JP2013046918A - Valve element in swing valve, method for manufacturing the same, and reheat steam stop valve having the valve element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide sufficient impact absorbability to the connection part of a valve element in a swing valve and a swing arm.SOLUTION: A method for manufacturing the valve element in the swing valve includes: a polygonal column forming step S10 of obtaining a polygonal column 130 formed of a heat-resistant steel by executing swaging and cogging of a steel block 100 of heat-resistant steel which is the base stock of a valve element 20; a stepped body forming step S20 of obtaining a stepped body 140 having a small diameter section 140b formed by executing tap forging of an end of the polygonal column and a large diameter section 140a; a disk-with-projection forming step S30 of obtaining a disk 150 with a projection by inserting the small diameter section in the stepped body in a hole 510 in a hole base 500, and swaging the stepped boy in its axial direction Z; and a machine-forming step S40 for machine-forming the disk with the projection so that a projection part 20b is formed from the small diameter part 150b in the disk with the projection, and a body 20a is formed from the large diameter part 150a.

Description

The present invention relates to a valve body in a swing valve, a manufacturing method thereof, and a reheat steam stop valve including the valve body.

  In the steam turbine apparatus, the reheat steam stop valve provided on the steam inlet side of the intermediate pressure steam turbine instantaneously shuts off the steam flowing through the intermediate pressure steam turbine when the rotational speed of the turbine exceeds a predetermined value. It is an important security device provided to prevent the turbine from becoming dangerous due to overspeed.

  As such a reheat steam stop valve, for example, there is one described in Patent Document 1, but in a type in which the valve body is driven linearly up and down as described in Patent Document 1, an inlet port and an outlet are used. Since the ports cannot be arranged in a straight line, there are problems that the pressure loss of the steam flow is large and a large space is required for the arrangement of the pipes.

  Therefore, the present inventors have developed a reheat steam stop valve to which the swing valve technology (for example, Patent Document 2) is applied. In a swing valve, generally, an inlet port and an outlet port can be arranged in a straight line, so that there is little pressure loss and a large space is not required for the arrangement of piping.

FIG. 8 is a front sectional view showing an outline of the configuration of the conventional reheat steam stop valve 2.
As shown in FIG. 8, the reheat steam stop valve 2 includes a casing 10, a valve body 60, a swing arm 30, and an arm drive unit 40. When the steam turbine device is in a normal operation state, the valve body 60 is disposed at a flow path opening position P1 (a position indicated by a two-dot chain line in the drawing). According to the reheat steam stop valve 2, when the rotational speed of the intermediate pressure steam turbine provided in the subsequent stage becomes equal to or higher than a predetermined value, the arm drive unit 40 moves the swing arm 30 around the horizontal axis J0 as shown in FIG. It is rotated in the clockwise direction. As a result, the valve body 60 is moved from the flow path opening position P1 to the flow path closing position P2 (position indicated by a solid line in the drawing) and is seated on the valve seat 14. As a result, the flow path from the inlet port 11 to the outlet port 12 is blocked, and the main steam ST flowing toward the intermediate pressure steam turbine is blocked.

  In the reheat steam stop valve 2, the connection structure of the valve body 60 and the swing arm 30 is as follows. That is, the swing arm 30 has a connecting end through hole 31 that penetrates in the rotational direction of the swing arm 30 at the connecting end with the valve body 60. On the other hand, the valve body 60 has a substantially bowl-shaped main body 60a, and a protrusion 60b that protrudes toward the convex surface at the center position of the main body 60a. The protrusion 60 b is formed integrally with the main body 60 a, and the outer diameter of the protrusion 60 b is a size that can be inserted into the connection end through hole 31. A male screw 60M is formed on the tip side of the protrusion 60b. Then, the valve body 60 and the swing arm 30 are connected by fastening the nut 52 to the male screw 60M in a state where the protrusion 60b is inserted into the connecting end through hole 31 in the swing arm 30. In addition, the valve body 60 has some play with respect to the swing arm 30, thereby providing an automatic alignment function. That is, the valve body 60 can be seated with a slight deviation from the swing arm 30.

About such a reheat steam stop valve 2, the manufacturing method of the valve body 60 is demonstrated. FIG. 9 is a view for explaining a conventional manufacturing method of the valve body 60 in the reheat steam stop valve 2. FIG. 9A shows a manufacturing process, and FIG. B shows a forging flow in a typical forged product in FIG. Indicates the state of the line.
First, a cylindrical steel ingot (ingot) 100 made of a nickel-based alloy is manufactured. Next, the steel ingot 100 is subjected to upset forging that compresses the steel ingot 100 in the axial direction (Z direction in the drawing) at a predetermined compression rate, so that a circular forged intermediate forged product 110 is obtained. Next, the intermediate forged product 110 is compressed at a predetermined area reduction rate in each of the X direction and the Y direction orthogonal to the Z direction to obtain a square columnar intermediate forged product 120. Next, each corner portion of the intermediate forged product 120 is forged into an octagonal columnar intermediate forged product 130 by performing a process of compressing each corner portion in the P direction and Q direction, which are diagonal directions, at a predetermined area reduction rate. At the stage of the intermediate forged product 130, the forging line T1 is parallel to the axial direction of the intermediate forged product 130 as shown in the left diagram of FIG. 9B.

