JP2021067484A - Build-up weld crack evaluation method, tubular body manufacturing method, and evaluation material - Google Patents

Abstract

To provide a method for appropriately evaluating a weld crack in a welded portion formed on the surface of a cylindrical tubular body.SOLUTION: A build-up weld crack evaluation method includes: a welding step (S101) in which build-up welding is performed to form a welded portion that extends spirally rounding the axis so as to cover a surface of a cylindrical heat transfer tube; a preparation step (S104) for preparing an evaluation material in which the welded portion is formed on an entire surface corresponding to the surface of the heat transfer tube, by cutting the heat transfer tube in which the welded portion is formed by the welding step (S101); a bending step (S105) for bending the evaluation material formed by the preparation step (S104); and a build-up weld crack evaluation step (S106) to evaluate whether or not weld cracks have occurred in the evaluation material bent by the bending step (S105).SELECTED DRAWING: Figure 9

Description

The present disclosure relates to a build-up weld crack evaluation method, a pipe body manufacturing method, and an evaluation material.

Some of the furnace walls used in boilers use heat transfer panels in which long heat transfer tubes through which water and steam flow and plate-shaped fins are alternately connected by welding. Then, in order to ensure the corrosion resistance of the heat transfer tube, it is known that spiral welding is performed on the surface of the heat transfer tube with a corrosion resistant material (see, for example, Patent Document 1 (paragraph 0072, etc.)). Patent Document 1 discloses that a corrosion-resistant layer is formed on the entire circumference of a raw pipe by spiral welding in which a TIG welding torch is sent while rotating the raw pipe.

Japanese Unexamined Patent Publication No. 2018-189282

Since the inside of the heat transfer tube used for the heat transfer panel is cooled by the cooling water and the outside is in a high temperature environment, a difference in heat elongation occurs between the inside and the outside of the heat transfer tube. Then, thermal stress is repeatedly applied due to the difference in thermal elongation generated in the heat transfer tube, which may cause weld cracks in the welded portion forming the overlay layer. In particular, when the overlay thickness of the welded portion where overlay welding is performed is thick or the unevenness of the welded portion is large, the possibility of welding cracks may increase.

Furthermore, unlike the evaluation of weld cracks in normal weld joints between structures, weld cracks include 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 clearer to the inventors that it is necessary to evaluate that it does not occur. In evaluating the appropriateness of the overlay welding conditions, the weld cracks generated by forming the overlay welds are described as overlay weld cracks.

Overlay welding In order to form a heat transfer tube that is less prone to cracking, it is necessary to evaluate the welding state of the heat transfer tube welded under various welding conditions and appropriately set the welding conditions based on the evaluation results. .. As a method for evaluating the welded state, Spec. Of ASME (American Society of Mechanical Engineers). The 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 welding cracks have occurred 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 by IX has no welded part in the entire surface area of the evaluation material on the surface where the welded part exists, and is a partial area centered on the position where the bending process is performed. Only welds are present. Therefore, although it is possible to evaluate the welded portion in the vicinity of the position where the bending process is performed, it may not be possible to appropriately evaluate the welded portion in the presence of other regions.

The present disclosure has been made in view of such circumstances, and it is possible to appropriately evaluate the overlay weld crack of the welded portion formed on the outer peripheral surface of the cylindrical pipe body. The purpose is to provide an evaluation method. Further, the present invention provides a manufacturing method for manufacturing a pipe body in which overlay welding is formed under appropriate overlay welding conditions based on the evaluation result by the overlay welding crack evaluation method capable of appropriately evaluating overlay welding cracks. The purpose is to do. Another object of the present invention is to provide an evaluation material that can be used in an overlay weld crack evaluation method capable of appropriately evaluating overlay weld cracks.

The overlay weld crack evaluation method according to one aspect of the present disclosure evaluates the weld crack after forming overlay welding on a cylindrical tubular body extending along an axis, and evaluates the weld crack on the outer peripheral surface of the tubular body. A build-up welding step of forming a welded portion spirally extending around the axis so as to cover the above, and a build-up welding step of cutting the pipe body on which the welded portion is formed by the build-up welding step are performed to cut the pipe. An evaluation material making 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 in which the evaluation material formed by the evaluation material making step is bent with a predetermined radius of curvature. It includes a step and a weld crack evaluation step of evaluating whether or not a weld crack has occurred in the evaluation material bent by the evaluation material bending step.

The evaluation material according to one aspect of the present disclosure is an evaluation material for evaluating overlay weld cracks in a welded portion formed by overlay welding on the outer peripheral surface of a cylindrical tube extending along an axis. From the pipe body in which overlay welding is formed by the welded portion spirally extending around the axis so as to cover the outer peripheral surface, the axial direction is the longitudinal direction and the circumferential direction around the axis is the lateral direction. The pipe is cut into strips of a size and bent at a predetermined radius of curvature so that it is possible to evaluate whether or not overlay welding cracks have occurred in the bent evaluation material (EM). The welded portion is formed on the entire surface corresponding to the outer peripheral surface of the body.

According to the present disclosure, it is possible to provide a build-up weld crack evaluation method capable of appropriately evaluating a build-up weld crack of a welded portion formed on the surface of a cylindrical pipe body. Further, the present invention provides a manufacturing method for manufacturing a pipe body in which overlay welding is formed under appropriate overlay welding conditions based on the evaluation result by the overlay welding crack evaluation method capable of appropriately evaluating overlay welding cracks. can do. Further, it is possible to provide an evaluation material that can be used in an overlay weld crack evaluation method capable of appropriately evaluating overlay weld cracks.

It is a vertical sectional view of the gasification furnace provided in the gasification furnace equipment which concerns on one Embodiment of this disclosure. It is a cross-sectional view which shows the schematic structure of the gasification furnace wall shown in FIG. It is an enlarged sectional view which shows the schematic structure of the gasification furnace wall shown in FIG. It is a side view of the welding apparatus which concerns on one Embodiment of this disclosure, and shows the state which started overlay welding on the surface of a heat transfer tube. It is a side view of the welding apparatus which concerns on one Embodiment of this disclosure, and shows the state which overlay welding is performed on the surface of a heat transfer tube. It is a side view of the welding apparatus which concerns on one Embodiment of this disclosure, and shows the state which completed the overlay welding to the surface of a heat transfer tube. It is a perspective view which shows the internal structure of the movable carriage shown in FIG. It is a schematic block diagram which shows the control structure of the welding apparatus shown in FIG. It is a flowchart which shows the overlay welding crack evaluation method of this embodiment. It is a cross-sectional view which shows the heat transfer tube which weld bead was formed on the surface. It is a perspective view which shows the evaluation material made by cutting a heat transfer tube. It is a side view which shows the cut surface extending along the longitudinal direction of an evaluation material. It is a figure which shows the state which installed the evaluation material in a bending jig. It is a figure which shows the state which the evaluation material was bent by the bending jig. It is a figure which looked at the evaluation material of this embodiment which was bent by a bending process from the surface where the welding bead was formed. It is a figure which looked at the evaluation material of the comparative example which was bent by a bending process from the surface where the weld bead was formed. It is an evaluation table which shows the evaluation of the surface roughness and the evaluation of the overlay welding crack with respect to the overlay welding condition.

