Apparatus for estimating thickness of centrifugally cast pipe, method for estimating thickness of centrifugally cast pipe, method for manufacturing centrifugally cast pipe, centrifugally cast pipe, and apparatus for manufacturing centrifugally cast pipe

Abstract

A configuration is provided that enables accurate non-contact estimation of the wall thickness of a centrifugally cast pipe when the surface temperature after centrifugal casting is high. [Solution] A pipe thickness estimation device 1 estimates the pipe thickness of a centrifugally cast pipe W cast by centrifugal casting, based on the outer surface temperature of the centrifugally cast pipe W. The pipe thickness estimation device 1 includes an outer surface temperature-related information acquisition unit 11 that acquires outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe W, and a pipe thickness estimation unit 12 that estimates the pipe thickness of the centrifugally cast pipe W based on the outer surface temperature-related information, using a pipe thickness estimation model in which the relationship between the outer surface temperature-related information and the pipe thickness is defined for each axial region of the centrifugally cast pipe W.

Description

[Technical Field]

[0001] The present invention relates to an apparatus for estimating the wall thickness of a centrifugally cast pipe, a method for estimating the wall thickness of a centrifugally cast pipe, a method for manufacturing a centrifugally cast pipe, a centrifugally cast pipe, and an apparatus for manufacturing a centrifugally cast pipe. [Background technology]

[0002] Centrifugal casting is a well-known technique for casting pipes. In this method, molten metal is centrifuged in a mold to form a ring shape. Since the thickness of pipes cast by centrifugal casting tends to vary in the axial direction depending on the casting conditions, controlling the thickness is important.

[0003] Devices for measuring pipe thickness for pipe thickness management are known. For example, Patent Document 1 discloses a pipe thickness measuring device that includes a traveling section that travels along the extension direction, a sending section that sends out ultrasonic waves toward the inner surface of the metal pipe, and a receiving section that receives the ultrasonic waves reflected by the inner surface, as well as a measuring unit mounted on the traveling section. The measuring unit can travel along the metal pipe even if the metal pipe contains bends. Therefore, the pipe thickness measuring device can quickly measure the pipe thickness even if the metal pipe contains bends.

[0004] Furthermore, as a method for measuring pipe thickness without contact, for example, Patent Document 2 discloses a hot wall thickness measurement method in which the temperature difference between the average temperature in the wall thickness direction and the outer surface temperature is calculated from a steel pipe temperature distribution model, this calculated value is added to the measurement value of an outer surface temperature measuring instrument of the steel pipe to estimate the average temperature in the wall thickness direction of the steel pipe, and the average ultrasonic velocity in the wall thickness direction is corrected from the estimated average temperature to calculate the wall thickness. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6691956 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-134321 Summary of the Invention [Problem to be solved by the invention]

[0006] The pipe wall thickness measuring device disclosed in Patent Document 1 cannot measure the pipe wall thickness when the surface temperature of the pipe is high after centrifugal casting because the measuring unit is in contact with the top of the metal pipe. In contrast, the hot wall thickness measuring method disclosed in Patent Document 2 can measure the pipe wall thickness even when the surface temperature of the pipe is high after centrifugal casting.

[0007] However, in the hot wall thickness measurement method of Patent Document 2, the steel pipe temperature distribution model used to calculate the temperature difference between the average temperature in the wall thickness direction and the outer surface temperature is the same model regardless of the position in the axial direction of the steel pipe. Therefore, if the relationship between the temperature difference and the wall thickness of the steel pipe varies depending on the position in the axial direction due to the manufacturing conditions of the pipe, there is a possibility that the wall thickness cannot be estimated with high accuracy.

[0008] A centrifugally cast pipe is cast into a ring shape by axially moving a mold and a molten metal supply unit that supplies molten metal into the mold relative to each other, and therefore the pipe wall thickness is likely to vary in the axial direction depending on the relative movement speed, the amount of molten metal supplied, etc. Therefore, for the centrifugally cast pipe, it is desirable to accurately estimate the pipe wall thickness by taking into account the change in the pipe wall thickness in the axial direction.

[0009] An object of the present invention is to provide a configuration that enables accurate estimation of the wall thickness of a centrifugally cast pipe in a non-contact manner even when the surface temperature after centrifugal casting is high. [Means for solving the problem]

[0010] A first configuration of a centrifugally cast pipe wall thickness estimation device according to one embodiment of the present invention is a device for estimating the wall thickness of a centrifugally cast pipe based on the outer surface temperature of the centrifugally cast pipe. The device includes an outer surface temperature-related information acquisition unit that acquires outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe, and a wall thickness estimation unit that estimates the wall thickness of the centrifugally cast pipe based on the outer surface temperature-related information using a wall thickness estimation model in which the relationship between the outer surface temperature-related information and the wall thickness is defined for each axial region of the centrifugally cast pipe.

[0011] This allows the thickness of a centrifugally cast pipe to be accurately estimated for each axial region of the pipe based on the outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe, thereby enabling accurate non-contact estimation of the thickness of a centrifugally cast pipe even when the surface temperature is high after centrifugal casting.

[0012] In the first configuration, the pipe thickness estimation model is configured to define the relationship between the outer surface temperature-related information and the pipe thickness for each of the regions determined depending on the relative axial movement speed between a mold used in centrifugal casting and a molten metal supply section that supplies molten metal to the mold (second configuration).

[0013] In centrifugal casting, the thickness of a centrifugally cast pipe varies depending on the relative axial speed between the mold and the molten metal supply unit that supplies molten metal to the mold. Therefore, in the pipe thickness estimation model, the relationship between the outer surface temperature-related information and the pipe thickness for each axial region determined by the relative axial speed between the mold and the molten metal supply unit can be defined. This makes it possible to estimate the pipe thickness for each axial region. Therefore, the pipe thickness of the centrifugally cast pipe can be accurately estimated in the axial direction.

