JP6765359B2 - Structure manufacturing method and structure - Google Patents

Description

The present invention relates to a method for producing a structure and the structure.

When manufacturing mechanical parts by casting, first, a wooden mold (which may be metal or resin) that serves as a model of the product is made, and a sand mold is made based on this wooden mold. Next, the casting water is poured into the sand mold to complete the cast article in the cavity of the sand mold. However, in such casting, it takes a lot of man-hours to produce a wooden mold or a sand mold, and the lead time until a finished product is obtained becomes long. Further, in the case of small-quantity production, the cost of wooden molds and sand molds is added to the product, which causes an increase in manufacturing cost.

On the other hand, there is an increasing need for modeling using a 3D printer as a new means of production, and research and development are being promoted toward the practical application of modeling using metal materials. A 3D printer for modeling a metal material uses a laser, an electron beam, or a heat source such as an arc to melt a metal powder or a metal wire and laminate the molten metal to produce a modeled object.

As a technique for laminating such molten metals to form a modeled object, there is known a technique for producing a mold using a welded bead (see, for example, Patent Document 1). Patent Document 1 describes a step of generating shape data expressing the shape of a mold, a step of dividing a mold into laminates along contour lines based on the generated shape data, and a obtained laminate. A method for manufacturing a mold including a step of creating a moving path of a welding torch for supplying a filler material based on the shape data of the above is described.

Further, Patent Document 2 describes a manufacturing method in which a metal molded body having a hollow portion is manufactured by using a metal lamination molding method, and the metal molded body is cast and wrapped to manufacture a cast product in which the hollow portion is communicated with the outside. There is.

Japanese Patent No. 3784539 Japanese Unexamined Patent Publication No. 2014-113610

However, the technique of Patent Document 1 relates to a method for manufacturing a mold, and does not describe a technique for mass-producing machine parts, particularly a technique for manufacturing machine parts produced in a small amount. Further, the technique of Patent Document 2 is a technique of manufacturing a cast article having a hollow portion by casting and wrapping a metal molded body formed by a metal additive manufacturing method. Therefore, a sand mold for casting and wrapping the metal molded body and a wooden mold for producing the sand mold are indispensable, and the lead time becomes long. In addition, when producing in small quantities, there remains a problem regarding the cost of wooden molds and sand molds.

When the cast article is manufactured, if the wall thickness of the casting portion differs depending on the portion, the casting water solidifies quickly in the portion where the wall thickness is small, and the casting water solidifies slowly in the portion where the wall thickness is large. As described above, if the cooling rate at the time of solidification of the casting water is different, the following problems (1) to (3) occur.
(1) Due to the non-uniform cooling rate, the mechanical properties of the cast portion become non-uniform.
(2) Residual stress is generated in the casting part.
(3) Defects (shrinkage cavities) and cracks (cracks) are likely to occur in thick-walled parts.

The present invention has been made in view of the above circumstances, and an object of the present invention is that a structure can be manufactured at low cost and with a short lead time, and moreover, differences in material properties, residual stress, defects, etc. It is an object of the present invention to provide a method for producing a structure capable of suppressing the occurrence, and the structure.

The present invention has the following configuration.
(1) A welded bead obtained by melting and solidifying a filler metal by an arc is laminated on a base to form a laminated wall portion including at least the outer shell of the structure, and then surrounded by the formed laminated wall portion. It is a method of manufacturing a structure in which casting water is poured into the inner space to form a casting part.
When a straight line passing through the casting portion and the pair of laminated wall portions sandwiching the casting portion in the horizontal cross section of the structure and the normal line at any position of the laminated wall portion is used as a feature line, the position A method for manufacturing a structure in which the total wall thickness of a pair of laminated wall portions along the feature line is changed according to the wall thickness of the casting portion sandwiched between the feature lines along the feature line.
(2) A structure having a laminated wall portion in which welded beads, which are melt-solidified bodies of filler metal, are laminated on a base, and a casting portion formed in an inner space surrounded by the laminated wall portion. ,
The position when a straight line passing through the casting portion and the pair of laminated wall portions sandwiching the casting portion in the horizontal cross section of the structure and the normal line at any position of the laminated wall portion is used as a feature line. A structure in which the total wall thickness of the pair of laminated wall portions along the feature line changes according to the wall thickness of the casting portion sandwiched between the feature lines along the feature line.

