JP7293080B2 - Overlay weld crack evaluation method, pipe manufacturing method, and evaluation material - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a method for evaluating overlay weld cracks, a method for manufacturing a tubular body, and an evaluation material.

2. Description of the Related Art Heat transfer panels in which long heat transfer tubes through which water or steam flows and plate-like fins are alternately welded to each other are used for furnace walls and the like used in boilers. In order to secure the corrosion resistance of the heat transfer tube, it is known to perform spiral winding welding on the surface of the heat transfer tube with a corrosion-resistant material (see, for example, Patent Document 1 (paragraph 0072, etc.)). Patent Literature 1 discloses that a corrosion-resistant layer is formed around the entire circumference of a blank pipe by spiral-wound welding in which a TIG welding torch is fed while rotating the blank pipe.

JP 2018-189282 A

The heat transfer tubes used in the heat transfer panel are cooled by cooling water on the inside while the outside is in a high-temperature environment. Then, thermal stress is repeatedly applied due to the difference in thermal elongation that occurs in the heat transfer tube, which may cause weld cracks in the welded portion forming the buildup layer. In particular, when the build-up thickness of the welded portion is thicker or the unevenness of the welded portion is larger, the possibility of weld cracking may increase.

Furthermore, unlike the evaluation of weld cracks in ordinary welded joints between structures, weld cracks including the heat-affected zone that occurs when overlay welding is continuously performed on the outer peripheral surface of the heat transfer tube It has become clear to the inventors that it is necessary to evaluate what does not happen. In evaluating the suitability of overlay welding conditions, weld cracks generated by forming overlay welds are described as overlay weld cracks.

In order to form a heat transfer tube that is resistant to build-up weld cracking, it is necessary to evaluate the welding state of heat transfer tubes welded under various welding conditions and appropriately set the welding conditions based on the evaluation results. . ASME (American Society of Mechanical Engineers) Spec. IX standard is known. This standard cuts out a part of an object whose surface has been welded as an evaluation material, bends the evaluation material, and evaluates whether or not weld cracks occur in the evaluation material (ASME Spec.IX QW-163, QW452.5, QW-462.2, QW-466.1, etc.).

However, ASME's Spec. The evaluation material specified in IX has no welds on the entire surface area of the evaluation material on the surface where the weld exists, and the partial area centered on the position where bending is performed Only welds are present. Therefore, although it is possible to evaluate welds in the vicinity of the position where bending is performed, it may not be possible to appropriately evaluate welds existing in other regions.

The present disclosure has been made in view of such circumstances, and provides an overlay weld crack capable of appropriately evaluating overlay weld cracks in welds formed on the outer peripheral surface of a cylindrical tubular body. The purpose is to provide an evaluation method. In addition, there is provided a manufacturing method for manufacturing a tubular body in which overlay welding is formed under appropriate overlay welding conditions based on the evaluation results of an overlay weld crack evaluation method that can appropriately evaluate overlay weld cracks. intended to Another object of the present invention is to provide an evaluation material that can be used in a method for evaluating overlay weld cracks that can appropriately evaluate overlay weld cracks.

A method for evaluating overlay weld cracks according to one aspect of the present disclosure is for evaluating weld cracks after overlay welds are formed on a cylindrical tubular body extending along the axis, and the outer peripheral surface of the tubular body A build-up welding step of performing build-up welding to form a welded portion spirally extending around the axis so as to cover the pipe, and cutting the pipe body in which the welded portion is formed by the build-up welding step, and An evaluation material creation step of creating an evaluation material in which the welded portion is formed on the entire surface corresponding to the surface of the body, and an evaluation material bending of bending the evaluation material formed by the evaluation material creation step with a predetermined curvature radius and a weld crack evaluation step of evaluating whether or not weld cracks have occurred in the evaluation material bent in the evaluation material bending process.

An evaluation material according to an aspect of the present disclosure is an evaluation material for evaluating build-up weld cracking of a weld formed by build-up welding on the outer peripheral surface of a cylindrical tubular body extending along the axis, From the tubular body on which overlay welding is formed by the weld portion that extends spirally around the axis so as to cover the outer peripheral surface, a predetermined The tube is cut into strips of a size and bent with a predetermined curvature radius so that it is possible to evaluate whether or not build-up weld cracks occur in the bent evaluation material (EM). The welded portion is formed on the entire surface corresponding to the outer peripheral surface of the body.

ADVANTAGE OF THE INVENTION According to this indication, the overlay-weld crack evaluation method which can evaluate appropriately the overlay-weld crack of the weld formed in the surface of a cylindrical tubular body can be provided. In addition, there is provided a manufacturing method for manufacturing a tubular body in which overlay welding is formed under appropriate overlay welding conditions based on the evaluation results of an overlay weld crack evaluation method that can appropriately evaluate overlay weld cracks. can do. In addition, it is possible to provide an evaluation material that can be used for an evaluation method for overlay weld cracks that can appropriately evaluate overlay weld cracks.

1 is a vertical cross-sectional view of a gasifier included in gasifier equipment according to an embodiment of the present disclosure; FIG. FIG. 2 is a cross-sectional view showing a schematic configuration of a gasification furnace wall shown in FIG. 1; FIG. 2 is an enlarged sectional view showing a schematic configuration of a gasification furnace wall shown in FIG. 1; 1 is a side view of a welding device according to an embodiment of the present disclosure, showing a state where build-up welding is started on the surface of a heat transfer tube; FIG. 1 is a side view of a welding device according to an embodiment of the present disclosure, showing a state in which build-up welding is being performed on the surface of a heat transfer tube; FIG. 1 is a side view of a welding device according to an embodiment of the present disclosure, showing a state in which build-up welding to the surface of a heat transfer tube is completed; FIG. FIG. 5 is a perspective view showing the internal structure of the movable carriage shown in FIG. 4; FIG. 5 is a schematic configuration diagram showing a control configuration of the welding device shown in FIG. 4; It is a flowchart which shows the overlay-weld crack evaluation method of this embodiment. FIG. 4 is a cross-sectional view showing a heat transfer tube having a weld bead formed on its surface; FIG. 4 is a perspective view showing an evaluation material prepared by cutting a heat transfer tube; FIG. 4 is a side view showing a cut surface extending along the longitudinal direction of the evaluation material; It is a figure which shows the state which installed the evaluation material in the bending jig. FIG. 4 is a diagram showing a state in which an evaluation material is bent by a bending jig; It is the figure which looked at the evaluation material of this embodiment bent by the bending process from the side in which the weld bead was formed. FIG. 10 is a view of the evaluation material of the comparative example that is bent by the bending process, viewed from the side on which the weld bead is formed; 4 is an evaluation table showing evaluation of surface roughness and evaluation of overlay weld cracking with respect to overlay welding conditions.

Hereinafter, a welding apparatus for welding the heat transfer tubes T evaluated by the overlay weld crack evaluation method according to an embodiment of the present disclosure will be described with reference to the drawings. The welding apparatus 200 of the present embodiment cools the heat transfer tube itself and its surroundings by circulating cooling water (cooling medium) inside the cylindrical heat transfer tube when performing build-up welding. It is a device for overlay welding of welding material to improve corrosion resistance and heat resistance on the surface. In the following description, descriptions of above and below, such as above and below, refer to above and below in the vertical direction.

