

[1.1.3. Upper anvil]
The upper anvil is made of a material that can lower the work material by moving up and down on a single axis with respect to the work material, and that can move in the center direction of the lower anvil.
The planar shape of the upper anvil is not particularly limited as long as the work material can be uniformly deformed by multiple radiation forging. Examples of the planar shape of the upper anvil include a rectangle, a square, a trapezoid, a triangle, a circle, and an ellipse.

The corner portion of the striking surface of the upper anvil needs to be subjected to a corner dropping process (C chamfering or R chamfering). When a hit is made using an upper anvil that has not been subjected to a corner dropping process, the work material may be torn by the corner. The width of the corner dropping process is not particularly limited, and an optimum value can be selected according to the purpose. The width of the corner dropping process is usually about 5 to 200 mm.
The upper anvil is a quadrilateral circumscribing the upper anvil, and the long side of the one with the smallest area (the circumscribed quadrilateral) is substantially parallel to the center direction of the lower anvil (or the work material to be placed thereon) It may be arranged so as to be or may be arranged so as to be non-parallel.

[1.1.4. Rotation angle of upper anvil and amount of movement in radial direction]
FIG. 1 shows a schematic diagram of a disk-shaped work material and an anvil used for the forging. In the example shown in FIG. 1, the planar shape of the upper anvil is a rectangle, and the long side of the upper anvil is arranged so as to be substantially parallel to the center direction (radial direction) of the disk-shaped work material. Yes.

In FIG. 1, L is the apparent center direction length of the upper anvil. “Apparent center direction length” is a parallel line drawn perpendicularly to the line connecting the center of gravity of the work material and the center of the upper anvil and drawn so as to touch the outline of the upper anvil The distance between parallel lines.
W is the apparent width of the upper anvil. W needs to satisfy W ≦ L. The “apparent width” is a parallel line drawn in a direction parallel to a line connecting the center of gravity of the work material and the center of the upper anvil, and two parallel lines drawn so as to touch the outline of the upper anvil The distance between.

L _eff is an effective value of the length in the center direction of the upper anvil (= L−width of the corner dropping process × 2).
W _eff is an effective value of the width of the upper anvil (= W−width of the corner dropping process × 2).
The width of the corner dropping process may be constant regardless of the location, or may be different depending on the location. “Corner drop processing width × 2” represents the sum of the widths of the corner drop processing formed on both sides of the upper anvil, and does not necessarily mean that the widths on both sides are the same.
In the example shown in FIG. 1, the width of the corner dropping process on the short side is longer than the width of the corner dropping process on the long side. In addition, a corner dropping process having the same width is performed on the short side on the center side (left side of the paper) and the short side on the outside (right side of the paper) of the work material. Similarly, a corner dropping process having the same width is performed on the upper long side and the lower long side of the sheet.

r is the distance from the center of the work material to the farthest position from the center of the work material in the contact surface when the upper anvil and the work material contact.
W (r) is the apparent width of the upper anvil at the position of the distance r.
W _eff (r) is an effective value of the width of the upper anvil at the position of the distance r (= W (r) −width of the corner dropping process × 2).
When the upper anvil is rectangular and the long side of the upper anvil is arranged so as to be substantially parallel to the center direction of the disc-shaped work material, W = W (r), W _eff = W _eff ( r).

To perform radial forging two or more rounds from the outer periphery to the center of the work piece without causing a relatively large remnant of the work material (in other words, a work that makes cross forging difficult) The following conditions must be satisfied.
First, the apparent center direction length (X) of the contact surface when the upper anvil and the work material are in contact with each other needs to satisfy the following expression (a).
X <L _eff (a)
Here, the “apparent center direction length (X) of the contact surface” is a parallel line drawn in a direction perpendicular to a line connecting the center of gravity of the work material and the center of gravity of the upper anvil, The distance between two parallel lines drawn so as to touch the contour.
The expression (a) means that the to-be-worked material is hit using a part of the hitting surface of the upper anvil. Thereby, the load per hit can be reduced.