According to the present invention, the structure can be manufactured at low cost and the lead time can be shortened, and the difference in material properties, residual stress, defects, and the like can be suppressed.

It is a schematic schematic block diagram of the manufacturing system which manufactures the structure of this invention. It is a perspective view of the structure of 1st configuration example. It is a process explanatory drawing which shows the state which moved the torch along the movement locus of the 1st layer on the base plate, and formed the welding bead of the 1st layer. It is sectional drawing in the horizontal direction of a structure. It is a partially enlarged view of the part A shown in FIG. It is a schematic perspective view of the structure of the 2nd configuration example. FIG. 6 is a sectional view taken along line VII-VII of the structure shown in FIG. It is a schematic perspective view of the structure of the 3rd configuration example. It is IX-IX line sectional view of the structure shown in FIG. It is a schematic perspective view of the structure of the 4th configuration example. FIG. 5 is a sectional view taken along line XI-XI of the structure shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic schematic configuration diagram of a manufacturing system for manufacturing the structure of the present invention.
The manufacturing system 100 having this configuration includes a laminated modeling device 11, a casting device 13, and a controller 15 that controls the laminated modeling device 11 in an integrated manner. The controller 15 may be controlled including the casting device 13.

The laminated modeling device 11 includes a welding robot 19 having a torch 17 on a tip shaft, and a filler material supply unit 23 that supplies a filler metal (welding wire) M to the torch 17.

The casting apparatus 13 has a crucible 27 for storing the casting water 25 heated by a heating furnace (not shown), and the casting water 25 can be supplied to a desired position by a pouring mechanism (not shown). As the laminated molding device 11 and the casting device 13, existing devices are used in this configuration.

The controller 15 includes a CAD / CAM unit 31, an orbit calculation unit 33, a storage unit 35, and a control unit 37 to which these are connected.
The welding robot 19 is an articulated robot, and the filler metal M is continuously supplied to the torch 17 provided on the tip shaft. The position and posture of the torch 17 can be arbitrarily set three-dimensionally within the range of freedom of the robot arm.

The torch 17 has a shield nozzle (not shown), and shield gas is supplied from the shield nozzle. The arc welding method may be either a consumable electrode type such as shielded metal arc welding or carbon dioxide arc welding, or a non-consumable electrode type such as TIG welding or plasma arc welding, and the outer shell and inner shell of the structure to be manufactured may be used. It is appropriately selected according to the laminated wall portion W.

For example, in the case of the consumable electrode type, a contact tip is arranged inside the shield nozzle, and the filler metal M to which the melting current is supplied is held by the contact tip. The torch 17 generates an arc from the tip of the filler metal M in a shield gas atmosphere while holding the filler metal M. The filler metal M is fed from the filler metal supply unit 23 to the torch 17 by a feeding mechanism (not shown) attached to a robot arm or the like. Then, when the filler metal M that is continuously fed is melted and solidified while moving the torch 17, a linear weld bead 43 that is a molten solidified body of the filler metal M is formed on the base plate 41.

The CAD / CAM unit 31 creates shape data of the laminated wall portion W which is the outer shell and the inner shell of the structure to be manufactured, and then divides the structure into a plurality of layers to generate layer shape data representing the shape of each layer. To do. The trajectory calculation unit 33 obtains the movement trajectory of the torch 17 based on the generated layer shape data. The storage unit 35 stores data such as the generated layer shape data and the movement locus of the torch 17.

The control unit 37 drives the welding robot 19 by executing a drive program based on the layer shape data stored in the storage unit 35 and the movement locus of the torch 17.

The manufacturing system 100 having the above configuration melts the filler metal M while moving the torch 17 by driving the welding robot 19 along the movement locus of the torch 17 generated from the set layer shape data. The filler metal M is supplied onto the base plate 41. As a result, a linear welded bead 43 is formed on the base plate 41, and the above-mentioned laminated wall portion W is formed on the base plate 41.

The base plate 41 is made of a metal plate such as a steel plate, and is basically one that is larger than the bottom surface (bottom layer surface) of the laminated wall portion W. The base plate 41 is not limited to a plate shape, and may be a base having another shape such as a block body or a rod shape.

After modeling the laminated wall portion W, the casting device 13 pours the casting water 25 into the inner space 45 of the formed laminated wall portion W. When the poured casting water 25 solidifies, a structure in which the casting portion 47 is formed inside the laminated wall portion W is obtained.

