JP2007090390A - Corrugated web girder welding method - Google Patents

Abstract

A good weld bead appearance is easily obtained.
In a corrugated web girder welding method for fillet welding a corrugated web plate 12 and a flange plate 14 of a corrugated web girder 10, welding torches 23, 25 of two automatic welding means 22, 24 are provided. Are arranged toward the same position in the substantially center of the parallel portion of the corrugated web, and welding is started at the same time, proceeding in the opposite directions from the same molten pool, without stopping each welding arc, It welds to the following parallel part E through an inclination part and the following circular arc part.
[Selection] Figure 3

Description

  The present invention relates to a corrugated web girder welding method for fillet welding a corrugated web plate and a flange plate of a corrugated web girder, and in particular, when corrugated steel web bridges of steel bridges are constructed in a factory. The present invention relates to a method for welding corrugated web girders capable of easily obtaining a good weld bead appearance.

  When the corrugated steel web bridge of the steel bridge is constructed in the factory, the fillet weld (also referred to as neck welding) between the corrugated web plate 12 and the flange plate 14 of the corrugated web girder 10 is generally bent as shown in FIG. Members are installed in a state where the corrugated web plate 12 is erected (hereinafter referred to as a standing construction method), and fillet welding is performed.

  The construction sequence of this standing construction method is, for example, as follows.

  (1) The corresponding member is carried in with the web plate 12 and the flange plate 14 being tack-welded. At this time, accessories (an angle 16 and a reinforcing bar) embedded in the concrete at the time of field installation are already delivered to the flange plate 14 while being welded to the outside (the side opposite to the web plate 12).

  (2) Although the member is arranged with the flange surface on one side facing down, it is fixed by avoiding the accessory (16).

  (3) Weld the lower fillet welds (downward horizontal fillet welds / both sides).

  (4) After welding is completed, the member is reversed and the construction is performed in the same manner as (2) and (3).

  In addition, although it is not a corrugated web girder, the welding method of the hull outer plate which is similarly complicated shape is described in patent document 1, and the automatic welding machine which drive | works a box-shaped cross-section steel structure on a rail is described. Patent Document 2 describes an automatic welding apparatus that uses and welds a pipe intersection using an articulated robot, and describes a control apparatus for welding using a plurality of welding robots. A control method is described in Patent Document 4.

Japanese Patent Laid-Open No. 7-9128 JP 2002-1535 A JP-A-10-58139 JP 2001-273022 A

  However, in the standing construction method, since the angle member 16 and the reinforcing bar are attached to the flange plate 14, when distributing and fixing the member upright, these must be fixed to avoid protrusions, It takes a lot of work time. Further, there are many web girder heights H exceeding 2 m, and fixing work and welding work become dangerous work, and it is necessary to pay close attention to safety.

  For this reason, the horizontal installation method in which the corrugated web plate 12 is placed horizontally rather than the vertical installation method generally eliminates the need for fixing the members and greatly improves safety. Therefore, advanced construction skills are required in semi-automatic welding. In addition, if the horizontal part and the inclined part are welded separately, a bead joint is generated at the start / end part connecting the respective weld points, and the seam treatment is smoothed to pass the appearance inspection of the weld bead. There was a problem that it was necessary to finish. That is, in welding construction in the bridge industry, discontinuous beads are not preferred, so in general, when a bead seam occurs, it is necessary to perform rework after welding, which requires a lot of labor and time. Generated and contributed to an increase in production costs.

  On the other hand, none of the techniques described in Patent Documents 1 to 4 are suitable for welding corrugated web girders as they are.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a method for welding corrugated web girders capable of easily obtaining a good weld bead appearance.

  The present invention relates to a welding method of a corrugated web girder for welding fillet at a joint between a corrugated web plate and a flange plate of a corrugated web girder, and includes a welding torch of two automatic welding means (welding robot and automatic welding machine). Arranged toward the same position in the center of the parallel part of the corrugated web, start welding at the same time, proceed in the opposite direction from the same molten pool, without stopping each welding arc, This problem is solved by welding to the next parallel part through the part and the next arc part.

  Further, by performing the welding with the corrugated web plate placed horizontally, the fixing operation of the member is unnecessary, the working time is shortened, and the safety is improved.

  Further, the welding is performed from the peak parallel part of the corrugated web to the valley parallel part.

  In addition, the welding is performed in a multi-layered manner so that it can cope with a case where the fillet leg length is long.

  Also, in the multi-layer welding, the welding trajectory control method is used to store the first layer scanning trajectory, and for the second and subsequent layers, the shift amount of the target position of the torch is added to the first layer welding tracing trajectory. In this way, appropriate welding copying can be performed even in multi-layer welding.

  In the multi-layer welding, at least the first layer is subjected to rotating arc welding that rotates the torch so that appropriate multi-layer welding can be performed.