A heat transfer tube to which a welding material is overlay-welded by the welding device 200 of the present embodiment is connected to a plurality of plate members by welding to form a heat transfer panel. The heat transfer panels are placed, for example, inside a boiler furnace or inside a gasification furnace. Hereinafter, a gasification furnace will be described with reference to the drawings as an example in which heat transfer panels using heat transfer tubes overlaid with a welding material are arranged. FIG. 1 is a vertical cross-sectional view of a gasifier according to one embodiment of the present disclosure.

A gasification furnace 101 shown in FIG. 1 is a device that generates a generated gas mainly containing hydrogen and carbon monoxide in an Integrated Coal Gasification Combined Cycle (IGCC) facility. As the fuel to be supplied to the gasification furnace 101, for example, a carbon-containing solid fuel such as coal is used. As a combustion method for generating combustible gas (produced gas) from fuel, an air combustion method using an oxidant mainly composed of air is used. The product gas generated by the gasification furnace 101 is supplied to a combustor of a gas turbine that drives a generator to rotate.

As shown in FIG. 1, the gasification furnace 101 is formed to extend in the vertical direction. It flows from the lower side toward the upper side. The gasification furnace 101 has a pressure vessel 110 and a gasification furnace wall 111 provided inside the pressure vessel 110 . A heat transfer panel including heat transfer tubes T is used as the gasification furnace wall 111 .

The gasification furnace 101 forms an annulus 115 in the space between the pressure vessel 110 and the gasification furnace wall 111 . In addition, in the space inside the gasifier wall 111, the gasifier 101 includes a combustor section 116, a diffuser section 117, and a reductor section 118 in this order from the lower side in the vertical direction (that is, the upstream side in the flow direction of the produced gas). forming

The pressure vessel 110 is formed in a cylindrical shape with a hollow space inside, and has a gas discharge port 121 formed at its upper end and a slag hopper 122 formed at its lower end (bottom). The gasification furnace wall 111 is formed in a cylindrical shape with a hollow space inside, and the wall surface is provided facing the inner surface of the pressure vessel 110 . In this embodiment, the pressure vessel 110 is, for example, cylindrical, and the diffuser portion 117 of the gasifier wall 111 is also formed, for example, cylindrical. The gasifier wall 111 is connected to the inner surface of the pressure vessel 110 by a supporting member (not shown).

Gasifier wall 111 separates the interior of pressure vessel 110 into interior space 154 and exterior space 156 . The gasifier wall 111 has a cross-sectional shape that changes at a diffuser portion 117 between a combustor portion 116 and a reductor portion 118 . The gasifier wall 111 has an upper vertically upper end connected to the gas discharge port 121 of the pressure vessel 110 and a vertically lower lower end spaced apart from the bottom of the pressure vessel 110 . ing.

The slag hopper 122 formed at the bottom of the pressure vessel 110 stores water, and the inside and outside of the gasifier wall 111 are sealed when the lower end of the gasifier wall 111 is submerged in the water. ing. Burner devices 126 and 127 are inserted into the gasification furnace wall 111 and the syngas cooler 102 is arranged in the internal space 154 .

The annulus portion 115 is a space formed between the inside of the pressure vessel 110 and the outside of the gasification furnace wall 111, that is, the external space 156. Nitrogen, which is an inert gas separated by air separation equipment (not shown), It is supplied through a nitrogen supply line (not shown). Therefore, the annulus portion 115 becomes a space filled with nitrogen. An in-furnace pressure equalizing pipe (not shown) for equalizing the pressure in the gasification furnace 101 is provided near the upper portion of the annulus portion 115 in the vertical direction. The in-furnace pressure equalizing pipe is provided to communicate the inside and outside of the gasification furnace wall 111, and the pressure between the inside (combustor section 116, diffuser section 117 and reductor section 118) and the outside (annulus section 115) of the gasification furnace wall 111 is The pressure is substantially equalized so that the difference is within a predetermined pressure.

The combustor section 116 is a combustion chamber in which pulverized coal and char (unreacted coal and ash) and air are partially combusted. A combustion device consisting of The high-temperature combustion gas that has partially combusted the pulverized coal and char in the combustor section 116 passes through the diffuser section 117 and flows into the reductor section 118 .

The reductor section 118 is maintained at a high temperature necessary for the gasification reaction, and supplies pulverized coal to the combustion gas from the combustor section 116 for partial oxidation combustion, removing pulverized coal from volatile components (carbon monoxide, hydrogen, lower hydrocarbons, etc.). etc.) and gasified to generate a product gas.

Next, the gasification furnace wall 111 will be described with reference to the drawings. FIG. 2 is a cross-sectional view showing a schematic configuration of the gasification furnace wall 111 shown in FIG. FIG. 3 is an enlarged cross-sectional view showing a schematic configuration of the gasification furnace wall 111 shown in FIG.

The cross-sectional shape of the gasifier wall 111 in the horizontal direction is a polygonal cylinder shape or a cylindrical cylindrical shape, but the embodiment shown in FIG. A water wall tube 142 is provided. That is, a plurality of water-cooled wall pipes 142 are concentrically arranged in a portion of the wall portion 140 .

The gasification furnace 101 has a cooling water circulation mechanism (not shown) that circulates a coolant (water or steam as cooling water) in the water-cooled wall pipe 142 . A plurality of water cooling wall pipes 142 are vertically extended over the entire area of the gasification furnace 101. A portion of the water wall pipes 142 are vertically extended without being cut, and are arranged side by side in the circumferential direction. A wall portion 140 of the gasification furnace 101 is formed.

As shown in FIG. 3, at least part of the water-cooled wall pipe 142 has a heat transfer tube T and a weld bead WB provided on the outer circumference of the heat transfer tube T. As shown in FIG. The heat transfer tube T is a pipeline through which cooling water flows. The weld bead WB is arranged all around the heat transfer tube T in the circumferential direction and covers the outer peripheral surface of the heat transfer tube T. As shown in FIG. The weld bead WB is formed by overlay welding on the outer peripheral surface of the heat transfer tube T using a welding device 200, which will be described later.

The wall portion 140 is provided with plate members (fins) 166 between the water-cooled wall pipes 142 and 142 . The wall portion 140 of the present embodiment forms a cylindrical shape by arranging a plurality of water-cooled wall pipes 142 concentrically and closing the space between the water-cooled wall pipes 142 with a plate material 166 . The wall portion 140 also has a weld portion 168 that connects the weld bead WB of the water-cooled wall pipe 142 and the plate material 166 . The welded portion 168 is formed at the inner space 154 side end and the outer space 156 side end of the contact portion between the weld bead WB and the plate material 166 . The welded portion 168 is formed by welding and is in close contact with both the weld bead WB and the plate member 166 to connect the weld bead WB of the water-cooled wall pipe 142 and the plate member 166 .

The gasifier wall 111 has heat transfer tubes T made of a first material and weld beads WB made of a second material. Plate 166 and weld 168 may also be made of a second material. The first material and the second material are metals. The second material has higher corrosion resistance (corrosion resistance) and higher heat resistance than the first material. The gasification furnace wall 111 can protect the heat transfer tubes T by forming the weld beads WB from a material having higher corrosion resistance and higher heat resistance than the heat transfer tubes T.

Specifically, in the internal space 154 inside the gasification furnace wall 111 where the combustible gas flows, the oxidant (oxygen-containing gas) and the fuel are partially combusted to form a gasified product gas, which flows at a high temperature. becomes. By covering the surface of the heat transfer tube T on the inner space 154 side with the weld bead WB, the heat transfer tube T can be protected from corrosion and a high-temperature environment.