Hereinafter, a welding apparatus for welding the heat transfer tube T evaluated by the overlay welding crack evaluation method according to the embodiment of the present disclosure will be described with reference to the drawings. When performing overlay welding, 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 to cool the outer periphery of the heat transfer tube. It is a device for overlay welding a welding material to improve corrosion resistance and heat resistance on the surface. In the following explanation, the above and below descriptions such as above and below shall indicate the above and below in the vertical direction.

The heat transfer tube in which the welding material is built-up welded by the welding device 200 of the present embodiment is connected to a plurality of plate materials by welding to form a heat transfer panel. The heat transfer panel is arranged, for example, inside the furnace of the boiler or inside the gasification furnace. In the following, as an example in which a heat transfer panel using a heat transfer tube in which the welding material is built-up welded is arranged, the gasification furnace will be described with reference to the drawings. FIG. 1 is a vertical sectional view of a gasifier according to an embodiment of the present disclosure.

The gasification furnace 101 shown in FIG. 1 is an apparatus that mainly produces a generated gas containing hydrogen and carbon monoxide in an integrated coal gasification combined cycle (IGCC). As the fuel to be supplied to the gasification furnace 101, for example, a carbon-containing solid fuel such as coal is used, and by pulverizing with a coal mill (not shown) or the like, pulverized coal pulverized into fine particles is supplied. As a combustion method for generating flammable gas (produced gas) from fuel, an air combustion method using an oxidizing agent mainly composed of air is used. The generated gas generated by the gasification furnace 101 is supplied to the combustor of the gas turbine that rotationally drives the generator.

As shown in FIG. 1, the gasification furnace 101 is formed so as to extend in the vertical direction, and pulverized coal and oxygen are supplied to the lower side in the vertical direction, and the generated gas gasified by partial combustion is in the vertical direction. It circulates from the lower side to the upper side. The gasifier 101 has a pressure vessel 110 and a gasifier wall 111 provided inside the pressure vessel 110. As the gasification furnace wall 111, a heat transfer panel including a heat transfer tube T is used.

The gasifier 101 forms an annulus portion 115 in the space between the pressure vessel 110 and the gasifier wall 111. Further, in the space inside the gasifier wall 111, the gasifier 101 has a convertor portion 116, a diffuser portion 117, and a reducer portion 118 in this order from the lower side in the vertical direction (that is, the upstream side in the flow direction of the generated gas). Is forming.

The pressure vessel 110 is formed in a tubular shape having a hollow space inside, and a gas discharge port 121 is formed at the upper end portion, while a slug hopper 122 is formed at the lower end portion (bottom portion). The gasification furnace wall 111 is formed in a tubular shape having a hollow space inside, and the wall surface thereof is provided so as to face the inner surface of the pressure vessel 110. In the present embodiment, the pressure vessel 110 is formed in a cylindrical shape, for example, and the diffuser portion 117 of the gasification furnace wall 111 is also formed in a cylindrical shape, for example. The gasification furnace wall 111 is connected to the inner surface of the pressure vessel 110 by a support member (not shown).

The gasifier wall 111 separates the inside of the pressure vessel 110 into an internal space 154 and an external space 156. The gasification furnace wall 111 has a shape in which the cross-sectional shape changes at the diffuser portion 117 between the convertor portion 116 and the reducer portion 118. The upper end of the gasifier wall 111 on the vertically upper side is connected to the gas discharge port 121 of the pressure vessel 110, and the lower end thereof on the vertically lower side is provided with a gap from the bottom of the pressure vessel 110. ing.

The stored water is stored in the slug hopper 122 formed at the bottom of the pressure vessel 110, and the lower end of the gasification furnace wall 111 is flooded with the stored water to seal the inside and outside of the gasification furnace wall 111. ing. Burner devices 126 and 127 are inserted into the gasification furnace wall 111, and a thin gas cooler 102 is arranged in the internal space 154.

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

The convertor section 116 is a combustion chamber that partially burns pulverized coal and char (unreacted coal and ash) and air, and a plurality of burner devices 126 are formed on the gasification furnace wall 111 of the convertor section 116. A combustion chamber consisting of is arranged. The high-temperature combustion gas obtained by burning the pulverized coal and a part of the char in the converter section 116 passes through the diffuser section 117 and flows into the reducer section 118.

The reducer section 118 is maintained at a high temperature state required for the gasification reaction, supplies pulverized coal to the combustion gas from the convertor section 116 and partially oxidatively burns the pulverized coal to volatile components (carbon monoxide, hydrogen, lower hydrocarbons). Etc.), and the space is gasified to generate the generated gas. A combustion device composed of a plurality of burner devices 127 is arranged on the gasification furnace wall 111 of the reducer unit 118.

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 horizontal cross-sectional shape of the gasification furnace wall 111 is a polygonal tubular shape or a cylindrical tubular shape, but the form shown in FIG. 3 is an example of a cylindrical shape, and a plurality of tubular wall portions 140 have a tubular shape. A water-cooled wall pipe 142 is provided. That is, a plurality of water-cooled wall pipes 142 are arranged concentrically on a part of the wall portion 140.

The gasifier 101 has a cooling water circulation mechanism (not shown) that circulates a refrigerant (water supply, steam, etc. as cooling water) in the water-cooled wall pipe 142. The plurality of water-cooled wall pipes 142 extend the gasifier 101 along the vertical direction over the entire area, extend vertically in the vertical direction without being partially cut, and are arranged side by side in the circumferential direction. The wall portion 140 of the gasifier 101 is formed.