Second, the rotation angle (θ _k ) between the k-th (1 ≦ k ≦ n−1) hit and the (k + 1) -th hit of the lower anvil needs to satisfy the following equation (b). is there.
(W (r) −W _eff (r)) / 2 <rθ _k ≦ W _eff (r) (b)
As shown in FIG. 1, “rθ” represents the length (l) of an arc cut by θ. When the length (l) of the arc is shorter than W _eff (r), there is no untouched portion in one round.
“(W (r) −W _eff (r)) / 2” represents an average value of the width of the corner drop formed in the width direction of the upper anvil. When the length (l) of the arc is shorter than the average value of the width of the corner drop, there is no practical benefit because the same location is hit.

The “rotation angle between the k-th hit and the (k + 1) -th hit” represents the rotation angle between adjacent hits. Note that “θ _n ” represents a rotation angle between the n-th hit and the first hit.
“K” and “k + 1” indicate the positions of hits, and do not necessarily indicate the order of hits. That is, when the first hit, the second hit, the third hit,... The nth hit are arranged along the circumferential direction, the hits may be performed in this order, or May be performed in a different order. For example, hitting may be performed first at odd-numbered positions, and then hitting at even-numbered positions.

Thirdly, the movement amount (s) of the upper anvil in the center direction of the work material needs to satisfy the following expressions (c1) and (c2).
s <L _eff (c1)
(L−L _eff ) / 2 <s <D / 4 + (L−L _eff ) / 2 (c2)
The expression (c1) is a condition necessary for preventing the unfinished portion from being generated when the upper anvil is moved toward the center of the work material.
“(L−L _eff ) / 2” represents an average value of the width of the corner drop formed in the center direction of the upper anvil. When the amount of movement (s) is shorter than the average value of the width of the corner drop, there is no actual profit because the same portion is hit.
The right side of the equation (c2) is a necessary condition for performing radial forging of two or more rounds on the work material without causing a relatively large untouched portion.

As long as the to-be-worked material is hit two or more times from the outer periphery to the center of the to-be-formed material and the above-described conditions are satisfied, the order of the individual hits is not limited.
For example,
(A) perform the first blow on the outer periphery of the work material;
(B) Without rotating the lower anvil, move the upper anvil to the inside of the work material and perform a second blow at a position close to the first blow,
(C) At the same time as rotating the lower anvil, the upper anvil may be moved to the outer periphery of the work material, and the above-described impact (a) and the impact (b) may be repeated.

However, the multiple radiation forging process is
While rotating the lower anvil intermittently, the upper anvil is moved in the center direction of the lower anvil and the towed material is crushed using the upper anvil, and a uniform strain is applied along the circumferential direction of the torn material. The circumferential forging process to give,
It is preferable to alternately repeat the moving step of moving the upper anvil toward the center of the lower anvil.
Further, when a total of n hits are arranged in the circumferential direction, the hits are preferably performed in this order.

When hitting an unprocessed region, the area of the contact surface between the upper anvil and the material to be forged becomes large, and thus a larger load is required to apply a certain strain. On the other hand, when the adjacent areas are successively forged, the area of the contact surface between the upper anvil and the work material is reduced according to the rotation angle (θ _k ) and / or the movement amount (s) except for the first impact, so that it is constant. It is possible to reduce the press load necessary for applying the strain of.

[1.1.5. Forging temperature and reheat temperature]
After the workpiece is heated to a predetermined forging temperature, multiple radiation forging is repeated until the temperature of the workpiece is lower than the temperature at which the workpiece can be forged. When the temperature of the work material falls below the forging temperature, the multiple radiation forging is interrupted and the work material is reheated.
Since the method according to the present invention has a smaller deformation resistance than the conventional method, forging can be continued even when the temperature of the work material is lowered to a temperature at which it is difficult to forge by the conventional method. .