In addition, slag such as coal adheres to and falls off of the heat transfer tube T, weld bead WB, and plate material 166 of the gasification furnace wall 111, which causes a temperature change on the wall surface of the gasification furnace wall 111, and the heat transfer tube If a temperature distribution occurs in T or the weld bead WB, the effect of the difference in thermal expansion due to the difference in material will increase, and local thermal stress may increase. there is

Furthermore, the internal space 154 inside the combustor portion 116, the diffuser portion 117, and the reductor portion 118 of the gasification furnace wall 111 is in a high-temperature atmosphere exceeding 1500° C., and the temperature difference tends to increase. Therefore, in this embodiment, the outer space 156 side and the inner space 154 side of the gasifier wall 111 have the same shape symmetrical with respect to the plane connecting the axis of the heat transfer tube T and the plate thickness center of the plate member 166. Even if a local temperature distribution occurs, an increase in thermal load due to a difference in thermal expansion can be suppressed, and the durability of the gasification furnace wall 111 can be improved.

Next, a welding device 200 for performing spiral overlay welding on the outer peripheral surface of the heat transfer tube T will be described with reference to the drawings. FIG. 4 is a side view of the welding device 200 according to an embodiment of the present disclosure, and shows a state in which build-up welding is started on the surface of the heat transfer tube T and a weld bead WB begins to be formed. FIG. 5 is a side view of a welding device 200 according to an embodiment of the present disclosure, showing a state in which overlay welding is performed on the outer peripheral surface of the heat transfer tube T to form a weld bead WB.

FIG. 6 is a side view of the welding device 200 according to an embodiment of the present disclosure, showing a state in which build-up welding to the surface of the heat transfer tube T is finished. FIG. 7 is a perspective view showing the internal structure of the movable carriage 10 shown in FIG. FIG. 8 is a schematic configuration diagram showing the control configuration of welding apparatus 200 shown in FIG.

The welding device 200 shown in FIGS. 4 to 6 forms a weld bead WB by spirally overlay-welding a welding material on the outer peripheral surface of the heat transfer tube T with respect to the water-cooled wall tube 142 of the gasification furnace wall 111. It is a device. As shown in FIGS. 4 to 6, the heat transfer tube T is a cylindrical tubular body arranged along an axis X extending in the horizontal direction of the paper. As shown in FIGS. 4 to 6, the welding device 200 includes a movable carriage 10, a build-up welding mechanism 20, a lower support mechanism 30, an upper support mechanism 40, a cooling mechanism 50, a measurement mechanism 60, a body A unit 70 , an imaging unit 80 , a display unit 85 , and a control unit 90 are provided.

The welding device 200 arranges the heat transfer tubes T at a constant height from the installation surface S so as to be parallel to the installation surface S and supports them by the lower support mechanism 30 and the upper support mechanism 40 . The welding device 200 rotates the heat transfer tube T at a predetermined speed around the axis X by using the movable carriage 10 while moving the heat transfer tube T along the moving direction MD at a predetermined speed. The welding device 200 is installed at a position fixed to the installation surface S above the paper surface with respect to the heat transfer tube T that rotates around the axis X while moving along the moving direction MD. Perform overlay welding.

Overlay welding is started on the surface of the heat transfer tube T in the state shown in FIG. Overlay welding to the surface is completed. The welding device 200 forms a weld bead WB in which the welding material is spirally overlaid on the surface of the heat transfer tube T by performing the operations shown in FIGS. 4 to 6 .

The movable carriage 10 is an example of a mechanism that rotates the heat transfer tube T at a predetermined speed while moving it along the axis X at a predetermined speed. As shown in FIG. 12 , the movable carriage 10 includes a moving mechanism 11 that moves the heat transfer tubes T along the axis X, and a rotation mechanism 12 that rotates the heat transfer tubes T around the axis X. As shown in FIG.

As shown in FIG. 7, the moving mechanism 11 rotates the first gear 11c connected to the drive shaft 11b in the direction coaxial with the drive shaft 11b by driving the moving motor 11a, thereby engaging the first gear 11c. The combined second gear 11d is rotated. The second gear 11d rotates the third gear 11f connected via the connecting shaft 11e. The third gear 11f is engaged with a rack gear 71 provided on a main body portion 70 fixed to the installation surface S on which the welding device 200 is installed. Therefore, when the third gear 11f rotates, the carriage portion 11g of the moving mechanism 11 moves along the rails 72 of the main body portion 70 in the moving direction MD. Here, the movement direction MD is a direction parallel to the axis X direction of the heat transfer tubes T. As shown in FIG.

The heat transfer tube T is rotatable about the axis X on the movable truck 10 by the rotation mechanism 12, and the outer peripheral surface of the heat transfer tube T is held by the fixing part 12e so as not to move in the direction of the axis X with respect to the moving mechanism 11. has been fixed. Therefore, when the moving mechanism 11 moves along the axis X, the heat transfer tubes T also move along the axis X accordingly. Thus, the moving mechanism 11 moves the heat transfer tube T along the axis X by driving the moving motor 11a. Driving of the movement motor 11 a is controlled by a control signal transmitted from the control section 90 .

As shown in FIG. 7, the rotation mechanism 12 rotates the first gear 12c connected to the drive shaft 12b by driving the rotation motor 12a, and rotates the second gear 12d engaged with the first gear 12c. rotate. The second gear 12d is connected to be integrated with a fixing portion 12e that holds the outer peripheral surface of the heat transfer tube T and is non-rotatably fixed to the second gear 12d. Therefore, when the second gear 12d rotates, the heat transfer tube T also rotates about the axis X accordingly.

In this manner, the rotation mechanism 12 rotates the heat transfer tube T around the axis X in a predetermined direction at a predetermined number of rotations by driving the rotation motor 12a. The driving of the rotation motor 12 a is controlled by a control signal transmitted from the control section 90 .

The build-up welding mechanism 20 is a device that spirally forms a weld bead WB while supplying a welding material to the outer peripheral surface of the heat transfer tube T passing through a predetermined welding position on the axis X. As shown in FIG. The build-up welding mechanism 20 is fixed via the body portion 70 to the installation surface S on which the welding device 200 is installed. The build-up welding mechanism 20 performs TIG (Tungsten Inert Gas) welding using, for example, a welding torch 21 having a tungsten electrode (not shown). The overlay welding mechanism 20 applies a voltage to the tungsten electrode according to a control signal transmitted from the control unit 90 to supply a current, so that a welding current is generated between the tip of the tungsten electrode and the outer peripheral surface of the heat transfer tube T. It flows and forms an arc which raises the temperature.

A welding wire (welding material) is supplied to the arc formed by the welding torch 21 . The welding wire is supplied with a predetermined feeding amount by a control signal transmitted from the control unit 90, and the welding wire is heated by Joule heat by applying an electric current to the welding wire. As the welding wire of the present embodiment, for example, a solid-solution-strengthened nickel-based alloy such as Inconel (registered trademark) or a corrosion-resistant material containing a high chromium-containing alloy can be used.

The build-up welding mechanism 20 is fixed to the body portion 70, but the heat transfer tubes T move along the movement direction MD and rotate around the axis X. As shown in FIG. Therefore, the overlay welding mechanism 20 performs welding to the heat transfer tube T at a fixed position of the main body 70, so that the corrosion-resistant material is spirally overlay-welded on the outer peripheral surface of the heat transfer tube T. . In addition, since the build-up welding mechanism 20 is at a fixed position on the main body 70, the positional relationship between the welding torch 21 and the heat transfer tubes T can be controlled with high accuracy.