Next, after soaking the intermediate forged product 130 under predetermined conditions, it is again subjected to upset forging which is compressed at a predetermined compression rate in the axial direction (Z direction in the figure), and again is a circular fork-shaped intermediate forging Product 340 is obtained. At the stage of the intermediate forged product 340, the diameter of the forged stream T3 is increased by upsetting so that the forging line T3 is curved along the outer surface of the intermediate forged product 340 as shown in the middle diagram of FIG. 9B. It becomes a shape. That is, it flows in a direction expanding from the axial direction as a whole.
Next, unnecessary portions are cut from the intermediate forged product 340 and finished into the shape of the valve body 60. That is, cutting is performed from the intermediate forged product 340 so that the main body 60a and the protrusion 60b remain. Finally, a male screw 60M (see FIG. 8) is formed at the tip of the protrusion 60b.
Thus, the valve body 60 is obtained by cutting an unnecessary part from the intermediate forged product 340 described above. Accordingly, the forged streamline T3 ′ of the valve body 60 also flows in a direction extending from the axial direction as a whole as shown in the right diagram of FIG. 9B.

Japanese Patent Laid-Open No. 11-343811 Japanese Patent Laid-Open No. 11-82775

The protrusion 60 b in the valve body 60 is a part for connecting the valve body 60 to the swing arm 30, and stress acts by an impact received from the valve seat 14 when the valve is closed. The valve body 60 is generally closed by performing self-alignment. That is, the valve body 60 is seated on the swing arm 30 with a slight deviation. Therefore, in addition to the force from the axial direction, a force from the direction orthogonal to the axial direction (hereinafter referred to as an axial orthogonal component force) acts on the protrusion 60b.
By the way, the reheat steam stop valve 2 is provided on the steam inlet side of the intermediate pressure steam turbine, and plays a backup role of an intercept valve (one of safety valves) in the intermediate pressure steam turbine. In other words, the reheat steam stop valve 2 may be operated without closing the intercept valve. When such a situation occurs, since the vapor pressure difference between the upstream side and the downstream side of the reheat steam stop valve 2 is large, the valve body 60 closes while being accelerated in response to this vapor pressure difference. In other words, a particularly large stress is generated at the base of the protrusion 60b when seated. The axial orthogonal component force at this time is considerably large.

  However, according to the conventional manufacturing method described above, the forging line T3 ′ formed in the valve body 60 flows in a direction that expands from the axial direction as a whole as shown in the right view of FIG. 9B. It becomes. That is, a high value cannot be expected for the shock absorption value for the axial orthogonal component force in the vicinity of the root of the protrusion 20b with respect to the main body 60a.

  The present invention has been made in view of the above-described problems, and provides a valve body in a swing valve capable of providing sufficient shock absorption at a connection portion between the valve body and the swing arm in the swing valve, a manufacturing method thereof, and the same It aims at providing the reheat steam stop valve provided with the valve body.

  In order to achieve the above object, the present invention employs the following means. In this column (“Means for Solving the Problems”) and “Claims”, the reference numerals in parentheses attached to each component clearly indicate the correspondence with the specific means described in the embodiments described later. It is to make. These symbols should not be used to interpret the technical scope of the invention.

  According to the first aspect of the present invention, the main body (20a) that can be seated on the valve seat (14) and the main body (20a) on the central axis (J1) of the main body (20a) are integrated with the main body (20a). And a protrusion (20b) connected to the movable end (30a) of the swing arm (30). The method of manufacturing the valve element (20) is a material of the valve element (20). A polygonal column forming step (S10) for obtaining a polygonal column (130) of the heat-resistant steel by performing upsetting and forging on the ingot of the heat-resistant steel, and tapping the end of the polygonal column (130) A stepped body forming step (S20) for forging to obtain a stepped body (140) having a small diameter part (140b) and a small diameter part (140b) and a large diameter part (140a); The small diameter portion (140b) in (140) is inserted into the hole (510) in the hole base (500). A stepped disk body forming step (S30) in which the stepped body (140) is installed in the axial direction (Z) to obtain a disk body with a protrusion (150), and a small diameter portion ( 150b), and a processing and molding step (S40) for processing and molding the projecting disk body (150) so that the projecting portion (20b) is formed and the main body (20a) is formed from the large-diameter portion (150a). It is characterized by.

