JP7019854B2 - Method of forming the insertion port protrusion - Google Patents

Description

The present invention relates to a method for forming a protrusion on the outer periphery of a pipe insertion.

Conventionally, as a pipe joint having a protrusion on the outer periphery of a pipe insertion port, for example, as shown in FIG. 12A, there is a slip-on type having a detachment prevention function. The pipe joint 901 is a rubber sealing material in which the insertion port 911 of one pipe 910 is inserted into the receiving port 921 of the other pipe 920 and seals between the inner circumference of the receiving port 921 and the outer periphery of the insertion port 911. The 922 is provided inside the receiving port 921.

Further, a lock ring 923 is provided on the inner side of the receiving port 921 on the back side of the sealing material 922. As will be described later, a protrusion 912 that can be engaged with the lock ring 923 from the back side of the receiving port 921 is formed on the outer periphery of the insertion port 911.

The surface 912a on the distal end side of the protrusion 912 is formed so as to be gently inclined with respect to the surface 912b on the opposite side to the distal end. As a result, the resistance when the protrusion 912 passes through the sealing material 922 and the lock ring 923 can be reduced, and the joining force (pushing force) required when the insertion port 911 is inserted into the receiving port 921 can be reduced. Further, when the insertion port 911 moves in the direction of detaching from the receiving port 921, the protrusion 912 engages with the lock ring 923 to exert the detachment prevention function.

Conventionally, as a method for forming an insertion port protrusion for forming such a protrusion, a method in which a ring member is arranged on the outer periphery of the insertion port and welded is generally used, for example, as described in Patent Document 1. On the other hand, Patent Document 2 describes a method of forming a protrusion by overlay welding. In the forming method described in Patent Document 2, as shown in FIG. 12B, a pair of copper rings 931 and 932 are externally fitted and fixed to the insertion port 911 as a mold member, and the insertion port 911 is axially centered. While rotating around, an iron-based weld metal 933 is supplied between the pair of rings 931 and 932 using a welding torch to perform overlay welding. Then, by removing the rings 931 and 932 from the insertion port 911, a protrusion 934 is formed on the outer periphery of the insertion port 911.

Japanese Unexamined Patent Publication No. 9-189388 Japanese Unexamined Patent Publication No. 2008-185114

However, in the forming method described in Patent Document 1, it is necessary to fit the ring member into the insertion port of the tube. Further, in the forming method described in Patent Document 2, it is necessary to attach / detach the rings 931 and 932. As described above, in the prior art, it is difficult to easily form the protrusion because it is necessary to attach or detach the substantially ring-shaped member to or from the pipe.

The present invention has been made in view of the above circumstances, and the problem to be solved thereof is to provide a method for forming an insertion port protrusion capable of easily forming a protrusion.

The problem to be solved by the present invention is as described above, and next, the means for solving this problem will be described.

In claim 1, the protrusion is formed by the overlay formed by performing overlay welding on the outer periphery of the pipe insertion port in the pipe joint having a detachment prevention function using the protrusion. A welding torch that forms a plurality of rows of built-up portions in order from the side opposite to the tip of the insertion slot to the tip end side of the insertion slot in the axial direction of the pipe. In the overlay welding step, the overlay welding step is the most opposite side of the plurality of rows of overlay portions in contact with the outer peripheral surface of the pipe, which is the side opposite to the tip of the insertion port . When forming the overlay portion of the first row located in, the welding torch is arranged so as to be inclined toward the tip end side of the insertion port with respect to the plane orthogonal to the axis of the pipe, and the first row. The built-up portion of the above has an inclined surface on the tip side of the insertion slot and on the side opposite to the tip of the insertion slot, respectively, and the inclined surface on the tip end side of the insertion slot is on the side opposite to the tip of the insertion slot. It is formed more gently than the inclined surface of.

In claim 2, when the plurality of rows of overlay portions in contact with the outer peripheral surface of the pipe are formed in the overlay welding step, the welding torch is said to have a surface orthogonal to the axis of the pipe. It is arranged so as to be inclined toward the tip side of the insertion slot .

In claim 3, in the overlay welding step, the welded portions of the overlay portions adjacent to each other in the axial direction of the pipe are formed so as to overlap each other .

In claim 4, when a plurality of overlay portions are formed in the radial direction of the pipe in the overlay welding step, one of the plurality of layers is overlayed so as to melt into the pipe. The other layer, which is welded and is different from the one layer among the plurality of layers, is built-up welded so as not to melt into the pipe .

In claim 5, in the overlay welding step, the welding torch is arranged so as to be parallel to a plane orthogonal to the axis of the pipe when overlay welding the other layers. Is.

In claim 6, in the overlay welding step, when overlay welding is performed while rotating the pipe around the axis, the welding torch is inclined to the downstream side in the rotation direction of the pipe with respect to the vertical upper direction. It is arranged like this.

In claim 7, in the overlay welding step, the welding torch is arranged so as not to face the axial center of the pipe when viewed from the axial direction of the pipe.

As the effect of the present invention, the following effects are exhibited.

In claim 1, the protrusion can be easily formed.

In claim 2, the protrusion can be easily formed .

In claim 3, stable strength can be ensured .

In claim 4, it is possible to easily secure a desired shape.

In claim 5, it is possible to easily secure a desired shape.

In claim 6, it is possible to easily secure a desired shape.

In claim 7, it is possible to easily secure a desired shape.