As shown in FIG. 3, at least a part of the water-cooled wall tube 142 has a heat transfer tube T and a weld bead WB provided on the outer periphery of the heat transfer tube T. The heat transfer tube T is a pipeline through which cooling water flows. The weld beads WB are arranged on the entire circumference of the heat transfer tube T in the circumferential direction and cover the outer peripheral surface of the heat transfer tube T. The welding bead WB is formed by performing overlay welding on the outer peripheral surface of the heat transfer tube T by a welding device 200 described later.

The wall portion 140 is provided with a plate material (fin) 166 between the water-cooled wall pipe 142 and the water-cooled wall pipe 142. The wall portion 140 of the present embodiment has a tubular shape by arranging a plurality of water-cooled wall pipes 142 concentrically and closing the space between the water-cooled wall pipes 142 and the water-cooled wall pipes 142 with a plate material 166. Further, the wall portion 140 has a welded 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 an end portion on the inner space 154 side and an end portion on the outer space 156 side 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 material 166 to connect the weld bead WB of the water-cooled wall pipe 142 and the plate material 166.

In the gasification furnace wall 111, the heat transfer tube T is made of the first material, and the weld bead WB is made of the second material. Further, the plate material 166 and the welded portion 168 may be made of a second material. The first material and the second material are metals. The second material is a material having higher corrosion resistance (corrosion resistance) and higher heat resistance than the first material. The gasification furnace wall 111 can protect the heat transfer tube T by forming the weld bead WB with a material having higher corrosion resistance and heat resistance than the heat transfer tube T.

Specifically, the internal space 154 inside the gasification furnace wall 111 through which the flammable gas flows flows as a gasified product gas obtained by partially burning the oxidant (gas containing oxygen) and the fuel, and has a high temperature. It becomes. By covering the surface of the heat transfer tube T on the internal space 154 side with the weld bead WB, the heat transfer tube T can be protected from corrosion and a high temperature usage environment.

Further, slag such as coal adheres to and falls off from the heat transfer tube T, the weld bead WB, and the plate material 166 of the gasification furnace wall 111, so that the temperature of the wall surface of the gasification furnace wall 111 changes, and the heat transfer tube When a temperature distribution occurs in T or the weld bead WB, the influence of the thermal expansion difference due to the difference in the material becomes large, and the local thermal stress may become large. Therefore, the weld bead WB is formed of a material having high heat resistance. There is.

Further, the internal space 154 inside the convertor portion 116, the diffuser portion 117, and the reducer portion 118 of the gasification furnace wall 111 has a high temperature atmosphere exceeding 1500 ° C., so that the temperature difference tends to be large. Therefore, in the present 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 surface connecting the axis of the heat transfer tube T and the plate thickness center of the plate material 166. Even if a local temperature distribution occurs, it is possible to suppress an increase in heat load due to a difference in thermal expansion, and it is possible to improve the durability of the gasification furnace wall 111.

Next, a welding device 200 that spirally overlays welds 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 apparatus 200 according to the embodiment of the present disclosure, showing a state in which overlay welding is started on the surface of the heat transfer tube T and the welding bead WB is started to be formed. FIG. 5 is a side view of the welding apparatus 200 according to the embodiment of the present disclosure, showing a state in which a weld bead WB is formed by overlay welding the outer peripheral surface of the heat transfer tube T.

FIG. 6 is a side view of the welding apparatus 200 according to the embodiment of the present disclosure, showing a state in which overlay welding to the surface of the heat transfer tube T is completed. 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 a control configuration of the welding apparatus 200 shown in FIG.

The welding apparatus 200 shown in FIGS. 4 to 6 spirally overlays the 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 to form a welding bead WB. It is a device. As shown in FIGS. 4 to 6, the heat transfer tube T is a cylindrical tube body arranged along the axis X extending in the horizontal direction of the paper surface. As shown in FIGS. 4 to 6, the welding apparatus 200 includes a movable carriage 10, an overlay welding mechanism 20, a lower support mechanism 30, an upper support mechanism 40, a cooling mechanism 50, a measurement mechanism 60, and a main body. A unit 70, an imaging unit 80, a display unit 85, and a control unit 90 are provided.

In the welding device 200, the heat transfer tube T is arranged at a constant height from the installation surface S so as to be parallel to the installation surface S, and is supported by the lower support mechanism 30 and the upper support mechanism 40. The welding device 200 rotates the heat transfer tube T around the axis X at a predetermined rotation speed while moving the heat transfer tube T along the moving direction MD at a predetermined speed by the movable carriage 10. The welding device 200 is provided by a build-up welding mechanism 20 installed at a position fixed to an installation surface S above the paper surface with respect to a heat transfer tube T that rotates around the axis X while moving along the movement direction MD. Overlay welding is performed.

Overlay welding is started on the surface of the heat transfer tube T in the state shown in FIG. 4, the range of the weld bead WB formed in a spiral shape increases as shown in FIG. 5, and the heat transfer tube T is in the state shown in FIG. Overlay welding to the surface is completed. By executing the operations of FIGS. 4 to 6, the welding apparatus 200 forms a weld bead WB in which the welding material is spirally overlaid on the surface of the heat transfer tube T.

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 for moving the heat transfer tube T along the axis X, and a rotating mechanism 12 for rotating the heat transfer tube T around the axis X.

As shown in FIG. 7, the moving mechanism 11 drives the moving motor 11a to rotate the first gear 11c connected to the drive shaft 11b in the coaxial direction with the drive shaft 11b, and engages with 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 the main body 70 fixed to the installation surface S on which the welding device 200 is installed. Therefore, as the third gear 11f rotates, the carriage portion 11g of the moving mechanism 11 moves along the rail 72 of the main body portion 70 in the moving direction MD. Here, the moving direction MD is a direction parallel to the axis X direction of the heat transfer tube T.

The heat transfer tube T is held by the fixing portion 12e on the outer peripheral surface of the heat transfer tube T so as not to move in the axis X direction with respect to the moving mechanism 11 in a state where the movable carriage 10 can rotate around the axis X by the rotating mechanism 12. And fixed. Therefore, when the moving mechanism 11 moves along the axis X, the heat transfer tube T also moves along the axis X accordingly. In this way, the moving mechanism 11 moves the heat transfer tube T along the axis X by driving the moving motor 11a. The drive of the moving motor 11a is controlled by a control signal transmitted from the control unit 90.