  Also, the end position of the multi-layer welding is shifted for each pass and cascaded so that the bead seam becomes inconspicuous.

  Further, the welding is repeated in the longitudinal direction of the corrugated web plate so that the bead joint is generated at the welding end portion, so that the bead joint can be welded cleanly over the entire length.

  In the present invention, as shown in FIG. 2, since the welding start points S of the two welding torches are substantially the same, two pools formed when two arcs are generated are combined into one pool. The maximum advantage can be obtained. That is, when the pool is made into one pool, there is no weld bead joint, and a smooth weld bead is obtained at the time of arc start, which looks like one continuous weld line. This eliminates the need for rework at the start point S.

  In particular, as shown in FIG. 2, in the method in which the corrugated web plate 12 is placed horizontally, the fixing operation of the members is generally unnecessary, and the safety is greatly improved. If the corrugated web plate 12 is placed horizontally, the welding posture changes from moment to moment. However, if a construction method is adopted in which welding is stopped and the welding conditions are changed in accordance with the change in the welding posture, Many seams are generated, and rework is required. Therefore, automatic welding means that can adjust the welding conditions in response to changes in the welding position from moment to moment, for example, the movement of the torch along the welding line and the welding conditions are controlled by a fixed sequence, and the same welded portion is repeatedly Welding robots that can weld to various workpiece shapes (for example, multiple welding) that set information such as welding members and welding conditions from an automatic welder that performs welding and a host controller, and perform welding using a multi-axis robot. It is desirable to use a joint welding robot.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In the first embodiment of the present invention, as shown in FIG. 3, the articulated twin welding robots 22 and 24 that can move in the horizontal direction on the robot slide shaft 20 and can perform two cooperative operations (for example, six axes) are provided. Is used to implement the present invention. In the figure, 23 and 25 are welding torches of the welding robots 22 and 24, respectively.

  At the time of construction, as shown in the procedure of FIG. 4, first, the corrugated web plate 12 and the flange plate 14 are temporarily attached with the distribution material of step 100, as shown in FIG.

  Next, in step 102, the robot reads the design drawing of the corrugated web plate 12 and inputs a weld line.

  Next, in step 104, the two welding robots 22 and 24 perform, for example, several points of wire touch sensing before welding, as shown in FIG. 5, and use the welding wire itself as a contact, The position of the base material is detected from the presence or absence of contact between the wire and the base material. Then, an assembly error or the like of the member shape is detected, and the weld line information read in step 102 is corrected. Also, in order to correct the error of the coordinate axes of the two welding robots 22 and 24, the same point is sensed and corrected.

  Next, the routine proceeds to step 106, where the first layer welding is performed. Specifically, as shown in FIG. 3, the welding arc points of the two welding robots 22 and 24 are close to each other in the vicinity of the center of the wave, and thereafter, as illustrated in FIG. The electrode nozzle 30 having the welding wire 34 that is fed to the center of the power supply tip and is eccentric by a predetermined amount at the tip of the energizing tip 32 is rotated by the motor 36 so that the arc at the tip of the wire rotates on the molten pool 38. Arc start (welding start) is simultaneously performed by the high-speed rotating arc welding method, and welding is advanced in the opposite directions. As a result, since the weld pool is pooled at the welding start point S, the weld bead seam is eliminated, and a smooth weld bead is obtained at the arc start point S.

  Thereafter, as shown in FIG. 2, while changing the welding conditions (welding current, arc voltage, welding speed, torch angle, etc.) at each welding part, the parallel part (referred to as a mountain parallel part) 12A To the upper arc portion 12B, the inclined (downward) straight portion 12C, the lower arc portion 12D, and the valley parallel portion 12E. At this time, in the inclined straight portion 12C, it is necessary to hold the molten pool with the arc pressure so that the molten pool does not sag due to gravity, and a welding condition combined with bead formation is selected. Then, the welding is stopped at the appropriate time of the valley parallel part 12E.

The dimensions of the corrugated web plate 12 are as shown in FIG. 7, and examples of initial layer welding conditions when a 1.2 mmφ solid wire is used as the welding wire 34 and Ar—CO ₂ mixed gas is used as the shielding gas are shown in Table 1. Show.

  At this time, since the welding line changes continuously, it is necessary to sense the arc position in all lines. For example, the welding line is copied by the high-speed rotating arc welding method, the distance between the tip and the base material with respect to the welding line, the welding The amount of deviation in the direction orthogonal to the line is captured from change information such as the welding current, arc voltage, or short-circuit transition state, and fed back to torch position correction. This is because cutting, assembly, and manufacturing errors occur between the information on the weld line obtained from the design drawing before welding and the actual weld line, and the influence cannot be ignored.