Side sectional view showing a pipe joint. Enlarged side sectional view showing the protrusion. The flowchart which shows the formation method of the insertion opening protrusion. (A) A side view showing the arrangement of welding torches. (B) Similarly, a front view. The figure which shows the condition of the welding torch according to the overlay welding process. The figure which shows the state of the 1st overlay welding process. The figure which shows the state of the 2nd overlay welding process. The figure which shows the state of the 3rd overlay welding process. An enlarged side sectional view showing the processing allowance and the inclination angle of the overlay portion. (A) An enlarged cross-sectional view showing a protrusion and an overlay according to the first modification. (B) An enlarged cross-sectional view showing a protrusion and a built-up portion according to a second modification. (A) An enlarged cross-sectional view showing a protrusion and a built-up portion according to a third modification. (B) An enlarged cross-sectional view showing a protrusion and an overlay according to a fourth modification. (A) Side sectional view showing a pipe joint in the prior art. (B) A side sectional view showing a method of forming an insertion port protrusion in the prior art.

In the following, the directions indicated by the arrows U, D, arrow F, arrow B, arrow L, and arrow R in the figure are defined as upward, downward, forward, backward, leftward, and rightward, respectively. I will explain.

Hereinafter, a method for forming an insertion port protrusion according to an embodiment of the present invention will be described.

First, with reference to FIGS. 1 and 2, the configuration of the pipe joint 1 including the protrusion 22 formed by the method for forming the insertion protrusion according to the present embodiment will be described.

The pipe joint 1 is for connecting two pipes. The pipe joint 1 has a detachment prevention function using the protrusion 22. The pipe joint 1 is composed of a receiving port 11 of the first pipe 10 and an insertion port 21 of the second pipe 20.

The first pipe 10 and the second pipe 20 shown in FIG. 1 are each formed in a substantially cylindrical shape with the axial center direction oriented in the front-rear direction. The first pipe 10 and the second pipe 20 are arranged side by side in front of and behind each other. The first pipe 10 and the second pipe 20 are each composed of a ductile cast iron pipe (an example of a metal pipe). The first pipe 10 is arranged on the front side of the second pipe 20.

The receiving port 11 of the first pipe 10 is a portion that receives the second pipe 20. The receiving port 11 is formed at the rear end portion of the first pipe 10. The receiving port 11 is formed so that the inner diameter and the outer diameter are larger than those of other portions (insertion port side). The receiving port 11 includes a seal groove 11a and a lock ring storage groove 11b.

The seal groove 11a is a groove for attaching the seal material 12 described later. The seal groove 11a is formed on the rear end side (open end side) of the inner circumference of the receiving port 11. The seal groove 11a is formed in a substantially annular shape along the circumferential direction of the receiving port 11.

The lock ring storage groove 11b is a groove for attaching the lock ring 14 described later. The lock ring storage groove 11b is formed in front of the seal groove 11a (on the back side of the receiving port). The lock ring storage groove 11b is formed in a substantially annular shape along the circumferential direction of the receiving port 11.

The receiving port 11 configured in this way is provided with a sealing material 12, a holder 13, and a lock ring 14.

The sealing material 12 seals between the inner circumference of the receiving port 11 and the outer periphery of the insertion port 21. The sealing material 12 is formed in a substantially annular shape. The sealing material 12 is made of an elastic body such as rubber. The sealing material 12 includes a heel portion 12a that is fitted into the lock ring storage groove 11b, and a valve portion 12b that is compressed between the inner circumference of the receiving port 11 and the outer circumference of the insertion port 21.

The holder 13 is for holding the lock ring 14 and for centering. The holder 13 is formed in a substantially annular shape. The holder 13 is made of resin or the like. The holder 13 is fitted into the lock ring storage groove 11b.

The lock ring 14 is for preventing the second tube 20 from coming out of the receiving port 11. The lock ring 14 is formed in a substantially ring shape divided into one at one position in the circumferential direction. The lock ring 14 is fitted to the holder 13.

The insertion port 21 of the second tube 20 is a portion inserted into the receiving port 11 of the first tube 10. The insertion port 21 is formed at the front end portion (tip portion) of the second pipe 20. The outer diameter of the insertion port 21 is formed to be smaller than the inner diameter of the receiving port 11. The insertion port 21 includes a protrusion 22.

The protrusion 22 is a portion formed so as to protrude on the outer periphery of the insertion port 21. The protrusion 22 is formed in a substantially annular shape along the circumferential direction of the insertion port 21. As shown in FIG. 2, the protrusion 22 is formed in a substantially trapezoidal shape in a side sectional view. The protrusion 22 is formed of a weld metal (welded bead). The protrusion 22 includes a rear inclined surface 22a and a front inclined surface 22b.

The rear inclined surface 22a is an inclined surface formed on the rear portion of the protrusion 22 (the side opposite to the tip of the second pipe 20). The rear inclined surface 22a is formed so as to be inclined with respect to the outer periphery of the insertion port 21 in the side sectional view.

The front inclined surface 22b is an inclined surface formed on the front portion of the protrusion 22 (the tip end side of the second pipe 20). The front inclined surface 22b is formed so that the inclination angle (inclination angle with respect to the outer periphery of the insertion port 21) is smaller than that of the rear inclined surface 22a.

By forming such a rear inclined surface 22a and a front inclined surface 22b, the protrusion 22 is formed into a substantially trapezoidal shape in which the center of gravity is biased rearward in a side sectional view.

The insertion port 21 of the second pipe 20 of the pipe joint 1 configured in this way is inserted into the receiving port 11 of the first pipe 10 shown in FIG. 1 from the rear. The protrusion 22 passes forward through the inside of the sealing material 12 and the lock ring 14. The protrusion 22 can reduce the resistance when passing through the sealing material 12 and the lock ring 14 due to the front inclined surface 22b (see FIG. 2) having a small inclination angle. The protrusion 22 passes through the lock ring 14 and is arranged in front of the lock ring 14 (on the back side of the receiving port).