[0014] In the first configuration, the outer surface temperature related information acquisition unit includes an infrared amount measurement unit that measures the amount of infrared rays on the outer surface of the centrifugally cast pipe. The pipe thickness estimation unit estimates the pipe thickness based on the time change in the amount of infrared rays measured by the infrared amount measurement unit using the pipe thickness estimation model (third configuration).

[0015] This allows the thickness of a centrifugally cast pipe to be estimated based on the change over time in the amount of infrared radiation on the outer surface of the centrifugally cast pipe. Therefore, even if the centrifugally cast pipe is in a high temperature state immediately after casting, the amount of infrared radiation on the outer surface of the centrifugally cast pipe can be measured, and the thickness of the centrifugally cast pipe can be estimated from the measurement results. Therefore, since the thickness of a centrifugally cast pipe can be estimated quickly and easily after casting, the estimated thickness of the centrifugally cast pipe can be reflected in the casting conditions, thereby improving the production efficiency of centrifugally cast pipes.

[0016] A first embodiment of the present invention provides a method for estimating the thickness of a centrifugally cast pipe based on the outer surface temperature of the centrifugally cast pipe. This method includes an outer surface temperature-related information acquisition step for acquiring outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe, and a thickness estimation step for estimating the thickness of the centrifugally cast pipe based on the outer surface temperature-related information acquired in the outer surface temperature-related information acquisition step using a thickness estimation model in which the relationship between the outer surface temperature-related information and the thickness of the centrifugally cast pipe is defined for each axial region of the centrifugally cast pipe (first method).

[0017] This allows the thickness of a centrifugally cast pipe to be accurately estimated for each axial region of the pipe based on the outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe, thereby enabling accurate non-contact estimation of the thickness of a centrifugally cast pipe even when the surface temperature is high after centrifugal casting.

[0018] A method for manufacturing a centrifugally cast pipe according to one embodiment of the present invention includes a centrifugal casting step of casting the centrifugally cast pipe by centrifugal casting, an outer surface temperature related information acquisition step of acquiring outer surface temperature related information relating to the outer surface temperature of the centrifugally cast pipe, a pipe thickness estimation step of estimating the pipe thickness of the centrifugally cast pipe based on the outer surface temperature related information acquired in the outer surface temperature related information acquisition step using a pipe thickness estimation model in which the relationship between the outer surface temperature related information and the pipe thickness is defined for each axial region of the centrifugally cast pipe, and a centrifugal casting condition adjustment step of adjusting the centrifugal casting conditions based on the pipe thickness estimated in the pipe thickness estimation step (second method).

[0019] This allows the centrifugal casting conditions to be adjusted based on the pipe thickness estimated for each axial region of the centrifugally cast pipe from the outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe obtained by centrifugal casting. Therefore, if the estimated pipe thickness is larger or smaller than the appropriate range, the centrifugal casting conditions can be adjusted to cast the centrifugally cast pipe so that the pipe thickness falls within the appropriate range. This makes it possible to produce a centrifugally cast pipe with a pipe thickness within the appropriate range.

[0020] In the second method, the centrifugal casting condition adjustment step adjusts the relative axial movement speed between the mold used in the centrifugal casting and a molten metal supply unit that supplies molten metal to the mold based on the pipe thickness estimated in the pipe thickness estimation step (third method).

[0021] The thickness of the centrifugally cast pipe can be easily changed by adjusting the relative axial movement speed between the mold used for centrifugal casting and the molten metal supply unit that supplies molten metal to the mold. Therefore, a centrifugally cast pipe having a thickness within an appropriate range can be easily cast based on the pipe thickness estimated in the pipe thickness estimation step.

[0022] In the second method, the centrifugal casting condition adjusting step adjusts the amount of molten metal supplied during centrifugal casting based on the pipe thickness estimated in the pipe thickness estimating step (fourth method).

[0023] This allows the amount of molten metal supplied to be adjusted based on the estimated pipe thickness, making it possible to accurately adjust the pipe thickness of the centrifugally cast pipe.

[0024] A centrifugally cast pipe according to one embodiment of the present invention is a centrifugally cast pipe produced by centrifugal casting using any one of the second to fourth methods (fourth configuration).

[0025] This allows the pipe wall to be accurately estimated while the surface temperature is high after centrifugal casting, and the centrifugal casting conditions are adjusted based on the estimated pipe wall, resulting in a centrifugally cast pipe that is efficiently produced with high dimensional accuracy in the pipe wall.

[0026] A fifth configuration of a centrifugally cast pipe manufacturing apparatus according to one embodiment of the present invention comprises a centrifugal casting unit that casts the centrifugally cast pipe by centrifugal casting, an outer surface temperature related information acquisition unit that acquires outer surface temperature related information relating to the outer surface temperature of the centrifugally cast pipe, a pipe thickness estimation unit that estimates the pipe thickness of the centrifugally cast pipe based on the outer surface temperature related information acquired by the outer surface temperature related information acquisition unit using a pipe thickness estimation model in which the relationship between the outer surface temperature related information and the pipe thickness is defined for each axial region of the centrifugally cast pipe, and a centrifugal casting condition adjustment unit that adjusts the centrifugal casting conditions based on the pipe thickness estimated by the pipe thickness estimation unit.

[0027] This allows the centrifugal casting conditions to be adjusted based on the pipe thickness estimated for each axial region of the centrifugally cast pipe from the outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe obtained by centrifugal casting. Therefore, if the estimated pipe thickness is larger or smaller than the appropriate range, the centrifugal casting conditions can be adjusted to cast the centrifugally cast pipe so that the pipe thickness falls within the appropriate range. This makes it possible to produce a centrifugally cast pipe with a pipe thickness within the appropriate range. [Effects of the Invention]

[0028] A pipe thickness estimation device for a centrifugally cast pipe according to one embodiment of the present invention has a pipe thickness estimation unit that estimates the pipe thickness of the centrifugally cast pipe based on outer surface temperature-related information using a pipe thickness estimation model in which the relationship between the outer surface temperature-related information and the pipe thickness is defined for each axial region of the centrifugally cast pipe.