  Here, advantages of using the rotary arc welding for the first layer are as follows. That is, in the sensing before the first layer in step 104, for example, wire touch sensing, it is practically impossible to sense the entire weld line, and it is impossible to detect a minute error of the actual workpiece. On the other hand, in rotating arc welding, the displacement in the groove width direction of the oscillation center from the groove center is sensed almost always during welding from the asymmetry of the welding current waveform and arc voltage waveform with respect to the oscillation center position. Thus, the welding torch is always controlled so that the target position of the welding torch is always at the groove center, so that the entire welding line can be sensed. Further, in the straight welding as shown in FIG. 8B in which the welding torch is moved only in the welding direction without moving the welding rod in the horizontal direction, the penetration shape tends to concentrate on the central portion, and the tendency is further strong in the high current region. . On the other hand, in the rotating arc welding shown in FIG. 8A, a flat penetration shape is obtained, which has the same tendency even when the current is increased. As a result, even in the downward welding of the linearly inclined portion 12C, a deep penetration shape can be obtained even in a wide range due to the rotating arc and high current.

  After the first layer welding by the rotating arc in step 106 is completed, if multi-layer welding is necessary according to the leg length size of fillet welding, the lamination welding in the second and subsequent passes is performed in step 108. The maximum leg length for fillet welding in a horizontal position is 9 to 11 mm, and it is impossible to perform one pass of 11 mm or more due to gravity, the weld metal hangs down, and the maximum leg length is further reduced to about 6 mm in downward welding. Therefore, for example, when the fillet leg length is 6 mm, one layer is one pass, when it is 9 mm, two layers are three passes, and when it is 13 mm, three layers are six passes. Specifically, the two welding robots 22 and 24 again approach the mountain top parallel part 12A to restart the arc, and the mountain parallel part 12A → the upper arc part 12B → the inclined linear part 12C → the lower arc part 12D → Welding proceeds to the valley parallel part 12E. In the upper layer welding after the second pass, straight welding is performed in which the welding torch is moved only in the welding direction and not in the lateral direction. This is because this straight welding is superior in arc stability particularly in the downward welding compared to the high-speed rotating arc welding. In particular, in the case of the second and subsequent layers, high-speed rotating arc welding tends to sag because it melts the previous weld bead.

  In the second and subsequent passes, since the same weld line as the first layer is welded, the same movement as the tracing locus of the first layer may be performed. However, in general, in the case of multi-layer assembling, the target position is changed (shifted) in consideration of the stacked bead shape so far, so the shift amount is taken into consideration. That is, in consideration of the formation of fillet welds, the target position of the torch is shifted as shown in FIG. 9, but there are the following two patterns for the correction by the welding line copying.

  (1) Based on the wire touch sensing information in step 104, the weld line is corrected.

  (2) The correction amount of the wire touch sensing in step 104 and the welding line scanning by the arc sensor in step 106 is stored, and the correction amount of both is corrected.

  Table 2 shows an example of welding conditions after the second pass.

  When thermal deformation due to the multi-layer build-up becomes a problem, the welding line scanning control similar to that in the first pass can be performed after the second pass.

  When it is determined in step 110 that the construction of one wave is completed, the process proceeds to step 112, the welding robots 22 and 24 are moved to the center of the adjacent wave, for example, the mountain, and steps 104 to 110 are repeated. The welding work of the member is sequentially performed until it is determined that one side is completed.

  When one side is completed, the process proceeds to step 118, the members are turned upside down, and steps 104 to 114 are repeated until it is determined in step 116 that both sides are completed, thereby completing the predetermined welding.

  In the case of multi-layer welding, when the bead seam at the end portion is overlapped at one place, the discontinuous portions overlap, and the bead shape at that portion is deteriorated. Therefore, in order to make the bead joint inconspicuous, as shown in FIG. 10, a discontinuous portion is made inconspicuous as much as possible by performing a cascade process. The cascade amount for each path can be set to 30 to 80 mm, for example.

  In this embodiment, since the seam of the bead is only the valley parallel part 12, the seam processing is easy and smoothing is easy. In particular, when the ends are connected to each other, the bead seams between the ends are easy to process and smooth.

  That is, at the bead seam, as shown in FIG. 11, (A) a start end-start end joint SS on which the next start end S is superimposed on the welding start point (start end) S, and (B) Welding end point (end) E is overlapped with the start end-terminal end SE, (C) The end point is overlapped with the start end S over the end end-start end end ES, and (D) the end end is over the end E. There are four types of end-to-end joint EE where E is overlapped. However, since the temperature of the base material has not yet risen at the start end S, the weld bead does not expand and tends to be a rounded convex bead. On the other hand, a dent called a crater occurs at the end E. Since this crater is larger as the current is higher, this crater is particularly problematic in high current construction robot construction. Therefore, the current and welding speed are lowered near the end point, and sometimes stop or reverse run to fill the dent.