When the first tube 10 and the second tube 20 move relative to each other in the state where the insertion port 21 is inserted into the receiving port 11 in this way, the protrusion 22 approaches the lock ring 14 and inclines. The rear inclined surface 22a having a large angle engages with the lock ring 14. In this way, the pipe joint 1 can prevent the second pipe 20 (insertion port 21) from coming off from the first pipe 10 (receptacle 11) by utilizing the protrusion 22.

Hereinafter, a method of forming the protrusion 22 as described above (method of forming the protrusion of the insertion port) will be described with reference to FIGS. 3 to 9.

The method for forming the insertion port protrusion according to the present embodiment includes a preparation step, a build-up welding step (from a first build-up welding step to a third build-up welding step), and a processing step.

The preparation step (step S10) is a step of preparing a pipe (second pipe 20) on which the protrusion 22 is not formed. In the preparation step, the second pipe 20 is supported by an appropriate support member (such as a roller described later). In the present embodiment, as shown in FIG. 4, the second pipe 20 is arranged so that the axial center direction is directed in the front-rear direction and the insertion port 21 is directed in the front direction.

As shown in FIG. 3, after the preparatory step is performed, the overlay welding step (from the first overlay welding step to the third overlay welding step) is performed. The overlay welding step is a step of forming an overlay portion on the outer periphery of the insertion port 21 of the second pipe 20. In this embodiment, three overlay welding steps (from the first overlay welding step to the third overlay welding step) are performed. In each overlay welding process, welding is performed using the welding torch 31.

More specifically, in each overlay welding process, a welding wire (not shown) is sent out from the welding torch 31 shown in FIG. 4 toward the outer periphery of the insertion port 21, and the welding wire is melted to perform overlay welding. Will be. In the present embodiment, such overlay welding is performed by a CMT (cold metal transfer) welding method. The CMT welding method repeats a step of sending the welding wire toward the molten pool in synchronization with the generation of an arc and a step of returning the weld wire when the welding wire reaches the molten pool when a short circuit is detected. It is a welding method.

In each overlay welding step, the welding torch 31 is arranged above the second pipe 20, and the tip of the welding torch 31 (the direction in which the welding wire is sent out) is arranged so as to face downward. Further, in each overlay welding step, overlay welding is performed with the welding torch 31 fixed at an appropriate position and orientation (inclination angle). More specifically, in each overlay welding process, overlay welding is performed while the welding torch 31 is fixed and the second pipe 20 is rotated counterclockwise in the front view by a predetermined roller. .. In each overlay welding step, by rotating the second pipe 20 once, a substantially annular overlay portion extending over the entire circumference of the second pipe 20 is formed. By performing the overlay welding process a plurality of times (three times in this embodiment) while appropriately changing the position and orientation of the welding torch 31 for each overlay welding process, an overlay portion having a desired shape is formed. be able to.

Here, with reference to FIGS. 4 and 5, conditions relating to the position, orientation, and the like of the welding torch 31 in each overlay welding process will be described.

In the present embodiment, as conditions regarding the position and orientation of the welding torch 31, it mainly has items such as axial inclination, circumferential inclination, off-center, radial position, and axial position. Hereinafter, each item will be described.

The axial inclination is an item for setting whether or not the welding torch 31 is inclined in the axial direction of the second pipe 20. Here, the inclination of the welding torch 31 in the axial direction of the second pipe 20 is the upper side (tip) of the welding torch 31 with respect to the plane (orthogonal plane P1) orthogonal to the axial center C20 of the second pipe 20. (On the opposite side) indicates that it is inclined toward the tip end side of the insertion port 21. In addition, in FIG. 4A, the magnitude of the axial inclination (inclination angle), that is, the angle formed by the orthogonal plane P1 and the axial center L1 of the welding torch 31 is shown by A1. In FIG. 4 and the like, for convenience, the description of the orthogonal plane P1 is simplified and shown by a straight line.

The circumferential inclination is an item for setting whether or not the welding torch 31 is inclined in the circumferential direction of the second pipe 20. Here, the inclination of the welding torch 31 in the circumferential direction of the second pipe 20 means that the welding torch 31 of the second pipe 20 is centered on the axis C20 of the second pipe 20 with respect to the vertical direction. It means that it is inclined to the downstream side in the direction of rotation. That is, when the second pipe 20 rotates in the counterclockwise direction in the front view as in the present embodiment, the upper side of the welding torch 31 is tilted to the left in the front view. In addition, in FIG. 4B, the magnitude of the circumferential inclination (inclination angle), that is, the angle formed by the vertical direction and the axial center L1 of the welding torch 31 is shown by A2.

The off-center is an item in which the presence or absence of horizontal displacement of the welding torch 31 with respect to the axis C20 of the second pipe 20 is set. Here, the horizontal displacement of the welding torch 31 with respect to the axis C20 of the second pipe 20 means that the axis L1 of the welding torch 31 is horizontal with respect to the axis C20 of the second pipe 20. (In particular, it means that the second pipe 20 is displaced to the downstream side in the rotation direction (left direction in this embodiment)). More specifically, when the off-center is not set, the tip of the welding torch 31 faces the axis C20 of the second pipe 20 when viewed from the axis direction (front) of the second pipe 20 (axis center). L1 is arranged so as to pass through the axis C20). When the off-center is set, the tip of the welding torch 31 does not face the axis C20 of the second pipe 20 when viewed from the axial direction (front) of the second pipe 20 (the axis L1 is the axis). (To pass to the left of heart C20). In FIG. 4B, the welding torch 31 when the off-center is not set is shown by a two-dot chain line, and the welding torch 31 when the off-center is set is shown by a solid line. Further, in FIG. 4B, the size of the off-center (displacement amount), that is, the horizontal (left-right direction) distance from the axis C20 of the second pipe 20 to the axis L1 of the welding torch 31 is L2. Shows.