[0029] This makes it possible to realize a configuration that allows for accurate estimation of the pipe wall thickness in a non-contact manner even when the surface temperature of a centrifugally cast pipe is high after centrifugal casting. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a pipe thickness estimation device according to the first embodiment. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of a manufacturing apparatus for centrifugally cast pipes. [Figure 3] FIG. 3 is a diagram showing changes in the moving speed of the carriage when the centrifugally cast pipe W of this embodiment is centrifugal cast. [Figure 4] FIG. 4 is a diagram showing an example of a pipe thickness estimation model at the beginning and end of the movement of the carriage. [Figure 5] FIG. 5 is a diagram showing an example of a pipe thickness estimation model in the middle of the movement of the bogie. [Figure 6] FIG. 6 is a flowchart showing a method for estimating the wall thickness of a centrifugally cast pipe. [Figure 7] FIG. 7 is a diagram showing a schematic configuration of a manufacturing apparatus for a centrifugally cast pipe W according to the second embodiment. [Figure 8] FIG. 8 is a diagram schematically showing an example of the relationship between the wall thickness of a centrifugally cast pipe estimated by the wall thickness estimation unit and the target wall thickness. [Figure 9] FIG. 9 is a flowchart showing a method for manufacturing a centrifugally cast pipe. DETAILED DESCRIPTION OF THE INVENTION

[0031] Each embodiment will be described below with reference to the drawings. In each drawing, the same parts are designated by the same reference numerals, and the description of the same parts will not be repeated. Note that the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components and the dimensional ratios of the components.

[0032] In the following description, the axial direction refers to the direction in which the axis P of the centrifugally cast pipe W extends. The radial direction refers to the direction perpendicular to the axis P of the centrifugally cast pipe W, i.e., the radial direction of the centrifugally cast pipe W.

[0033] Furthermore, in the following description, the expressions "fix," "connect," and "attach" (hereinafter referred to as "fixing") include not only cases where members are directly fixed to each other, but also cases where members are fixed via other members. In other words, in the following description, the expression "fixing" includes both direct and indirect fixing of members to each other.

[0034] [Embodiment 1] 1 is a diagram showing a schematic configuration of a pipe thickness estimation device 1 according to a first embodiment of the present invention. The pipe thickness estimation device 1 is a device that estimates the pipe thickness of a centrifugally cast pipe W cast by centrifugal casting based on outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe W.

[0035] (centrifugally cast pipe) First, the centrifugal casting of a centrifugally cast pipe W will be described with reference to Figure 2. Figure 2 is a diagram showing the schematic configuration of an apparatus 100 for manufacturing a centrifugally cast pipe W. As shown in Figure 2, the apparatus 100 for manufacturing a centrifugally cast pipe W includes a carriage 101 that is movable along an axis P, a mold 102 supported on the carriage 101, and a molten metal supply unit 111 that supplies molten metal into the mold 102. For the sake of explanation, Figure 2 shows a schematic configuration of the apparatus 100 for manufacturing a centrifugally cast pipe W, and also shows a cross section of the mold 102.

[0036] The mold 102 has a casting space 102a therein for casting the centrifugally cast pipe W. The casting space 102a is defined within the mold 102 by the inner surface of the mold 102, which has a shape corresponding to the outer shape of the centrifugally cast pipe W. The mold 102 is supported by a carriage 101 so as to be rotatable about an axis P.

[0037] The molten metal supply section 111 supplies molten metal into the casting space 102a of the mold 102. The molten metal supply section 111 has a molten metal inlet section 112 and a supply pipe section 113. The molten metal inlet section 112 is connected to one end of the tubular supply pipe section 113. The molten metal inlet section 112 is configured to allow the molten metal flowing from the molten metal accommodation section 121, in which the molten metal is accommodated, to flow into the supply pipe section 113 (see the solid arrow in FIG. 2). The supply pipe section 113 is configured to extend from the molten metal inlet section 112 into the casting space 102a of the mold 102. The other end of the supply pipe section 113 is provided with a supply port (not shown) for supplying the molten metal flowing therethrough into the casting space 102a of the mold 102.

[0038] In the example shown in Figure 2, the mold 102 rotates around the axis P relative to the carriage 101, and moves from a state in which the other end of the supply pipe section 113 is positioned at the other end of the mold 102 (the receiving port side of the centrifugal casting pipe W) by the carriage 101, in a direction away from the molten metal supply section 111 along the axis P (see the white arrow shown in Figure 2).

[0039] As a result, the molten metal supplied onto the inner surface of the mold 102, which defines the casting space 102a, is formed into a tubular shape by extending uniformly in the circumferential direction on the inner surface of the mold 102 due to centrifugal force generated by rotation of the mold 102 about its axis P. Moreover, as the mold 102 is moved in the axial direction by the carriage 101, the molten metal is supplied axially onto the inner surface of the mold 102 and formed into a ring shape extending in the axial direction. Thus, a tubular centrifugally cast pipe W is cast by the mold 102. The centrifugally cast pipe W cast by the mold 102 is removed from the mold 102.

[0040] (Pipe thickness estimation device) As shown in Figure 1, the pipe wall thickness estimation device 1 is an apparatus that can estimate the pipe wall thickness of a centrifugally cast pipe W cast as described above in a non-contact manner, even when the surface temperature after centrifugal casting is high. The pipe wall thickness estimation device 1 has an outer surface temperature related information acquisition unit 11 that acquires the outer surface temperature related information, and a pipe wall thickness estimation unit 12 that estimates the pipe wall thickness of the centrifugally cast pipe W.

[0041] The outer surface temperature related information acquisition unit 11 acquires outer surface temperature related information relating to the outer surface temperature of the centrifugally cast pipe W. The outer surface temperature related information acquisition unit 11 measures, for example, the amount of infrared rays radiated from the outer surface of the centrifugally cast pipe W as the outer surface temperature related information. In this case, the outer surface temperature related information acquisition unit 11 has an infrared amount measurement unit 21. The infrared amount measurement unit 21 is, for example, an infrared camera, a hyperspectral camera, or the like.