According to the invention of claim 1, as shown in FIG. 5, in the first polygonal column forming step (S10), the forging line (T1) formed in the polygonal column (130) is the polygonal column (130). ) Parallel to the axial direction. In the next stepped body forming step (S20), tap forging is applied to the end of the polygonal column body (130), thereby forming a dense streamline (T2) on the small diameter portion (140b) of the stepped body (140). ) Is formed.
In the next step of forming the disc body with protrusions (S30), the small diameter portion (140b) of the stepped body (140) is set up in the step of subjecting the stepped body (140) to hole base upsetting forging. , The radial direction is kept constant. As a result, a dense forging line (T2) parallel to the axial direction is maintained even in the small diameter portion (150b) obtained at this time. On the other hand, the large-diameter portion (140a) of the stepped body (140) is compressed in the axial direction by upsetting and expanded in the radial direction. As a result, in the large diameter portion (150a) obtained at this time, a forged flow line (T3) curved so as to follow the outer surface (150d) of the disc body with protrusions (150) is formed. This forging line (T3) is continuous with the forging line (T2).
As described above, the disk body with protrusions (150) manufactured in this way has a dense flow line (T2) parallel to the axial direction at the small diameter portion (150b), and thus is orthogonal to the axial direction. High shock absorption with respect to impact from the direction. Further, in the vicinity of the root of the small diameter portion (150b) with respect to the large diameter portion (150a), the forging line (T2) in the small diameter portion (150b) is continuous with the forging line (T3) in the large diameter portion (150a). To do. Accordingly, in the vicinity of the base, high shock absorption is provided for impacts from both the axial direction and the direction orthogonal to the axial direction.
In the next processing and molding step (S40), the protrusion (20b) and the main body (20b) of the valve body (20) are respectively associated with the small diameter portion (150b) and the large diameter portion (150a) of the protruding disk body (150). 20a) is formed.
Accordingly, the valve body (20) has the same properties as the stepped stepped body (150). That is, in the vicinity of the base of the protrusion (20b) with respect to the main body (20a), high shock absorption is provided with respect to an impact from either the axial direction or the direction orthogonal to the axial direction.

  According to a second aspect of the present invention, the hole (510) drilled in the hole base (500) has a tapered surface that narrows from top to bottom in the vicinity of the upper end.

  According to the invention of claim 2, since the installation is performed using the hole base (500) provided with the hole (510) having the tapered surface, in the vicinity of the root of the small diameter portion (150b) with respect to the large diameter portion (150a). The forged lines (T2, T3) gradually change from the small diameter portion (150b) to the large diameter portion (150a). For this reason, it becomes difficult for the internal stress to concentrate (accumulate), and the non-rupture property is excellent.

  According to the invention of claim 3, the main body (20a) that can be seated on the valve seat (14), and the main body (20a) on the central axis (J1) of the main body (20a) are integrated with the main body (20a). And a protrusion (20b) connected to the movable end (30a) of the swing arm (30), and a method of manufacturing the valve body (20). A polygonal column forming step (S10 ′) for obtaining a polygonal column (230) of the heat-resistant steel by performing upsetting and forging on a steel ingot that is twice as much as the heat-resistant steel as a material, and a polygonal column Stepping to obtain a stepped body (240) having a small-diameter portion (140b), a large-diameter portion (140a), and small-diameter portions (140b) on both sides thereof by tapping forging both ends of the body (230). The body forming step (S20 ′) and the small diameter portions (240b) on both sides of the stepped body (240) By inserting the stepped body (240) in the axial direction (Z) by inserting it into the hole (510) in the upper and lower target hole base (500), the protruding disk body (250) having protrusions on both the upper and lower sides is obtained. A step of forming a disc body with protrusions (S30 '), a step of dividing the disc body with protrusions (250) by a plane (S1) perpendicular to the axis thereof and dividing it into two (S35'), and a disc body with protrusions ( 250), the protrusions (20b) are formed from the small-diameter portions (250b) on both sides and the main bodies (20a) are formed from the large-diameter portions (250a). And a processing molding step (S40 ′).

  According to invention of Claim 3, it implements to a disk body formation step (S30 ') of a back | latter stage with respect to the steel ingot of twice the amount of heat-resistant steel which is a raw material per valve body (20). Thereby, the disk body with protrusions (250) obtained by applying the disk body with protrusions (150) according to claim 1 to the vertical object can be obtained. Basically, by adding the dividing step (S35 ') to the series of steps shown in claim 1, two valve bodies (20) can be finally produced, and the productivity is excellent.

  In the invention of claim 4, the main body (20a) that can be seated on the valve seat (14), and the main body (20a) on the central axis (J1) of the main body (20a) are integrated with the main body (20a). And a protrusion (20b) connected to the movable end (30a) of the swing arm (30), the protrusion (20b) being parallel to the axial direction thereof. A forged streamline (T2) is formed, and in the main body (20a), a forged streamline (T3) curved along the outer surface (150d) is formed, and these two types of forged lines (T2, T3) are In the vicinity of the base of the projection (20b) with respect to the main body (20a), the axial direction of the projection (20b) gradually changes from the radial direction of the main body (20a).

