JP7186140B2 - Automatic overlay welding method for curved pipes - Google Patents

Description

The present invention relates to an automatic build-up welding method for bent pipes.

Overlay welding of pipes is welding in which the surfaces of pipes are covered with weld metal, unlike normal welding that joins pipes together. For this reason, build-up welding of pipes forms a thicker layer on the surface of the pipe than thermal spraying or plating, and the layer and the pipe are metallurgically bonded, so it is effective in increasing the durability of the pipe. is.

When the object of build-up welding is a straight pipe, the axial direction of the straight pipe is a straight line, so the weld line along this axial direction is also a straight line, which facilitates the automation of the build-up welding. On the other hand, when the object of build-up welding is a bent pipe, the axial direction of the bent pipe is curved, so the weld line along this axial direction is also curved, making it difficult to automate build-up welding.

On the other hand, conventionally, there has been proposed a method of automated build-up welding to an object having a curved weld line (see, for example, Patent Document 1).

Japanese Patent No. 6303673

By the way, in the method described in Patent Literature 1, since the welding line of overlay welding is a very simple curve of a perfect circle, automation is relatively easy. However, since a bent pipe generally has a complicated curve in the axial direction, automated build-up welding by the method described in Patent Document 1 is impossible for such a bent pipe.

It is conceivable to input the positional information of the weld line along the axial direction of the bent tube into the current automatic overlay welding device in advance, and to perform automatic overlay welding according to the input positional information. However, this method can result in excessive or insufficient overlap of adjacent weld beads, depending on the automatic build-up welding conditions, resulting in improper build-up welds.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an automatic build-up welding method for a bent pipe that can perform appropriate automatic build-up welding on the bent pipe.

In order to solve the above-mentioned problems, an automatic build-up welding method for a bent pipe according to a first invention includes an arrangement step of arranging the bent pipe sideways;
a side surface welding step of placing a weld bead by automatic build-up welding along the axial direction of the bent pipe on the side surface of the bent pipe arranged sideways in the arranging step;
a distance calculation step of calculating the distance from the upper toe of the weld bead placed on the bend to a reference height parallel to the axis of the bend;
As the distance calculated in the distance calculation step increases/decreases, the welding conditions are adjusted so that the width of the next adjacent weld bead increases/decreases. and a side upper surface welding step in which fill welding is performed.

Further, in the automatic overlay welding method for curved pipes according to the second invention, the adjustment of the welding conditions in the side and upper surface welding step of the automatic overlay welding method for curved pipes according to the first invention is calculated in the distance calculation step. In this method, the welding conditions are selected from the welding condition selection table according to the distance.

Further, in the automatic build-up welding method for curved pipes according to the third invention, the automatic build-up welding in the side and upper surface welding process of the automatic build-up welding method for bent pipes according to the first or second invention is performed by weaving. I,
The method wherein the welding conditions adjusted in the side upper surface welding process include the welding speed along the axial direction of the bend and the frequency and amplitude of the weaving.

In addition, the automatic build-up welding method for a bent pipe according to a fourth aspect of the invention is such that the automatic build-up welding in the side and upper surface welding step of the automatic build-up welding method for a bent pipe according to any one of the first to third inventions is performed. , the width of the placed weld bead is adjusted on the upper toe side of the weld bead.

A bent pipe automatic build-up welding method according to a fifth aspect of the present invention is the automatic bend pipe build-up welding method according to any one of the first to fourth inventions, wherein the bent pipe is placed horizontally in the placement step. a gap calculation step of calculating the gap between two weld beads each adjacent to the weld bead to be placed along the vertex of the
As the gap calculated in the gap calculation step is larger/smaller, the welding conditions are adjusted so that the width of the weld bead placed next on the vertex is larger/smaller, and the automatic wall thickness is adjusted along the axial direction of the bent pipe. and a vertex welding step of performing fill welding.

Further, in the automatic overlay welding method for curved pipes according to the sixth invention, the adjustment of the welding conditions in the vertex welding process of the automatic overlay welding method for curved pipes according to the fifth invention is calculated in the gap calculation step. In this method, the welding conditions are selected from the welding condition selection table according to the interval.

Further, in the automatic build-up welding method for a bent pipe according to the seventh invention, the automatic build-up welding in the vertex welding process of the automatic build-up welding method for a bent pipe according to the fifth or sixth invention is performed by weaving. ,
The method wherein the welding conditions adjusted in the apex welding process include the welding speed along the axial direction of the bend and the frequency and amplitude of the weaving.