As shown in FIG. 7, the rotation mechanism 12 drives the rotation motor 12a to rotate the first gear 12c connected to the drive shaft 12b, and causes the second gear 12d engaged with the first gear 12c to rotate. Rotate. The second gear 12d is connected so as to be integrated with a fixing portion 12e that holds the outer peripheral surface of the heat transfer tube T and is fixed to the second gear 12d so as not to rotate. Therefore, when the second gear 12d rotates, the heat transfer tube T also rotates around the axis X accordingly.

In this way, the rotation mechanism 12 drives the rotation motor 12a to rotate the heat transfer tube T around the axis X in a fixed direction at a predetermined rotation speed. The drive of the rotary motor 12a is controlled by a control signal transmitted from the control unit 90.

The overlay welding mechanism 20 is a device that spirally forms a weld bead WB while supplying a welding material to the outer peripheral surface of a heat transfer tube T that passes through a predetermined welding position on the axis X. The overlay welding mechanism 20 is fixed to the installation surface S on which the welding device 200 is installed via the main body 70. The overlay welding mechanism 20 performs TIG (Tungsten Inert Gas) welding with, for example, a welding torch 21 having a tungsten electrode (not shown). The overlay welding mechanism 20 applies a voltage to the tungsten electrode by 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 to form an arc and the temperature rises.

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

The overlay welding mechanism 20 is fixed to the main body 70, but the heat transfer tube T moves along the moving direction MD and rotates around the axis X. Therefore, the overlay welding mechanism 20 spirally overlays the corrosion-resistant material on the outer peripheral surface of the heat transfer tube T by welding the heat transfer tube T at a fixed position of the main body 70. .. Further, since the overlay welding mechanism 20 is at a fixed position of the main body 70, the positional relationship between the welding torch 21 and the heat transfer tube T can be managed with high accuracy.

The lower support mechanism 30 is a mechanism that supports the heat transfer tube 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 outer peripheral surface on the lower side of the heat transfer tube T at the position closest to the overlay welding mechanism 20, and is fixed to the main body portion 70 to which the overlay welding mechanism 20 is fixed. There is. The second lower support portion 32 is arranged adjacent to the first lower support portion 31, and is arranged on the upstream side (right side of the paper surface) of the moving direction MD of the heat transfer tube T along the axis X from the first lower support portion 31. Has been done.

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

The height adjusting mechanism 33c has a support state in which the tip of the third lower support portion 33 is held at a position that supports the heat transfer tube T, and the tip of the third lower support portion 33 is retracted at a position that does not support the heat transfer tube T. It is a mechanism that can switch between the retracted state. The height adjusting mechanism 33c is a mechanism for moving the tip position of the third lower support portion 33 along a direction orthogonal to the installation surface S (vertical direction on the paper surface). The height adjusting mechanism 33c is, for example, a mechanism that expands and contracts vertically in the vertical direction 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 portions 33, those arranged at a plurality of locations on the downstream side of the moving direction MD of the heat transfer tube T with respect to the first lower supporting portion 31 come into contact with each other when the movable carriage 10 moves in the moving direction MD. The height adjusting mechanism 33c moves the tip position downward so as to prevent the tip from being retracted. In the state shown in FIGS. 4 and 5, the third lower support portion 33 arranged on the most downstream side of the moving direction MD of the heat transfer tube T does not pass through the movable carriage 10, so that the third lower support portion 33 does not come into contact with the movable carriage 10. In order to avoid this, the tip position of the third lower support portion 33 is retracted. 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 support state.

Among the third lower support portions 33, those arranged at a plurality of locations on the upstream side of the moving direction MD of the heat transfer tube T with respect to the first lower support portion 31 are height adjusting mechanisms so as not to come into contact with the cooling mechanism 50. The tip position of the third lower support portion 33 is moved by the 33c so as to be in the retracted state. In the state shown in FIG. 4, the third lower support portion 33 arranged on the most upstream side of the moving direction MD of the heat transfer tube T does not pass through the cooling mechanism 50, so that the tip position of the third lower support portion 33 is It becomes a support state. On the other hand, in the states shown in FIGS. 5 and 6, since the cooling mechanism 50 has passed through, the tip position of the third lower support portion 33 is in the 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 tube T from above, and is fixed to the main body 70 to which the overlay welding mechanism 20 is fixed. The upper support mechanism 40 welds the overlay welding mechanism 20 by supporting the heat transfer tube T on the upstream side of the moving direction MD of the heat transfer tube T and closer to the overlay welding mechanism 20 than the overlay welding mechanism 20. It suppresses fluctuations in 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 the welding torch 21. The upper support mechanism 40 can adjust the distance in the direction orthogonal to the installation surface S at the tip position supporting the heat transfer tube T (up and down direction on the paper surface) by the height adjusting mechanism.

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

The cooling mechanism 50 circulates the cooling water that has flowed into the heat transfer tube T from the upstream end Tu to the downstream end Td along the moving direction MD of the heat transfer tube T. The region from the upstream end Tu of the heat transfer tube T to the welding position is a region where the welding bead WB is not formed. Therefore, the cooling water is supplied to the vicinity of the welding position, which is the highest temperature in the heat transfer tube T, in a state where the temperature is not raised by being heated, and the heat transfer tube T in the vicinity of the welding position can be appropriately and effectively cooled. it 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 the heat effect and warpage deformation of the heat transfer tube T due to thermal stress.

The measuring mechanism 60 is a mechanism that is arranged on the downstream side of the MD in the moving direction from the welding position where the overlay welding mechanism 20 is arranged. The measuring mechanism 60 is a mechanism for measuring the outer diameter of the heat transfer tube T passing through the measuring position by using, for example, a non-contact type sensor. The control unit 90 builds up the weld bead WB based on the outer diameter of the heat transfer tube T that has not been overlaid welded and the outer diameter of the heat transfer tube T that has been overlaid welded, which is transmitted from the measuring mechanism 60. It is possible to judge whether or not the thickness is appropriate.

For example, when the control unit 90 determines that the overlay 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 overlay thickness is out of the target range and is not an appropriate thickness. Let me. Further, the control unit 90 may control the overlay welding mechanism 20 so as to temporarily stop the overlay welding of the heat transfer tube T by the overlay welding mechanism 20. At this time, the control unit 90 displays information on the difference between the various overlay welding conditions of the heat transfer tube T by the overlay welding mechanism 20 and the set value on the display unit 85, and the overlay thickness is an appropriate thickness. It may be possible to make it easier to determine the factors that deviate from the above.