The lower support mechanism 30 is a mechanism that supports the heat transfer tubes T from below, and is fixed to the installation surface S. The lower support mechanism 30 includes a first lower support portion 31 , a second lower support portion 32 and a third lower support portion 33 . The first lower support portion 31 supports the lower outer peripheral surface of the heat transfer tube T at a position closest to the build-up welding mechanism 20, and is fixed to the body portion 70 to which the build-up welding mechanism 20 is fixed. there is The second lower support part 32 is arranged adjacent to the first lower support part 31, and is arranged on the upstream side (on the right side of the drawing) of the movement direction MD of the heat transfer tube T along the axis X from the first lower support part 31. It is

The third lower support part 33 has a plurality of locations on the downstream side (left side of the drawing) in the moving direction MD of the heat transfer tube T with respect to the first lower support part 31 and at a plurality of locations where the heat transfer tube T moves with respect to the second lower support part 32 . They are arranged at a plurality of locations on the upstream side (right side of the paper surface) in the direction MD. The third lower support portion 33 includes a height adjustment mechanism (switching mechanism) 33c capable of adjusting a distance in a direction perpendicular to the installation surface S of the tip position supporting the heat transfer tube T (vertical direction on the paper surface).

The height adjustment mechanism 33c has a support state in which the tip of the third lower support part 33 is held at a position where the heat transfer tube T is supported, and a position at which the heat transfer tube T is not supported. It is a mechanism that can switch between a retracted state and a retracted state. The height adjustment mechanism 33c is a mechanism for moving the tip position of the third lower support portion 33 along a direction perpendicular to the installation surface S (vertical direction on the paper surface). The height adjustment mechanism 33c is, for example, a mechanism that vertically expands and contracts by the pressure of compressed air supplied from a compressed air source (not shown) and manages the tip position of the third lower support portion 33 with a stopper (not shown). It has become.

Among the third lower support parts 33, those arranged at a plurality of locations downstream of the first lower support part 31 in the moving direction MD of the heat transfer tubes T come into contact with each other when the movable carriage 10 moves in the moving direction MD. The height adjustment mechanism 33c is used to move the tip position downward so as to be in a retracted state. In the state shown in FIGS. 4 and 5 , the movable truck 10 does not pass through the third lower support portion 33 arranged on the most downstream side in the moving direction MD of the heat transfer tube T, so that the third lower support portion 33 does not come into contact with the movable truck 10 . In order to avoid this, the tip position of the third lower support portion 33 is put into a retracted state. On the other hand, in the state shown in FIG. 6, since the movable carriage 10 has passed, the tip position of the third lower support portion 33 is in the supported state.

Among the third lower support portions 33 , those arranged at a plurality of locations on the upstream side of the first lower support portion 31 in the moving direction MD of the heat transfer tubes T are height-adjusting mechanisms so as not to come into contact with the cooling mechanism 50 . By 33c, the tip position of the third lower support portion 33 is moved to the retracted state. In the state shown in FIG. 4, the cooling mechanism 50 does not pass through the third lower support portion 33 arranged on the most upstream side in the movement direction MD of the heat transfer tube T, so the tip position of the third lower support portion 33 is be in a supported state. On the other hand, in the state shown in FIGS. 5 and 6, the cooling mechanism 50 is passing, so the tip position of the third lower support portion 33 is in a retracted state in order to avoid contact with the cooling mechanism 50 .

The upper support mechanism 40 is a mechanism that supports the heat transfer tubes T from above, and is fixed to the body portion 70 to which the overlay welding mechanism 20 is fixed. The upper support mechanism 40 supports the heat transfer tubes T at a position closer to the build-up welding mechanism 20 than the build-up welding mechanism 20 in the movement direction MD of the heat transfer tubes T. The positional relationship between the welding torch 21 and the heat transfer tube T, such as the distance from the torch 21 to the heat transfer tube T and the angle with respect to the welding torch 21, is suppressed from fluctuating. The upper support mechanism 40 can adjust the distance in the direction perpendicular to the mounting surface S of the tip position supporting the heat transfer tube T (vertical direction on the paper surface) by the height adjustment mechanism.

The cooling mechanism 50 causes cooling water (cooling medium) to flow into the heat transfer tubes T from the upstream end Tu of the heat transfer tubes T in the movement direction MD, and causes cooling water to flow from the downstream end Td of the heat transfer tubes T in the movement direction MD. is a mechanism for cooling the heat transfer tube T from the inside by flowing out from the inside of the heat transfer tube T. In addition to water, the cooling medium may be a heat medium, a liquid such as mechanical hydraulic oil, or a gas such as nitrogen.

The cooling mechanism 50 circulates the cooling water flowing into the heat transfer tubes T from the upstream end Tu to the downstream end Td along the movement direction MD of the heat transfer tubes T. A region from the upstream end Tu of the heat transfer tube T to the welding position is a region where no weld bead WB is formed. Therefore, the cooling water is supplied to the vicinity of the welding position where the temperature is the highest among the heat transfer tubes T in a state in which the temperature is not increased, and the heat transfer tubes T in the vicinity of the welding position can be cooled appropriately and effectively. can. As a result, when the weld bead WB of the heat transfer tube T is formed, it is possible to suppress a change in the amount of penetration due to thermal influence and warp deformation of the heat transfer tube T due to thermal stress.

The measurement mechanism 60 is a mechanism arranged downstream in the movement direction MD from the welding position where the build-up welding mechanism 20 is arranged. The measurement mechanism 60 is a mechanism that measures the outer diameter of the heat transfer tube T passing through the measurement position by using, for example, a non-contact sensor. The control unit 90 determines the build-up thickness of the weld bead WB based on the outer diameter of the heat transfer tube T without overlay welding and the outer diameter of the heat transfer tube T with overlay welding transmitted from the measuring mechanism 60. It is possible to judge whether the thickness is appropriate.

For example, when the control unit 90 determines that the build-up thickness of the weld bead WB is not an appropriate thickness, the control unit 90 displays on the display unit 85 information indicating that the build-up thickness is outside the target range of the build-up thickness and is not an appropriate thickness. Let Further, the control unit 90 may control the build-up welding mechanism 20 to temporarily stop the build-up welding of the heat transfer tubes T by the build-up welding mechanism 20 . At this time, the control unit 90 displays information on the difference between the set values and the various build-up welding conditions for the heat transfer tube T by the build-up welding mechanism 20 on the display unit 85, and the appropriate build-up thickness is obtained. You may make it easy to judge the factor which deviated from.

Body portion 70 is a housing fixed to installation surface S on which welding device 200 is installed. The overlay welding mechanism 20 , the first lower support portion 31 , and the upper support mechanism 40 are fixed to the body portion 70 . The main body 70 includes a rack gear 71 and rails 72 shown in FIG. 7, and the movable carriage 10 can reciprocate along the rails 72 in a moving direction MD parallel to the axis X direction.

The imaging unit 80 is an imaging device that captures an image of the vicinity of the welding position including the tip of the tungsten electrode provided at the tip of the welding torch 21 and the outer peripheral surface of the heat transfer tube T. The imaging unit 80 can output the captured image of the vicinity of the welding position to the display unit 85 . A worker who operates the welding device 200 can visually check the image displayed on the display unit 85 to confirm whether or not the weld bead WB formed on the heat transfer tube T by the build-up welding mechanism 20 is normal. can be done. When the operator determines that the weld bead WB is abnormal, the operator temporarily stops the operation of the welding device 200 . Further, if the control unit 90 analyzes the image captured by the imaging unit 80 and determines that there is an abnormality, the operation of the welding device 200 may be automatically stopped temporarily by a signal from the control unit 90 .