The forging temperature and the reheat temperature are not particularly limited, and an optimum temperature can be selected according to the composition of the material to be trained and the target crystal grain size.
For example, when the work material is the above-described Ni-based alloy, the forging temperature and the reheat temperature in the multiple radiation forging process are 800 ° C. or higher and 1150 ° C. or lower in order to stably obtain a structure of ASTM grain size ≧ # 4. It is preferable to be within the range.
Further, when the work material is a Ni-base superalloy having the above-described composition, in order to stably obtain a structure of ASTM grain size ≧ # 4, the forging temperature and the reheat temperature in the multiple radiation forging process are 950 ° C. It is preferably within the range of 1030 ° C. or lower.

[1.2. Cross forging process]
The cross forging step is a step of cross forging the unprocessed portion remaining in the center of the to-be-formed material after the multiple radiation forging step.
In the case of performing multiple radiation forging, if the amount of movement (s) in the center direction of the work material is optimized, the entire work material can be uniformly forged only by multiple radiation forging. However, multiple radiation forging requires a larger number of forgings than the conventional method. Therefore, when the area of the unprocessed portion is reduced to some extent, the unprocessed portion may be cross-forged.

[1.3. Solution treatment process]
The solution treatment step is a step of performing a solution treatment of the work material after the forging of the work material (multiple radiation forging or multiple radiation forging + cross forging) is completed.
Depending on the forged product, it can be used for various purposes as it is after the forging is completed. However, crystal grains are generally non-uniform immediately after forging. Therefore, in order to make the crystal grains have the same size by recrystallization, it is preferable to perform a solution treatment after the end of forging.

In general, if the solution treatment temperature is too low, sufficient effects cannot be obtained. On the other hand, when the solution treatment temperature is too high, the crystal grains become coarse.
The optimum temperature varies depending on the composition and application of the work material. For example, when the work material is made of the above-described Ni-base superalloy, the solution treatment temperature is preferably 950 ° C. or higher and 1030 ° C. or lower in order to be able to stabilize the structure of ASTM grain size ≧ # 4.

[2. Action]
In FIG. 2, the schematic diagram for demonstrating cross forging, radiation forging, and multiple radiation forging is shown.
“Cross forging” means that the center of the work material and the center of the upper anvil are substantially coincided as shown in “1” of FIG. 2, and the upper anvil is rotated intermittently about the center of the work material as the rotation axis. It is a forging method that repeats striking while. Cross forging has the advantage that there are few passes to forging completion.
However, since cross forging has a large contact area between the work material and the upper anvil, as the diameter of the work material increases, a larger rolling load is required, and it becomes difficult to apply a predetermined amount of strain.

“Radiation forging” means that, as shown in “3” of FIG. 2, the upper anvil is placed on the outer periphery of the work material, and the upper anvil is intermittently rotated with the center of the work material as the rotation axis. Is a forging method that repeats. When the unprocessed portion exists in the central portion of the work material after the completion of the radiation forging, the cross-forging of the unprocessed portion is performed as shown by “4” in FIG. Radial forging can reduce the rolling load by suppressing the contact area between the upper anvil and the work material when there is no allowance for the rolling load.
However, if the size of the work material is further increased, even a radial forging requires a larger rolling load, making it difficult to apply a predetermined amount of strain.

  On the other hand, “multiple radiation forging” is a forging method in which, as shown in “2” and “3” in FIG. Multiple radial forging may be performed until there is no unprocessed portion in the center of the work material, or after performing multiple multiple radial forging, as shown in “4” in FIG. Cross forging of the part may be performed.

In multi-radiation forging, the forging time increases dramatically, so the temperature of the work material tends to decrease. However, the contact area between the upper anvil and the work material can be made smaller than that of radiation forging.
Therefore, a relatively large disk-shaped forged product can be manufactured with a relatively small upper metallization. Moreover, even if the capacity | capacitance of a press machine is constant, there is substantially no restriction | limiting in the magnitude | size of the workable material which can be processed. Furthermore, not only can a large work material be plastically processed, but also a strain sufficient to recrystallize the work material can be imparted to the work material.

