JPH07116840A - Automatic gas-shielded arc welding method - Google Patents

Abstract

PURPOSE:To provide the automatic gas-shielded arc welding method capable of detecting a bread shape without relying on monitoring of a welder, automatically judging the propriety thereof and contributing to automation, de-skilling and unmanned operation of welding in its turn. CONSTITUTION:The bead shape in automatic gas-shield arc welding is detected by using a beam, the radius RC of curvature and the center P of curvature thereof are obtained in the vicinity 9 of the bead center, the radius RL of curvature thereof is obtained in a bead toe part 10 and the propriety of the bead shape of the bead position is judged from those pieces of information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to automatic GTA, MIG,
The present invention relates to a gas shield arc automatic welding method such as MAG welding.

[0002]

2. Description of the Related Art In GTA, MIG, and MAG welding, it is essential to secure a proper bead shape in order to obtain a sound welded joint without a penetration defect, as the welding progresses while forming a bead. The shapes are welding current, arc voltage,
Since it is formed under the influence of many factors such as the electrode position, in some cases, the conditions may collapse and the proper bead shape may not be maintained. Therefore, in order to avoid such a situation, the welder constantly monitors the bead shape, judges the quality of the bead, and adjusts the welding conditions in the case of failure.

[0003]

SUMMARY OF THE INVENTION The present invention has been proposed in view of such circumstances, and the bead shape can be detected and the quality of the bead can be automatically determined without relying on the supervision of a welder. It is an object of the present invention to provide a gas shield arc automatic welding method that can contribute to automation, de-skilling and unmanned welding.

[0004]

To this end, the present invention detects the bead shape in gas shielded arc automatic welding using a beam, determines the radius of curvature and the center of curvature in the vicinity of the center of the bead, and at the bead toe, It is characterized in that the radius of curvature is obtained and the quality of the bead shape and the bead position is judged from the information.

[0005]

In the gas shielded arc automatic welding method of the present invention, a bead shape is detected by arranging a detection means by a beam such as a laser beam behind the welding torch, and the radius of curvature is detected near the center of the bead of the detected bead shape. And the center of curvature are obtained, and information about the unevenness of the bead is obtained from the radius of curvature, and information about the inclination and position of the bead is obtained from the position of the center of curvature. In addition, the radius of curvature of the bead-shaped toe portion is obtained to obtain information on wetting that affects the generation of defective penetration. Then, the quality of the bead shape and the bead position is judged from the various information, and the welding conditions are adjusted if necessary.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the gas shielded arc automatic welding method of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining the procedure of the present method. FIG. Illustration of how to find the center position,
FIG. 2B is an explanatory diagram of the procedure for obtaining the radius of curvature at the bead toe portion, FIG. 2 is a diagram for explaining the quality of the obtained bead shape, and FIG. 2A is an explanatory diagram of goodness, and FIG. ) Is an explanatory view of no, and FIG. 3 is a schematic view of an apparatus for carrying out the method.

First, in FIG.
Explaining how to find the radius of curvature and the center of curvature of the vicinity 9 of the center of the bead 8 detected by using the beam when one pass per layer is welded, the position PC at the center of the bead is calculated as 1/2 of the bead width W. , then calculating the position P _L and P _R of both sides at a distance U from your PC. U is a predetermined constant. Next, a circle intersecting these three positions is obtained, and its radius RC and its center position P are obtained. The following judgment is made based on the above information of PC, RC and P. If (W / 2) −α ≦ P ≦ (W / 2) + α, the position of the bead 8 is regarded as normal. If P <(W / 2) -α, the position of the bead 8 is shifted to the left and it is considered defective. If P> (W / 2) + α, the position of the bead 8 is shifted to the right, and it is determined to be defective. If RC ^* ≦ | RC |, it is normal (RC ^* is predetermined). If | RC | <RC ^* , it is determined to be defective.

Next, referring to FIG. 1B, the procedure for obtaining the radius of curvature of the bead toe 10 detected when the bead 8 is in contact with the groove side wall 11 'will be described. Let PL1 be the point of intersection of the straight line L (1) with the left bead toe and the straight line L (1) shifted in the X direction by ΔX (where X> 0, a predetermined constant). Let L (2) and the intersections with the groove wall and the bead shape be PG and PB, respectively. A circle that intersects with PL1, PG, and PB is obtained, and its radius of curvature is _RL . Similarly, R _R at the groove side wall on the right side is obtained. The following judgment is made from the above R _L and R _R. That R ^* ≦ R _L, and normal if _R ^* ≦ R R (R ^* is determined in advance). By the above procedure, the vicinity 9 of the bead center and the bead toe 1
If both are determined to be normal, the bead shape is normal.

FIG. 2 (A) shows the case of a normal bead thus determined and obtained, and FIG. 2 (B) shows the case of poor wetting and tilting of the bead. In the case of FIG. 2 (A),
(W / 2) −α ≦ P ≦ (W / 2) + α, RC ^* ≦ | RC
|, R ^* ≦ R _L, because it satisfies all of the _R ^* ≦ R R, are determined to be good bead shape. But Figure 2
In (B), P <(W / 2) -α, R ^* > _RL , R ^* >
It is determined that the bead shape is defective due to R _R. However, in this case, α = W / 3, W = 12 mm, RC ^* = 7 mm, R ^*
= 3 mm.

Next, referring to FIG. 3, an apparatus for carrying out the method will be described. A welding power source 4 is connected to a base material 1 and an electrode 3 of a welding torch 2, and a shield gas 5 is jetted from the tip of the welding torch 2. At the same time, the filler wire 6 is fed to the welding portion, and the filler wire 6 is melted by the arc 7 generated between the base material 1 and the electrode 3 to form the bead 8. When the bead shape of the bead 8 is detected by using the beam, the bead 8 is irradiated with the slit-shaped laser beam 12 behind the welding torch 2, and the reflected light is imaged by the CCD camera 13 to bead the bead. Detect shape.

[0011]

In summary, according to the present invention, the bead shape in gas shielded arc automatic welding is detected using a beam, the radius of curvature and the center of curvature are determined near the center of the bead, and the radius of curvature is determined at the bead toe. By determining the quality of the bead shape and the bead position based on the information obtained, the bead shape can be detected without relying on the supervision of the welder, and the quality can be automatically determined. The present invention is extremely useful industrially because a gas shielded arc automatic welding method that can contribute to realization and unmanned operation is obtained.

[Brief description of drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view for explaining a procedure in one embodiment of a gas shielded arc automatic welding method of the present invention. FIG. 1A is an explanatory view of a procedure for obtaining a radius of curvature and a curvature center position near the center of a bead. (B) is an explanatory view of the procedure for obtaining the radius of curvature at the bead toe.

2A and 2B are diagrams for explaining whether the obtained bead shape is good or bad. FIG. 2A is an explanatory diagram of goodness and FIG. 2B is an explanatory diagram of badness.

FIG. 3 is a schematic diagram of an apparatus for carrying out the present method.

[Explanation of symbols]

 1 Base Metal 2 Welding Torch 3 Electrode 4 Welding Power Supply 5 Shield Gas 6 Filler Wire 7 Arc 8 Bead 9 Near the Center of Bead 10 Bead Toe 11 Groove 11 ′ Groove Sidewall 12 Laser Beam 13 CCD Camera

Claims (1)

[Claims] 1. A bead shape in gas shielded arc automatic welding is detected by using a beam, a radius of curvature and a center of curvature are obtained in the vicinity of the center of the bead, and a radius of curvature is obtained at the toe of the bead. A gas shield arc automatic welding method characterized by determining the quality of a bead shape and a bead position.