KR101245228B1 - manufacturing method of big size ball using a ball-valve - Google Patents

Abstract

The present invention minimizes the material thrown away during the manufacture of balls for large ball valves, and improves mechanical properties such as strength, hardness, impact properties, and abrasion resistance, especially for spherical ball surfaces, and freely forgings profiles to refine and homogenize tissues. It relates to a ball manufacturing method for a large ball valve through the technology.
To this end, the present invention is a material cutting step of cutting the plate-shaped raw material into a cuboid shape; A primary molding step of molding the material obtained through the material cutting step into a flat cylindrical shape pressed in the axial direction; A hole forming step of forming a hole through the material in the axial direction through the primary forming step; A secondary molding step of molding the material obtained through the hole forming step into a forged product having a hollow cylindrical shape; In addition, a method of manufacturing a ball for a large ball valve is provided, comprising: a forging step of molding a material obtained through the secondary molding step into a ball shape of a complete shape using a mold having a spherical surface formed therein. .

Description

Manufacturing method of big size ball using a ball-valve}

The present invention relates to a ball valve ball, and more specifically, to minimize the material discarded in the manufacture of the ball for the large ball valve, in particular to remove the cast structure, pores, segregation, etc. in the spherical ball, the strength, The present invention relates to a ball manufacturing method for a large ball valve through a grain homogenization profile free forging technology for improving mechanical properties such as hardness and impact value.

In general, the valve is a device for regulating or blocking the flow of fluid, and is one of important components used in various industries.

The valve is configured in various ways depending on the application site or operation method, the ship ball valve is used as an emergency valve for blocking excess fuel from the fuel pump of the ship engine.

In addition, the ball valve is a spherical 90-degree rotary valve has the advantage of very good airtight characteristics, and has a very low fluid resistance.

However, the ball valve is repeatedly loaded by a working fluid, and is often used at high temperature and cryogenic temperature, and thus requires a material having rigidity suitable for the surrounding environment, material, use, etc., and a strict production method and quality control.

As described above, a variety of methods for producing the ball for a ball valve are provided. In general, a manufacturing process through a casting process and a closed forging molding process are mainly used.

At this time, the manufacturing method through the above-mentioned casting process is currently used mainly for the production of large balls, while having a low manufacturing cost and a short manufacturing time, strength, hardness, low temperature impact characteristics, wear resistance and fatigue Its disadvantage is that its service life is short due to its low mechanical properties. This is because defects such as casting structure, processing and segregation remain in the ball.

In addition, the closed forging process is generally used to produce small balls of less than 15 inches, which is also highly productive but requires the use of a pie (Φ) cross-sectional extruded raw material to supply raw materials. Due to the constraints, and the molding load is very high, a large-capacity press and a high-strength and extra-large mold are required, so it is not applicable to large forgings.

The present invention has been made to solve the various problems according to the prior art described above, the object of the present invention is to remove the internal defects of the large ball and to improve the mechanical properties such as strength and hardness, impact characteristics and wear resistance and constant To provide a ball valve manufacturing method using a free forging technology of a new type of grain homogenization profile to homogenize easily.

According to the ball manufacturing method for a ball valve of the present invention for achieving the above object, a material cutting step of cutting a plate-shaped raw material into a cuboid shape; A primary molding step of molding the material obtained through the material cutting step into a flat cylindrical shape pressed in the axial direction; A hole forming step of forming a hole through the material in the axial direction through the primary forming step; A secondary molding step of molding the material obtained through the hole forming step into a forged product having a hollow cylindrical shape; In addition, the forging step of molding the material obtained through the secondary molding step into a ball shape of a complete shape using a mold in which the spherical surface is formed, characterized in that the progress is included.

Here, the primary forming step may include a first upsetting process of upsetting the raw material, a cogging process of forming the upset material into a cylindrical shape, and upsetting the formed cylindrical material again. And a second upsetting process for molding into a flat cylindrical shape.

In addition, the first upsetting process is characterized in that the pressing proceeds while rotating the raw material by 90 °.

In addition, the cogging process is characterized in that it proceeds to form a cylindrical shape gradually by pressing the upset material to gradually increase the number of corners.

The hole forming step may include a first piercing process of piercing using a punch from either the top or the bottom of the material formed through the first molding step, and the top or bottom of the material on which the first piercing is made. And a secondary piercing process of piercing using a punch from the other direction.

In addition, the secondary molding step is characterized in that the material formed through the hole forming step is progressed by gradually expanding the inner and outer diameter in the form of a ring by the ring rolling process.