(Example 1, Comparative Example 1)
[1. Preparation of sample]
[1.1. Example 1]
Upset forging and cross forging were performed on a forged material made of a Ni-base superalloy having a diameter of 700 mm and a height of 1680 mm, to obtain a disk having a diameter of 1800 mm and a height of 450 mm.
Next, for this disc,
(A) Double radiation forging / upper surface (the same forging conditions as “normal radiation forging / upper surface” in Comparative Example 1),
(B) Double radiation forging and lower surface outer periphery (leaving an unforged region of φ1100 mm in the center),
(C) Double radiation forging, lower surface inner periphery (leaves a non-forged region of φ400 mm in the center), and
(D) Cross forging (cross forging of unforged area remaining in the center)
And a forged product having a diameter of 1900 mm was obtained. The forged material was reheated as necessary until forging was completed. The forging temperature and the reheat temperature were 980 ° C., respectively.
After completion of forging, it was air-cooled (AC) to room temperature. Furthermore, the forged product was reheated to a solution treatment (ST) temperature. The solution treatment temperature was 980 ° C.

[1.2. Comparative Example 1]
For a disk-shaped work material with a diameter of 1800 mm and a height of 450 mm,
(A) Normal radial forging / upper surface (the same forging conditions as “double radial forging / upper surface” in Example 1),
(B) Normal radiation forging, lower surface (leaving a φ600 mm unforged region in the center), and
(C) Cross forging (cross forging of unforged area remaining in the center),
Went. The forging temperature was 980 ° C.

[2. Test method]
[2.1. Reduced load]
The rolling load was measured for each pass.
[2.2. Crystal grain size]
ASTM grain size was measured by a method according to ASTM E112.

[3. result]
[3.1. Reduced load]
FIG. 3 shows the relationship between the number of passes and the rolling load when a forged product having a diameter of 1900 mm is manufactured by multiple radial forging (Example 1) and normal radial forging (Comparative Example 1). The following can be seen from FIG.
(1) Forging of the upper surface (number of passes: -45), since forging was performed under substantially the same conditions in both Example 1 and Comparative Example 1, almost no difference was found in the forging load.
(2) After the forging of the upper surface was completed, the to-be-worked material was inverted and the normal radial forging of the lower surface was performed. When the lower surface was forged (pass number: 45 to 105), the rolling load increased significantly. This is because the contact area between the to-be-worked material and the upper anvil increased as the diameter of the to-be-worked material increased.
(3) After the forging of the upper surface is finished, the work material is inverted and the lower surface is subjected to multiple (double) radial forging. When the lower surface is forged (number of passes: 45 to 80) and the inner surface of the lower surface At any time of forging (pass number: 80 to 160), no significant increase in the rolling load was observed. This is because the contact area between the work material and the upper anvil is reduced by the multiple radiation forging.

[3.2. Crystal grain size]
FIG. 4 shows the particle size distribution of a forged product having a diameter of 1900 mm manufactured by multiple radiation forging. In FIG. 4, “1”, “2”, and “3” respectively represent the upper, middle, and lower crystal grain sizes on the left side of the work material. “4”, “5”, and “6” represent the upper, middle, and lower grain sizes of the center of the work material, respectively. “7”, “8”, and “9” represent the upper, middle, and lower crystal grain sizes on the right side of the work material.
From FIG. 4, it can be seen that ASTM crystal grain size ≧ # 4 can be achieved after the solution treatment even in the case of multiple radiation forging.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

  The method for manufacturing a disk-shaped forged product according to the present invention can be used as a method for manufacturing a gas turbine disk, a steam turbine disk, a compressor disk, and the like.