The control unit 90 is a device that controls each part of the welding device 200 including the moving mechanism 11, the rotating mechanism 12, and the build-up welding mechanism 20, as shown in the control configuration diagram of FIG. The control unit 90 causes the moving mechanism 11 to move the heat transfer tube T along the axis X in the moving direction MD at a predetermined constant moving speed, and the rotation mechanism 12 rotates the heat transfer tube T around the axis X at a predetermined constant speed. The build-up welding mechanism 20 is controlled to perform helical build-up welding on the outer peripheral surface of the heat transfer tube T in a state of rotating at a high speed.

The control unit 90 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. A series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, for example, and the CPU reads out this program to a RAM or the like, and executes information processing and arithmetic processing. As a result, various functions are realized.

In this embodiment, the heat transfer tubes T are made of low alloy steel, for example. The outer diameter of the non-welded heat transfer tube T is, for example, 30 mm or more and 50 mm or less. Also, the length of the heat transfer tube T along the axis X is, for example, 2000 mm or more and 8000 mm or less. The welding device 200 performs welding by the overlay welding mechanism 20 so that the overlay thickness of the weld bead WB formed on the outer peripheral surface of the heat transfer tube T is, for example, 1 mm or more and 2.5 mm or less. The build-up thickness of the weld bead WB is set so as to protect the heat transfer tube T from, for example, corrosion resistance and heat resistance.

The control unit 90 sets a predetermined moving speed of the heat transfer tube T in the direction of the axis X by the moving mechanism 11 so that the build-up thickness of the weld bead WB is 1 mm or more and 2.5 mm or less. A predetermined rotational speed of the heat transfer tube T around the axis X is set by . The control unit 90 controls the outer diameter of the heat transfer tube T and/or the build-up thickness of the weld bead WB based on the measured value transmitted from the measuring mechanism 60 so that the build-up thickness of the weld bead WB is within the target specification range. , the moving speed of the heat transfer tube T in the direction of the axis X and the rotation speed of the heat transfer tube T around the axis X may be controlled within a predetermined range.

The control unit 90 controls the moving mechanism 11 so that the moving speed (feeding speed) of the heat transfer tubes T in the direction of the axis X is, for example, 20 mm/min or more and 50 mm/min or less. Further, the control unit 90 controls the rotation mechanism 12 so that the rotation speed of the heat transfer tube T around the axis X is, for example, 5 rpm or more and 10 rpm or less.

Next, a build-up weld crack evaluation method for evaluating build-up weld cracks of the weld bead WB formed on the outer peripheral surface of the heat transfer tube T by the welding apparatus 200 of the present embodiment will be described with reference to the drawings. FIG. 9 is a flow chart showing a method for evaluating build-up weld cracking according to this embodiment. FIG. 10 is a cross-sectional view showing a heat transfer tube T having a weld bead WB formed on its outer peripheral surface.

FIG. 11 is a perspective view showing an evaluation material EM prepared by cutting the heat transfer tube T. FIG. FIG. 12 is a side view showing a cut surface CS extending along the longitudinal direction of the evaluation material EM. FIG. 13 is a diagram showing a state in which the evaluation material EM is installed on the bending jig 300. As shown in FIG. FIG. 14 is a diagram showing a state in which the evaluation material EM is bent by the bending jig 300. As shown in FIG.

The overlay weld cracking evaluation method of the present embodiment shown in FIG. 9 evaluates overlay weld cracking of a weld bead WB formed on the outer peripheral surface of a cylindrical heat transfer tube (tubular body) T extending along the axis X. It is a thing.
In step S101, the control unit 90 performs a first welding step of overlay welding to form a weld bead WB spirally extending around the axis X so as to cover the outer peripheral surface of the heat transfer tube T installed in the welding device 200. Control the welding device 200 to execute.

When executing the first welding process, the control unit 90 sets predetermined overlay welding conditions and performs overlay welding. The overlay welding conditions include the rotation speed Rt of the heat transfer tube T around the axis X with respect to the overlay welding mechanism 20 that welds the heat transfer tube T, and the moving speed of the heat transfer tube T in the axis X direction with respect to the overlay welding mechanism 20. Weld pitch (Vt/Rt), which is the ratio of Vt, is included.

In step S102, an evaluation material EM for evaluating build-up weld cracking of the heat transfer tubes T is prepared. As shown in FIGS. 10 to 12, the evaluation material EM is produced by cutting a part of the heat transfer tube T having the weld bead WB formed on the outer peripheral surface by the first welding process. In the evaluation material EM, a weld bead WB is spirally formed on the entire circumference of the weld surface WS corresponding to the outer peripheral surface of the heat transfer tube T, and the surface substantially orthogonal to the weld surface WS is the cut surface CS.

As shown in FIG. 11, the evaluation material EM created in step S102 is cut into strips having the axis X direction as the longitudinal direction and the circumferential direction around the axis X as the lateral direction. The longitudinal length L1 of the evaluation material EM is, for example, 200 mm or more and 300 mm or less. The length L2 of the evaluation material EM in the lateral direction is, for example, approximately 10 mm. A weld bead WB is formed on the entire surface of the evaluation material EM in one direction.

In step S103, the surface roughness is measured as unevenness of the weld bead WB portion of the heat transfer tube T on which the weld bead WB is formed by the first welding process, and whether the surface roughness satisfies the evaluation criteria is evaluated. do. As shown in FIG. 12, the surface roughness is defined as BUmax, which is the highest position of the weld bead WB in a portion of the heat transfer tube T (for example, a portion having a longitudinal direction of 50 mm along the axis X). , BUt, which is the difference from BUmin where the height of the weld bead WB is the lowest. For example, if BUt is 0.15 mm or less, the evaluation criterion is satisfied, and if BUt is greater than 0.15 mm, the evaluation criterion is not satisfied.

In step S104, if the surface roughness BUt is, for example, 0.15 mm or less, it is determined that the evaluation criteria are satisfied, and the process proceeds to step S105. After making a decision, the process proceeds to step S110.

In step S105, an evaluation material bending process is performed to bend the evaluation material EM created in step S102. The evaluation material bending step of step S105 is performed using the bending jig 300 . As shown in FIGS. 13 and 14 , the bending jig 300 has a pressing jig 310 and a main jig 320 .

The pressurizing jig 310 is a member having a semi-cylindrical (arcuate) outer peripheral surface 311 with a radius of curvature r1 at its tip. The main body jig 320 is a member having a semi-cylindrical (arcuate) inner peripheral surface 321 with a radius of curvature r2. The difference between the curvature radius r2 and the curvature radius r1 substantially matches the length L2 of the evaluation material EM in the lateral direction. The radius of curvature r1 is a predetermined radius of curvature that is appropriately set within a range in which the heat transfer tube T does not undergo buckling fracture due to bending with respect to the size of the evaluation material EM cut into strips, for example, about 20 mm. and the curvature radius r2 is set by r2=r1+L2±cutting error of the evaluation material EM.

In step S105, the operator of the bending jig 300 places the main body jig 320 so that the longitudinal central portion of the evaluation material EM coincides with the vertical direction. As shown in FIG. 13, the evaluation material EM is arranged such that a pressurizing jig 310 is abutted against the cut surface CS extending in the longitudinal direction. After that, the operator abuts the outer peripheral surface 311 of the tip of the pressing jig 310 against the central portion in the longitudinal direction of the evaluation material EM.