[0042] The outer surface temperature related information acquiring unit 11 may detect a physical quantity other than the amount of infrared rays as long as it can acquire outer surface temperature related information related to the outer surface temperature of the centrifugally cast pipe W. The outer surface temperature related information acquiring unit 11 may include, for example, a radiation thermometer.

[0043] The outer surface temperature related information acquisition unit 11 may be configured to be movable in the circumferential direction relative to the centrifugally cast pipe W. This allows the outer surface temperature related information acquisition unit 11 to acquire outer surface temperature related information related to the outer surface temperature of the centrifugally cast pipe W over the entire circumferential direction of the centrifugally cast pipe W.

[0044] The outer surface temperature related information acquisition unit 11 may be configured to be movable in the axial direction relative to the centrifugally cast pipe W. This allows the outer surface temperature related information acquisition unit 11 to acquire outer surface temperature related information related to the outer surface temperature of the centrifugally cast pipe W over the entire axial direction of the centrifugally cast pipe W.

[0045] The centrifugally cast pipe W may be supported by a support device configured to be rotatable in the circumferential direction relative to the outer surface temperature related information acquisition unit 11. Alternatively, the centrifugally cast pipe W may be supported by a support device configured to be movable in the axial direction relative to the outer surface temperature related information acquisition unit 11.

[0046] The outer surface temperature related information acquisition unit 11 outputs the acquired outer surface temperature related information to the pipe thickness estimation unit 12. If the outer surface temperature related information acquisition unit 11 has an infrared amount measurement unit 21, the infrared amount measurement unit 21 outputs the measured amount of infrared rays to the pipe thickness estimation unit 12 as outer surface temperature related information.

[0047] The pipe thickness estimation unit 12 uses a pipe thickness estimation model to estimate the pipe thickness of the centrifugally cast pipe W based on the outer surface temperature-related information output from the outer surface temperature-related information acquisition unit 11. When the outer surface temperature-related information output from the outer surface temperature-related information acquisition unit 11 is information about the amount of infrared light emitted from the outer surface of the centrifugally cast pipe W, the pipe thickness estimation unit 12 calculates the ratio of the amounts of infrared light at two wavelengths and regards the change in that ratio over time as the change in the amount of infrared light over time. This cancels the effect of the emissivity of the outer surface of the centrifugally cast pipe W, making it possible to accurately determine the change in the amount of infrared light on the outer surface.

[0048] In addition, the pipe thickness estimation unit 12 may estimate the pipe thickness of the centrifugally cast pipe W using a value related to the temperature conversion other than the ratio of the amount of infrared rays, as long as it can estimate the pipe thickness based on the temperature change on the outer surface of the centrifugally cast pipe W.

[0049] The pipe thickness estimation model is a model in which the relationship between outer surface temperature-related information and pipe thickness is defined for each axial region of the centrifugally cast pipe W. Specifically, the pipe thickness estimation model defines the relationship between the change over time in the amount of infrared rays radiated from the outer surface of the centrifugally cast pipe W and the pipe thickness for each axial region of the centrifugally cast pipe W.

[0050] When the wall thickness of the centrifugally cast pipe W is large, the amount of infrared radiation radiated from the outer surface of the centrifugally cast pipe W changes little over time, whereas when the wall thickness of the centrifugally cast pipe W is small, the amount of infrared radiation changes much over time. The wall thickness estimation model reflects these characteristics. The wall thickness estimation model may be a relational expression that defines the relationship between the change in the amount of infrared radiation over time and the wall thickness of the centrifugally cast pipe W, or it may be table data, etc.

[0051] 3 is a diagram showing changes in the moving speed of the carriage 101 when centrifugal casting the centrifugally cast pipe W of this embodiment. As shown in FIG. 3, when centrifugal casting the centrifugally cast pipe W, the moving speed of the carriage 101 of the manufacturing apparatus 100 is not constant, and the moving speed of the carriage 101 at the beginning and end of its movement is relatively slower than the moving speed of the carriage 101 in the middle of its movement.

[0052] The initial, middle, and final periods of movement are obtained by dividing the movement range of the carriage 101 according to the movement speed of the carriage 101. In this embodiment, the initial period of movement is a period during which the speed of the carriage 101 increases from zero. The middle period of movement is a period during which the speed of the carriage 101 is constant. The final period of movement is a period during which the speed of the carriage 101 decreases. When the centrifugally cast pipe W to be centrifugally cast is divided into regions in the axial direction, the initial, middle, and final periods of movement each correspond to each region in the axial direction of the centrifugally cast pipe W during centrifugal casting.

[0053] Because the supply rate of molten metal when centrifugal casting a centrifugally cast pipe W varies depending on the axial position, the relationship between the surface temperature and the pipe thickness of the centrifugally cast pipe W after centrifugally casting also varies depending on the axial position. The pipe thickness estimation model includes a model in which the relationship between the change in the amount of infrared rays over time and the pipe thickness varies depending on the axial position at which the supply rate of molten metal when centrifugally casting a centrifugally cast pipe W changes. As a result, the pipe thickness estimation model can accurately estimate the pipe thickness of the centrifugally cast pipe W in the axial direction from the change in the amount of infrared rays over time on the outer surface of the centrifugally cast pipe W, taking into account the change in the axial position of the supply rate of molten metal when centrifugally casting a centrifugally cast pipe W.

[0054] FIG. 4 is a diagram showing an example of a pipe thickness estimation model at the beginning and end of the movement of the bogie 101. FIG. 5 is a diagram showing an example of a pipe thickness estimation model at the middle of the movement of the bogie 101. As shown in FIGS. 4 and 5, the pipe thickness estimation model at the beginning and end of the movement of the bogie 101 and the pipe thickness estimation model at the middle of the movement of the bogie 101 differ, for example, in the relationship between the change in the amount of infrared rays over time and the pipe thickness. Specifically, in the examples shown in FIGS. 4 and 5, the pipe thickness changes linearly with the change in the amount of infrared rays over time, but the slopes are different. The change in the amount of infrared rays over time means the amount of change (decrease or increase) in the amount of infrared rays per unit time.