According to the automatic build-up welding method for a bent pipe, since a weld bead having an appropriate width is placed in the side upper surface welding process after the distance calculation process, suitable automatic build-up welding can be performed on the bent pipe.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of a bent pipe on which automatic build-up welding is performed by the automatic build-up welding method for bent pipes according to the embodiment of the present invention; It is sectional drawing of the same bending pipe. It is the photograph which image|photographed the bending pipe partially by planar view. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view showing a state in which a bent pipe used in an automatic build-up welding method for a bent pipe according to an embodiment of the present invention is horizontally arranged; It is a perspective view of a bent tube on which a weld bead is placed in a side welding process in the same automatic overlay welding method. It is a perspective view which shows the distance from the upper toe of the same weld bead to the vertex of a bent pipe. It is a left side view of the bent pipe on which the same welding bead is placed. It is a perspective view which shows the state which detects the upper toe of the same weld bead with a sensor. FIG. 4 is a left side view of a bent pipe on which a weld bead is placed in a side upper surface welding process in the same automatic overlay welding method; It is sectional drawing which shows the space|interval calculated by the space|interval calculation process in the same automatic build-up welding method. FIG. 11 is a plan view of FIG. 10; It is a schematic diagram of an automatic build-up welding device using the same automatic build-up welding method.

An automatic build-up welding method for bent pipes according to an embodiment of the present invention will be described below with reference to the drawings.

First, a bent pipe subjected to automatic build-up welding by the automatic build-up welding method will be described.

As shown in FIG. 1, the bent pipe P is a pipe whose axis O is bent and includes all pipes other than straight pipes. As shown in FIGS. 2 and 3, automatic build-up welding is performed on the bent pipe P so that the entire outer peripheral surface in a predetermined range is covered with weld beads B1 to B9 along the direction of the axis O. there is In the present embodiment, the upper toe b of the weld beads B1 to B8 does not refer to the uppermost end line of the weld beads B1 to B8, but the outer peripheral surface of the bend pipe P of the weld beads B1 to B8. It refers to the uppermost edge line in the part that touches the Although the upper toe b is indicated by a dot in FIG. 2, which is a cross-sectional view, it has a length along the direction of the axis O because it is an end line.

Next, the automatic build-up welding method will be described.

First, as an arrangement step included in the automatic build-up welding method, as shown in FIG. 4, the bent pipe P before automatic build-up welding is carried out is arranged sideways on the upper surface of the stand 30 or the like. Here, arranging the bent pipe P sideways means arranging the bent pipe P such that the axis O of the bent pipe P is less than ±45° with respect to the horizontal. In order to improve the accuracy of automatic build-up welding performed on the bent pipe P, the bent pipe P is preferably arranged so that its axis O is horizontal (substantial error is allowed). Here, the substantial error is about ±0.1°. In order to keep the error within this range, the position of the bending pipe P is adjusted by a spacer 32 or the like. It is preferable that the bent pipe P arranged laterally is held by a holder 31 or the like so as not to move during automatic build-up welding.

Next, as a side welding step provided in the automatic overlay welding method, as shown in FIG. Weld beads B1 and B2 are placed by automatic overlay welding. Here, the weld beads B1 and B2 placed in the side welding process are not necessarily at the same height as the axis O of the bent pipe P, and may be vertically deviated from this height. Although FIG. 5 shows only the weld beads B1 and B2 placed in the side welding process, the weld beads are not limited to these. The weld beads may be, for example, weld beads B1 to B6 excluding weld bead B9 at vertex T of bent pipe P and weld beads B7 and B8 adjacent thereto, as indicated by symbols B1 to B6 in FIG. Alternatively, it may be placed in the side welding step. The gist of the present invention is not the side welding process but the side upper surface welding process that has undergone the distance calculation process described later. A larger number of beads is also preferable for improving the quality of automatic overlay welding.