Next, a specific procedure for obtaining a structure by forming the laminated wall portion W and forming the casting portion 47 by the manufacturing system 100 having the above configuration will be described in detail.
<First configuration example>
FIG. 2 is a perspective view of the structure of the first configuration example.
The structure 51 having the present configuration shown as an example is a hollow casing used as an outer cylinder of a gear pump. The structure 51 has a laminated wall portion W and a casting portion 47 which is solidified by pouring casting water into the inner space 45 of the laminated wall portion W.

The laminated wall portion W has an outer shell 55 having a substantially elliptical cross section forming the skeleton of the outer cylinder of the gear pump, and an inner shell 57 having an arcuate cross section formed inside the outer shell 55. The inner shell 57 has a shape in which two cylindrical bodies are arranged in parallel closer than each other's radial distance and connected as one inner wall. A pump rotor is inserted into each of the hollow spaces defined by a pair of partially cylindrical inner walls, and the inner surface of the inner shell 57 serves as a facing surface of the rotor.

The structure 51 having the above configuration is produced by the procedure shown below. That is, the CAD / CAM unit 31 shown in FIG. 1 inputs the shape data of the laminated wall portion W of the structure 51 of the storage unit 35, and each layer P divided in parallel with each other based on the input shape data. (1), P (2), ..., P (n) layer shape data is generated.

Then, the trajectory calculation unit 33 generates the movement locus of the torch 17 in each layer P (1), P (2), ..., P (n) based on each layer shape data, and generates a drive program for the welding robot 19. To do. Then, the control unit 37 drives the welding robot 19 based on the generated drive program.

FIG. 3 is a process explanatory view showing a state in which the torch 17 is moved on the base plate 41 along the movement locus of the first layer to form the welded bead 43 of the first layer.
While moving the torch 17 on the base plate 41, the filler metal M and the base plate 41 are melted by an arc, so that the melted filler metal M is raised and served on the base plate 41. As a result, the welded bead 43 of the first layer of the outer shell 55 and the inner shell 57 is formed. The welded beads 43 of the second and subsequent layers are formed by melting only the filler metal M.

That is, the welded bead 43 in which the filler metal M is melted and solidified is formed into a closed linear layer in a plan view on the base plate 41. Then, the linear layers are laminated in the vertical direction without gaps to form a laminated wall portion W, and a bottomed tubular laminated model is formed.

Next, modeling based on the above-mentioned layer shape data will be described in more detail.
FIG. 4 is a cross-sectional view of the structure 51 in the horizontal direction, and FIG. 5 is a partially enlarged view of part A shown in FIG.
In the horizontal cross section of the structure 51 shown in FIG. 4, the position of the outer shell 55 where the outer shell 55 and the inner shell 57 are closest to each other is Pt1 and faces the hole 57a of the inner shell 57 at the center of the longitudinal axis of the outer shell 55. The position of the outer shell 55 is Pt2.

The normal line of the outer shell 55 at the position Pt1 is defined as the feature line L1. The feature line L1 passes through the casting portion 47 and the outer shell 55 and the inner shell 57, which are a pair of laminated wall portions sandwiching the casting portion 47. The thickness of the casting portion 47 along this characteristic line L1 _{t c1,} the thickness of the outer shell 55 along the characteristic line L1 _{t out1,} the thickness of the inner shell 57 along the characteristic line L1 and _{t in1} ..
Further, the normal line of the outer shell 55 at the position Pt2 is defined as the feature line L2. Similarly, the feature line L2 passes through the casting portion 47 and the outer shell 55 and the inner shell 57, which are a pair of laminated wall portions sandwiching the casting portion 47. The thickness of the casting portion 47 along this characteristic line L2 _{t c2,} the thickness of the outer shell 55 along a characteristic line L2 _{t out2,} the thickness of the inner shell 57 along the characteristic line L2 and _{t in2} ..

Here, in the structure 51 having the present configuration, the relationship between the thicknesses of the outer shell 55, the inner shell 57, and the casting portion 47 at the positions Pt1 and Pt2 of the outer shell 55 shown as an example satisfies the equation (1). Each is decided.