In addition, after the completion of the secondary molding step and before performing the mold forging step characterized in that the taper forming step of forming a tapered corner portion of the material obtained through the secondary forming step in the taper process is further included .

In addition, after the material cutting step and the primary molding step, the hole forming step and the secondary molding step is completed, respectively, the heating step for heating the material before proceeding to the next step is characterized in that the progress is further included.

As described above, the ball manufacturing method for a large ball valve according to the present invention has a fine and homogenized crystal grain inside the ball due to the use of the profile free forging process, thereby improving the mechanical properties.

In particular, before performing the above-mentioned free forging process, free forging can be performed more smoothly by sequentially performing upsetting, cogging, piercing, ring rolling, and taper forming, and forging by the upsetting process. Defects and impurities such as pores, knitting, etc. are removed, and the grains can be refined by the forging structure by the ring rolling process, and the final free forging can be used to achieve the dimension, shape precision and grain homogenization and refinement of the ball surface part. do.

In addition, the ball manufacturing method for a large ball valve of the present invention is compared with the conventional die forging process that processes the central hole after the complete forging of the ball by the molding to the center hole of the ball by the piercing process after the first forming step. The amount of material loss can be minimized, and thus the material recovery rate can be improved.

1 is a schematic flowchart showing a ball manufacturing method for a large ball valve according to an embodiment of the present invention.
Figure 2 is a schematic process diagram showing to explain the overall progress of the ball manufacturing process for a large ball valve according to an embodiment of the present invention
Figure 3 is a process diagram shown to explain the material cutting step of the ball manufacturing process for a large ball valve according to an embodiment of the present invention
Figure 4 is a process diagram shown to explain the first upsetting process of the first forming step of the ball manufacturing process for a large ball valve according to an embodiment of the present invention
Figure 5 is a process diagram shown to explain the cogging process of the primary forming step of the ball manufacturing process for a large ball valve according to an embodiment of the present invention
Figure 6 is a process diagram shown to explain the second upsetting process of the primary forming step of the ball manufacturing process for a large ball valve according to an embodiment of the present invention
Figure 7 is a process diagram shown to explain the piercing process of the hole forming step of the ball manufacturing process for a large ball valve according to an embodiment of the present invention
8 is a view showing a ring rolling process of the secondary forming step of the ball manufacturing process for a large ball valve according to an embodiment of the present invention
Figure 9 is a process diagram shown for explaining the tapered forming step of the ball manufacturing process for a large ball valve according to an embodiment of the present invention
Figure 10 is a process diagram shown to explain the forging step of the mold manufacturing process for a large ball valve according to an embodiment of the present invention

Hereinafter, a preferred embodiment of the ball manufacturing method for a large ball valve of the present invention will be described with reference to FIGS. 1 to 10.

First of all, the method for manufacturing a ball for a large ball valve of the present invention is based on the use of a profile free forging technique, and through the presentation of each preceding process for this, a large ball such as a 24 inch completed through the profile free forging. To achieve homogenization of the grains.

To this end, in the preferred embodiment of the ball manufacturing method for a large ball valve of the present invention, the material cutting step (S100), the first forming step, the hole forming step, and the second forming step are sequentially performed profile It is proposed that the large sized ball can be completed by performing the forging step of the mold by the free forging technique.

This will be described in more detail in each step with reference to the flowchart of FIG. 1 and the process diagrams of FIGS. 2 to 10 as follows.

First, the material cutting step (S100) is a series of processes for cutting the plate-shaped raw material into a cuboid shape.

That is, in the embodiment of the present invention by cutting the material slab (Slab) in the form of slab (slab) (1) to be cut to be equal to the weight of the ball (ball) to be finally finished (billet) of the square ( Material) 10.

Next, the primary molding step (S200) is a series of processes for molding the material (square billet) 10 obtained through the material cutting step (S100) into a flat cylindrical shape pressed in the axial direction.

In this case, the first forming step (S200) is carried out including a first upsetting process (S210) and a cogging process (S220).

That is, in the embodiment of the present invention, the forging is organized while forming the material 10 in the form of a square block through the first upsetting process (S210), and then the material (10) through the cogging process (S220). ) Is to form a cylindrical shape.

At this time, the first upsetting step (S210) is characterized in that the material 10 to proceed by pressing while rotating by 90 °. In the first upsetting process (S210), a dead metal zone (DMZ) is formed by a rigid body motion in a region in contact with the upsetting anvil 21. Since almost no addition, the casting structure remains as it is, and thus the probability of mechanical properties and UT (Ultrasonic Testing) bonding is very high. Therefore, the pressure direction is continuously changed in the first upsetting process (S210) to solve this problem. While the strain is to be added to the DMZ.