Next, as a distance calculation step provided in the automatic build-up welding method, as shown in FIGS. A distance W to a reference height parallel to the axis O (vertex T of the bend P in FIGS. 6 and 7) is calculated. As shown in FIG. 7, the calculated distance W fluctuates according to the vertical fluctuation of the top toe b of the weld bead B1, and therefore has a large value _WL and a small value _WS . The distance W need not be calculated continuously over a predetermined range of the bent pipe P, and may be intermittently calculated at a certain pitch (for example, several mm to several hundred mm). Here, the reference height parallel to the axis O of the bent pipe P is not particularly limited. It is preferable because it can be easily determined by detecting at . Further, when the bent pipe P is arranged at a known angle such as horizontally, the plane of the known angle may be set as a reference height parallel to the axis O of the bent pipe P. For example, if the bend P is placed on the upper surface of the horizontal platform 30, the reference height parallel to the axis O of the bend P is the upper surface of the horizontal platform 30 (i.e., the bottom point of the bend P). ). As shown in FIG. 8, the upper toes b of the weld beads B1 and B2 placed on the bent pipe P are detected by a sensor 13, for example. The upper toe b of the weld bead detected by the sensor 13 can be calculated with the reference height parallel to the axis O of the bent pipe P when it is acquired in the sensor coordinate system, which is the coordinates unique to the sensor 13. Converted to coordinate system.

Next, as a side _upper surface welding process provided in the automatic overlay welding method, as shown in _FIG . Welding conditions are adjusted so that the width of the weld bead B3 is large _BL /small _BS , and automatic build-up welding is performed along the direction of the axis O of the bent pipe P. As shown in FIG. Although FIG. 9 shows only the weld bead B3 placed in the side upper surface welding process, it is not limited to this. The weld beads placed in the side upper surface welding process are, as indicated by symbols B3 to B8 in FIG. It is preferable that the weld beads B3 to B8 are excluded. In this case, in order to place these weld beads B3 to B8 on the bent pipe P, the side upper surface welding process after the distance calculation process is repeated by the number of times.

It is preferable that the adjustment of the welding conditions in the side upper surface welding step selects the welding conditions from the welding condition selection table according to the distance W calculated in the distance calculating step. By using the welding condition selection table to select the appropriate welding conditions, it is sufficient to select the appropriate welding conditions and no complicated calculations are required, making it more suitable for automation.

The automatic build-up welding in the side upper surface welding step is preferably performed by weaving. This is because weaving makes it possible to easily adjust the width of the weld beads B3 to B8 while keeping the quality of the weld beads B3 to B8 uniform. The parameters of the welding conditions that affect the width and quality of the weld beads B3-B8 are the welding speed along the axis O of the bend P, the weaving frequency (reciprocations per second) and the amplitude. To increase/reduce the width of the weld beads B3 to B8 by the weaving, the amplitude of the weaving is increased/reduced as a welding condition. If the amplitude of the weaving is increased/decreased, the welding speed along the axis O direction of the bend P is decreased/increased and the frequency of the weaving is decreased in order to make the quality of the weld beads B3-B8 uniform. / Make more. The amplitude of this weaving is preferably adjusted on the upper toe side of the weld beads B3 to B8 placed by the weaving. This is because the quality of the boundaries between the weld beads B3 to B8 and the weld beads B1 to B6 adjacent below the weld beads B3 to B8 becomes uniform along the direction of the axis O of the bent pipe P. .

Table 1 below shows an example of a welding condition selection table used to select appropriate welding conditions when automatic build-up welding is performed by weaving in the side upper surface welding process.

Such welding condition selection tables may be the same or different for the weld beads B3 to B8. Weld beads B3, B5, and B7 (B4, B6, and B8) are different in the direction of gravity received during automatic build-up welding. It is preferable to use different welding condition selection tables suitable for B7 (B4, B6, B8).

Next, as an interval calculation step included in the automatic overlay welding method, as shown in FIG. Interval G between the two weld beads B7 and B8 to be welded is calculated. When the sensor 13 is used in the distance calculation step, the sensor 13 is also used in the interval calculation step to detect the top toes b of the two weld beads B7 and B8, in order to simplify the configuration. is also preferred. As shown in FIG. 11, the calculated gap G fluctuates according to the vertical fluctuation of the top toes b of the two weld _beads B7 and B8 _. be. The interval G need not be calculated continuously over a predetermined range of the bent pipe P, and may be intermittently calculated at a certain pitch (for example, several mm to several hundred mm).

Next, as the vertex welding process included in the automatic overlay welding method, the larger _GL /smaller _GS the gap G calculated in the gap calculating process is, the larger the width of the weld bead B9 placed at the vertex T is. / is adjusted to be small, and automatic build-up welding is performed along the direction of the axis O of the bent pipe P.