The main body 70 is a housing fixed to the installation surface S on which the 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 main body portion 70. Further, the main body 70 includes the rack gear 71 and the rail 72 shown in FIG. 7, and the movable carriage 10 can reciprocate in the moving direction MD parallel to the axis X direction along the rail 72.

The imaging unit 80 is an imaging device that images 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 an image in the vicinity of the imaged welding position to the display unit 85. The operator who operates the welding apparatus 200 visually confirms whether or not there is any abnormality in the welding bead WB formed on the heat transfer tube T by the overlay welding mechanism 20 by visually observing the image displayed on the display unit 85. Can be done. When the operator determines that the welding bead WB has an abnormality, the operator suspends the operation of the welding device 200. Further, when the control unit 90 analyzes the image captured by the image pickup unit 80 and determines that there is an abnormality, the operation of the welding device 200 may be automatically suspended by a signal from the control unit 90.

As shown in the control configuration diagram of FIG. 8, 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 overlay welding mechanism 20. In the control unit 90, the moving mechanism 11 moves the heat transfer tube T along the axis X in the moving direction MD at a predetermined constant moving speed, and the rotating mechanism 12 rotates the heat transfer tube T around the axis X at a predetermined constant speed. The overlay welding mechanism 20 controls the overlay welding to be spirally performed on the outer peripheral surface of the heat transfer tube T in a state of being rotated at a high speed.

The control unit 90 is composed of, 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. Then, as an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized.

In this embodiment, the heat transfer tube T is made of, for example, low alloy steel. The outer diameter of the unwelded heat transfer tube T is, for example, 30 mm or more and 50 mm or less. 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 apparatus 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 overlay thickness of the weld bead WB is set so as to be able to protect the heat transfer tube T from, for example, corrosion resistance and heat resistance.

In the control unit 90, a predetermined moving speed of the heat transfer tube T in the axial X direction by the moving mechanism 11 is set by the moving mechanism 11 so that the overlay thickness of the weld bead WB is 1 mm or more and 2.5 mm or less, and the rotation mechanism 12 A predetermined rotation speed of the heat transfer tube T around the axis X is set. The control unit 90 adjusts the outer diameter of the overlaid heat transfer tube T and / or the overlaid thickness of the weld bead WB to be within the target specifications based on the measured value transmitted from the measuring mechanism 60. , The moving speed of the heat transfer tube T in the axis X direction 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 tube T in the axis X direction 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 the build-up weld crack of the weld bead WB formed on the outer peripheral surface of the heat transfer tube T by the welding device 200 of the present embodiment will be described with reference to the drawings. FIG. 9 is a flowchart showing the overlay weld crack evaluation method of the present embodiment. FIG. 10 is a cross-sectional view showing a heat transfer tube T in which a weld bead WB is formed on the outer peripheral surface.

FIG. 11 is a perspective view showing the evaluation material EM produced by cutting the heat transfer tube T. 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. FIG. 14 is a diagram showing a state in which the evaluation material EM is bent by the bending jig 300.

The overlay weld crack evaluation method of the present embodiment shown in FIG. 9 evaluates the overlay weld crack of the weld bead WB formed on the outer peripheral surface of the cylindrical heat transfer tube (tube 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 welding 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. The welding device 200 is controlled to perform.

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

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

As shown in FIG. 11, the evaluation material EM created in step S102 is formed by cutting out a strip shape having the axial X direction as the longitudinal direction and the circumferential direction around the axis X as the lateral direction. The length L1 of the evaluation material EM in the longitudinal direction 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, about 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 the undulations of the uneven shape of the weld bead WB portion of the heat transfer tube T in which the weld bead WB is formed by the first welding step, and it is evaluated whether or not the surface roughness satisfies the evaluation criteria. To do. As shown in FIG. 12, the surface roughness is defined as BUmax, which is the position where the height of the weld bead WB is the highest in a part 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, which is the position where the height of the weld bead WB is the lowest. For example, if the BUt is 0.15 mm or less, the evaluation standard is satisfied, and if the BUt is larger than, for example, 0.15 mm, the evaluation standard 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 standard is satisfied, and the process proceeds to step S105. If the surface roughness But is larger than, for example, 0.15 mm, the evaluation standard is not satisfied. The determination is made and the process proceeds to step S110.

In step S105, the evaluation material bending step of bending the evaluation material EM created in step S102 is executed. The evaluation material bending step of step S105 is executed by using the bending jig 300. As shown in FIGS. 13 and 14, the bending jig 300 includes a pressurizing jig 310 and a main body jig 320.

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

In step S105, the operator of the bending jig 300 places the jig 320 so that the central portion of the main body jig 320 and the central portion of the evaluation material EM in the longitudinal direction coincide with each other in the vertical direction. As shown in FIG. 13, the evaluation material EM is arranged so that the 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 pressurizing jig 310 against the central portion of the evaluation material EM in the longitudinal direction.

After installing the evaluation material EM in the state shown in FIG. 13, the operator moves the pressurizing jig 310 downward by a pressurizing mechanism such as a hydraulic cylinder, and applies the evaluation material EM to the central portion in the longitudinal direction. The evaluation material EM is bent by abutting the outer peripheral surface 311 of the pressure jig 310. When the pressurizing jig 310 is pushed down to a position where the evaluation material EM comes into contact with the inner peripheral surface 321 of the main body 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 so as to be in contact with both the outer peripheral surface 311 of the pressurizing jig 310 and the inner peripheral surface 321 of the main body jig 320 without a gap. Each size such as the length L2 in the lateral direction of the evaluation material EM, the radius of curvature r1 of the outer peripheral surface 311 of the pressurizing jig 310, the radius of curvature 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 case, it is bent to a state where the gap becomes small and becomes a substantially U-shape.

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

Conventionally, sufficient evaluation as a product has not been performed for overlay welding, but whether or not welding cracks have occurred in the evaluation material EM bent by the bending jig 300, for example, by a penetrant inspection test. By evaluating, evaluation is performed in consideration of the decrease in strength due to bending of the heat-affected zone of the weld bead WB and heat transfer tube T, and it is possible to appropriately evaluate whether or not the heat transfer tube T can be used as a product without problems. it can.