[0055] Note that the pipe thickness estimation model at the beginning and end of the movement of the bogie 101 and the pipe thickness estimation model at the middle of the movement of the bogie 101 may have different parameters other than the slope, as long as the relationship between the change in the amount of infrared light over time and the pipe thickness is different. The pipe thickness estimation model may have a relationship in which the pipe thickness changes in a curved manner rather than a linear relationship with the change in the amount of infrared light over time, or the relationship between the change in the amount of infrared light over time and the pipe thickness may be expressed by a polynomial.

[0056] Furthermore, the relationship between the change in the amount of infrared rays over time and the pipe thickness may be different between the pipe thickness estimation model at the beginning of the movement of the bogie 101 and the pipe thickness estimation model at the end of the movement of the bogie 101. The relationship between the change in the amount of infrared rays over time and the pipe thickness may be the same between the pipe thickness estimation model at the beginning of the movement of the bogie 101 and the pipe thickness estimation model at the middle of the movement of the bogie 101. The relationship between the change in the amount of infrared rays over time and the pipe thickness may be the same between the pipe thickness estimation model at the middle of the movement of the bogie 101 and the pipe thickness estimation model at the end of the movement of the bogie 101.

[0057] The device 1 for estimating the thickness of a centrifugally cast pipe W according to this embodiment is a device for estimating the thickness of a centrifugally cast pipe W cast by centrifugal casting based on the outer surface temperature of the centrifugally cast pipe W. The device 1 includes an outer surface temperature-related information acquisition unit 11 that acquires outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe W, and a thickness estimation unit 12 that estimates the thickness of the centrifugally cast pipe W based on the outer surface temperature-related information using a thickness estimation model in which the relationship between the outer surface temperature-related information and the thickness is defined for each axial region of the centrifugally cast pipe W.

[0058] This allows for accurate estimation of the wall thickness for each axial region of the centrifugally cast pipe W based on the outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe W. Therefore, the wall thickness of the centrifugally cast pipe W can be accurately estimated in a non-contact manner even when the surface temperature of the centrifugally cast pipe W is high after centrifugal casting.

[0059] The pipe thickness estimation model is configured to define the relationship between the outer surface temperature-related information and the pipe thickness for each of the regions determined according to the relative axial movement speed between the mold 102 used in centrifugal casting and the molten metal supply section 111 that supplies molten metal to the mold 102.

[0060] In centrifugal casting, the thickness of the centrifugally cast pipe W varies depending on the relative axial movement speed between the mold 102 and the molten metal supply unit 111 that supplies molten metal to the mold 102. Therefore, in the pipe thickness estimation model, the relationship between the outer surface temperature-related information and the pipe thickness is defined for each axial region determined by the relative axial movement speed between the mold 102 and the molten metal supply unit 111. This makes it possible to estimate the pipe thickness for each axial region. Therefore, the pipe thickness of the centrifugally cast pipe W can be estimated with high accuracy in the axial direction.

[0061] The outer surface temperature related information acquisition unit 11 has an infrared amount measurement unit 21 that measures the amount of infrared rays on the outer surface of the centrifugally cast pipe W. The pipe thickness estimation unit 12 uses the pipe thickness estimation model to estimate the pipe thickness based on the amount of change over time in the amount of infrared rays measured by the infrared amount measurement unit 21.

[0062] This makes it possible to estimate the wall thickness of a centrifugally cast pipe W based on the change over time in the amount of infrared radiation on the outer surface of the centrifugally cast pipe W. Therefore, even when the centrifugally cast pipe W is in a high temperature state immediately after casting, the amount of infrared radiation on the outer surface of the centrifugally cast pipe W can be measured and the wall thickness of the centrifugally cast pipe W can be estimated from the measurement results. Therefore, because the wall thickness of a centrifugally cast pipe W can be estimated quickly and easily after casting, by reflecting the estimated wall thickness of the centrifugally cast pipe W in the casting conditions, the number of centrifugally cast pipes W whose wall thickness is outside the appropriate range can be reduced, and the production efficiency of centrifugally cast pipes W can be improved.

[0063] (Method for estimating the thickness of centrifugally cast pipes) Next, a method for estimating the wall thickness of a centrifugally cast pipe W using the wall thickness estimation device 1 having the above-described configuration will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the method for estimating the wall thickness of a centrifugally cast pipe W.

[0064] First, a centrifugally cast pipe W is formed by centrifugal casting using an apparatus 100 for manufacturing a centrifugally cast pipe W (step SA1). Thereafter, the centrifugally cast pipe W is removed from the mold 102 of the manufacturing apparatus 100 (step SA2).

[0065] Next, in step SA3, the outer surface temperature-related information acquisition unit 11 of the pipe thickness estimation device 1 acquires outer surface temperature-related information related to the temperature of the outer surface of the centrifugally cast pipe W. For example, the outer surface temperature-related information acquisition unit 11 measures the amount of infrared rays radiated from the outer surface of the centrifugally cast pipe W as the outer surface temperature-related information. The outer surface temperature-related information acquisition unit 11 outputs the acquired outer surface temperature-related information to the pipe thickness estimation unit 12 of the pipe thickness estimation device 1.

[0066] In the next step SA4, the pipe wall thickness estimation unit 12 of the pipe wall thickness estimation device 1 uses the pipe wall thickness estimation model to estimate the pipe wall of the centrifugally cast pipe W based on the outer surface temperature related information acquired by the outer surface temperature related information acquisition unit 11. Then, this flow ends.

[0067] Here, step SA3 corresponds to an outer surface temperature related information acquisition step, and step SA4 corresponds to a pipe thickness estimation step.