The radial position is an item in which the position (distance) of the welding torch 31 with respect to the outer circumference of the second pipe 20 is set. Here, the position (distance) of the welding torch 31 with respect to the outer circumference of the second pipe 20 is the direction from the outer circumference of the second pipe 20 to the tip of the welding torch 31 along the axis L1 of the welding torch 31. The distance. In FIG. 4A, the radial position is indicated by Y.

The axial position is an item in which the position of the welding torch 31 in the axial direction of the second pipe 20 is set. Here, the position of the welding torch 31 in the axial direction of the second pipe 20 is a position in the front-rear direction of the welding torch 31 with a predetermined position in the axial direction of the second pipe 20 as a reference position. .. In the present embodiment, as will be described later, the position of the welding torch 31 (welding position on the surface of the second pipe 20) when welding the overlay portion formed on the rearmost side (first overlay welding step). Is used as a reference position, and the axial position X is defined.

In each overlay welding process, as shown in FIG. 5, the above-mentioned conditions (axial inclination, circumferential inclination, etc.) are individually set. In each overlay welding step, overlay welding is performed on the second pipe 20 in a state where the position and orientation of the welding torch 31 are adjusted according to the conditions shown in FIG. For example, as in the first overlay welding process and the second overlay welding process, by performing overlay welding a plurality of times without changing the axial position X, a plurality of overlay weldings are performed in the radial direction of the second pipe 20. It can be formed by laminating the built-up portions of the layers. Further, as in the first overlay welding process, the second overlay welding process, and the third overlay welding process, the second pipe 20 is performed by performing overlay welding a plurality of times by shifting the axial position X. It is possible to form a plurality of rows of overlays in the axial direction of.

As shown in FIG. 5, in the present embodiment, it is assumed that the presence or absence of axial inclination, circumferential inclination, etc. is set as a condition regarding the position and orientation of the welding torch 31, but in reality, it is assumed. Not only the presence or absence of axial inclination, but also the size (inclination angle, displacement amount, distance, etc.) is specifically set. The specific value of the size is not particularly limited, and can be appropriately set according to the type of the second pipe 20 and the like. Further, although the description is omitted in the present embodiment, other conditions related to welding (for example, welding speed, welding current, welding voltage, etc.) are appropriately set in each overlay welding process.

Hereinafter, the first overlay welding process to the third overlay welding process will be specifically described.

As shown in FIG. 3, after the preparatory step is performed, first, the first overlay welding step (step S20) is performed. The first overlay welding step is a step of forming the first overlay portion 41 on the outer periphery of the insertion port 21. As shown in FIG. 6, the first overlay portion 41 is a welded metal that is first laminated on the outer periphery of the insertion port 21. In the first overlay welding step, by overlay welding the outer periphery of the insertion port 21, the base metal (second pipe 20) is melted (while forming the penetration portion 51), and the overlay portion 41 is formed. Can be formed.

In the first overlay welding step, as shown in FIGS. 5 and 6, overlay welding is performed with the axial inclination, the circumferential inclination, and the off-center set to “Yes”. Further, in the first overlay welding step, overlay welding is performed with the radial position Y set to "Y1" and the axial position X set to "0". Since the radial position Y and the axial position X are set in this way, the welding torch 31 does not move in the radial direction and the axial center direction of the second pipe 20 in the first overlay welding step. Welding is performed while being fixed in a fixed position.

In the first overlay welding step, by setting the axial inclination to "Yes", a relatively gentle inclined surface 41a can be formed on the front side of the first overlay portion 41. Specifically, in overlay welding, a surface substantially perpendicular to the direction of the welding torch 31 is formed on the weld metal (first overlay portion 41). Therefore, when the welding torch 31 is tilted forward with respect to the orthogonal plane P1, a plane perpendicular to the direction of the welding torch 31, that is, an inclined surface 41a that approaches the outer periphery of the insertion port 21 as it goes forward is formed. It can be formed on the front side of the first overlay portion 41. The inclined surface 41a is formed so as to be a gentler surface than the inclined surface 41b formed on the rear side of the first overlay portion 41.

Further, by setting the circumferential inclination to "Yes", welding can be performed at a position shifted to the downstream side in the rotational direction from the top of the second pipe 20 shown in FIG. 4 (b). At the top of the second pipe 20, gravity is applied in the direction in which the molten metal collapses with respect to the molten metal during welding (the direction in which the height of the molten metal decreases, that is, the direction toward the axis C20 of the second pipe 20). Therefore, if welding is performed on the top, the molten metal may be crushed and a built-up portion having a low height may be formed. On the other hand, in the present embodiment, by performing welding at a position deviated from the top, gravity is less likely to be applied to the molten metal in the direction of being crushed during welding, and the height of the first overlay portion 41 is increased. Can be prevented from becoming low.

Further, by setting the off-center to "Yes", welding can be performed at a position shifted from the top of the second pipe 20 to the downstream side in the rotation direction. Therefore, it is possible to prevent the height of the first overlay portion 41 from becoming low.

As described above, in the first overlay welding process, by performing welding with the axial inclination, the circumferential inclination and the off-center set to "Yes", as shown in FIG. 6, a gentle inclined surface on the front side is performed. It is possible to form the first overlay portion 41 having 41a and having a secured height. Further, by the first overlay welding step, it is possible to form a substantially trapezoidal shape in which the center of gravity is biased rearward in a side sectional view, that is, a first overlay portion 41 having a shape similar to the protrusion 22. By further forming the overlay portion in the second overlay welding step and the third overlay welding step described later so as to be laminated or adjacent to the first overlay portion 41, a desired shape (that is, a protrusion) is formed. A built-up portion having a shape similar to that of the portion 22) can be easily formed.