After setting the evaluation material EM in the state shown in FIG. 13, the operator moves the pressurizing jig 310 downward using a pressurizing mechanism such as a hydraulic cylinder, and presses the evaluation material EM in the central portion in the longitudinal direction. The evaluation material EM is bent by abutting the outer peripheral surface 311 of the pressing jig 310 . When the pressing jig 310 is pushed down to a position where the evaluation material EM contacts the inner peripheral surface 321 of the main jig 320, the state shown in FIG. 14 is obtained.

In the state shown in FIG. 14, the evaluation material EM is bent into a substantially U shape by contacting both the outer peripheral surface 311 of the pressurizing jig 310 and the inner peripheral surface 321 of the main body jig 320 without gaps. Sizes such as the length L2 in the lateral direction of the evaluation material EM, the curvature radius r1 of the outer peripheral surface 311 of the pressing jig 310, the curvature radius r2 of the inner peripheral surface 321 of the main body jig 320, and the cutting error of the evaluation material EM. Depending on the situation, it is bent to a state in which the gap becomes small and becomes a substantially U shape.

In step S106, whether or not weld cracking has occurred on the surface of the weld bead WB of the evaluation material EM bent by the bending jig 300 in step S105 and between the weld surface WS and the weld bead WB (heat-affected zone). Evaluate whether Evaluation of build-up weld cracking may be performed, for example, by penetrant testing.

Conventionally, cladding welding has not been sufficiently evaluated as a product. By performing the evaluation, it is possible to appropriately evaluate whether or not the heat transfer tube T can be used as a product without any problem by considering the strength reduction due to bending of the heat affected zone of the heat transfer tube T and the weld bead WB. can.

Penetrant testing is performed according to the following procedure. First, impurities such as oil and dirt adhering to the evaluation material EM are removed using a cleaning liquid or the like. Next, a colored penetrating liquid having a high permeability to weld cracks is applied to the entire area of the weld bead WB of the evaluation material EM. When weld cracks occur in the evaluation material EM, the penetrant penetrates into the weld cracks. Next, the penetrant applied to the surface of the evaluation material EM is removed using water or the like. When weld cracking occurs in the evaluation material EM, the penetrating liquid that permeates the weld crack portion remains without being removed by water or the like.

Next, a developer that penetrates into the weld crack is applied to the entire area of the weld bead WB. When a weld crack occurs in the evaluation material EM, the developer penetrates into the weld crack portion, and the permeating liquid is sucked up on the surface of the evaluation material EM due to the penetration of the developer. The penetrating liquid sucked up on the surface of the evaluation material EM spreads over a region that is larger than the weld crack portion. Therefore, an operator who observes the evaluation material EM can appropriately evaluate whether or not weld cracks have occurred by visually observing the appearance.

In step S107, the operator visually checks the appearance of the evaluation material EM that has been subjected to the penetrant test to determine whether or not weld cracks have occurred in the evaluation material EM. If no weld crack occurs in the evaluation material EM, it is determined that the overlay welding satisfies the evaluation criteria, and the process proceeds to step S108. On the other hand, if weld cracking occurs in the evaluation material EM, it is determined that the overlay welding does not satisfy the evaluation criteria, and the process proceeds to step S110.

If the colored penetrant is visible, the worker determines that weld cracking has occurred and the overlay welding does not meet the evaluation criteria. It is determined that the overlay welding satisfies the evaluation criteria. In addition, even if the colored penetrant can be visually recognized, if the area where the penetrant spreads is a predetermined size or less (for example, the maximum length is 3 mm or less), the weld crack may be determined to have not occurred, and the process may proceed to step S108.

In step S108, the operator determines that the surface roughness of the heat transfer tube T on which overlay welding has been performed in step S101 satisfies the evaluation criteria, and the evaluation material cut from the heat transfer tube T on which overlay welding has been performed in step S101. Since the EM satisfies the weld crack evaluation criteria, the overlay welding conditions in step S101 are set in the welding apparatus 200 as appropriate overlay welding conditions.

In step S109, the welding apparatus 200 performs a second welding step of overlay-welding the surface of the heat transfer tube T on which the weld bead WB is not formed under the overlay-welding conditions set in step S108. Since the overlay welding conditions set in step S108 are appropriate overlay welding conditions that do not cause weld cracks in the overlay-welded heat transfer tubes T, appropriate overlay-welded heat transfer tubes that do not generate weld cracks. T is produced. When step S109 ends, the processing of this flowchart ends.

In step S110, the operator evaluates the surface roughness of the heat transfer tube T on which overlay welding is performed in step S101 that does not satisfy the evaluation criteria, or evaluates the cut heat transfer tube T on which overlay welding is performed in step S101. Since the material EM does not satisfy the weld crack evaluation criteria, the overlay welding conditions in step S101 are changed, and new overlay welding conditions are set in the welding apparatus 200. FIG.

As the overlay welding conditions, for example, the operator sets the number of rotations Rt about the axis X of the heat transfer tube T with respect to the overlay welding mechanism 20 that welds the heat transfer tube T, and the axis X of the heat transfer tube T with respect to the overlay welding mechanism 20. By changing either or both of the moving speed Vt in the direction, the welding pitch (Vt/Rt), which is the ratio between the moving speed Vt and the rotation speed Rt, is changed.

By executing the flowchart shown in FIG. 9 above, the surface roughness of the heat transfer tube T on which overlay welding was performed satisfies the evaluation criteria, and the evaluation material EM cut from the heat transfer tube T on which overlay welding was performed was performed. Overlay welding conditions are set so that the weld cracking evaluation criteria can be met. Then, it is possible to manufacture the heat transfer tube T in which overlay welding is performed under appropriate overlay welding conditions that satisfy the required overlay welding product specifications.

Next, with reference to FIGS. 15 to 17, an example comparing the evaluation method of the present embodiment and the evaluation method of the comparative example will be described. FIG. 15 is a view of the evaluation material EM of this embodiment, which is bent by the evaluation material bending process, viewed from the side on which the weld bead WB is formed. FIG. 16 is a view of the evaluation material EM′ of the comparative example, which is bent by the evaluation material bending process, viewed from the side on which the weld bead WB is formed. FIG. 17 is an example of an evaluation table showing evaluation of surface roughness and evaluation of overlay weld cracking with respect to overlay welding conditions.

As shown in FIG. 15, the evaluation material EM of this embodiment has a weld bead WB formed on the entire weld surface WS corresponding to the surface of the heat transfer tube T. As shown in FIG. On the other hand, as shown in FIG. 16, in the evaluation material EM' of the comparative example, the weld bead WB' is formed only in the vicinity of the longitudinal central portion of the welding surface WS corresponding to the surface of the heat transfer tube T, and the evaluation material A weld bead WB' is formed only in the vicinity of the area bent by the bending process.

First, evaluation of surface roughness will be described. In the welding device 200, when the movement speed of the heat transfer tube T in the direction of the axis X relative to the build-up welding mechanism 20 increases, the interval (bead interval) between the weld beads WB formed by the build-up welding mechanism 20 along the axis X There is a condition in which the weld bead WB is widened and the uneven shape of the weld bead WB becomes more undulating, so that build-up weld cracking is likely to occur. In FIG. 17, the welding pitch of Condition 3 is taken as the reference (1.0), and the other conditions are shown as ratios to the reference.

As shown in FIG. 17, under condition 5 where the welding pitch is 1.17 times larger than under condition 3, the surface roughness is greater than 0.15 mm and does not satisfy the evaluation criteria for surface roughness. On the other hand, if the welding pitch is less than or equal to the welding pitch of Condition 4 (1.08 times the welding pitch of Condition 3), the welding pitch is small, and thus satisfies the evaluation criteria for surface roughness.