  In the case of bead splicing in robot welding, it is difficult to carry a rod that eliminates the narrow convex bead at the start end S, and the operation of filling the crater at the end E is relatively easy. In particular, a bead joint tends to be more convex by overlapping two weld lines. Therefore, in the bead joint, the starting end S is avoided as much as possible, or the starting end S on the side welded later is avoided. In particular, in both the first welding and the subsequent welding, the starting edge S is difficult and difficult. Further, even when reworking occurs at the bead joint portion, the bead joint in which the starting end S remains as shown in FIGS. 11A and 11C requires overlay welding + grinder cutting, but FIG. The bead joint where the starting edge S does not remain as in (D) is often only required by grinder cutting, and the construction can be completed with a minimum of labor. Therefore, terminal E-terminal E shown in FIG.

  Next, referring to FIG. 12, a second embodiment of the present invention in which welding is performed using a small automatic welding machine as shown in FIG. 13 will be described.

  In the present embodiment, welding is performed by welding torches 43 and 45 on two small welding carts 42 and 44 that travel on the traveling rail 40. 13, 46 is a holder of the welding torch 43, 47 is a wheel of the carriage 42, 48 is a cable, 50 in FIG. 12 is a welding condition setting, welding / running on / off management, and two welding carriages 42. , 44 is a control box for performing synchronous control.

  In each of the above embodiments, the web of the corrugated web plate 12 is set horizontally, so that the construction is particularly easy. The application target of the present invention is not necessarily limited to horizontal placement.

  Further, the same side of the web plate 12 may not be continuously welded, but may be alternately welded one by one. The welding start position is not limited to the center position of the mountain parallel part 12A, and welding may be started from a position shifted from the center or from the valley parallel part 12E. The present invention can be applied if the number of web waves is 1 or more.

  Further, the welding line scanning control method is not limited to the one using the wire touch sensor (before welding) or the arc sensor (during welding), and the amount of deviation from the welding line can be adjusted by another method using an optical sensor or the like. The welding torch position may be controlled accordingly.

The perspective view which shows the state which stood up the waveform web girder of welding object The perspective view which shows the welding line by this invention The side view which shows the construction condition by 1st Embodiment of this invention Flow chart showing welding procedure (A) Top view and (B) Side view showing examples of wire sensing positions The perspective view which shows the high-speed rotation arc welding state similarly used for first layer welding Side view showing an example of corrugated web plate dimensions (A) Perspective view and plan view showing movement of welding torch and welding bead of high-speed rotating arc welding and (B) straight welding Similarly, (A) Front view showing the target position of each pass and (B) shift amount between each pass of multi-layer welding The perspective view which similarly shows the cascade process of a bead joint A plan view comparing various bead joints The perspective view which shows the construction condition by 2nd Embodiment of this invention The perspective view which shows the example of the automatic welding machine used by 2nd Embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Corrugated web girder 12 ... Corrugated web board 12A ... Mountain parallel part 12B ... Upper circular arc part 12C ... Inclined straight line part 12D ... Lower circular arc part 12E ... Valley parallel part 14 ... Flange plate 20 ... Robot slide shaft 22, 24 ... Welding robot 23, 25, 43, 45 ... Welding torch 38 ... Weld pool (pool)
40 ... travel rails 42, 44 ... welding cart 50 ... control box

Claims (8)

In the welding method of the corrugated web girder for welding the fillet weld of the corrugated web plate and the flange plate of the corrugated web girder,
Place the welding torches of the two automatic welding means toward the same position in the approximate center of the parallel part of the corrugated web,
Start welding at the same time, proceed in the opposite direction from the same molten pool,
A welding method for a corrugated web girder, wherein welding is performed up to a next parallel portion through an arc portion, an inclined portion, and a next arc portion without stopping each welding arc.   2. The corrugated web girder welding method according to claim 1, wherein the welding is performed with the corrugated web plate placed horizontally.   The welding method for corrugated web girders according to claim 1 or 2, wherein the welding is performed from a peak parallel portion of the corrugated web to a valley parallel portion.   4. The corrugated web girder welding method according to claim 1, wherein the welding is performed in a multi-layered manner.   In the multi-layer welding, the welding trajectory control method is used to store the tracing trajectory of the first layer, and in the second and subsequent layers, welding is performed by adding the shift amount of the torch target position to the tracing trajectory of the first layer welding. 5. The corrugated web girder welding method according to claim 4, wherein copying is performed.   6. The corrugated web girder welding method according to claim 4, wherein in the multi-layer welding, at least a first layer is subjected to high-speed rotating arc welding in which a torch is rotated.   7. The corrugated web girder welding method according to claim 4, wherein the end position of the multi-layer welding is shifted for each pass and cascaded.   8. The method for welding corrugated web girders according to claim 1, wherein the welding is repeated in the longitudinal direction of the corrugated web plate so that a bead joint is generated at a welding end portion.

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