As shown in FIG. 3, after the first overlay welding step is performed, the second overlay welding step (step S30) is performed. The second overlay welding step is a step of forming the second overlay portion 42. In the second overlay welding step, by welding to the first overlay 41, an overlay is formed on the first overlay 41 (the second overlay 42 is laminated). be able to.

In the second overlay welding step, as shown in FIGS. 5 and 7, overlay welding is performed with the circumferential inclination and the off-center set to “Yes”. Further, in the second overlay welding step, the radial position Y is set to "Y2" (in this embodiment, Y2> Y1), and the axial position X is set to "0", respectively. Welding is done. That is, in the second overlay welding process, overlay welding is performed at the same axial position X (same row) as in the first overlay welding process. As a result, the second build-up portion 42 is formed so as to be laminated with respect to the first build-up portion 41. Further, the radial position Y is set to "Y2", which is larger than "Y1", in consideration of the height of the previously formed layer (first overlay portion 41). Further, as in the first overlay welding process, in the second overlay welding process, the welding torch 31 does not move in the radial direction and the axial direction of the second pipe 20, and is fixed at a fixed position. Welding is done at.

Further, in the second overlay welding process, unlike the first overlay welding process, overlay welding is performed with the axial inclination set to “none”. As shown in FIG. 7, the welding torch 31 is arranged parallel to the orthogonal plane P1 orthogonal to the axis C20 of the second pipe 20. As a result, overlay welding can be performed so that the welded metal is piled up high outward in the radial direction. According to this, the second overlay portion 42 can be laminated high without waste to secure the height of the second overlay portion 42, and by extension, the two-layer overlay portion (first overlay portion) having a high height can be secured. The ridge 41 and the second build-up portion 42) can be formed.

Further, in the second overlay welding step, overlay welding is performed so that it melts only in the first overlay portion 41, in other words, does not melt into the second pipe 20. As a result, the second build-up portion 42 can be laminated high without waste, and the height of the second build-up portion 42 can be secured.

As shown in FIG. 3, after the second overlay welding step is performed, the third overlay welding step (step S40) is performed. The third overlay welding step is a step of forming the third overlay portion 43 on the outer periphery of the insertion port 21. In the third overlay welding step, the outer periphery of the insertion port 21 (the portion in front of the first overlay 41 and the second overlay 42) is welded to the first overlay 41 and the first overlay. A build-up portion (third build-up portion 43) can be formed in a row adjacent to the two build-up portions 42.

In the third overlay welding step, as shown in FIGS. 5 and 8, overlay welding is performed with the axial inclination, the circumferential inclination, and the off-center set to “Yes”. Further, in the third overlay welding step, the radial position Y is set to "Y3" (in this embodiment, Y3 <Y1), and the axial position X is set to "X1", respectively. Welding is done. Since the radial position Y is set to "Y3" in this way, the welding torch 31 is fixed at a position closer to the outer periphery of the second pipe 20 than in the first overlay welding step. Further, since "X1" is set in the axial position X, the welding torch 31 is fixed at a position moved by X1 from the reference position toward the tip end side of the second pipe 20. Further, as in the first overlay welding process and the second overlay welding process, in the third overlay welding process, the welding torch 31 does not move in the radial direction and the axial center direction of the second pipe 20, and is constant. Welding is performed while being fixed at the position of.

In this way, by performing overlay welding with the axial position X set to "X1", as shown in FIG. 8, the position where the welding torch 31 is moved forward (first overlay portion 41). And another row of overlays can be formed on the front side of the second overlay 42). As a result, a plurality of overlay portions (from the first overlay portion 41 to the third overlay portion 43) can be formed in a plurality of rows in the front-rear direction, and the width of the build-up portion in the front-rear direction can be secured. Further, by forming the third built-up portion 43 adjacent to the front side of the previously formed rear built-up portion (first built-up portion 41 and second built-up portion 42), the rear side is formed. It is possible to form an inclined surface 43a that tilts forward from the overlay portion. In particular, in the present embodiment, by setting the axial inclination, a gentle inclined surface 43a can be easily formed on the third built-up portion 43.

Further, in the third overlay welding step, a penetration portion 53 is formed on the outer periphery of the insertion port 21 so as to overlap the penetration portion 51 formed in the first overlay welding step in the front-rear direction. By overlapping the blending portions 53 in this way, it is possible to eliminate the gaps between the front and rear blending portions 51 and 53 and secure the strength of the built-up portion.

As described above, in the first overlay welding step to the third overlay welding step, the cross-sectional shape is a protrusion by combining the overlay welding of a plurality of layers in the same row and the overlay welding to different rows. It forms a build-up portion that is one size larger than 22.

Further, according to the first overlay welding step to the third overlay welding step, the overlay portion (the first overlay portion) having a substantially trapezoidal shape in which the center of gravity is biased rearward in the side cross-sectional view, that is, a shape close to the protrusion 22. A third overlay 43) can be formed from the one overlay 41. The built-up portion is formed in a substantially trapezoidal shape with a side cross section in which the inclination angle D11 of the front inclined surface 43a is smaller than the inclination angle D12 of the rear inclined surface 41b (see FIG. 9).