  In the invention of claim 5, the impact absorption energy value in the valve body (20) is 2.0 kg · m or more in all directions. The invention of claim 5 is suitable as a valve body when a swing valve is applied to the reheat steam stop valve. The “omnidirectional” here refers to the tangential direction and the axial direction.

  A sixth aspect of the present invention is a reheat steam stop valve provided with the valve body (20) according to the fourth or fifth aspect.

  According to the present invention, a valve body in a swing valve capable of providing sufficient shock absorption at a connection portion between the valve body and the swing arm in the swing valve, a manufacturing method thereof, and a reheat steam stop valve including the valve body Is provided.

It is front sectional drawing which shows the structure outline | summary of the reheat steam stop valve which concerns on this invention. It is side surface sectional drawing which shows the structure outline | summary of the reheat steam stop valve which concerns on this invention. It is front sectional drawing which shows the connection structure of a swing arm and a valve body. It is a figure for demonstrating the self-aligning function of the reheat steam stop valve which concerns on this invention. It is a figure for demonstrating the manufacturing method of the valve body in the reheat steam stop valve which concerns on this invention, A figure shows the process of manufacture, B figure is the state of the forge line in the typical forging in FIG. Indicates. It is a figure which shows the energy absorption value in the predetermined several places in the intermediate forging manufactured with the manufacturing method of this invention. It is a figure for demonstrating the manufacturing method which manufactures the valve body in the reheat steam stop valve which concerns on this invention with sufficient productive efficiency. It is front sectional drawing which shows the structure outline | summary of the conventional reheat steam stop valve. It is a figure for demonstrating the conventional manufacturing method of the valve body in a reheat steam stop valve, A figure shows the process of manufacture, B figure shows the state of the forge line in the typical forging in A figure. .

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front sectional view showing the outline of the configuration of the reheat steam stop valve according to the present invention, FIG. 2 is a side sectional view showing the outline of the configuration of the reheat steam stop valve according to the present invention, and FIG. It is front sectional drawing which shows the connection structure with. In each figure, the same code | symbol is attached | subjected about the component same as the conventional reheat steam stop valve 2 shown in FIG. The difference between the reheat steam stop valve 1 according to the present invention and the conventional reheat steam stop valve 2 is in the valve body. Although the valve body 20 and the valve body 60 are the same in appearance, they are made by different manufacturing methods, and the form of the forged line formed inside is different.

  As shown in FIGS. 1 and 2, the reheat steam stop valve 1 includes a casing 10, a valve body 20, a swing arm 30, an arm drive unit 40, and the like.

  The casing 10 is made of a substantially barrel-shaped body made of a ferritic heat resistant steel containing 9 to 12 mol. Inside the casing 10 are an inlet port 11 that serves as an inlet for the main steam ST, an outlet port 12 that serves as an outlet for the main steam ST, a valve chamber 13 communicating with the inlet port 11 and the outlet port 12, and a valve chamber 13. It has the valve seat 14 which makes a ring-shaped surface. The upper surface of the casing 10 is a lid body 10a, and a stopper bolt 15 is attached to the lower part of the lid body 10a.

The valve body 20 is arranged in the valve chamber 13 and has a function of temporarily blocking the main steam ST flowing from the inlet port 11 to the outlet port 12. The valve body 20 is made of heat-resistant steel such as a nickel-base alloy, and includes a main body 20a and a protrusion 20b. The main body 20 a has a substantially bowl shape and includes an outer side surface 201 and an inner side surface 202. The outer side surface 201 is a convex surface formed on the non-opposing side of the valve seat. The inner side surface 202 is a concave surface formed on the valve seat facing side. The peripheral portion of the inner side surface 202 is in a closed state by being seated on the valve seat 14. The protrusion 20 b is provided at the center position of the main body 20 a so as to protrude toward the outer surface 201, and functions as a connecting portion with the swing arm 30.
The protrusion 20b is formed integrally with the main body 20a, and has an outer diameter that is sized to be inserted into a connecting end through hole 31 (described later) in the swing arm 30. In addition, the length of the protrusion 20 b is a length that allows the protrusion 20 b to protrude outward from the swing arm 30 in a state of being inserted into the connecting end through hole 31 in the swing arm 30. A male screw 20M is formed on the tip side of the protrusion 20b.

  The swing arm 30 is formed of a thick inverted triangular plate (see FIG. 2) made of ferritic heat resistant steel containing 9 to 12 mol. The swing arm 30 is pivotally supported by a horizontal rod 42 inside the casing 10 so as to be rotatable around the horizontal axis J0 on the bottom side 30b. The movable end (vertex side) 30 a of the swing arm 30 is a part connected to the valve body 20 and includes a connecting end through hole 31 that penetrates in the rotational direction of the swing arm 30. As shown in FIG. 3, the periphery of the connecting end through hole 31 (see FIG. 3) is welded with Stellite (registered trademark) 32 to enhance the corrosion resistance.