( _Tin1 + t _out1 ) / t _c1 = (t _in2 + t _out2 ) / t _c2 ... (1)

The above equation (1) shows the relationship of thickness with respect to the positions Pt1 and Pt2, but also at other points of the outer shell 55 (for example, any point such as Pti), the outer shell 55 and the inner shell 57, The relationship of the wall thickness of the casting portion 47 (to _ti , t _ini , t _{ci at the} position Pti) is determined in the same manner as in Eq. (1). That is, the larger the wall thickness of the casting portion 47, the larger the total wall thickness of the outer shell 55 and the inner shell 57, and the smaller the wall thickness of the casting portion 47, the smaller the total wall thickness of the outer shell 55 and the inner shell 57. To do. As a result, the volume ratio of the laminated wall portion W (outer shell 55, inner shell 57) along the feature lines L1, L2, Li at each position and the casting portion 47 is made constant. Further, the configuration may not satisfy the equation (1) at all the positions of the outer shell 55, but may satisfy the equation (1) at a plurality of representative points.

The wall thicknesses of the outer shell 55 and the inner shell 57 are preferably equal to or substantially equal to each other. As a result, the difference between the amount of heat radiated from the outer shell 55 and the amount of heat radiated from the inner shell 57 becomes small, and the cooling rate of the casting portion 47 is less likely to become uneven. Further, when heat dissipation on the outer shell 55 side tends to be more active than on the inner shell 57 side where heat tends to be trapped, it is preferable to make the wall thickness of the outer shell 55 larger than the wall thickness of the inner shell 57.

Specifically, as shown in FIG. 5, the thickness of the outer shell 55 and the inner shell 57 is changed according to the wall thicknesses t _c1 and t _c2 of the casting portion 47, and the bead width in the horizontal cross section of the welded bead 43. It can be done by increasing or decreasing. When the weld beads 43 are formed in parallel as shown in the illustrated example, the bead width is increased or decreased by adjusting the number of rows of the weld beads 43. This adjustment is performed by the CAD / CAM unit 31 and the trajectory calculation unit 33.

After forming the welded bead 43 of the layer P1 (1) as described above, the welded beads 43 of the layers P (2), P (3), ..., P (n) are formed in this order in the same manner, and a plurality of layers are formed. Welded beads 43 of P (1), P (2), P (3), ..., P (n) are laminated. As a result, a laminated wall portion W having an outer shell 55 and an inner shell 57 can be obtained.

Then, the casting water 25 is poured into the inner space 45 defined by the outer shell 55 and the inner shell 57 of the laminated wall portion W and solidified to form the casting portion 47. The base plate 41 is cut with a cutting machine such as a wire saw or a diamond cutter, if necessary, to form a structure 51 having a desired shape.

As described above, according to the manufacturing method of the structure 51 having the present configuration, since the laminated wall portion W is formed by laminating the welding beads 43, it is not necessary to make a mold for casting, and the casting man-hours and the mold material are not required. The cost of manufacturing the structure 51 can be reduced, and the lead time for manufacturing the structure 51 can be shortened. Further, the use of the laminated material, which is relatively expensive, is limited to the outer shell 55 and the inner shell 57, and the material cost can be suppressed and the manufacturing cost can be reduced.

Further, the laminated wall portion W includes the wall thickness of the casting portion 47 along the normal direction of the outer shell 55 (feature lines L1, L2, ..., Li), that is, the thickness of the inner space 45 shown in FIG. The ratio to the total wall thickness of the outer shell 55 and the inner shell 57 along the feature line of is a preset ratio. According to this, the cooling rate of the casting water poured into the inner space 45 is adjusted according to the wall thickness of each part of the casting part 47, and the cooling rate becomes uniform for all parts. Therefore, each part of the poured casting water is solidified at the same time in the horizontal cross section, and a homogeneous casting part 47 is obtained. Therefore, non-uniform mechanical properties of the structure 51, residual stress of the casting portion 47, defects such as shrinkage cavities in the thick portion of the casting portion 47, and cracks such as cracks can be suppressed, and the structure is of high quality. Body 51 can be manufactured.

In the method for manufacturing the structure 51 described above, the ratio of the wall thickness of the casting portion 47, that is, the thickness of the inner space 45 to the total wall thickness of the outer shell 55 and the inner shell 57 is constant, but this ratio The value may be determined by predicting in advance the ratio at which the mechanical properties of the structure 51 become uniform by analysis, or may be determined based on a method of setting the plate thickness of the chilled metal in the casting field or the like. ..