Since the surface of the overlay portion is not flat (unevenness is formed or bent), the above-mentioned inclination angle D11 and inclination angle D12 are approximately estimated from the surface shape of the overlay portion. It can be thought of as the tilt angle of the tilted surface. However, when strictly controlling the shape of the built-up portion, the inclination angle D11 and the inclination angle D12 can be appropriately defined. For example, FIG. 9 shows an example of a method for defining the tilt angle D11 and the tilt angle D12.

In FIG. 9, the angle formed by the straight line L11 connecting the position P11 of the radial inner end portion of the front inclined surface 43a and the position P12 of the intermediate portion of the inclined surface 43a and the outer periphery of the insertion port 21 is inclined toward the front side. It is defined as the inclination angle D11 of the surface 43a. Further, the angle formed by the straight line L12 connecting the position P13 of the radial inner end portion of the inclined surface 41b on the rear side and the position P14 of the intermediate portion of the inclined surface 41b and the outer periphery of the insertion port 21 is the inclined surface on the rear side. It is defined as the inclination angle D12 of 41b. Further, the positions P12 and P14 are located apart from the outer periphery of the insertion port 21 in the radial direction by a predetermined distance (for example, 1.5 mm).

Further, in the present embodiment, the rear side (first overlay portion 41 and second overlay portion 42) is overlay welded, and then the front side (third overlay portion 43) is overlay welded. In this way, by performing overlay welding from the side opposite to the tip of the second pipe 20, it is possible to secure the height on the opposite side (rear side) and then perform overlay welding on the tip side. As a result, a gently inclined surface 43a can be formed on the tip side.

Further, since the rear built-up portion (first built-up portion 41 and second built-up portion 42) comes into contact with the lock ring 14 when preventing the pipe joint 1 from coming off, a load is applied when preventing the pipe joint 1 from coming off. easy. By first forming the overlay portion on the rear side where such a load is easily applied, the outer periphery of the insertion port 21 is surely melted (forms the penetration portion 51) when the overlay portion is formed, and the welding accuracy is achieved. Can be stabilized and stable strength can be ensured.

As shown in FIG. 3, after the third overlay welding step is performed, the processing step (step S50) is performed. In the processing step, the shape of the first overlay 41 to the third overlay 43 is formed by processing the third overlay 43 from the first overlay 41 (for example, cutting, grinding, etc.). Is a step of forming a protrusion 22 (see FIG. 9) on the outer periphery of the insertion port 21. In the processing step, the protrusion 22 having a desired shape is formed by removing a portion (machining allowance) unnecessary for the shape of the protrusion 22 from the build-up portion formed in the build-up welding step. The processing method in the processing process is not particularly limited.

As described above, in the present embodiment, the overlay portion (first overlay portion 41 to third overlay portion 43) having a shape close to the protrusion 22 is formed by the first overlay welding step to the third overlay welding step. Is forming. According to this, in the processing step, it is possible to reduce the processing allowance of the overlay portion (the shaded portion of each overlay portion shown in FIG. 9). Further, according to the present embodiment, unlike the conventional technique shown in FIG. 12, the protrusion 22 can be easily formed without using a substantially ring-shaped member.

Further, in the present embodiment, by adopting the CMT welding method from the first overlay welding process to the third overlay welding process, the amount of heat input can be reduced as compared with other welding methods (for example, arc welding method). can. As a result, the height of the first overlay portion 41 to the third overlay portion 43 can be secured. According to this, the number of weldings can be reduced as compared with the case where the overlay portion is formed by other welding having a relatively large amount of heat input. Further, according to the CMT welding method, it is possible to suppress the generation of spatter. This makes it possible to reduce the burden of work for removing spatter.

As described above, the method for forming the insertion port protrusion according to the present embodiment is described above on the outer periphery of the insertion port 21 of the second pipe 20 (tube) in the pipe joint 1 having the detachment prevention function using the protrusion 22. Insertion port for forming the protrusion 22 This is a method of forming the protrusion, and the welding torch 31 is provided with the tip of the insertion port 21 with respect to the orthogonal surface P1 (the surface orthogonal to the axial center C20 of the second pipe 20). It includes a overlay welding step (steps S20 and S40) in which overlay welding is performed on the outer periphery of the insertion port 21 by inclining it to the side.

With this configuration, the protrusion 22 can be easily formed. Specifically, the protrusion 22 for the detachment prevention function forms a relatively gentle front inclined surface 22b on the tip side of the insertion port 21, and is relatively steep on the side opposite to the tip of the insertion port 21. It is necessary to form the rear inclined surface 22a. By inclining the welding torch 31 toward the tip end side of the insertion port 21, the first overlay portion 41 and the third overlay portion 43 having relatively gentle inclined surfaces 41a and 43a on the tip end side of the insertion port 21 are formed. Can be formed. Thereby, the protrusion 22 having the front inclined surface 22b at a desired angle can be easily formed. Further, since it is easy to form the protrusion 22 having a desired shape, when the overlay portions 41 to 43 formed by welding are further processed, the processing allowance can be reduced.

Further, as described above, the method for forming the insertion port protrusion according to the present embodiment is the outer circumference of the insertion port 21 of the second pipe 20 (tube) in the pipe joint 1 having the detachment prevention function using the protrusion 22. A method for forming a protrusion 22 in the above, wherein the insertion port 21 is formed from a side opposite to the tip of the insertion port 21 in the axial direction (front-back direction) of the second pipe 20. It includes a overlay welding step (steps S20 to S40) in which overlay welding is performed using a welding torch 31 so as to form a plurality of rows of overlay portions 41 to 43 in order toward the tip end side.

With this configuration, an inclined surface 43a that is gently inclined from the previously formed first overlay 41 and second overlay 42 toward the surface of the second pipe 20 is formed. Can be done. This makes it possible to easily form a protrusion 22 having a relatively gentle front inclined surface 22b on the tip end side of the insertion port 21.