  The valve body 20 and the swing arm 30 are connected as follows. That is, the nut 52 is fastened to the male screw 20M in a state where the protrusion 20b of the valve body 20 is inserted into the connecting end through hole 31 of the swing arm 30.

  Here, the nut 52 is a nut with a locking function made of heat-resistant steel such as a nickel-base alloy, and includes a female screw that can be screwed into the male screw 20M in the protruding portion 20b. Moreover, as shown in FIG. 3, the pin hole 54a for mounting | wearing with the pin 53a for loosening is provided. The locking function is realized by mounting a locking pin 53a in the pin hole 54a.

  As shown in FIG. 3, the outer diameter of the protruding portion 20 b is slightly smaller than the inner diameter of the connecting end through hole 31, and is between the outer peripheral surface of the protruding portion 20 b and the inner peripheral surface of the connecting end through hole 31. The first gap D1 is formed at the same time. A second gap D <b> 2 is formed between the inner surface of the nut 52 and the outer surface of the swing arm 30. The first gap D1 and the second gap D2 are means for providing the valve body 20 with a self-aligning function by having play. Moreover, it is a means for preventing each member from adhering to each other due to a scale generated during operation of the steam turbine.

  The arm drive unit 40 is a component that drives the swing arm 30 to rotate about the horizontal axis J0. Specifically, as shown in FIGS. 1 and 2, a linear drive source 41, a horizontal rod 42, and a link mechanism. 43. The linear drive source 41 is configured by an electric servo motor, a hydraulic servo motor, or the like that includes an actuator capable of linear drive. The horizontal rod 42 is a member that pivotally supports the swing arm 30 with respect to the casing 10 so as to be rotatable around the horizontal axis J0. The link mechanism 43 is a transmission mechanism that connects the linear motion drive source 41 and the horizontal rod 42 to convert the linear motion of the linear motion drive source 41 into a rotational motion of the horizontal rod 42.

  In the reheat steam stop valve 1 having the above-described components, when the rotational speed of the intermediate pressure steam turbine provided in the subsequent stage becomes equal to or higher than a predetermined value, the swing arm 30 is illustrated by the arm drive unit 40. 1 is rotated in the counterclockwise direction. As a result, the valve body 20 is moved from the channel opening position P1 to the channel closing position P2, and is seated on the valve seat 14. As a result, the flow path from the inlet port 11 to the outlet port 12 is blocked, and the main steam ST flowing toward the intermediate pressure steam turbine is blocked.

  Here, it is ideal that the central axis J1 of the valve body 20 when the valve body 20 is in the flow path closing position P2 coincides with the central axis J2 of the valve seat 14. However, in reality, both shaft centers may be slightly shifted due to a temperature difference between the casing 10 and the swing arm 30. The reheat steam stop valve 1 has a centering function that automatically corrects the misalignment even when such misalignment occurs.

For example, as shown in FIG. 4A, when there is an error in parallelism between the central axis J1 of the valve body 20 and the central axis J2 of the valve seat 14 when the valve body 20 is at the flow path closing position P2. The automatic alignment is performed as follows.
When the swing arm 30 is driven in the counterclockwise direction by the arm drive unit 40, the valve body 20 at the flow path opening position P1 follows the arc trajectory toward the flow path closing position P2. As shown in FIG. 4A, when the central axis J2 of the valve seat 14 is on the downstream side with respect to the central axis J1 of the valve body 20, the upper part 20U of the valve body first contacts the valve seat 14. Abut. Here, since the first gap D1 and the second gap D2 are formed, the protruding portion 20b is swingable in the connecting end through hole 31. That is, the valve body 20 can be deflected with respect to the swing arm 30. Therefore, the valve body 20 first rotates the valve body upper portion 20U against the valve seat 14 and then further rotates counterclockwise independently of the swing arm 30 as shown in FIG. 4B. . As a result, the valve body lower portion 20D contacts the valve seat 14 with a slight delay from the contact of the valve body upper portion 20U. In this way, the valve body 20 is completely seated on the valve seat 14. That is, it is excellent in the adhesiveness of the valve body 20 to the valve seat 14, and it can prevent reliably that a steam leak arises.

  In the reheat steam stop valve 1, the protrusion 20 b is a part for connecting the valve body 20 to the swing arm 30, and stress is applied by an impact received from the valve seat 14 when the valve is closed. The timing at which the valve body 20 is closed when the rotation speed of the intermediate pressure steam turbine becomes equal to or higher than a predetermined value is normally after the intercept valve provided downstream of the reheat steam stop valve 1 is closed. In this case, when the intercept valve is closed, the vapor pressure difference between the upstream side and the downstream side of the reheat steam stop valve 2 is reduced, and this produces a kind of damper effect, so that the valve body 20 is closed slowly. Specifically, the speed when the valve body 20 is closed is about 0.3 m / s. Here, the reheat steam stop valve 1 serves as a backup for the intercept valve. That is, a situation may occur in which the reheat steam stop valve 1 operates without closing the intercept valve. Under such a situation, the vapor pressure difference between the upstream side and the downstream side of the reheat steam stop valve 1 is large. For this reason, the valve body 20 closes while being accelerated by receiving this large vapor pressure difference, and a particularly large stress is generated at the base of the projection 20b when seated. In addition, the speed of the valve body 20 at this time is specifically about 1.5 m / s.