[0068] The method for estimating the thickness of a centrifugally cast pipe W, which is produced by centrifugally casting, is a method for estimating the thickness of the centrifugally cast pipe W from the outer surface temperature of the centrifugally cast pipe W. This method includes an outer surface temperature-related information acquisition step SA3 for acquiring outer surface temperature-related information relating to the outer surface temperature of the centrifugally cast pipe W, and a thickness estimation step SA4 for estimating the thickness of the centrifugally cast pipe W based on the outer surface temperature-related information acquired in the outer surface temperature-related information acquisition step SA3, using a thickness estimation model in which the relationship between the outer surface temperature-related information and the thickness is defined for each axial region of the centrifugally cast pipe W.

[0069] This allows for accurate estimation of the wall thickness for each axial region of the centrifugally cast pipe W based on the outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe W. Therefore, the wall thickness of the centrifugally cast pipe W can be accurately estimated in a non-contact manner even when the surface temperature of the centrifugally cast pipe W is high after centrifugal casting.

[0070] [Embodiment 2] 7 is a diagram showing the schematic configuration of an apparatus 200 for manufacturing a centrifugally cast pipe W according to a second embodiment. When the apparatus 200 for manufacturing a centrifugally cast pipe W performs centrifugal casting, the casting conditions are changed based on the thickness of the centrifugally cast pipe W estimated by the thickness estimation unit 12. This makes it possible to centrifugally cast a centrifugally cast pipe W having an appropriate thickness. In the following description, components similar to those in the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0071] The manufacturing apparatus 200 for the centrifugally cast pipe W includes a centrifugal casting section 210, an outer surface temperature related information acquisition section 11, a pipe thickness estimation section 12, and a centrifugal casting condition adjustment section 220.

[0072] The centrifugal casting unit 210 has a carriage 201, a mold 202, and a molten metal supply unit 211. The carriage 201, the mold 202, and the molten metal supply unit 211 are similar to the respective components of the manufacturing apparatus 100 of the first embodiment, except that the casting conditions can be changed by a centrifugal casting condition adjustment unit 220, as will be described later, and therefore detailed explanation of the components will be omitted.

[0073] The outer surface temperature related information acquisition unit 11 and the pipe wall thickness estimation unit 12 are the outer surface temperature related information acquisition unit 11 and the pipe wall thickness estimation unit 12 in the pipe wall thickness estimation device 1 of embodiment 1. That is, the manufacturing apparatus 200 for a centrifugally cast pipe W according to this embodiment includes the pipe wall thickness estimation device 1 of embodiment 1.

[0074] The centrifugal casting condition adjustment unit 220 adjusts the casting conditions for the centrifugally cast pipe W in the centrifugal casting unit 210 based on the pipe wall thickness of the centrifugally cast pipe W estimated by the pipe wall thickness estimation unit 12. Figure 8 is a diagram schematically showing an example of the relationship between the pipe wall thickness of the centrifugally cast pipe W estimated by the pipe wall thickness estimation unit 12 and the appropriate range of pipe wall thickness. As shown in Figure 8, if the estimated pipe wall thickness (the estimated value in Figure 8, indicated by the white circle in Figure 8) is smaller than the appropriate range, the centrifugal casting condition adjustment unit 220 adjusts the casting conditions for the centrifugally cast pipe W so that the pipe wall thickness of the centrifugally cast pipe W approaches the appropriate range (see the white arrow in Figure 8).

[0075] Specifically, the centrifugal casting condition adjustment unit 220 adjusts, for example, the axial movement speed of the carriage 201 of the centrifugal casting unit 210, i.e., the relative axial movement speed between the mold 202 and the molten metal supply unit 211, based on the estimated pipe thickness. For example, if the estimated pipe thickness is larger than the appropriate range of pipe thicknesses, the centrifugal casting condition adjustment unit 220 increases the relative movement speed. On the other hand, for example, if the estimated pipe thickness is smaller than the appropriate range of pipe thicknesses, the centrifugal casting condition adjustment unit 220 decreases the relative movement speed.

[0076] The centrifugal casting condition adjustment unit 220 may adjust, for example, the amount of molten metal supplied by the molten metal supply unit 211 of the centrifugal casting unit 210 based on the estimated pipe thickness. For example, when the estimated pipe thickness is larger than an appropriate range of pipe thicknesses, the centrifugal casting condition adjustment unit 220 decreases the amount of molten metal supplied. On the other hand, when the estimated pipe thickness is smaller than an appropriate range of pipe thicknesses, the centrifugal casting condition adjustment unit 220 increases the amount of molten metal supplied. The amount of molten metal supplied can be adjusted by changing the tilt angular velocity of the molten metal accommodation unit 121 or by changing the amount of molten metal supplied into the molten metal accommodation unit 121.

[0077] The centrifugal casting condition adjusting unit 220 may adjust the viscosity of the molten metal or the amount of molten metal to be supplied, thereby adjusting the time for the molten metal to flow through the molten metal supply unit 211. The centrifugal casting condition adjusting unit 220 may also adjust the rotation speed of the mold 201.

[0078] By adjusting the centrifugal casting conditions using the centrifugal casting condition adjustment unit 220 as described above, the thickness of the centrifugally cast pipe W cast by the centrifugal casting unit 210 can be easily changed. Therefore, the thickness of the centrifugally cast pipe W can be easily controlled to fall within an appropriate range. The centrifugal casting condition adjustment unit 220 may adjust both the relative axial movement speed between the mold 202 and the molten metal supply unit 211 and the amount of molten metal supplied by the molten metal supply unit 211.

[0079] The manufacturing apparatus 200 for centrifugally cast pipes W according to this embodiment includes a centrifugal casting section 210 that casts centrifugally cast pipes W by centrifugal casting, an outer surface temperature related information acquisition section 11 that acquires outer surface temperature related information relating to the outer surface temperature of the centrifugally cast pipe W, a pipe thickness estimation section 12 that estimates the pipe thickness of the centrifugally cast pipe W based on the outer surface temperature related information acquired by the outer surface temperature related information acquisition section 11 using a pipe thickness estimation model in which the relationship between the outer surface temperature related information and the pipe thickness is defined for each axial region of the centrifugally cast pipe W, and a centrifugal casting condition adjustment section 220 that adjusts the conditions for the centrifugal casting based on the pipe thickness estimated by the pipe thickness estimation section 12.