Claims (5)

A method for producing a disk-shaped forged product having the following configuration.
(1) The method of manufacturing the disk-shaped forged product is as follows:
An initial diameter D and an initial height H (≦ D) can be placed on a disk-shaped work material, and a lower anvil that can rotate around a single axis;
With respect to the to-be-worked material, it is possible to reduce the to-be-worked material by moving up and down on a single axis, and using an upper anvil that is movable in the center direction of the lower anvil,
E Bei multiple radiation forging step of performing an outer radiation forged two laps or more toward the center from the object 鍛材,
In the multiple radiation forging step, heating and reheating are performed, and plastic deformation and crystal grain refinement are performed .
(2) The upper anvil is subjected to a corner dropping process at the corner of the striking surface.
(3) The multiple radiation forging process includes:
The apparent central direction length of the upper anvil is L,
The apparent width of the upper anvil is W (≦ L),
The effective value of the length of the upper anvil in the center direction (= L−the width of the corner dropping process × 2) is expressed as L _eff ,
The effective value of the width of the upper anvil (= W−the width of the corner dropping process × 2) is expressed as W _eff ,
The distance from the center of the work material to the position farthest from the center of the work material among the contact surfaces when the upper anvil and the work material contact each other, r,
The apparent width of the upper anvil at the position of distance r is W (r),
When the effective value of the width of the upper anvil at the position of the distance r (= W (r) −width of the corner dropping process × 2) is W _eff (r),
(A) The apparent central direction length (X) of the contact surface when the upper anvil and the work material contact each other satisfies X <L _eff ,
(B) The rotation angle (θ _k ) between the k-th (1 ≦ k ≦ n−1) hit and the (k + 1) -th hit of the lower anvil is
(W (r) −W _eff (r)) / 2 <rθ _k ≦ W _eff (r)
(C) The amount of movement (s) of the upper anvil toward the center of the work material is s <L _eff , and
In order to satisfy (L−L _eff ) / 2 <s <D / 4 + (L−L _eff ) / 2,
Radial forging is performed two or more times from the outer periphery to the center of the work material.
(4) The work material is made of a nickel-based alloy. The multiple radiation forging process includes:
While intermittently rotating the lower anvil, the work material is crushed using the upper anvil without moving the upper anvil in the center direction of the lower anvil, and along the circumferential direction of the work material. Circumferential forging process that gives uniform strain,
The manufacturing method of the disk-shaped forged product according to claim 1, wherein the moving step of moving the upper anvil in the center direction of the lower anvil is repeated alternately. 3. The method for producing a disk-shaped forged product according to claim 1 , wherein the multiple radiation forging step has a forging temperature and a reheat temperature in a range of 800 ° C. or higher and 1150 ° C. or lower. The manufacturing method of the disk-shaped forged product of any one of Claim 1 to 3 further provided with the following structures.
(1) The nickel-base alloy is
15.0 ≦ Cr ≦ 17.0 mass%,
28.0 ≦ Fe ≦ 44.0 mass%,
2.8 ≦ Nb ≦ 3.3 mass%,
1.4 ≦ Ti ≦ 2.2 mass%,
0.1 ≦ Al ≦ 0.4 mass%,
C ≦ 0.06 mass%,
Cu ≦ 0.3 mass%,
Mn ≦ 0.35 mass%,
Si ≦ 0.35 mass%,
S ≦ 0.015 mass%,
P ≦ 0.02 mass%,
B ≦ 0.006 mass%, and
Co ≦ 1.0 mass%
Comprising the Ni-base superalloy with the balance being Ni ,
It is a structure of ASTM grain size ≧ # 4.
(2) In the multiple radiation forging step, the forging temperature and the reheat temperature are in the range of 950 ° C. to 1030 ° C.
(3) The method further includes a solution treatment step of performing a solution treatment on the work material at a temperature of 950 ° C. or more and 1030 ° C. or less after the forging of the work material is completed. The disk-shaped forged product according to any one of claims 1 to 4 , further comprising a cross-forging step for cross-forging the unprocessed portion remaining in the center portion of the work material after the multiple radiation forging step. Manufacturing method.

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