Next, evaluation of overlay weld cracks will be described. In the welding device 200, when the rotation speed Rt of the heat transfer tube T around the axis X with respect to the build-up welding mechanism 20 increases, the interval (bead interval) between the weld beads WB formed by the build-up welding mechanism 20 along the axis X becomes narrower and the overlap of the weld bead WB increases, the heat effect concentrates locally, the heat effect on the heat transfer tube T during overlay welding increases, and the toughness of the heat transfer tube T decreases. Cracks are more likely to occur due to fill welding.

As shown in FIG. 17, when the evaluation material EM of this embodiment is used to evaluate the evaluation of overlay weld cracking, when the welding pitch is equal to or greater than the welding pitch of condition 3, the heat effect due to overlay welding is localized. is not excessively concentrated, and build-up weld cracking does not occur. On the other hand, when the welding pitch of condition 2 (0.97 times the welding pitch of condition 3) or less, the heat effect due to overlay welding is excessively concentrated locally, and the toughness of the heat transfer tube T is reduced, resulting in weld cracking. is evaluated as occurring.

On the other hand, when evaluation of overlay weld cracking is performed using the evaluation material EM' of the comparative example, if the weld pitch is equal to or greater than the weld pitch of Condition 2, the thermal effects of overlay welding are not excessively concentrated locally. It is evaluated that it did not lead to the occurrence of overlay weld cracking. On the other hand, when the welding pitch is equal to or less than the welding pitch of Condition 1 (0.93 times the welding pitch of Condition 3), the thermal effect is locally concentrated excessively, and the toughness of the heat transfer tube T is reduced, resulting in weld cracking. evaluated to be

Comparing the evaluation method of overlay weld cracking using the evaluation material EM of this embodiment with the evaluation method of overlay weld cracking using the evaluation material EM' of the comparative example, it is found that in the evaluation method of this embodiment, condition 2 is On the other hand, in the evaluation method of the comparative example, Condition 2 is evaluated as a build-up welding condition in which build-up weld cracks do not occur. Under the same condition 2, evaluation results of build-up weld cracking are different between the evaluation material EM of this embodiment and the evaluation material EM' of the comparative example.

In the evaluation method of this embodiment, condition 2 is evaluated as a build-up welding condition in which build-up weld cracks occur. This is because the weld bead WB is present not only in other areas, but also in other areas. In the evaluation method of the present embodiment, it is appropriately evaluated that there is a condition where build-up weld cracking is likely to occur due to build-up welding being performed at a position distant from the position where bending is performed, and condition 2 is inappropriate. Appropriate build-up welding conditions can be determined.

As described above, when the evaluation methods of the present embodiment and the comparative example are compared, the evaluation method of overlay weld cracking using the evaluation material EM of the present embodiment is farther from the bending position than the comparative example. Therefore, it is possible to appropriately determine whether the overlay welding conditions that cause overlay weld cracking at the position where the overlay weld cracks occur are inappropriate.

The overlay weld crack evaluation method described in each of the embodiments described above is grasped, for example, as follows.
The overlay weld crack evaluation method according to the present disclosure is a overlay weld crack evaluation method for evaluating weld cracks after forming overlay welds on a cylindrical tubular body extending along the axis, wherein the tubular body A build-up welding step of performing build-up welding to form a weld portion extending spirally around the axis so as to cover the outer peripheral surface of the above; An evaluation material creation step of creating an evaluation material in which the welded portion is formed on the entire surface corresponding to the surface of the tubular body, and an evaluation material of bending the evaluation material formed by the evaluation material creation step with a predetermined curvature radius. a bending step; and a build-up weld crack evaluation step of evaluating whether or not a weld crack occurs in the evaluation material bent by the evaluation material bending step.

According to the overlay weld crack evaluation method according to the present disclosure, the evaluation material that is bent in the evaluation material bending process cuts the tubular body in which the spirally extending welded portion is formed, and the surface corresponding to the outer peripheral surface of the tubular body A welded part is formed in the whole. The evaluation material has welded portions not only in a partial area around the position where evaluation material bending is performed, but also in other areas. Therefore, it is possible to appropriately evaluate not only overlay weld cracking at the position where bending is performed, but also overlay weld cracking at a position distant from the position where bending is performed.

In the overlay weld crack evaluation method according to the present disclosure, the evaluation material preparation step prepares the strip-shaped evaluation material having the axial direction as the longitudinal direction and the circumferential direction around the axis as the lateral direction.
Since the longitudinal direction of the evaluation material to be evaluated is the axial direction in which the tubular body extends, the boundary of each turn of the spirally formed welded portion can be arranged in one evaluation material over multiple locations. . As a result, a large number of places where weld cracks are likely to occur can be arranged on one evaluation material, and build-up weld cracks can be appropriately evaluated.

In the evaluation method for overlay weld cracking according to the present disclosure, the evaluation material bending step bends the central portion in the longitudinal direction of the cut surface of the evaluation material.
According to the overlay weld crack evaluation method according to the present disclosure, in the evaluation material bending step, the cut surface of the evaluation material is elongated at the central portion in the longitudinal direction of the evaluation material. Therefore, the boundary portion between the welded portion formed on the outer peripheral surface of the tubular body and the tubular body undergoes the greatest deformation among the evaluation materials. Since the boundary portion between the welded portion and the tubular body is a portion where build-up weld cracking is particularly likely to occur, by significantly deforming this portion, build-up weld cracking can be appropriately evaluated.

In the method for evaluating overlay weld cracks according to the present disclosure, in the evaluation material bending step, a jig having an arc-shaped outer peripheral surface including a region with the predetermined curvature radius is provided at the center of the evaluation material in the longitudinal direction. Push and bend.
According to the method for evaluating overlay weld cracks according to the present disclosure, the central portion of the evaluation material in the longitudinal direction is bent by a jig having an arc-shaped outer peripheral surface, so that the arc-shaped outer peripheral surface having an appropriate radius of curvature is used. As a result, the entire central portion of the evaluation material in the longitudinal direction is substantially uniformly deformed, so that build-up weld cracks can be appropriately evaluated without localized excessive deformation.

In the overlay weld crack evaluation method according to the present disclosure, the overlay weld crack evaluation step is performed by impregnating the bent evaluation material with the penetrant liquid and then sucking up the penetrant liquid onto the surface of the evaluation material with a developer. It is evaluated whether or not weld cracks have occurred in the evaluation material by a penetrant testing that observes.
According to the overlay weld crack evaluation method according to the present disclosure, the penetrant test is performed to absorb the penetrant that has permeated the location where the overlay weld crack has occurred, to expand the weld crack and make it visible, and the overlay weld. Cracks can be properly evaluated.

The manufacturing method of the tubular body (T) described in the embodiment described above is grasped, for example, as follows.
A method for manufacturing a tubular body (T) on which overlay welding is formed according to the present disclosure is a method for manufacturing a cylindrical tubular body extending along an axis, and A first welding step (S101) for performing build-up welding to form a weld portion extending spirally to the top, and cutting the tubular body in which the weld portion is formed by the first welding step, and on the surface of the tubular body An evaluation material creation step (S104) of creating an evaluation material in which the welded portion is formed on the entire corresponding surface, and an evaluation material bending step (S105) of bending the evaluation material formed by the evaluation material creation step (S105); An overlay weld crack evaluation step (S106) for evaluating whether or not a weld crack has occurred in the weld formed in the evaluation material by the evaluation material bending step, and an evaluation result of the overlay weld crack evaluation step. Overlay welding condition setting step (S108) for setting overlay welding conditions when forming the welded portion based on, and based on the overlay welding conditions set by the overlay welding condition setting step, the pipe and a second welding step (S109) of performing build-up welding to form a weld portion spirally extending around the axis so as to cover the outer peripheral surface of the body.