Further, the above ratio is preferably a constant value, but it may be allowed to fluctuate within an appropriate range. That is, depending on the shape of the structure 51, even if the ratio between the wall thickness of the cast portion 47 and the total wall thickness of the outer shell 55 and the inner shell 57 is not constant as shown in the equation (1), the ratio is approximately the same. It may be constant. Even in that case, the cooling rate of the casting water becomes substantially uniform regardless of the portion, and the occurrence of defects in the casting portion 47 can be suppressed. The ratio can be, for example, 0.015 to 2, preferably 0.1 to 1.5, and more preferably 0.4 to 1. Within this range, a good casting portion 47 can be obtained.

Further, the above feature lines L1, L2, ..., Li are set as the normals of the outer shell 55, but are not limited to this, and may be set as the normals of the inner shell 57. Further, the normal of the outer shell 55 and the normal of the inner shell 57 may be mixed. In that case, even if the structure 51 has a complicated shape, the wall thicknesses of the outer shell 55 and the inner shell 57 can be set more appropriately. When the structure 51 has a more complicated shape, a normal line (a line or curve connecting the tops of the surface having irregularities) or a circumscribed circle with respect to the outer surface of the outer shell 55 and the inner surface of the inner shell 57. The feature line may be set from the normal of the line such as. In that case, the mechanical properties of the structure 51 can be made more uniform by uniformly cooling the casting portion 47.

Further, although the above ratio is obtained from the length in the horizontal cross section of the structure 51, it may be a ratio obtained from the length in the cross section intersecting the horizontal cross section. For example, when the vertical direction of the laminated wall portion W at the time of laminated molding is different from the vertical direction of the laminated wall portion W at the time of injecting the casting hot water, the vertical direction at the time of injecting the casting hot water is used as a reference. It is preferable to form the laminated wall portion W.

<Second configuration example>
FIG. 6 is a schematic perspective view of the structure 51A of the second configuration example, and FIG. 7 is a sectional view taken along line VII-VII of the structure 51A shown in FIG.
Structure 51A of the structure shown in FIG. 6 is entirely formed in a truncated cone shape, and a laminated wall W _A and the casting portion 47A. Laminated wall _{W A} has an inner shell 57 and outer shell 55. The outer shell 55 is formed in a conical shape that gradually narrows upward. The inner shell 57 is formed in a cylindrical shape having substantially the same diameter in the vertical direction. Casting unit 47A includes pouring Soleil the inner space 45 between the inner shell 57 and outer shell 55 of laminated wall W _A, it is formed by coagulation. The outer shell 55, inner shell 57, and casting portion 47A of the structure 51A have different wall thicknesses in horizontal cross sections along the stacking direction (vertical direction).

As shown in FIG. 7, in the structure 51A having the present configuration, the wall thickness of the casting portion 47A along the feature line L in the normal direction at an arbitrary point of the outer shell 55 in the horizontal cross section is t _c , and the feature is the same as described above. the thickness _{t out} of the outer shell 55 along the line L, and the thickness of the inner shell 57 along the feature line to _{t in.} In the structure 51A having this configuration, the wall thickness t _c of the casting portion 47A is smaller toward the upper side, but as shown in equation (2), the wall thickness (t _c ) of the casting portion along the feature line L and the laminated wall part _W ratio _{R 1} between the total thickness of the outer shell 55 and inner shell 57 is _{a (t} in ₊ t _out) is constant.

R ₁ = (t _in + ton _out ) / t _c ... (2)

According to the structure 51A of this configuration, the outer shell 55 and inner shell 57 are stacked wall W _A, variations in the volume ratio of the casting portion 47A is reduced. Therefore, non-uniform mechanical properties of the structure 51A, residual stress of the casting portion 47A, defects such as shrinkage cavities in the thick portion of the casting portion 47A, and cracks such as cracks can be suppressed, and the structure is of high quality. 51A can be manufactured.

<Third configuration example>
FIG. 8 is a schematic perspective view of the structure 51B of the third configuration example, and FIG. 9 is a sectional view taken along line IX-IX of the structure 51B shown in FIG.
The structure 51B of the present configuration shown in FIG. 8 does not include the inner shell 57 of the structure 51A of the second configuration example, and the casting portion 47B is formed in the entire inner space of the outer shell 55. The outer shell 55 of the structure 51B and the casting portion 47A have different wall thicknesses in horizontal cross sections along the stacking direction (vertical direction).

Here, as shown in FIG. 9, the thickness of the casting portion 47A along the feature line L in the normal direction at an arbitrary point of the outer shell 55 in the horizontal cross section is t _c , and the outer shell 55 along the feature line L. _Let the thickness of be to _out .