  The valve body 20 in the present embodiment can withstand such a strong impact. That is, by manufacturing the valve body 20 by a method different from the conventional method, a high value is obtained for the impact absorption value for the impact force from the direction orthogonal to the axial direction near the base of the projection 20b with respect to the main body 20a. ing.

Next, the manufacturing method of the valve body 20 which concerns on this invention is demonstrated. FIG. 5 is a view for explaining a manufacturing method of the valve body 20 according to the present invention. FIG. 5A shows a manufacturing process, and FIG. B shows a state of forging lines in a typical forged product in FIG. .
First, a cylindrical steel ingot 100 made of a nickel-based alloy is manufactured. Next, the steel ingot 100 is subjected to upset forging that compresses the steel ingot 100 in the axial direction (Z direction in the drawing) at a predetermined compression rate, so that a circular forged intermediate forged product 110 is obtained. Next, the intermediate forged product 110 is compressed at a predetermined area reduction rate in each of the X direction and the Y direction orthogonal to the Z direction to obtain a square columnar intermediate forged product 120. Next, each corner portion of the intermediate forged product 120 is subjected to compression processing in the diagonal direction P direction and Q direction, respectively, and forged into an octagonal columnar intermediate forged product 130 (step S10). Up to this step, the manufacturing method is the same as the conventional manufacturing method shown in FIG. At the stage of the intermediate forged product 130, the forging line T1 is parallel to the axial direction of the intermediate forged product 130, as shown in step S10 of FIG.

Next, after performing soaking on the intermediate forged product 130 under predetermined conditions, one end of the intermediate forged product 130 is tapped forged using a pair of vertically symmetric anvils (not shown) called tap anvils, An intermediate forged product 140 that is a stepped shaft member is obtained (step S20). The intermediate forged product 140 includes a large-diameter portion 140a and a small-diameter portion 140b connected to one side of the large-diameter portion 140a via a tapered portion 140c. By applying tap forging to one end portion of the intermediate forging 130, this one end portion becomes a small-diameter portion 140b. As shown in step S20 of FIG. 5B, the small-diameter portion 140b has a dense forging line T2. It is formed.
Next, the small-diameter portion 140b of the intermediate forged product 140 is inserted into the hole 510 in the hole base 500 and subjected to hole base upsetting forging that compresses in the axial direction (Z direction in the drawing) at a predetermined compression rate. Thereby, the intermediate forge product 150 which is a compressed stepped shaft material is obtained (step S30). As the hole 510 formed in the hole base 500, a hole having a tapered surface that is tapered from the top to the bottom in the vicinity of the upper end portion thereof is used. In addition, the hole base upsetting forging is performed by repeating the operation of heating the intermediate forged product 130 to an appropriate temperature in a heating furnace and performing upsetting many times. Thereby, the formed crystal flow can be densified.

In the step of subjecting the intermediate forged product 140 to the hole-upset forging process, the radial direction of the small diameter portion 140b of the intermediate forged product 140 is kept constant by the upsetting. As a result, even in the small diameter portion 150b obtained at this time, a dense forging line T2 parallel to the axial direction is maintained. On the other hand, the large-diameter portion 140a of the intermediate forged product 140 is compressed in the axial direction by upsetting and expanded in the radial direction. As a result, in the large diameter portion 150a obtained at this time, a forged line T3 that is curved along the outer surface 150d of the intermediate forged product 150 is formed. This forging line T3 is smoothly continuous with the forging line T2.
The intermediate forged product 150 manufactured in this way has a dense forge line T2 parallel to the axial direction in the small diameter portion 150b as described above, and therefore, against an impact from a direction orthogonal to the axial direction. High shock absorption. Further, in the vicinity of the root of the small diameter portion 150b with respect to the large diameter portion 150a, the forging line T2 in the small diameter portion 150b smoothly continues to the forging line T3 in the large diameter portion 150a. Accordingly, in the vicinity of the base, high shock absorption is provided for impacts from both the axial direction and the direction orthogonal to the axial direction. In addition, since the forging lines T3 and T2 are smoothly continuous, the internal stress is less likely to concentrate (accumulate), and the non-breaking property is excellent.