According to the method for manufacturing a tubular body according to the present disclosure, the evaluation material that is bent in the evaluation material bending step is obtained by cutting the tubular body having the spirally extending welded portion formed thereon, and forming a surface corresponding to the outer peripheral surface of the tubular body. A welded part is formed on the whole. In the evaluation material, welded portions exist not only in a partial region around the position where bending is performed, but also in other regions. Therefore, it is possible to appropriately evaluate not only overlay weld cracking at the position where bending is performed, but also overlay weld cracking by performing overlay welding at a position distant from the position where bending is performed. . Then, since the second welding process is performed based on the overlay welding conditions set based on the evaluation results, a pipe body in which overlay welding is formed under appropriate overlay welding conditions that are less likely to cause overlay weld cracks is produced. can be manufactured.

In the method for manufacturing a tubular body according to the present disclosure, the welding conditions include the number of rotations of the tubular body around the axis with respect to a build-up welding mechanism (20) that performs build-up welding on the tubular body, and the build-up welding mechanism. to the speed of movement of the tubular body in the axial direction.
When the number of rotations around the axis of the pipe against the build-up welding mechanism increases, the interval (bead interval) along the axis of the weld formed by the build-up welding mechanism becomes narrower, and the heat effect due to build-up welding becomes localized. Due to the excessive concentration, the toughness of the heat transfer tube T is lowered, and build-up weld cracks are likely to occur.

In addition, when the moving speed of the tubular body in the axial direction with respect to the overlay welding mechanism increases, the interval (bead interval) along the axis of the welded portion formed by the overlay welding mechanism increases, and the irregular shape of the welded portion increases. Undulation becomes large, and build-up weld cracks are likely to occur. Therefore, according to the method for manufacturing a tubular body according to the present disclosure, by appropriately adjusting the ratio of the number of rotations around the axis of the tubular body to the speed of movement of the tubular body in the axial direction, build-up weld cracks are less likely to occur. It is possible to manufacture a tubular body in which overlay welding is formed under appropriate overlay welding conditions.

The evaluation materials (EM) described in the embodiments described above are grasped, for example, as follows.
The evaluation material (EM) according to the present disclosure is for evaluating build-up weld cracking of a weld (WB) formed by build-up welding on the outer peripheral surface of a cylindrical tubular body extending along the axis. , from the tubular body in which the welded portion spirally extending around the axis so as to cover the outer peripheral surface is formed, a predetermined By cutting into strips of a size and bending them with a predetermined curvature radius, build-up welds are formed so that it is possible to evaluate whether or not build-up weld cracks occur in the bent evaluation material. The welded portion is formed on the entire surface corresponding to the outer peripheral surface of the tubular body.

According to the evaluation material according to the present disclosure, not only evaluation of overlay weld cracking at the position where bending is performed, but also overlay weld cracking by performing overlay welding at a position away from the position where bending is performed. Evaluation can also be performed appropriately.

10 Movable carriage 11 Moving mechanism 20 Overlay welding mechanism 21 Welding torch 30 Lower support mechanism 40 Upper support mechanism 50 Cooling mechanism 60 Measuring mechanism 70 Main unit 80 Imaging unit 85 Display unit 90 Control unit 200 Welding device 300 Bending jig 310 Pressure jig 311 Outer peripheral surface 320 Main jig 321 Inner peripheral surface BUt Surface roughness CS Cut surface EM, EM' Evaluation material T Heat transfer tube (tubular body)
WB, WB' Weld bead (welded portion)
WS Welding surface X Axes r1, r2 Curvature radius

Claims (8)

A build-up weld crack evaluation method for evaluating weld cracks after build-up welds are formed on a cylindrical tubular body extending along an axis, comprising:
a build-up welding step of performing build-up welding to form a weld portion spirally extending around the axis so as to cover the outer peripheral surface of the tubular body;
An evaluation material creation step of cutting the tubular body having the welded portion formed by the build-up welding step to create an evaluation material having the welded portion formed on the entire surface corresponding to the surface of the tubular body;
an evaluation material bending step of bending the evaluation material formed by the evaluation material creating step with a predetermined radius of curvature;
and a build-up weld crack evaluation process for evaluating whether or not weld cracks occur in the evaluation material bent in the evaluation material bending process. 2. The method for evaluating overlay weld cracking according to claim 1, wherein the evaluation material preparation step prepares the evaluation material in the form of a strip having the axial direction as the longitudinal direction and the circumferential direction around the axis as the lateral direction. 3. The method for evaluating build-up weld cracking according to claim 2, wherein the evaluation material bending step bends a central portion in the longitudinal direction of the cut surface of the evaluation material. In the step of bending the evaluation material, a jig having an arc-shaped outer peripheral surface including the region with the predetermined radius of curvature abuts against the central portion of the evaluation material in the longitudinal direction to bend the evaluation material. The described overlay weld crack evaluation method. In the build-up weld crack evaluation step, the bent evaluation material is impregnated with a penetrant, and then the penetrant is observed by a developer on the surface of the evaluation material. The method for evaluating overlay weld cracking according to any one of claims 1 to 4, wherein whether or not cracking occurs is evaluated. A method for manufacturing a tubular body in which a cylindrical build-up weld extending along an axis is formed,
a first welding step of performing build-up welding to form a weld portion spirally extending around the axis so as to cover the outer peripheral surface of the tubular body;
an evaluation material preparation step of cutting the tubular body on which the welded portion is formed by the first welding step, and creating an evaluation material in which the welded portion is formed on the entire surface corresponding to the outer peripheral surface of the tubular body; ,
an evaluation material bending step of bending the evaluation material formed by the evaluation material creation step;
An overlay weld crack evaluation step for evaluating whether or not a weld crack has occurred in the weld formed in the evaluation material by the evaluation material bending step;
an overlay welding condition setting step of setting an overlay welding condition for forming the weld based on the evaluation result of the overlay weld crack evaluation step;
A second welding for forming a weld portion spirally extending around the axis so as to cover the outer peripheral surface of the tubular body based on the overlay welding conditions set in the overlay welding condition setting step. A method for manufacturing a tubular body on which build-up welding is formed, comprising the steps of: The overlay welding conditions are the number of rotations of the tubular body about the axis with respect to the overlay welding mechanism that performs overlay welding on the tubular body, and the moving speed of the tubular body in the axial direction with respect to the overlay welding mechanism. 7. The method of manufacturing a tubular body with build-up welds according to claim 6, comprising a ratio of . An evaluation material for evaluating build-up weld cracking of a weld formed by build-up welding on the outer peripheral surface of a cylindrical tubular body extending along the axis,
A strip of a predetermined size having the longitudinal direction in the axial direction and the lateral direction in the circumferential direction around the axis is formed from the tubular body in which the welded portion spirally extending around the axis so as to cover the outer peripheral surface is formed. The tube in which overlay welds are formed so that it is possible to evaluate whether or not overlay weld cracks occur in the bent evaluation material by bending it with a predetermined curvature radius. An evaluation material in which the welded portion is formed on the entire surface corresponding to the outer peripheral surface of the body.

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