In the structure 51B having this configuration, the wall thickness t _c of the casting portion 47A is smaller toward the upper side, but as shown in equation (3), the wall thickness t _c of the casting portion along the feature line L and the laminated wall portion W is constant at any position of the ratio R ₂ is a horizontal cross-section of the wall thickness t _out of the outer shell 55 is _B.

R ₂ = 2t _out / t _c ... (3)

Also in the case of the structure 51B having this configuration, the variation in the volume ratio between the outer shell 55 and the cast portion 47A becomes small, and a high-quality structure 51B can be obtained as in the first and second configuration examples.

<Fourth configuration example>
10 is a schematic perspective view of the structure 51C of the fourth configuration example, and FIG. 11 is a sectional view taken along line XI-XI of the structure 51C shown in FIG.
The structure 51C having the present configuration shown in FIG. 10 is formed in a shape in which a structure 51B having the same shape is inverted and stacked on the structure 51B of the third configuration example. That is, the casting unit 47C includes large diameter portion, the small diameter portion from the lower side in the drawing, are formed integrally as a large diameter portion, the outer shell 55 is a laminated wall W _C is the outer diameter of the horizontal cross section of the casting portion 47C It is integrally formed as a wide portion, a narrow portion, and a wide portion accordingly.

Also in the case of the structure 51C having this configuration, as shown in FIG. 11, the ratio R ₂ of the wall thickness t _c of the casting portion along the feature line L and the wall thickness to _out of the outer shell 55 ((2) above). (See formula) is constant in all horizontal sections. As a result, a high quality structure 51C can be obtained.

The present invention is not limited to the above-described embodiment, and can be modified or applied by those skilled in the art based on the combination of the configurations of the embodiments with each other, the description of the specification, and well-known techniques. It is the planned invention and is included in the scope of seeking protection.

For example, the present invention can be applied to a structure in which the wall thickness changes along at least one of the horizontal direction and the vertical direction. For example, a square tube-shaped structure, a rectangular shape in a plan view, and a triangular shape. It can also be applied to structures having various shapes such as a shape and an elliptical shape.

Further, in the above-described structure manufacturing method, the welding wire is melted by arc discharge to form a welded bead, and the structure is manufactured at low cost and with a short lead time. The formation of the welded bead is not limited to arc discharge, and other heating methods such as a heating method using both arc discharge and a laser, a heating method using a laser, and a friction stir welding method may be adopted. When heating with a laser, the amount of heating can be controlled more finely, the state of the welded bead can be maintained more appropriately, and the quality of the laminated wall portion can be further improved.

Further, in the above description, the structure in which the welded beads are formed into one closed linear layer is shown, but the closed lines due to the welded beads are present at a plurality of locations on the same horizontal cross section. You may. Further, in the closed linear layer, there may be a welded bead portion extending further to the outside or the inside of the line by the welded bead. In either case, a structure having a more complicated shape can be produced by pouring the casting water into each of the closed regions. The closed area in this case is not limited to a circle or an ellipse, and may be any shape such as a square, a rectangle, or a polygon.

Further, in the above description, the laminated wall portion is formed by one linear welding bead, but the welding bead is formed while swinging the torch 17 as in the weaving operation, or the welding robot 19 is driven. Therefore, the torch 17 may be moved while drawing a locus such as a circle or a triangle. In that case, since the torch 17 is moved with a moving component in a direction different from the welding direction, the welding bead width can be increased or decreased, and the widths of the outer shell 55 and the inner shell 57 can be arbitrarily adjusted.

As described above, the following matters are disclosed in this specification.
(1) A welded bead obtained by melting and solidifying a filler metal by an arc is laminated on a base to form a laminated wall portion including at least the outer shell of the structure, and then surrounded by the formed laminated wall portion. It is a method of manufacturing a structure in which casting water is poured into the inner space to form a casting part.
When a straight line passing through the casting portion and the pair of laminated wall portions sandwiching the casting portion in the horizontal cross section of the structure and the normal line at any position of the laminated wall portion is used as a feature line, the position A method for manufacturing a structure in which the total wall thickness of a pair of laminated wall portions along the feature line is changed according to the wall thickness of the casting portion sandwiched between the feature lines along the feature line.
According to this method for manufacturing a structure, since the laminated wall portion is formed by laminating welded beads, it is not necessary to prepare a mold for casting, the man-hours for casting and the cost of the mold material can be reduced, and the structure is manufactured. Lead time is shortened. Further, the use of a relatively high-cost laminated material is only required for the laminated wall portion, and the material cost can be suppressed and the manufacturing cost can be reduced.
Then, the normal line of the laminated wall portion in the horizontal cross section of the structure is used as a feature line, and the total wall thickness of the pair of laminated wall portions is changed according to the wall thickness of the casting portion along the feature line. The cooling rate of the casting water poured into the inner space between the laminated walls becomes uniform. As a result, it is possible to suppress non-uniform mechanical properties of the structure, residual stress in the casting portion, defects such as shrinkage cavities in the thick portion of the casting portion, and cracks such as cracks. Therefore, a high quality structure can be manufactured.