Next, unnecessary portions are cut from the intermediate forged product 150 and processed into the shape of the valve body 20. Specifically, this cutting is performed so that the protruding portion 20b protruding in the axial direction remains at the center position of the small-diameter portion of the intermediate forged product 150, and the surface on which the protruding portion 20b remains is a convex surface. 201. Further, the back surface is a concave surface 202. Finally, a male screw 20M (see FIG. 1) is formed at the tip of the protrusion 20b (step S40).
Thus, in step S40, the protrusion 20b and the main body 20a are formed corresponding to the small diameter portion 150b and the large diameter portion 150a in the intermediate forged product 150, respectively.
Therefore, the valve body 20 has the same properties as the intermediate forged product 150. That is, in the vicinity of the base of the protruding portion 20b with respect to the main body 20a, high shock absorption is provided with respect to an impact from either the axial direction or the direction orthogonal to the axial direction. Further, the internal stress is less likely to concentrate, and the non-breaking property is excellent.

  Next, the strength of the valve body 20 manufactured as described above will be described. FIG. 6 is a diagram showing energy absorption values at a predetermined plurality of locations of the intermediate forged product 150 obtained by the hole stand upset forging process.

The values shown in each table of FIG. 6 are the Charpy impact test (JIS) for the Charpy specimens taken from specific locations A, B, C, and D in the intermediate forged product 150.
Z 2242) is carried out, and the energy absorption value obtained at that time is shown. In addition, the Charpy test piece was extract | collected about the axial direction and tangent direction of the intermediate forging 150. The upper part in each table shows the test results at room temperature, and the lower part shows the test results at 610 ° C. The test was performed three times for each of the specific locations A, B, C, and D, and all were 2 kg · m or more. Incidentally, when manufactured by the conventional manufacturing method, the energy absorption value corresponding to each test result of the intermediate forged product 150 was about 0.7 kg · m. As described above, in the manufacturing method according to the present embodiment, the Charpy impact value is higher in both the axial direction and the tangential direction than in the conventional manufacturing method.

  By the way, in the manufacturing method of the valve body shown in FIG. 5, much time and labor are required. This is because, in the hole base upsetting forging process, the intermediate forging product 130 is heated to an appropriate temperature in a heating furnace and the upsetting is repeated many times. From this point of view, the valve body manufacturing method shown in FIG. 5 cannot be said to be excellent in production efficiency. Therefore, a manufacturing method that is excellent in production efficiency will be described with reference to FIG. The main point of the method to be described below is that the forging in step S20 in FIG. 5 is performed on both ends of the shaft member, and this stepped body is subjected to hole base upset forging from both sides in the axial direction, so that the middle of the vertically symmetrical integral object is obtained. After obtaining the forged product 250, the integrated object is divided into two members in the vertical direction.

FIG. 7 is a view for explaining an efficient manufacturing method of the valve body 20 of the reheat steam stop valve 1 according to the present invention.
First, a cylindrical steel ingot 200 made of a nickel-based alloy is manufactured. The size (amount) of the steel ingot 200 is twice that of the steel ingot 100 shown in FIG.
Next, the steel ingot 200 is subjected to upsetting forging in which the steel ingot 200 is compressed at a predetermined compression rate in the axial direction (Z direction in the drawing) to obtain a circular forged intermediate forged product 210. Next, this intermediate forged product 210 is compressed at a predetermined area reduction rate in each of the X direction and Y direction perpendicular to the Z direction to obtain a square columnar intermediate forged product 220. Next, each corner portion of the intermediate forged product 220 is subjected to processing for compressing in the P direction and Q direction, respectively, and forged into an octagonal columnar intermediate forged product 230.

Next, after performing soaking on the intermediate forged product 230 under predetermined conditions, both ends of the intermediate forged product 230 are tapped forged using a pair of vertically symmetric anvils (not shown) called tap anvils, An intermediate forged product 240 that is a stepped shaft member is obtained (step S20 ′). The intermediate forged product 240 includes a large-diameter portion 240a and small-diameter portions 240b connected to both sides of the large-diameter portion 240a via tapered portions 240c.
Next, the lower diameter small portion 240b in the intermediate forged product 240 is inserted into the hole 510 in the hole base 500 installed on the lower side, and the upper small diameter portion 240b in the intermediate forged product 240 is installed on the upper side. The intermediate forged product 250 is obtained by subjecting the intermediate forged product 240 to the axial direction (Z direction in the drawing) at a predetermined compression rate in a state where the intermediate forged product 240 is inserted into the hole 510 in the hole base 500. (Step S30 ').
Next, the intermediate forged product 250 is cut into two parts by cutting the upper and lower objects along a plane S1 orthogonal to the axis thereof to obtain an intermediate forged product 250X (step S35 ').
Next, unnecessary portions of each of the intermediate forged products 250X after cutting are cut and processed into the shape of the valve body 20 (step S40 ′).
The form of the forged streamline of the valve body 20 finally obtained is the same as that obtained in the process of FIG.
According to this manufacturing method, when focusing on the number of processes, it is necessary to add two “processes to be divided” shown in step S35 ′ to the series of processes shown in FIG. The valve body 20 is obtained. For this reason, it is excellent in productivity.