[0080] This allows the centrifugal casting conditions to be adjusted based on the wall thickness estimated for each axial region of the centrifugally cast pipe W from the outer surface temperature-related information related to the outer surface temperature of the centrifugally cast pipe W obtained by centrifugal casting. Therefore, if the estimated wall thickness is larger or smaller than the appropriate range, the centrifugal casting conditions can be adjusted to cast the centrifugally cast pipe W so that the wall thickness falls within the appropriate range. This makes it possible to manufacture a centrifugally cast pipe W having a wall thickness within the appropriate range.

[0081] (Manufacturing method of centrifugally cast pipes) A method for manufacturing a centrifugally cast pipe W using the centrifugally cast pipe W manufacturing apparatus 200 having the above-described configuration will be described with reference to Fig. 9. Fig. 9 is a flowchart showing the method for manufacturing a centrifugally cast pipe W. In Fig. 9, steps SA1 to SA4 are the same as steps SA1 to SA4 in the flowchart shown in Fig. 6 for the first embodiment.

[0082] 9, after the centrifugally cast pipe W is centrifugally cast (step SA1), the centrifugally cast pipe W is removed from the mold 202 (step SA2). After that, the outer surface temperature related information acquisition unit 11 acquires outer surface temperature related information of the centrifugally cast pipe W (step SA3). Next, the pipe thickness estimation unit 12 estimates the pipe thickness of the centrifugally cast pipe W based on the outer surface temperature related information using a pipe thickness estimation model (step SA4).

[0083] Then, in step SB5, the centrifugal casting condition adjustment unit 220 determines whether the wall thickness of the centrifugally cast pipe W estimated by the wall thickness estimation unit 12 is within the appropriate range. If it is determined in step SB5 that the estimated wall thickness is within the appropriate range (YES in step SB5), there is no need to change the casting conditions for the centrifugally cast pipe W, and the flow ends (END). On the other hand, if it is determined in step SB5 that the estimated wall thickness is not within the appropriate range (NO in step SB5), the flow proceeds to step SB6, where the centrifugal casting condition adjustment unit 220 adjusts the casting conditions for the centrifugally cast pipe W so that the wall thickness of the centrifugally cast pipe W falls within the appropriate range. Then, the flow ends (END).

[0084] In the flowchart shown in FIG. 9, after step SB6, the flow may start again from step SA1.

[0085] Here, step SA1 corresponds to the centrifugal casting step, step SA3 corresponds to the outer surface temperature related information obtaining step, step SA4 corresponds to the pipe thickness estimating step, and steps SB5 and SB6 correspond to the centrifugal casting condition adjusting step.

[0086] The manufacturing method of the centrifugally cast pipe according to this embodiment includes a centrifugal casting step SA1 in which a centrifugally cast pipe W is cast by centrifugal casting; an outer surface temperature related information acquisition step SA3 in which outer surface temperature related information relating to the outer surface temperature of the centrifugally cast pipe W is acquired; a pipe thickness estimation step SA4 in which the pipe thickness of the centrifugally cast pipe W is estimated based on the outer surface temperature related information acquired in the outer surface temperature related information acquisition step SA3 using a pipe thickness estimation model in which the relationship between the outer surface temperature related information and the pipe thickness is defined for each axial region of the centrifugally cast pipe W; and centrifugal casting condition adjustment steps SB5 and SB6 in which the conditions of the centrifugal casting are adjusted based on the pipe thickness estimated in the pipe thickness estimation step SA4.

[0087] This allows the centrifugal casting conditions to be adjusted based on the wall thickness estimated for each axial region of the centrifugally cast pipe W from information related to the outer surface temperature of the centrifugally cast pipe W obtained by centrifugal casting. Therefore, if the estimated wall thickness is larger or smaller than the appropriate range, the centrifugal casting conditions can be adjusted to cast the centrifugally cast pipe W so that the wall thickness falls within the appropriate range. This makes it possible to manufacture a centrifugally cast pipe W having a wall thickness within the appropriate range.

[0088] The centrifugal casting condition adjustment steps SB5 and SB6 adjust the relative axial movement speed between the mold 202 used for the centrifugal casting and the molten metal supply section 211 that supplies molten metal to the mold 202, based on the pipe thickness estimated in the pipe thickness estimation step SA4.

[0089] The wall thickness of the centrifugally cast pipe W can be easily changed by adjusting the relative axial movement speed between the mold 202 used for centrifugal casting and the molten metal supply unit 211 that supplies molten metal to the mold 202. Therefore, a centrifugally cast pipe W having a wall thickness within an appropriate range can be easily cast based on the wall thickness estimated in wall thickness estimation step SA4.

[0090] In centrifugal casting condition adjusting steps SB5 and SB6, the amount of molten metal supplied during centrifugal casting is adjusted based on the pipe thickness estimated in pipe thickness estimating step SA4.

[0091] This allows the amount of molten metal supplied to be adjusted based on the estimated pipe thickness, so that the pipe thickness of the centrifugally cast pipe W can be adjusted with high precision.

[0092] (Other embodiments) Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and it is possible to appropriately modify the above-described embodiments within the scope of the spirit of the present invention.

[0093] In each of the above-described embodiments, the manufacturing apparatus 100, 200 for a centrifugally cast pipe W includes a carriage 101, 201 that supports a mold 102, 202 rotatably about an axis P and that is movable along the axis P. However, in the manufacturing apparatus for a centrifugally cast pipe, the molten metal supply unit may be configured to be movable along the axis P. In this case, the carriage may be fixed so as not to move along the axis P.