(2) The laminated wall portion includes an inner shell formed by the welded bead inside the outer shell.
The method for manufacturing a structure according to (1), wherein the total wall thickness of the laminated wall portion is a thickness obtained by combining the wall thickness of the outer shell and the wall thickness of the inner shell.
According to the method for manufacturing this structure, a casting portion is provided between the outer shell and the inner shell formed by the welding bead, and the casting portion is solidified at a uniform cooling rate regardless of the portion.

(3) The method for manufacturing a structure according to (2), wherein the feature line is a normal of the outer shell.
According to the method for manufacturing this structure, when the outer shell has a simpler shape than the inner shell, it is possible to set a more appropriate wall thickness.

(4) The method for manufacturing a structure according to (2), wherein the feature line is a normal of the inner shell.
According to the method for manufacturing this structure, when the inner shell has a simpler shape than the outer shell, it is possible to set a more appropriate wall thickness.

(5) The ratio of the wall thickness of the casting portion along the feature line to the total wall thickness of the pair of laminated wall portions is set in advance.
The description in any one of (1) to (4), wherein the wall thickness of the casting portion along the feature line and the total wall thickness of the pair of the laminated wall portions are determined based on the set ratio. Method of manufacturing the structure.
According to this method for manufacturing a structure, it is possible to reduce the variation in the volume ratio between the pair of laminated wall portions and the cast portion, and it is possible to manufacture a higher quality structure.

(6) The method for manufacturing a structure according to (5), wherein the ratio is a constant value within the horizontal cross section of the structure.
According to the method for manufacturing this structure, the wall thickness of the pair of laminated wall portions and the casting portion is determined at a constant ratio, so that the casting portion can be solidified at a more uniform cooling rate.

(7) The method for manufacturing a structure according to (6), wherein the ratio is the same constant value in the horizontal cross sections of the structures having different heights from each other.
According to the manufacturing method of this structure, the wall thickness of the pair of laminated wall portions and the casting portion is determined at a constant ratio also in the height direction, so that the casting portion can be solidified at a more uniform cooling rate. it can.

(8) A structure having a laminated wall portion in which welded beads, which are melt-solidified bodies of filler metal, are laminated on a base, and a casting portion formed in an inner space surrounded by the laminated wall portion. ,
The position when a straight line passing through the casting portion and the pair of laminated wall portions sandwiching the casting portion in the horizontal cross section of the structure and the normal line at any position of the laminated wall portion is used as a feature line. A structure in which the total wall thickness of the pair of laminated wall portions along the feature line changes according to the wall thickness of the casting portion sandwiched between the feature lines along the feature line.
According to this structure, since the laminated wall portion is formed by laminating the welded beads, it is not necessary to prepare a mold for casting, the man-hours for casting and the cost of the mold material can be reduced, and the lead time for manufacturing the structure is reduced. It will be shortened. Further, the use of a relatively high-cost laminated material is only required for the laminated wall portion, and the material cost can be suppressed and the manufacturing cost can be reduced.
Then, the normal line of the laminated wall portion in the horizontal cross section of the structure is used as a feature line, and the total wall thickness of the pair of laminated wall portions is changed according to the wall thickness of the casting portion along the feature line. The cooling rate of the casting water poured into the inner space between the laminated walls becomes uniform. As a result, it is possible to suppress non-uniform mechanical properties of the structure, residual stress in the casting portion, defects such as shrinkage cavities in the thick portion of the casting portion, and cracks such as cracks.

(9) The laminated wall portion includes an outer shell of the structure and an inner shell formed by the welding bead inside the outer shell.
The structure according to (8), wherein the total wall thickness of the pair of laminated wall portions is a total thickness of the wall thickness of the outer shell and the wall thickness of the inner shell.
According to this structure, a casting portion is provided between the outer shell and the inner shell formed by the welding bead, and the casting portion is solidified at a uniform cooling rate regardless of the portion.