  As mentioned above, although embodiment of this invention was described, embodiment disclosed above is an illustration to the last, Comprising: The scope of the present invention is not limited to this embodiment. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

14 Valve seat 20 Valve body 20a Main body 20b Projection part 30 Swing arm 30a Movable end part 130 Intermediate forged product (polygonal column)
140 Intermediate forged product (stepped body)
140a Large diameter part 140b Small diameter part 150 Intermediate forged product (disc body with protrusion)
150a Diameter large portion 150b Diameter small portion 240 Intermediate forged product (stepped body)
240a Large-diameter portion 240b Small-diameter portion 250 Disc body with protrusion 250a Large-diameter portion 250b Small-diameter portion 500 Hole base 510 Hole J1 Central axis S10 Step (polygonal column forming step)
S10 'step (polygonal column forming step)
S20 step (stepped body forming step)
S20 'step (stepped body forming step)
S30 step (discoid forming step with protrusions)
S30 'step (disc body forming step with protrusion)
S35 'step (dividing step)
S40 step (working molding step)
S40 'step (work molding step)
T2 Forging stream line T3 Forging line Z-axis direction

Claims (6)

A main body (20a) that can be seated on the valve seat (14), and a swing arm (10a) that protrudes integrally with the main body (20a) on the counter valve seat side on the central axis (J1) of the main body (20a). 30) a valve body (20) comprising a protrusion (20b) connected to the movable end (30a) of 30),
A polygonal column forming step (S10) for obtaining a polygonal column (130) of the heat-resistant steel by performing upsetting and forging on the ingot of the heat-resistant steel that is a material of the valve body (20);
Stepped to obtain a stepped body (140) having a small-diameter portion (140b) and a small-diameter portion (140b) and a large-diameter portion (140a) by tapping forging the end of the polygonal column (130). Body formation step (S20);
The protrusion-equipped disk is obtained by inserting the small diameter portion (140b) of the stepped body (140) into the hole (510) of the hole base (500) and setting the stepped body (140) in the axial direction (Z). A disc body forming step with protrusions (S30) to obtain a body (150);
The disk body with protrusions (150) is processed so that the protrusion part (20b) is formed from the small diameter part (150b) and the main body (20a) is formed from the large diameter part (150a) in the disk body with protrusions (150). A process for producing a valve body, comprising: a molding step (S40) for molding.   The method for manufacturing a valve body according to claim 1, wherein the hole (510) drilled in the hole base (500) has a tapered surface that narrows from top to bottom in the vicinity of the upper end. A main body (20a) that can be seated on the valve seat (14), and a swing arm (10a) that protrudes integrally with the main body (20a) on the counter valve seat side on the central axis (J1) of the main body (20a). 30) a valve body (20) comprising a protrusion (20b) connected to the movable end (30a) of 30),
Formation of a polygonal column body that obtains a polygonal column body (230) of the heat-resistant steel by performing upsetting and forging on a steel ingot that is twice as much as the heat-resistant steel that is a material per valve body (20) Step (S10 ′);
A stepped body (240) having a small-diameter portion (140b), a large-diameter portion (140a), and small-diameter portions (140b) on both sides thereof is obtained by tapping forging the end of the polygonal column (230). A stepped body forming step (S20 ′);
The small diameter portions (240b) on both sides of the stepped body (240) are respectively inserted into the holes (510) of the upper and lower hole bases (500), and the stepped body (240) is installed in the axial direction (Z). A disc body forming step with protrusions (S30 ′) to obtain a disc body with protrusions (250) having protrusions on both upper and lower sides by inserting,
A dividing step (S35 ′) in which the disc body with protrusions (250) is cut by a plane perpendicular to its axis and divided into two (S35 ′);
The protrusion-equipped disc body (250b) is formed so that each protrusion portion (20b) is formed from the small diameter portion (250b) on both sides of the protrusion-shaped disc body (250) and each main body (20a) is formed from the large diameter portion (250a). 250). A method for manufacturing a valve body, comprising: a processing molding step (S40 ′) for processing and molding 250). A main body (20a) that can be seated on the valve seat (14), and a swing arm (10a) that protrudes integrally with the main body (20a) on the counter valve seat side on the central axis (J1) of the main body (20a). 30) a valve body (20) comprising a protrusion (20b) connected to the movable end (30a) of
The protrusion (20b) is formed with a forging line (T2) parallel to the axial direction, and the main body (20a) is formed with a forging line (T3) curved along its outer surface (150d). The two types of forged lines (T2, T3) are gradually changing from the axial direction of the protrusion (20b) to the radial direction of the main body (20a).   The valve body according to claim 5, wherein an impact absorption energy value in the valve body (20) is 2.0 kg · m or more in all directions.   The reheat steam stop valve provided with the valve body (20) of Claim 4 or Claim 5.

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