[0094] In each of the above-described embodiments, the molten metal supply section 111, 211 includes a supply pipe section 113 and a molten metal inlet section 112. However, the molten metal supply section may have any configuration as long as it is capable of supplying molten metal into the casting space of the mold to produce a centrifugally cast pipe.

[0095] In each of the above embodiments, the pipe wall thickness estimation model defines the relationship between the change over time in the amount of infrared rays emitted from the outer surface of the centrifugally cast pipe W and the pipe wall thickness for each axial region of the centrifugally cast pipe W. The axial regions are divided according to the classification of the moving speed of the carriage 101 (initial, middle, and final stages of movement). However, the axial regions may also be divided by a parameter other than the moving speed of the carriage. [Industrial Applicability]

[0096] The present invention can be used in a pipe wall thickness estimation device that estimates the pipe wall of a centrifugally cast pipe. [Explanation of symbols]

[0097] 1 Pipe thickness estimation device 11. External surface temperature related information acquisition unit 12 Pipe thickness estimation section 21 Infrared amount measuring unit 100, 200 Centrifugal casting pipe manufacturing equipment 101, 201 bogies 102, 202 Mold 102a Casting space 111, 211 Molten metal supply section 112 Molten metal inlet 113 Supply pipe section 121 Molten metal container 210 Centrifugal Casting Department 220 Centrifugal Casting Condition Adjustment Department W Centrifugal Cast Pipe P axis

Claims

1. 1. A device for estimating the wall thickness of a centrifugally cast pipe, which estimates the wall thickness of a centrifugally cast pipe based on an outer surface temperature of the centrifugally cast pipe, an outer surface temperature related information acquiring unit that acquires outer surface temperature related information relating to the outer surface temperature of the centrifugally cast pipe; a pipe thickness estimation unit that estimates the pipe thickness of the centrifugally cast pipe based on the outer surface temperature-related information by using a pipe thickness estimation model in which a relationship between the outer surface temperature-related information and a pipe thickness is defined for each axial region of the centrifugally cast pipe; having A device for estimating the thickness of centrifugally cast pipes.

2. 2. The apparatus for estimating the thickness of a centrifugally cast pipe according to claim 1, the pipe wall thickness estimation model is configured to define a relationship between the outer surface temperature related information and the pipe wall thickness for each of the regions determined depending on a relative moving speed in the axial direction between a mold used in centrifugal casting and a molten metal supply unit that supplies molten metal to the mold. A device for estimating the thickness of centrifugally cast pipes.

3. 2. The apparatus for estimating the thickness of a centrifugally cast pipe according to claim 1, the outer surface temperature related information acquisition unit has an infrared amount measurement unit that measures an amount of infrared rays on the outer surface of the centrifugally cast pipe, The pipe thickness estimation unit estimates the pipe thickness based on the amount of change over time of the infrared ray amount measured by the infrared ray amount measurement unit using the pipe thickness estimation model. A device for estimating the thickness of centrifugally cast pipes.

4. A method for estimating the wall thickness of a centrifugally cast pipe, which is cast by centrifugal casting, from the outer surface temperature of the centrifugally cast pipe, comprising: an outer surface temperature related information acquiring step of acquiring outer surface temperature related information relating to the outer surface temperature of the centrifugally cast pipe; a pipe thickness estimating step of estimating the pipe thickness of the centrifugally cast pipe based on the outer surface temperature-related information acquired in the outer surface temperature-related information acquiring step, using a pipe thickness estimation model in which a relationship between the outer surface temperature-related information and a pipe thickness is defined for each axial region of the centrifugally cast pipe; having A method for estimating the thickness of centrifugally cast pipes.

5. A method for manufacturing a centrifugally cast pipe, comprising: a centrifugal casting step of casting the centrifugally cast pipe by centrifugal casting; an outer surface temperature related information acquiring step of acquiring outer surface temperature related information relating to the outer surface temperature of the centrifugally cast pipe; a pipe thickness estimating step of estimating the pipe thickness of the centrifugally cast pipe based on the outer surface temperature-related information acquired in the outer surface temperature-related information acquiring step, using a pipe thickness estimation model in which a relationship between the outer surface temperature-related information and a pipe thickness is defined for each axial region of the centrifugally cast pipe; a centrifugal casting condition adjusting step of adjusting the conditions of the centrifugal casting based on the pipe thickness estimated in the pipe thickness estimating step; having Manufacturing method of centrifugally cast pipe.

6. 6. The method for producing a centrifugally cast pipe according to claim 5, The centrifugal casting condition adjusting step adjusts a relative moving speed in the axial direction between a mold used in the centrifugal casting and a molten metal supply unit that supplies molten metal to the mold, based on the pipe thickness estimated in the pipe thickness estimating step. Manufacturing method of centrifugally cast pipe.

7. 6. The method for producing a centrifugally cast pipe according to claim 5, the centrifugal casting condition adjusting step adjusts the amount of molten metal supplied during the centrifugal casting based on the pipe thickness estimated in the pipe thickness estimating step. Manufacturing method of centrifugally cast pipe.

8. A centrifugally cast pipe produced by centrifugal casting using the manufacturing method according to any one of claims 5 to 7.

9. An apparatus for manufacturing centrifugally cast pipes, comprising: a centrifugal casting unit for casting the centrifugally cast pipe by centrifugal casting; an outer surface temperature related information acquiring unit that acquires outer surface temperature related information relating to the outer surface temperature of the centrifugally cast pipe; a pipe thickness estimation unit that estimates the pipe thickness of the centrifugally cast pipe based on the outer surface temperature-related information acquired by the outer surface temperature-related information acquisition unit, using a pipe thickness estimation model in which the relationship between the outer surface temperature-related information and the pipe thickness is defined for each axial region of the centrifugally cast pipe; a centrifugal casting condition adjusting unit that adjusts the conditions of the centrifugal casting based on the pipe thickness estimated by the pipe thickness estimating unit; having Centrifugal casting pipe manufacturing equipment.

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