In particular, when the above-described primary upsetting process (S210) is completed when the first up-up considering that the barrel (barreling) occurs in a direction perpendicular to the pressing direction of the anvil of each portion of the material (billet) 10 After the completion of the setting process (S210) and before performing the cogging process (S220), it is more preferable that the barrel ring can be removed by further performing an upsetting process in a direction perpendicular to the anvil pressing direction. The illustration thereof is omitted.

In addition, in the cogging process (S220), pressure molding (for example, 4, 8, 16, 32, etc.) to gradually increase the edge of the material 10 formed through the first upsetting process (S210). It is gradually formed into a cylindrical shape by forming into a polygon through a gradual annealing process. At this time, the cogging process (S220) is preferably proceeded to be formed into a gradual cylindrical shape by pressing the material 10 at a reduction ratio of approximately 10% while rotating by 10 °.

On the other hand, the embodiment of the present invention suggests that after performing the cogging process (S220) of the above-mentioned primary molding step (S200) to perform a second upsetting process (S230).

This, in consideration of the non-uniform deformation may occur at both ends of the material (cylindrical billet) 10 in the cogging process (S220) again upsetting process before the piercing process to remove such non-uniform deformation It is to perform (S230) additionally.

Of course, the secondary upsetting process (S230) has the advantage that the cylindrical shape of the material 10 can be relatively flat toward the axial direction, thereby forming the hole more smoothly.

In particular, the microstructures such as micropores and segregation present in the material 10 during the first molding step (S200) as described above are mostly miniaturized to a level that disappears or hardly appears.

Next, the hole forming step (S300) is a series of processes for molding the hole 11 penetrating the center in the axial direction in the material 10 obtained through the primary forming step (S200). At this time, the hole 11 serves as a flow path through which fluid passes as a central hole of the ball for the ball valve.

The hole forming step (S300) is a first piercing process of piercing using a punch 31 from any one of the top or bottom of the material 10 formed through the primary forming step (S200), and It includes a secondary piercing process of piercing using the punch 32 from the other of the top or bottom of the material 10, the primary piercing is made.

In this case, the punches 31 and 32 may use various types of punches, such as a solid type and a hollow type. In the embodiment of the present invention, the punches 31 and 32 may be used to increase the material recovery rate for the material 10. Is an example of a solid punch. Of course, the material recovery rate is low, but if you want to reduce the deformation of the material 10 may be a hollow punch.

Next, the secondary forming step (S400) is a series of processes for molding the material 10 obtained through the hole forming step (S300) into a forged product made of a hollow cylindrical shape.

That is, the secondary molding step S400 is performed by gradually expanding the inner and outer diameters of the material 10 formed through the hole forming step S300 in the form of a hollow cylinder by a ring rolling process.

At this time, in the ring rolling process, the main roll 41 and the mandrel 42 are rotated in contact with the inner and outer diameter surfaces of the raw material 10 to rotate, thereby increasing the height of the inner and outer diameters of the raw material 10. It is carried out to be molded simultaneously in the direction.

In particular, by performing the ring rolling process as described above, the material 10 is substantially made of grain flow tissue and tissue homogenization.

On the other hand, it is more preferable to form the taper 12 in the corner portion of the material 10 before performing the mold forging step (S600) to be described later after the secondary molding step (S400) as described above.

That is, when defects such as surface wrinkles are easily generated due to contact between balls and square billets (materials) during the shape rolling process, surface defects such as wrinkles may occur at the corners of the ring-shaped material during the mold forging step. It is preferable to mold the taper 12 in order to prevent this in advance, and furthermore, the ring-shaped material is substantially closer to the spherical shape due to the taper, which is more smooth in the mold forging step S600. Spherical molding is possible.

Accordingly, in the embodiment of the present invention, the ring-shaped material 10 obtained through the secondary molding step (S400) by a taper process before performing the mold forging step (S600) after the completion of the secondary molding step (S400). The tapered forming step (S500) of tapering the corner portion of the) is further suggested to proceed.

At this time, the taper forming step (S500) may be performed by a process using a flat enville (not shown), and a process using a V-type anvil 51, a process using a common flat is usually the material (10) And mandrel (not shown) are inclined at an angle of 45 °, which increases the likelihood of interference between the anvil and the mandrel during operation, as well as the high risk of breakage of the anvil or the mandrel. Rotation is also somewhat difficult. Therefore, in the embodiment of the present invention, the taper forming step (S500) is presented as an example that is performed by a process using a V-type anvil (51).