The penetrant inspection is carried out according to the following procedure. First, impurities such as oil and dirt adhering to the evaluation material EM are removed by using a cleaning liquid or the like. Next, a colored penetrant having high permeability to the weld crack portion is applied to the entire region of the weld bead WB of the evaluation material EM. When the evaluation material EM has weld cracks, the penetrant permeates the weld cracks. Next, the penetrant applied to the surface of the evaluation material EM is removed using water or the like. When the evaluation material EM has weld cracks, the penetrant that has penetrated into the weld cracks remains without being removed by water or the like.

Next, a developer that penetrates into the weld crack portion is applied to the entire region of the weld bead WB. When welding cracks occur in the evaluation material EM, the developer invades the weld cracked portion, and the penetrant is sucked up to the surface of the evaluation material EM due to the invasion of the developer. The penetrant sucked up on the surface of the evaluation material EM spreads in an enlarged region rather than the weld crack portion. Therefore, the operator observing the evaluation material EM can appropriately evaluate whether or not welding cracks have occurred by visually observing the appearance.

In step S107, the operator visually determines the appearance of the evaluation material EM subjected to the penetrant inspection test to determine whether or not welding cracks have occurred in the evaluation material EM. When the evaluation material EM does not have welding cracks, it is determined that the overlay welding satisfies the evaluation criteria, and the process proceeds to step S108. On the other hand, if welding cracks occur 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.

The operator determines that welding cracks occur when the colored penetrant is visible and the overlay welding does not meet the evaluation criteria, and when the colored penetrant is not visible, welding cracks occur. It is judged that the overlay welding meets the evaluation criteria. Even when the colored penetrant is visible, the operator can crack the weld if the area where the penetrant spreads is less than a predetermined size (for example, the maximum length is 3 mm or less). May be determined and the process proceeds to step S108.

In step S108, the operator can see that the surface roughness of the heat transfer tube T subjected to overlay welding in step S101 satisfies the evaluation criteria, and the evaluation material cut out from the heat transfer tube T subjected to overlay welding in step S101. In order for the EM to satisfy the evaluation criteria for welding cracks, 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 executes a second welding step of overlay welding on the surface of the heat transfer tube T in which the welding bead WB is not formed under the overlay welding conditions set in step S108. Since the build-up welding condition set in step S108 is an appropriate build-up welding condition in which welding cracks do not occur in the build-up welded heat transfer tube T, an appropriate build-up welded heat transfer tube in which weld cracks do not occur. T is manufactured. When step S109 ends, the processing of this flowchart ends.

In step S110, the operator evaluates that the surface roughness of the heat transfer tube T subjected to overlay welding in step S101 does not meet the evaluation criteria, or is cut out from the heat transfer tube T subjected to overlay welding in step S101. Since the material EM does not satisfy the evaluation criteria for welding cracks, the overlay welding conditions in step S101 are changed, and new overlay welding conditions are set in the welding apparatus 200.

As the overlay welding conditions, the operator can use, for example, the rotation speed Rt around the axis X of the heat transfer tube T with respect to the overlay welding mechanism 20 for welding the heat transfer tube T, and the axis X of the heat transfer tube T with respect to the overlay welding mechanism 20. The welding pitch (Vt / Rt), which is the ratio of the moving speed Vt and the rotation speed Rt, is changed by changing either or both of the moving speed Vt in the direction.

By executing the flowchart shown in FIG. 9 above, the surface roughness of the heat transfer tube T subjected to overlay welding satisfies the evaluation criteria, and the evaluation material EM cut out from the heat transfer tube T subjected to overlay welding. The overlay welding conditions are set so that overlay welding can be performed appropriately so that the weld cracks satisfy the evaluation criteria. 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 product specifications for overlay welding.

Next, with reference to FIGS. 15 to 17, an example in which the evaluation method of the present embodiment and the evaluation method of the comparative example are compared will be described. FIG. 15 is a view of the evaluation material EM of the present embodiment bent by the evaluation material bending step as viewed from the surface on which the weld bead WB is formed. FIG. 16 is a view of the evaluation material EM'of the comparative example bent by the evaluation material bending step as viewed from the surface on which the weld bead WB is formed. FIG. 17 is an example of an evaluation table showing the evaluation of the surface roughness under the overlay welding conditions and the evaluation of the overlay welding cracks.

As shown in FIG. 15, in the evaluation material EM of the present embodiment, the weld bead WB is formed on the entire weld surface WS corresponding to the surface of the heat transfer tube T. 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 central portion in the longitudinal direction of the welded surface WS corresponding to the surface of the heat transfer tube T, and the evaluation material is evaluated. The weld bead WB'is formed only in the vicinity region bent by the bending step.

First, the evaluation of surface roughness will be described. In the welding device 200, when the moving speed of the heat transfer tube T with respect to the overlay welding mechanism 20 in the axis X direction increases, the interval (bead interval) along the axis X of the welding beads WB formed by the overlay welding mechanism 20. There is a condition that the undulations of the uneven shape of the weld bead WB become large and the overlay welding cracks are likely to occur. In FIG. 17, the welding pitch of condition 3 is used as a reference (1.0), and other conditions are shown as ratios to the reference.

As shown in FIG. 17, under the condition 5 in which the welding pitch is 1.17 times larger than the condition 3, the surface roughness becomes larger than 0.15 mm and does not satisfy the evaluation standard of the surface roughness. On the other hand, when the welding pitch is equal to or less than the welding pitch of the condition 4 (1.08 times the welding pitch of the condition 3), the welding pitch is small and the surface roughness evaluation standard is satisfied.

Next, the evaluation of overlay weld cracks will be described. In the welding apparatus 200, when the rotation speed Rt around the axis X of the heat transfer tube T with respect to the overlay welding mechanism 20 becomes high, the interval (bead interval) along the axis X of the weld bead WB formed by the overlay welding mechanism 20. Is narrowed and the overlap of the weld beads WB is increased, so that the heat effect is concentrated locally and the heat effect on the heat transfer tube T during overlay welding is increased, and the toughness of the heat transfer tube T is reduced, so that the meat is thickened. Cracks are likely to occur due to build-up welding.

As shown in FIG. 17, when the evaluation of overlay welding cracks is evaluated using the evaluation material EM of the present embodiment, if the welding pitch is equal to or greater than the welding pitch of Condition 3, the thermal effect of overlay welding is local. It is evaluated that the concentration of the overlay is not excessive and the build-up weld crack 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 becomes excessively concentrated locally, and the toughness of the heat transfer tube T decreases, resulting in welding cracking. Is evaluated to have occurred.