Further, in the overlay welding step, the first overlay 41 and the third overlay 43, which are adjacent to each other in the axial direction of the second tube 20, are integrated into the second tube 20 with portions 51 and 53. , Are formed so as to overlap each other.

With such a configuration, stable strength can be ensured.

Further, in the overlay welding step, when the first overlay 41 and the second overlay 42 of a plurality of layers are formed in the radial direction of the second pipe 20, the first overlay 41 (the plurality of layers) is formed. (One layer) is built-up welded so as to melt into the second pipe 20, and the second build-up portion 42 (the other layer of the plurality of layers different from the one layer) is It is built-up welded so as not to melt into the second pipe 20.

With such a configuration, it becomes easy to secure the heights of the first built-up portion 41 and the second built-up portion 42, and it is possible to easily secure a desired shape.

Further, in the overlay welding step, when the first overlay portion 41 is overlay welded, the welding torch 31 with respect to an orthogonal surface P1 (a surface orthogonal to the axis C20 of the second pipe 20). It is arranged so as to be inclined toward the tip end side of the insertion port 21.

With this configuration, it is possible to form the first build-up portion 41 having an inclined surface 41a (inclined surface on the tip end side of the insertion port 21) substantially perpendicular to the welding torch 31. As a result, it is possible to easily form the protrusion 22 having the front inclined surface 22b at a desired angle, and it is possible to easily secure the desired shape.

Further, in the overlay welding step, when the second overlay portion 42 is overlay welded, the welding torch 31 with respect to an orthogonal surface P1 (a surface orthogonal to the axis C20 of the second pipe 20). They are arranged so as to be parallel to each other.

With such a configuration, it becomes easy to secure the height of the second overlay portion 42, and it is possible to easily secure a desired shape.

Further, in the overlay welding step, when overlay welding is performed while rotating the second pipe 20 around the axis C20, the welding torch 31 rotates the second pipe 20 with respect to the vertical direction. It is arranged so as to incline toward the downstream side in the direction.
Further, in the overlay welding step, the welding torch 31 is arranged so as not to face the axial center C20 of the second pipe 20 when viewed from the axial direction of the second pipe 20. ..

With this configuration, it is possible to prevent the first build-up portion 41 to the third build-up portion 43 from being deformed (crushed in the direction of gravity) due to the influence of gravity, so that it is easy to secure a desired shape. can do.

The second pipe 20 according to the present embodiment is an embodiment of the pipe according to the present invention.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above configuration, and various modifications can be made within the scope of the invention described in the claims.

For example, the overlay welding is performed by the CMT welding method, but the method is not limited to this, and any welding method can be used. It is desirable that the welding method adopted for overlay welding is a welding method in which the amount of heat input to the second pipe 20 is relatively small. Thereby, it is possible to easily secure the height from the first overlay portion 41 to the third overlay portion 43. Such a welding method having a relatively small amount of heat input is not limited to the CMT welding method as in the present embodiment, and is another welding method in which the process of sending out the welding wire and the process of returning the welding wire are repeated, for example, AWP welding. It may be a method or the like. Further, the welding method adopted for overlay welding is not limited to the welding method having a relatively small amount of heat input, but is another welding method having a relatively large amount of heat input (for example, an arc welding method). May be good.

Further, when overlay welding a row adjacent to the front side with respect to the rear row as in the third overlay welding step of the present embodiment, the axial inclination is large (larger than the first overlay step). ) May. As a result, the overlay portion can be formed so that the height of the overlay portion in the front row (particularly, the height of the rear end portion) is high. As a result, the upper surface of the overlay portion laminated in the rear row and the overlay portion in the front row can be smoothly continuous.

Further, in the first overlay welding process to the third overlay welding process, the circumferential inclination and the off-center are set to "Yes", but the present invention is not limited to this, and for example, the circumferential inclination is set. And the off-center may be set to "None". Further, only one of the circumferential inclination and the off-center may be set to "Yes".

Further, in the first overlay welding step to the third overlay welding step, the second pipe 20 is assumed to rotate, but the present invention is not limited to this, and for example, the welding torch 31 is inserted into the insertion port 21. It may orbit the outside.

Further, in the present embodiment, the processing step is performed, but the present invention is not limited to this, and the processing step may not be performed. In the first modification shown in FIG. 10A, the protrusion 122 is formed by performing the first overlay welding step to the third overlay welding step of the present embodiment. According to the first modification, the cost required for the processing process can be reduced, and the manufacturing cost of the second pipe 20 can be reduced.

Further, in the present embodiment, one layer of the overlay portion (second overlay portion 42) is laminated on the first overlay portion 41, but the overlay portion laminated on the first overlay portion 41. The number of is not limited to this, and can be set arbitrarily. In the second modification shown in FIG. 10B, the number of built-up portions laminated on the first built-up portion 241 is increased from one layer to two layers. In the second modification, the second build-up portion 242 and the third build-up portion 243 are laminated on the first build-up portion 241. In the second modification, the second build-up portion 242 and the third build-up portion 243 are formed (laminated), and then the fourth build-up portion 244 is formed. In this way, by increasing the number of the built-up portions to be laminated, it is possible to easily secure the height of the built-up portions. Thereby, the protrusion 222 having a larger radial width than the protrusion 22 of the present embodiment can be easily formed.

Further, in each row, it is not necessary to form a plurality of built-up portions so as to be laminated. The third modification shown in FIG. 11A shows an example of a configuration in which a plurality of built-up portions are not laminated. In the third modification, the build-up portion is not laminated on the first build-up portion 341, and the second build-up portion 342 is formed so as to be adjacent to the front of the first build-up portion 341. With such a configuration, it is possible to easily form a protrusion 322 having a radial width smaller than that of the protrusion 22 of the present embodiment.