In adjusting the welding conditions in the apex welding process, the welding conditions can be selected from the welding condition selection table in accordance with the gap G calculated in the gap calculating process, similarly to the adjustment of the welding conditions in the side upper surface welding process. preferable. By using the welding condition selection table to select the appropriate welding conditions, it is sufficient to select the appropriate welding conditions and no complicated calculations are required, making it more suitable for automation.

Automatic build-up welding in the apex welding process is also preferably performed by weaving for the same reason as in the side upper surface welding process. Welding condition parameters that affect the width and quality of the weld bead B9 are also the welding speed along the axis O direction of the bent tube P, the weaving frequency (round trip per second number) and amplitude.

Table 2 below shows an example of a welding condition selection table used to select appropriate welding conditions in the vertex welding process.

As described above, the upper half of the bent pipe P is automatically welded. Then, in order to perform automatic build-up welding also on the lower half of the bent pipe P, after the bent pipe P is turned upside down, the above-mentioned automatic Perform the build-up welding method. As a result, the bent pipe P is entirely covered with a weld bead extending in the direction of the axis O of the outer peripheral surface in a predetermined range.

As described above, according to the automatic build-up welding method for the bent pipe P, the welding beads B3 to B8 having appropriate widths are placed in the side upper surface welding process after the distance calculation process. Welding can be performed.

In addition, the use of the welding condition selection table makes it more suitable for automation, so that more appropriate automatic build-up welding to the bent pipe P can be performed.

Furthermore, since the automatic overlay welding is performed by weaving and appropriate parameters of the welding conditions are adjusted, the quality becomes more uniform, and as a result, more appropriate automatic overlay welding to the bend pipe P can be performed. .

In addition, the width of the weld beads B3 to B8 is adjusted on the upper toe side of the weld bead in the side upper surface welding process, so that the weld beads B3 to B8 and the weld beads B1 to B6 adjacent below. Since the quality of is uniform, more appropriate automatic build-up welding to the bent pipe P can be performed.

In addition, since the quality of the weld bead B9 placed at the vertex T becomes uniform by the vertex welding process, more appropriate automatic build-up welding to the bent pipe P can be performed.

Next, an automatic build-up welding apparatus for performing the above-described automatic build-up welding method for the bent pipe P will be described.

As shown in FIG. 12, this automatic build-up welding apparatus 10 includes an automatic build-up welding robot 11 that performs automatic build-up welding, and a control panel 21 that controls the automatic build-up welding.

The automatic overlay welding robot 11 has a welding torch 12 that places the weld beads B1 to B9 on the outer peripheral surface of the bent pipe P by automatic overlay welding, and a sensor 13 that detects the upper toes b of the weld beads B1 to B8. . In addition, the automatic overlay welding robot 11 includes a slide structure 14 that slidably moves the welding torch 12 and the sensor 13 in the longitudinal direction of the bent pipe P (main direction of the axis O direction of the bent pipe P), and an articulated structure 15 for directing the welding torch 12 and the sensor 13 toward the desired outer peripheral surface of the bent pipe P.

The control panel 21 includes a sensor information input unit 22 to which information detected by the sensor 13 is input, and information in the sensor coordinate system acquired by the sensor 13 to the coordinate system of the automatic overlay welding robot 11. It has a coordinate system conversion unit 23 for conversion and a CAD data input unit 24 for inputting three-dimensional CAD data of the bent pipe P as the coordinate system of the automatic overlay welding robot 11 .

Further, the control panel 21 obtains a reference height (for example, a vertex T) parallel to the axis O of the bent pipe P from the three-dimensional CAD data of the bent pipe P, and determines the height of the weld bead placed on the bent pipe P. It has a distance calculator 25 for calculating the distance W from the upper toe b to the reference height parallel to the axis O of the bent pipe P.

Further, the control panel 21 has a gap calculator 26 for calculating the gap G between the two weld beads B7 and B8 adjacent to the weld bead B9 to be placed along the vertex T of the bent pipe P.

In addition, the control panel 21 has a welding condition selection table 27 that selects appropriate welding conditions for automatic overlay welding according to the distance W and the gap G calculated by the distance calculator 25 and the gap calculator 26, respectively. and a welding instruction unit 28 for instructing the automatic overlay welding robot 11 to perform automatic overlay welding under the welding conditions selected from the welding condition selection table 27 .