On the other hand, when the evaluation of overlay welding cracks is evaluated using the evaluation material EM'of the comparative example, if the welding pitch is equal to or greater than the welding pitch of condition 2, the thermal effect of overlay welding is excessively concentrated locally. Therefore, it is evaluated that the overlay welding crack did not occur. On the other hand, when the welding pitch is less than or equal to the welding pitch of condition 1 (0.93 times the welding pitch of condition 3), the heat effect is excessively concentrated locally, and the toughness of the heat transfer tube T is lowered, so that welding cracks occur. It is evaluated as being.

Comparing the evaluation method of the build-up weld crack using the evaluation material EM of the present embodiment and the evaluation method of the build-up weld crack using the evaluation material EM'of the comparative example, the condition 2 is satisfied in the evaluation method of the present embodiment. While it is evaluated as an overlay welding condition in which overlay welding cracks occur, in the evaluation method of the comparative example, condition 2 is evaluated as an overlay welding condition in which overlay welding cracks do not occur. Under the same condition 2, the evaluation material EM of the present embodiment and the evaluation material EM'of the comparative example have different evaluation results of overlay weld cracks.

In the evaluation method of the present embodiment, the condition 2 is evaluated as the build-up welding condition in which cracks occur in the build-up welding in the evaluation material EM in a partial region centered on the position where the bending process is performed. 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 in which overlay welding is likely to occur due to overlay welding performed at a position away from the position where bending is performed, and condition 2 is not satisfied. It can be determined that the overlay welding conditions are appropriate.

As described above, when the evaluation methods of the present embodiment and the comparative example are compared, the evaluation method of the overlay weld crack using the evaluation material EM of the present embodiment is farther from the position where the bending process is performed than the comparative example. It is possible to appropriately determine that the overlay welding conditions in which cracks occur in the overlay weld at the above position are inappropriate.

The overlay weld crack evaluation method described in each of the above-described embodiments can be grasped as follows, for example.
The build-up weld crack evaluation method according to the present disclosure is a build-up weld crack evaluation method for evaluating a weld crack after forming a build-up weld on a cylindrical pipe body extending along an axis, and is the pipe body. A build-up welding step of forming a welded portion spirally extending around the axis so as to cover the outer peripheral surface of the above, and a build-up welding step in which the welded portion is formed by the welding step are cut and described. An evaluation material making step of creating an evaluation material in which the welded portion is formed on the entire surface corresponding to the surface of the pipe body, and an evaluation material for bending the evaluation material formed by the evaluation material making step with a predetermined radius of curvature. It includes a bending step and an overlay weld crack evaluation step for evaluating whether or not a weld crack has occurred 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 bent by the evaluation material bending step is a surface corresponding to the outer peripheral surface of the pipe body by cutting the pipe body in which the welded portion extending spirally is formed. A welded portion is formed on the entire surface of the. The evaluation material has welded portions not only in a partial region centered on the position where the evaluation material bending process is performed, but also in other regions. Therefore, not only the evaluation of the build-up weld crack at the position where the bending process is performed but also the evaluation of the build-up weld crack at the position away from the position where the bending process is performed can be appropriately performed.

In the overlay weld crack evaluation method according to the present disclosure, the evaluation material making 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 evaluation material to be evaluated has the axial direction in which the pipe body extends as the longitudinal direction, the boundary of each circumference of the welded portion formed in a spiral shape can be arranged in one evaluation material over a plurality of places. .. As a result, a large number of places where welding cracks are likely to occur can be arranged on one evaluation material, and overlay welding cracks can be appropriately evaluated.

In the overlay weld crack evaluation method according to the present disclosure, the evaluation material bending step bends the central portion of the cut surface of the evaluation material in the longitudinal direction.
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 stretched at the central portion in the longitudinal direction of the evaluation material. Therefore, the boundary portion between the welded portion and the pipe body formed on the outer peripheral surface of the pipe body is deformed most among the evaluation materials. Since the boundary portion between the welded portion and the pipe body is a portion where overlay welding cracks are particularly likely to occur, the overlay welding cracks can be appropriately evaluated by significantly deforming this portion.

In the overlay weld crack evaluation method according to the present disclosure, in the evaluation material bending step, a jig having an arc-shaped outer peripheral surface including a region having a predetermined radius of curvature is provided at the central portion of the evaluation material in the longitudinal direction. Butt and fold.
According to the overlay weld crack evaluation method 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 has an appropriate radius of curvature. As a result, the entire central portion of the evaluation material in the longitudinal direction is deformed substantially uniformly, so that overlay welding cracks can be appropriately evaluated without causing excessive deformation locally.

In the overlay weld crack evaluation method according to the present disclosure, in the overlay weld crack evaluation step, the penetrant is soaked into the bent evaluation material and then sucked up on the surface of the evaluation material by a developer. It is evaluated whether or not welding cracks are generated in the evaluation material by a penetrant inspection test.
According to the overlay welding crack evaluation method according to the present disclosure, the penetrant that has soaked into the location where the overlay welding crack has occurred is sucked up so that the weld crack can be enlarged and visually recognized by the penetration flaw detection test, and the overlay welding Cracks can be evaluated appropriately.

The method for manufacturing the tubular body (T) according to the embodiment described above is grasped as follows, for example.
The 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 is around the axis so as to cover the surface of the tubular body. The first welding step (S101) in which overlay welding is performed to form a welded portion extending in a spiral shape, and the tubular body in which the welded portion is formed by the first welding step are cut and formed on the surface of the tubular body. An evaluation material making step (S104) for creating an evaluation material in which the welded portion is formed on the entire corresponding surface, and an evaluation material bending step (S105) for bending the evaluation material formed by the evaluation material making step. Evaluation results of the overlay weld crack evaluation step (S106) for evaluating whether or not weld cracks are generated in the welded portion formed on the evaluation material by the evaluation material bending step, and the overlay weld crack evaluation step. Based on the overlay welding condition setting step (S108) for setting the overlay welding conditions when forming the welded portion and the overlay welding conditions set by the overlay welding condition setting step, the pipe A second welding step (S109) is provided in which overlay welding is performed to form a welded portion spirally extending around the axis so as to cover the outer peripheral surface of the body.