Further, in the present embodiment, two rows of overlay portions (the first overlay portion 41 and the second overlay portion 42 on the rear side and the third overlay portion 43 on the front side) are formed in the front and rear, but the overlay is formed. The number of rows forming the portions back and forth is not limited to two rows, and may be three or more rows. In the fourth modification shown in FIG. 11B, the number of rows forming the overlay portion is increased from two rows to three rows. In the fourth modification, the build-up portions 441 to 443 in the three rows are not laminated with the build-up portions. Further, in the fourth modification, with the formation of the three rows of built-up portions 441 to 443, the three rows of fused portions are formed so as to be lined up in the front-rear direction, and the fused portions adjacent to the front and rear are formed so as to overlap each other. (Not shown). It should be noted that the overlay portion does not necessarily have to be formed in a plurality of rows in the front-rear direction, and may be formed in only one row, for example.

The number of overlaid portions and the number of rows forming the overlaid portions in the front-rear direction can be appropriately changed according to the shape of the protrusions. For example, in the present embodiment and the modified examples (first modified example to the fourth modified example), the overlay portion having a desired shape (and by extension, the protrusion 22) is formed by the plurality of overlay portions formed by the plurality of overlay welding steps. ) Is formed, but it is also possible to form the protrusion 22 by the overlay formed by one overlay welding step, depending on the shape of the protrusion 22. For example, it is also possible to perform only the first overlay welding step (see FIG. 6) and form the protrusion 22 only by the first overlay portion 41.

Further, in the present embodiment and the modified examples (first modified example to the fourth modified example), the built-up portion is not laminated on the built-up portion on the front side (second row and subsequent rows), but the shape of the protruding portion is formed. Depending on the situation, for example, the overlay portion may be laminated on the overlay portion on the front side. In this way, when laminating a plurality of overlay portions in a plurality of rows, it is desirable to laminate all the required number of overlay portions in one row and then perform welding in the other rows. With such a configuration, the number of movements of the welding torch 31 in the front-rear direction (the axial direction of the second pipe 20) can be reduced, and the overlay welding process can be simplified.

Further, in the present embodiment, the second build-up portion 42 is assumed to be melted only in the first build-up portion 41, but the present invention is not limited to this, and the first build-up portion 41 and the second pipe 20 are not limited thereto. It may be one that melts into the outer periphery of the.

Further, in the present embodiment, the front and rear melting portions 51 and 53 are formed so as to overlap each other, but the present invention is not limited to this, and the melting portions 51 and 53 may be separated from each other.

Further, in the present embodiment, the slip-on type pipe joint 1 as shown in FIG. 1 is exemplified, but the present invention is not limited to the slip-on type. That is, the present invention can be applied to other types of pipe joints (for example, those using push wheels) as long as they are pipe joints having a detachment prevention function using a protrusion.

1 Pipe fitting 20 Second pipe (pipe)
21 Insertion port 31 Welding torch P1 Orthogonal plane (plane orthogonal to the axis of the pipe)

Claims (7)

It is a method of forming an insertion port protrusion in which a protrusion is formed by an overlay weld formed by overlay welding on the outer periphery of a pipe insertion port in a pipe joint having a detachment prevention function using a protrusion. hand,
Overlay welding is performed using a welding torch so as to form a plurality of rows of overlay portions in order from the side opposite to the tip of the insertion slot toward the tip end side of the insertion slot in the axial direction of the pipe. Including overlay welding process
In the overlay welding process,
When forming the first row of overlays located on the side opposite to the tip of the insertion slot among the plurality of rows of overlays in contact with the outer peripheral surface of the pipe, the welding torch is the pipe. It is arranged so as to be inclined toward the tip end side of the insertion port with respect to the plane orthogonal to the axis.
The overlay in the first row is
It has inclined surfaces on the tip side of the insertion slot and on the side opposite to the tip of the insertion slot, respectively.
The inclined surface on the tip end side of the insertion slot is formed more gently than the inclined surface on the opposite side to the tip end of the insertion slot.
How to form the protrusion of the insertion port. In the overlay welding process,
When forming the plurality of rows of built-up portions in contact with the outer peripheral surface of the pipe, the welding torch is arranged so as to be inclined toward the tip end side of the insertion port with respect to the plane orthogonal to the axis of the pipe. ,
The method for forming an insertion port protrusion according to claim 1. In the overlay welding process,
The integrated portions of the overlay portions adjacent to each other in the axial direction of the pipe are formed so as to overlap each other.
The method for forming an insertion port protrusion according to claim 1 or 2. In the overlay welding process,
When forming a multi-layered overlay in the radial direction of the pipe,
One of the plurality of layers is overlaid welded so as to melt into the pipe.
Of the plurality of layers, the other layer different from the one layer is overlaid welded so as not to melt into the pipe.
The method for forming an insertion port protrusion according to any one of claims 1 to 3 . In the overlay welding process,
The welding torch is
When the other layers are overlaid welded, they are arranged so as to be parallel to the plane orthogonal to the axis of the pipe.
The method for forming an insertion port protrusion according to claim 4 . In the overlay welding process,
When overlay welding while rotating the pipe around the axis
The welding torch is
Arranged so as to incline toward the downstream side in the rotation direction of the pipe with respect to the vertical upper direction.
The method for forming an insertion port protrusion according to any one of claims 1 to 5. In the overlay welding process,
The welding torch is
Arranged so as not to face the axial center of the tube when viewed from the axial direction of the tube.
The method for forming an insertion port protrusion according to any one of claims 1 to 6.

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