Next, the mold forging step (S600) is a series of processes for molding the material 10 obtained through the secondary molding step (S400) to a ball shape of a complete form.

The die forging step S600 is performed using the molds 61 and 62 in which spherical surfaces are formed, and suggests that the above-described molding of the ball shape can be achieved by free forging.

That is, by forming the spherical ball by free forging, the shape of the ball forged product can be formed into a perfect spherical shape, and the mechanical properties can be improved, and the grain size and homogenization can be achieved.

At this time, a large amount of flash may be generated in the curvature portion during the molding of the material 10 into the ball shape during the mold forging step S600, and the overlapping phenomenon may be caused by the continuous rotation of the material 10. Surface wrinkles may occur, but the above problems can be prevented by increasing the curvature of the spherical shapes formed on the molds 61 and 62 and reducing the initial stroke.

On the other hand, after the operation of each step (S100, S200, S300, S4400, S500, S600) is completed during the operation of each step as described above, the temperature of the material 10 is lowered and then the process work proceeds smoothly. It's hard to be.

Accordingly, in the embodiment of the present invention after the work of each step (material cutting step, primary molding step, hole molding step, secondary molding step, taper molding step) is completed before proceeding to the next step It is suggested that the heating step of heating is further included.

That is, after the cogging process S220 of the first forming step S200 is performed, the surface of the material 10 is lowered as a whole by the repeated contact between the cogging envel 22 and the material 10, thereby allowing the temperature to be lowered. Reheating to a temperature (900 ~ 1250 ℃) that can be smoothly piercing by performing the heating step, and after the hole forming step (S300) is completed, since the temperature is lowered again temperature (900) ring rolling can be made smoothly (900) ˜1250 ° C.), and reheats to a temperature at which taper molding can be smoothly performed since the temperature is lowered again after the secondary molding step (S400) by the ring rolling is completed, and again after the taper molding is completed. Because the temperature is lowered, it is reheated to a temperature (about 900 ~ 1250 ° C.) that can be freely forged smoothly.

As a result, a ball for a large ball valve is completed through a series of processes as described above, and the finished ball can be homogenized in grain and mechanical properties due to the free forging process.

Particularly, in the present invention, the molding of the central hole of the ball is performed by the piercing process after the first molding step, thereby minimizing the material loss compared to the conventional die forging process of processing the central hole after the complete forging of the ball. As a result, the material recovery rate is improved.

1. Slab 10. Material
11. Hole 21. Anvil for upsetting
22. Anvils for cogging 31,32. punch
41.Main roll 42.Mandrel
51.V type anvil 61,62. mold

Claims (8)

A raw material cutting step of cutting the plate-shaped raw material into a cuboid shape;
A primary upsetting process of upsetting the plate-shaped material obtained through the material cutting step, a cogging process of forming the upset material into a cylindrical shape, and the formed cylindrical material again up in the axial direction A primary molding step including a secondary upsetting process of setting and molding into a flat shape;
A hole forming step of forming a hole through the material in the axial direction through the primary forming step;
A secondary molding step of molding the material obtained through the hole forming step into a forged product having a hollow cylindrical shape; And,
A large ball valve comprising: a forging step of forming a surface in a ball shape of a complete shape through a free forging process of tapping a material obtained through the second forming step into a mold in which a spherical surface is formed; Dragon ball manufacturing method. delete The method of claim 1,
The first upsetting process
Method for producing a large ball valve, characterized in that by proceeding by pressing while rotating the raw material by 90 °. The method of claim 1,
The cogging process is a ball production method for a large ball valve, characterized in that to proceed to form a cylindrical shape by gradually pressing the upset material to increase the number of corners. The method of claim 1,
The hole forming step
A first piercing process of piercing using a punch from either the top or the bottom of the material formed through the first molding step;
And a secondary piercing process of piercing using a punch from one of the upper and lower portions of the material on which the primary piercing is made. delete The method of claim 1,
After the completion of the secondary molding step and before performing the mold forging step, the taper forming step of forming a tapered corner portion of the material obtained through the secondary forming step in the taper process is further included Method for manufacturing ball for valves. The method according to any one of claims 1, 3, 4, 5, and 7,
For the large ball valve, characterized in that the material cutting step and the primary molding step, and the hole forming step and the secondary molding step, respectively, and further comprises a heating step for heating the material before proceeding to the next step, respectively. Ball manufacturing method.

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