According to the method for manufacturing a pipe body according to the present disclosure, the evaluation material bent by the evaluation material bending step is a surface corresponding to the outer peripheral surface of the pipe body by cutting the pipe body having a spirally extending welded portion formed therein. A welded portion is formed as a whole. The evaluation material has welded portions not only in a partial region centered on the position where the bending process is performed but also in other regions. Therefore, not only the evaluation of the build-up weld crack at the position where the bending process is performed, but also the evaluation of the build-up weld crack by performing the build-up weld at a position away from the position where the bending process is performed can be appropriately performed. .. Then, since the second welding step is executed based on the build-up welding conditions set based on the evaluation result, the pipe body in which the build-up welding is formed under the appropriate build-up welding conditions in which cracks in the build-up welding are unlikely to occur is formed. Can be manufactured.

In the method for manufacturing a pipe body according to the present disclosure, the welding conditions are the number of rotations of the pipe body around the axis with respect to the build-up welding mechanism (20) that performs overlay welding on the pipe body, and the build-up welding mechanism. Includes the ratio of the moving speed of the tube to the axial direction.
When the number of rotations around the axis of the pipe with respect to the overlay welding mechanism increases, the interval (bead interval) along the axis of the weld formed by the overlay welding mechanism becomes narrower, and the thermal effect of overlay welding becomes local. Overlay welding cracks are likely to occur due to excessive concentration and a decrease in the toughness of the heat transfer tube T.

Further, when the moving speed of the pipe 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 becomes wider, and the uneven shape of the welded portion becomes wider. The undulations become large and overlay welding cracks are likely to occur. Therefore, according to the method for manufacturing a pipe body according to the present disclosure, by appropriately adjusting the ratio between the rotation speed around the axis of the pipe body and the moving speed of the pipe body in the axial direction, overlay welding cracks are unlikely to occur. It is possible to manufacture a pipe body in which overlay welding is formed under appropriate overlay welding conditions.

The evaluation material (EM) described in the above-described embodiment is grasped as follows, for example.
The evaluation material (EM) according to the present disclosure is for evaluating overlay weld cracks in a welded portion (WB) formed by overlay welding on the outer peripheral surface of a cylindrical tube extending along an axis. From the tubular body in which the welded portion spirally extending around the axis is formed so as to cover the outer peripheral surface, the axial direction is the longitudinal direction and the circumferential direction around the axis (X) is the lateral direction. Overlay welding is formed so that it is possible to evaluate whether or not overlay welding cracks have occurred in the bent evaluation material by cutting it into strips of size and bending it with a predetermined radius of curvature. The welded portion is formed on the entire surface corresponding to the outer peripheral surface of the pipe body.

According to the evaluation material according to the present disclosure, not only the evaluation of the build-up weld crack at the position where the bending process is performed, but also the build-up weld crack due to the build-up welding at the position away from the position where the bending process is performed. Evaluation can also be performed appropriately.

10 Movable trolley 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 body 80 Imaging unit 85 Display 90 Control unit 200 Welding device 300 Bending jig 310 Pressure jig 311 Outer peripheral surface 320 Main body jig 321 Inner peripheral surface But Surface roughness CS Cut surface EM, EM'Evaluation material T Heat transfer tube (tube body)
WB, WB'Welded bead (welded part)
WS Welding Helmet X Axis r1, r2 Curvature Radius

Claims (8)

This is a build-up weld crack evaluation method for evaluating weld cracks after forming build-up welds on a cylindrical tube body extending along an axis.
A overlay welding step of performing overlay welding to form a welded 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 pipe body on which the welded portion is formed by the overlay welding step and creating an evaluation material in which the welded portion is formed on the entire surface corresponding to the surface of the pipe body.
An evaluation material bending step of bending the evaluation material formed by the evaluation material preparation step with a predetermined radius of curvature, and an evaluation material bending step.
A build-up weld crack evaluation method comprising a build-up weld crack evaluation step for evaluating whether or not a weld crack has occurred in the evaluation material bent by the evaluation material bending step. The overlay welding crack evaluation method according to claim 1, wherein the evaluation material making step is to prepare a strip-shaped evaluation material having the axial direction as the longitudinal direction and the circumferential direction around the axis as the lateral direction. The overlay welding crack evaluation method according to claim 2, wherein the evaluation material bending step bends a central portion of the cut surface of the evaluation material in the longitudinal direction. The evaluation material bending step according to claim 2 or 3, wherein a jig having an arcuate outer peripheral surface including a region having a predetermined radius of curvature is abutted against the central portion of the evaluation material in the longitudinal direction and bent. The overlaid weld crack evaluation method described. In the overlay welding crack evaluation step, the bent evaluation material is impregnated with the penetrant and then welded to the evaluation material by a penetrant inspection test in which the penetrant sucked up on the surface of the evaluation material by a developer is observed. The overlay weld crack evaluation method according to any one of claims 1 to 4, which evaluates whether or not cracks have occurred. It is a method of manufacturing a pipe body in which a cylindrical overlay weld extending along an axis is formed.
The first welding step of performing overlay welding to form a welded 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 pipe 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 pipe body. ,
An evaluation material bending step of bending the evaluation material formed by the evaluation material preparation step, and an evaluation material bending step.
An overlay weld crack evaluation step for evaluating whether or not a weld crack is generated in the welded portion formed on the evaluation material by the evaluation material bending step, and a build-up weld crack evaluation step.
An overlay welding condition setting step for setting overlay welding conditions when forming the welded portion based on the evaluation result of the overlay welding crack evaluation process, and an overlay welding condition setting step.
Second welding for overlay welding to form a welded portion spirally extending around the axis so as to cover the outer peripheral surface of the pipe body based on the overlay welding conditions set by the overlay welding condition setting step. A method of manufacturing a tubular body in which overlay welding is formed, comprising a process. The overlay welding conditions are the number of rotations of the tubular body around the axis with respect to the overlay welding mechanism for overlay welding the tubular body and the moving speed of the tubular body in the axial direction with respect to the overlay welding mechanism. The method for manufacturing a pipe body on which overlay welding is formed according to claim 6, which includes a ratio of An evaluation material for evaluating overlay weld cracks in a welded portion formed by overlay welding on the outer peripheral surface of a cylindrical tube extending along an axis.
From the pipe body in which the welded portion spirally extending around the axis is formed so as to cover the outer peripheral surface, a strip of a predetermined size having the axis direction as the longitudinal direction and the circumferential direction around the axis as the minor direction. The pipe in which overlay welding is formed so that it is possible to evaluate whether or not overlay welding cracks have occurred in the bent evaluation material by being cut out and bent at a predetermined radius of curvature. An evaluation material in which the welded portion is formed on the entire surface corresponding to the outer peripheral surface of the body.

Images