JPS63248571A - Fillet welding method - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a blowhole, a pit, etc., by giving the time difference to both welding torches to perform the welding while allowing the other welding torch to precede or succeed with respect to one welding torch at the time of performing the fillet welding. CONSTITUTION:One welding torch 3A is made to a reference and the welding torch 3A to be the reference is moved at the travel speed Vx of a welding carriage 10 and the mating welding torch 3B is moved at the travel speed Vt(<Vx) till the quantity of shift of both the welding torches attains a preset prescribed value. The retrogradation of a slider 50B is stopped at the position where the quantity of shift of both the welding torches 3A and 3B attains the prescribed value and afterward, both the welding torches are moved at the carriage speed Vx. By this method, the impurities of materials to be welded are burnt by the preceding welding torch and can be released to the outside and the occurrence of the blowhole, etc., is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fillet welding method for reinforcing materials used when welding a stiffener or the like to a main material in large structures such as shipbuilding or bridges.

[Conventional technology]

In large structures such as shipbuilding and bridges, reinforcing materials such as stiffeners are welded to the long main material. For example, in a bridge, the main material (I
The main material is reinforced by welding horizontal reinforcing materials (H stiffeners) in the longitudinal direction of the shaped steel material and vertical reinforcing materials (■ stiffeners) perpendicular to the horizontal reinforcing materials in a fixed arrangement pattern.
These reinforcing materials are generally welded by performing fillet welding on both sides of the edges that contact the main material, and by performing square wrap welding on the ends. In this case, a twin-torch type welding device having two welding torches is used as the welding device,
The positions and postures of the two welding torches are controlled so that they are symmetrical with respect to the center in the thickness direction of the reinforcing material, so that symmetrical positions on both sides of the edge are simultaneously welded.

[Problem that the invention seeks to solve]

However, this method of simultaneously welding symmetrical positions on both sides of the edge using two welding torches has the disadvantage that the gas generated during welding cannot escape to the outside of the molten pool, and blowholes, pits, etc. are likely to occur. This is particularly noticeable when the surface of the material to be welded has oil or rust attached to it, or when the surface is coated. In order to eliminate this drawback, (
1) Slow down the welding speed, or (2) increase the heat input by increasing the arc voltage, current, etc. to delay the solidification of the molten pool and release the above gas to the outside of the molten pool quickly. However, in the former case there is a problem that work efficiency cannot be improved, and in the latter case there is a problem from an economic point of view.

These problems occur, for example, when two welding torches are shifted relative to each other, one leading and the other trailing, as shown in Japanese Patent Application Laid-Open No. 54-1) 7343. This can be solved by moving the reinforcement material with
Start two welding torches at the same time, or
Since the other welding torch must be started before the molten pool has solidified, the amount of shift is limited and it is difficult to take a sufficient amount of shift, so the advantages of shifting the welding torches relative to each other are not utilized. In addition, there is always some welding leftover at the welding end, so you have to reset the equipment and weld from the welding end, which is a hassle.Furthermore, there is always a bead joint, so welding Quality issues arise.

This invention was made in order to solve the above-mentioned problems, and it is possible to weld the entire path from the starting square wrap weld to the terminal square wrap weld without the need for bead joints, and to perform better and more efficiently than conventional methods. The purpose of the present invention is to provide a fillet welding method that allows for.

[Means to solve the problem]

In this invention, two welding torches are each supported by a sub-shaft drive mechanism that can reciprocate in directions parallel to each other, and are also supported by a main shaft drive mechanism including a welding cart, to position the square winding welding at the start and end of welding. Then, both the welding torches are placed opposite each other at the same position in the welding line direction, and when fillet welding, the two welding torches are set to have a speed difference, and one welding torch is welded with the other welding torch leading or trailing. This is a configuration that allows this to be performed.