As described above, according to the automatic build-up welding apparatus 10, the above-described automatic build-up welding method for the bent pipe P is performed, so that the same effects as those of the automatic build-up welding method can be obtained.

By the way, in the above embodiment, the order of placing the weld beads by automatic overlay welding is B1, B2, B3, B4, B5, B6, B7, B8, and B9 shown in FIG. alternately with the side), but it may be in the order of B1, B3, B5, B7, B2, B4, B6, B8, B9 (that is, after finishing the construction of the upper left side, construct the upper right side). , or vice versa (i.e., finish construction of the upper right side and then construct the upper left side).

Further, in the above embodiment, the welding condition selection table 27 is used, but other means such as calculation formulas may be used to select the welding conditions.

Furthermore, in the above embodiment, the automatic overlay welding is described as weaving, but the present invention is not limited to this, and any automatic overlay welding capable of adjusting the width of the weld bead may be used.

In addition, in the drawings for explaining the above-described embodiments, the outer peripheral surface of the bent pipe P is illustrated as being a perfect circle, but it may be other shapes such as an ellipse or a square.

Further, in the above-described embodiment, the distance W calculated by the distance calculation step and the distance calculation unit 25 was not described as either the straight-line distance or the distance along the outer peripheral surface of the bent pipe P. Either is fine. Of course, the distance W is preferably a distance along the outer peripheral surface of the bent pipe P in order to improve the quality of automatic build-up welding.

Moreover, the above embodiment is an example in all respects and is not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims. Of the configurations described in the above embodiments, the configuration other than the configuration described as the first invention in "Means for Solving the Problems" is an arbitrary configuration, and can be deleted and changed as appropriate.

P bent tube O axis W distance G interval T vertex 10 automatic overlay welding device 11 automatic overlay welding robot 12 welding torch 13 sensor 21 control panel 25 distance calculator 26 interval calculator 27 welding condition selection table

Claims (7)

an arranging step of arranging the bent pipe sideways;
a side surface welding step of placing a weld bead by automatic build-up welding along the axial direction of the bent pipe on the side surface of the bent pipe arranged sideways in the arranging step;
a distance calculation step of calculating the distance from the upper toe of the weld bead placed on the bend to a reference height parallel to the axis of the bend;
As the distance calculated in the distance calculation step increases/decreases, the welding conditions are adjusted so that the width of the next adjacent weld bead increases/decreases. A method for automatic build-up welding of a bent pipe, characterized by comprising a side upper surface welding step in which build-up welding is performed. 2. The automatic build-up welding of bent pipe according to claim 1, wherein the adjustment of the welding conditions in the side upper surface welding step selects the welding conditions from the welding condition selection table according to the distance calculated in the distance calculation step. Method. Automatic overlay welding in the side upper surface welding process is performed by weaving,
3. The bent pipe according to claim 1 or 2, wherein the welding conditions adjusted in the side upper surface welding process include a welding speed along the axial direction of the bent pipe and the frequency and amplitude of the weaving. Automatic overlay welding method. 4. The automatic bending pipe according to any one of claims 1 to 3, wherein the automatic overlay welding in the side upper surface welding process adjusts the width of the weld bead to be placed on the upper toe side of the weld bead. Overlay welding method. an interval calculation step of calculating an interval between two weld beads adjacent to the weld bead to be placed along the vertex of the bent pipe arranged laterally in the placement step;
As the gap calculated in the gap calculation step is larger/smaller, the welding conditions are adjusted so that the width of the weld bead placed next on the vertex is larger/smaller, and the automatic wall thickness is adjusted along the axial direction of the bent pipe. The automatic build-up welding method for a bent pipe according to any one of claims 1 to 4, further comprising a vertex welding step of performing build-up welding. 6. The automatic build-up welding method for a bent pipe according to claim 5, wherein the adjustment of the welding conditions in the apex welding step selects the welding conditions from the welding condition selection table according to the gap calculated in the gap calculating step. . Automatic overlay welding in the vertex welding process is performed by weaving,
7. The automatic welding of pipe bends according to claim 5 or 6, wherein the welding conditions adjusted in the apex welding process include the welding speed along the axial direction of the pipe bend and the frequency and amplitude of the weaving. Overlay welding method.

Images