(10) The method for manufacturing a structure according to (9), wherein the feature line is a normal of the outer shell.
According to this structure, when the outer shell has a simpler shape than the inner shell, it is possible to set a more appropriate wall thickness.

(11) The method for manufacturing a structure according to (9), wherein the feature line is a normal of the inner shell.
According to this structure, when the inner shell has a simpler shape than the outer shell, it is possible to set a more appropriate wall thickness.

(12) The ratio of the wall thickness of the casting portion to the total wall thickness of the laminated wall portion along the feature line is constant in any one of (8) to (11) in the horizontal cross section. The method for manufacturing the described structure.
According to this structure, it is possible to reduce the variation in the volume ratio between the pair of laminated wall portions and the casting portion.

(13) The structure according to (12), wherein the ratio is constant in the horizontal cross sections different from each other of the structure.
According to this structure, the wall thickness of the pair of laminated wall portions and the casting portion is determined at a constant ratio also in the height direction, so that the cooling rate of the casting portion becomes more uniform.

25 Casting water 41 Base plate (base)
43 weld bead 45 inside the space 47 and 47A, 47B, 47C casting portion 51, 51A, 51B, shell 51C structure 55 within the shell 57 L, L1, L2, Li characteristic line M filler material _W, W _A, W _B , _{W C} laminated wall

Claims (13)

A welded bead obtained by melting and solidifying a filler metal by an arc is laminated on a base to form a laminated wall portion including at least the outer shell of the structure, and then an inner space surrounded by the formed laminated wall portion. It is a method of manufacturing a structure in which casting water is poured into a structure to form a casting portion.
When a straight line passing through the casting portion and the pair of laminated wall portions sandwiching the casting portion in the horizontal cross section of the structure and the normal line at any position of the laminated wall portion is used as a feature line, the position A method for manufacturing a structure in which the total wall thickness of a pair of laminated wall portions along the feature line is changed according to the wall thickness of the casting portion sandwiched between the feature lines along the feature line. The laminated wall portion includes an inner shell formed by the welding bead inside the outer shell.
The method for manufacturing a structure according to claim 1, wherein the total wall thickness of the laminated wall portion is a thickness obtained by combining the wall thickness of the outer shell and the wall thickness of the inner shell. The method for manufacturing a structure according to claim 2, wherein the feature line is a normal of the outer shell. The method for manufacturing a structure according to claim 2, wherein the feature line is a normal of the inner shell. The ratio of the wall thickness of the casting portion along the feature line to the total wall thickness of the pair of laminated wall portions is set in advance.
The invention according to any one of claims 1 to 4, wherein the wall thickness of the casting portion along the feature line and the total wall thickness of the pair of laminated wall portions are determined based on the set ratio. How to manufacture the structure. The method for manufacturing a structure according to claim 5, wherein the ratio is a constant value within the horizontal cross section of the structure. The method for manufacturing a structure according to claim 6, wherein the ratio is the same constant value in the horizontal cross sections of the structures having different heights from each other. A structure having a laminated wall portion in which welded beads, which are melt-solidified bodies of filler metal, are laminated on a base, and a casting portion formed in an inner space surrounded by the laminated wall portion.
The position when a straight line passing through the casting portion and the pair of laminated wall portions sandwiching the casting portion in the horizontal cross section of the structure and the normal line at any position of the laminated wall portion is used as a feature line. A structure in which the total wall thickness of the pair of laminated wall portions along the feature line changes according to the wall thickness of the casting portion sandwiched between the feature lines along the feature line. The laminated wall portion includes an outer shell of the structure and an inner shell formed by the welding bead inside the outer shell.
The structure according to claim 8, wherein the total wall thickness of the pair of laminated wall portions is a total thickness of the wall thickness of the outer shell and the wall thickness of the inner shell. The structure according to claim 9, wherein the feature line is a normal of the outer shell. The structure according to claim 9, wherein the feature line is a normal of the inner shell. The structure according to any one of claims 8 to 11, wherein the ratio of the wall thickness of the casting portion to the total wall thickness of the laminated wall portion along the feature line is constant within the horizontal cross section. body. The structure according to claim 12, wherein the ratio is constant in the horizontal cross sections different from each other of the structure.

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