[Effect]

In this invention, the mutual shift amount of the pair of welding torches is made variable, and the entire welding path is divided, and changes and changes are made according to each division area.
Since the welding is corrected, it is possible to perform the entire process of welding from the starting end corner wrap welding to the end corner wrap welding in a good and efficient manner.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining the operation of a pair of welding torches 3A and 3B when horizontal fillet welding of a reinforcing material 2 to a main material 1 of a large structure is performed by the method of this embodiment. ,2
F indicates the starting end of the reinforcing material 2, 2R indicates the ending end of the reinforcing material 2, and 7
A and 7B indicate weld lines.

FIG. 2 shows an example of the main body portion of a welding robot applied to the fillet welding of this embodiment. In FIG. 2, reference numeral 10 denotes a concave welding cart, which runs on the rail 1) while being driven and controlled by an X-axis drive mechanism (not shown). This running direction is defined as the X-axis direction. A torch truck 20 is driven and controlled by a Y-axis drive mechanism (not shown) and runs on the rail 12 on the crossbeam 10A of the welding truck 10. This running direction is perpendicular to the above-mentioned X-axis direction, and this running direction is defined as the Y-axis. Reference numeral 30 denotes a hollow torch support shaft, which is connected to a two-axis drive mechanism (not shown) through a rack and pinion engagement, and is guided so as to be vertically movable by the torch cart 20 (this vertical direction is the X-axis direction). ), and the lower end has a torch rotation mechanism (
The θ axis>40 is held. The above X-axis, Y-axis, Z-axis, and θ-axis are collectively called the principal axis, and 10.20.30 and 4
0 constitutes the principal axis system. The torch turning mechanism 40 is a mutually parallel slider mechanism 50A (first sub-shaft drive mechanism).
, 50B (second sub-shaft drive mechanism), and the welding torches 3A and 3B are connected to the slider portions of the slider mechanisms 50A and 50B via vertical shafts 51A and 51B. The sliding directions of the slider mechanisms 50A and 50B are defined as a TI axis and a T2 axis. Note that the control unit 60 of this welding robot
is controlled by an NC control device that reads NC data from a bubble cassette that stores NC data, converts related data of the main axis system and sub-axis system into signals, and controls the servo system of each axis, and the corresponding servo system. It is equipped with a motor for each axis, a position detector such as an encoder that feeds back position data to the servo system, and controls the voltage and current supplied to each axis and the welding torch from the welding power supply device. Further, this welding robot does not have a weaving mechanism, but if a weaving mechanism is provided, it may be connected to the lower ends of the vertical shafts 51A and 51B.

Next, fillet welding according to this embodiment will be explained with reference to FIG. 3.

(1) Starting end square wrap welding (section A in Figure 3) Welding torch 3A
and 3B are positionally controlled to the welding start point coordinates Lsa and Lsb.

These welding start point coordinates Lsa and Lsb are on the extension line of welding lines 7A and 7B that are a distance a forward from the reinforcing material starting end 2A.

The value of a is 2 to 3 mm depending on the thickness of the reinforcing material.
is appropriate. Welding torches 3A and 3B are used for square wrap welding at the starting end.
By operating sliders 50A and 50B at the same speed while maintaining the relative shift amount between them at O, welding torches 3A and 3B are moved forward by a distance a in the TI axis and T2 axis directions, respectively. do.

(2) Fillet welding (section B-D in Figure 3) After the starting square wrap welding is completed, the welding cart 10 is run, but at this time, one welding torch 3A is used as a reference, and the welding torch 3A is used as the reference. is moved at the running speed Vx of the welding cart 10, and the mating welding torch 3B is moved at the running speed vt (<VW) until the shift amount of both welding torches reaches a predetermined value S. This speed vt is determined by moving the slider portion of the slider 50B at a constant speed ΔVX in the opposite direction to the traveling direction of the welding cart 10.
(=V-Vt). If the distance until the shift amount S is obtained is l8, and the time is tl, then Vt
-3/l+ -t+ =j! A relationship of +/VX holds true, and (2) is preferably about 15% of Vx. welding torch 3
At positions Lma and Lmb where the shift amount between A and 3B reaches a predetermined value S, the slider 50B is stopped from moving backward, and thereafter both welding torches are moved at the truck speed Vx.

The welding torches 3A and 3B move toward the terminal end 2R while performing fillet welding along the welding lines 7A and 7B, and reach positions Lpa and Lpb a predetermined distance before the terminal end 2R (these coordinate positions are set in advance). ), the welding end point Lea
= In order to set the shift amount to O at Leb, the slider part of the slider mechanism 50B is moved at a constant speed in the traveling direction of the welding cart 10, and the moving speed of the welding torch 3B is increased from the moving speed of the welding torch 3A. do. If the distance from position Lpa to welding end point Lra is j23, then V, = S/
l.

1j3=I13/Vx holds true. This action causes
The shift amount of both welding torches 3A and 3B becomes zero at the reinforcing material end 2R.

(3) End square wrap welding (section E in Figure 3) Both welding torches 3
After A and 3B reach the reinforcing material terminal end 2R, end angle wrap welding is started and the slider mechanism moves Lea=Leb. Lea=Leb is located at a distance from the terminal end 2R of the reinforcing member 2. Although this distance depends on the thickness of the reinforcing material 2, it is preferably 2 to 3 mm.

When the welding torches 3A and 3B reach the welding end points Lea and Leb, the running direction of the welding cart 10 is reversed, the welding current is reduced, and the welding torches 3A and 3B are moved back to the illustrated position Lqa=Lqb with a shift amount of 0. Finish welding.

As described above, in this embodiment, during starting square wrap welding, both welding torches 3A and 3B are moved symmetrically without being shifted relative to each other, so that good square wrap welding can be obtained without creating a bead joint. can. During fillet welding, the welding torch is shifted, but since the welding torch can be shifted sufficiently, impurities in the welded material can be completely burned by the preceding welding torch and released to the outside, eliminating blowholes, pits, etc. can be prevented from occurring.

In addition, until the above-mentioned predetermined amount of shift is established,
Even before the shift is eliminated, the solidification time of the molten pool is longer than in the case where no shift is taken, so that desired good welding can be performed over the entire welding path.

In addition, if an appropriate welding speed is selected for each of the above-mentioned sections A-E over the entire path, welding can be performed at a higher speed than in the past.

In the above embodiment, the speed of one welding torch 3A is kept constant and the speed of the other welding torch 3B is changed to ensure the required shift and eliminate the shift. It is obvious that the required shift may be secured or the shift may be canceled by speeding up, decelerating the other welding torch, or the like.

〔Effect of the invention〕

As explained above, in this invention, fillet welding is performed by mutually shifting the pair of welding torches, but since the shift amount is set to O during square wrap welding at the beginning and end, good welding is achieved over the entire welding path. It can be performed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between reinforcing materials and characteristic welding positions for detailed explanation of this invention, and FIG. 2 is a perspective view showing an example of a welding device used to carry out this invention. , FIG. 3 is a time chart for explaining the above embodiment. 1-Main material, 2-Reinforcing material, 3A, 3B-Welding torch, 7A
, 7B--Welding, 10-Welding truck, 20-Torch truck, 30-1--Torch support shaft, 40...Torch rotation mechanism,
50A, 50B-Slider.

Claims (2)

[Claims] (1) Welding the left and right corner parts of the main material abutment part of the reinforcing material erected on the main material using two welding torches that move along the welding line while controlling their posture toward each corner. In the flesh welding method, the two welding torches are each supported by a subshaft drive mechanism that can reciprocate in parallel directions, and are also supported by a main shaft drive mechanism that includes a welding cart, during square wrap welding at the start and end of welding. Both of the welding torches are placed facing each other at the same position in the welding line direction, and when fillet welding, welding is performed with a speed difference between the two welding torches and one welding torch leading or trailing the other. A fillet welding method characterized by: (2) The two welding torches have a predetermined speed difference until a predetermined distance has passed from the starting end of the reinforcing material, and once they reach a position a predetermined distance before the end of the reinforcing material, the two welding torches have a predetermined speed difference again. Claim 1 characterized in that
Fillet welding method described in section.