JPH06640A - Horizontal multilayer welding method - Google Patents

Abstract

PURPOSE:To automate a horizontal multilayer welding by welding a path contacting with a groove wall by groove copying control of arc sensor system and welding a path not in contact. with the groove wall by the reproduced copying control for the previous path. CONSTITUTION:In the horizontal multilayer welding, when the path in contact with the groove wall (path number 1-6 and 8 for a small route gap and path number 1-5, 7, 8 and 11 for a large route gap) is welded, high speed rotary welding under groove copying of arc sensor system is used and when the intermediate path not in contact with the groove wall (path number 7 for a small route gap and path number 6, 9 and 10 for a large route gap) is welded, the work is executed according to the reproduced control data for the previous path. Thus, continuous automatic horizontal multilayer welding is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal multi-layer welding method using high-speed rotary arc welding.

[0002]

2. Description of the Related Art A rotary arc welding method is known in which welding is performed while circularly moving an arc generated between a welding wire and a member to be welded (Japanese Patent Publication No. 63-39346). According to this rotary arc welding method, the bead shape can be smoothed and the penetration shape can be improved by the action of dispersing the arc force and arc heat. The centrifugal force of rotation increases the melting speed of the welding wire,
The efficiency is higher than when the arc is not rotated. In fillet welding and welding with a groove, it is possible to perform groove-probe control using an arc sensor method that utilizes the waveforms of welding current and arc voltage. There are features such as.

[0003]

However, the conventional rotary arc welding is generally targeted for downward welding or horizontal welding, and even in the case of multi-layer welding, it is mainly for narrow gaps.

On the other hand, when horizontal multi-layer welding is performed at a relatively high current without rotating the arc, the bead sagging phenomenon easily occurs at each welding pass, the bead shape is poor, and welding defects such as insufficient penetration occur. To do.

In the case of horizontal welding, since a generally rectangular groove is used, even if the conventional high-speed rotary arc welding method is applied, the groove-following control of the arc sensor type is applied in the intermediate pass not in contact with the groove wall. There are places where you can't.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a horizontal multi-layer welding method capable of automatic welding while maintaining the advantages of the high-speed rotary arc welding method. I am trying.

[0007]

SUMMARY OF THE INVENTION The present invention provides a method for applying a high-speed rotary arc welding method to horizontal multilayer welding.
When welding a path in contact with the groove wall, the welding is performed by the groove profile control of the arc sensor method, and when welding an intermediate pass that does not contact the groove wall, the data of the groove profile control when welding in the previous pass is performed. By using the horizontal multi-pass welding method of regenerating and welding, automatic welding is made possible, and the arc force by the rotation of the arc, the bead shape smoothing by the dispersion action of the arc heat, and the effect of improving the penetration shape make it relatively It enables horizontal multi-pass welding at high current.

[0008]

In the present invention, the number of passes is automatically determined by the base metal plate thickness, welding conditions, root gap G, and groove angle θ. And you can see the number of the path that touches the groove wall. For example, as shown in FIG. 1, when the route gap is small, path numbers 1 to 6 and 8 are paths that contact the groove wall, and path number 7 is an intermediate path that does not contact the groove wall. If the route gap is large, pass numbers 1 to 5 and 7, 8,
11 is a path that contacts the groove wall, and the path numbers are 6, 9 and 1
0 is an intermediate pass that does not touch the groove wall.

The high-speed rotating arc welding is performed in the order of the pass numbers, but the place of the pass contacting the groove wall is a groove having a relatively good shape between the weld bead formed in the previous time and one groove wall. Since this is formed, it is possible to perform automatic welding at that location by the groove profile control of the arc sensor method.

However, the position of the intermediate pass is an apparent groove formed only by the weld bead already formed, and the center line and shape of the groove are unstable. If the above procedure is performed, the bead shape may be collapsed, resulting in insufficient penetration of the next pass.

Therefore, it is decided to obtain substantially the same bead shape and welding amount at the position of the intermediate pass by reproducing the groove tracking control data of the last time. In this way, continuous automatic welding of horizontal multilayer welding becomes possible.

[0012]

FIG. 2 is a schematic view of an automatic welding machine used in the horizontal multi-layer welding method according to the present invention. In the figure, reference numeral 31 denotes a self-propelled carriage that travels on a rail 32 in the welding advancing direction (the front and back directions of the paper). Reference numeral 33 is a horizontal X-axis feed mechanism installed on the carriage 31 and includes X-axis slide blocks 34, X.
It is composed of a shaft motor 35, a ball screw 36 and the like, and feeds the electrode groove 21 in the depth direction of the groove 20.
Reference numeral 37 denotes a vertical Y-axis feed mechanism installed on the X-axis slide block 34, which has the same configuration as the X-axis feed mechanism 33 and includes a Y-axis slide block 38, a Y-axis motor (not shown), a ball screw, and the like. The Y-axis feed mechanism 37 feeds the electrode nozzle 21 in the width direction of the groove 20. Reference numeral 40 denotes a rotating mechanism for the electrode nozzle 21, which is designed to give a precession motion to the electrode nozzle 21 by the rotating motor 41 via the eccentric gear mechanism 42 with the base end portion as the fulcrum 23. The tip of the arc moves circularly and the arc can be rotated. Reference numeral 43 denotes a housing of the rotating mechanism 40, which is attached to the Y-axis slide block 38 via a torch angle adjusting mechanism 44. Torch angle adjustment mechanism 4
Reference numeral 4 is a gear 46 of an torch angle motor (not shown) meshed with an arc gear 45 centered on the tip of the wire 22 attached to the side surface of the Y-axis slide block 38. The torch angle α with respect to can be adjusted according to the welding pass. A torch angle motor (not shown) is attached to the housing 43. In the figure, reference numeral 24 is a power feeding unit.

This automatic welding machine is constructed as described above, and when the number of passes is determined by the base metal plate thickness, welding conditions, the root gap G, and the groove angle θ, the passes shown in FIG. Start welding in numerical order. That is, the electrode nozzle 21 is precessed by the rotating mechanism 40, thereby rotating the tip of the welding wire 22 and welding while rotating the arc at a high speed. At the same time as performing such well-known high-speed rotary arc welding, the groove profile control of the arc sensor system is performed. In this case, the X-axis feed mechanism 33 keeps the arc length constant and the Y-axis feed mechanism 37 controls the arc rotation center to be located at the groove center.

Such groove tracking control is performed only for the path in contact with the groove wall as described above. When welding an intermediate pass at a position not in contact with the groove wall, the groove-following control data used during the welding of the previous pass is called from the memory of the control device (not shown) and the data is reproduced and executed.
That is, in the case of FIG. 1A, the welding of the intermediate pass 7 reproduces and welds the data of the sixth pass, and in the case of FIG. 1B,
The welding of the intermediate pass 6 uses the data of the fifth pass, the intermediate pass 9 uses the data of the eighth pass, and the intermediate pass 10
In the case of, similarly, the data of the 8th pass is regenerated and welded. In addition, for welding, X-axis feed mechanism 3 is used for each pass.
Needless to say, this is performed after the electrode nozzle 21 is shifted by a predetermined amount by means of 3 and the torch angle is adjusted again by the torch angle adjusting mechanism 44. In this way, horizontal multilayer welding can be continuously and automatically performed until the final pass.

FIG. 3 shows the cross-sectional shape of the first layer bead produced by high-speed rotary arc welding. In addition, the bead cross-sectional shape when welding was performed without rotating the arc is shown by a dotted line. The root gap was 6 mm, the groove angle was 35 °, the welding current was 320 A, the welding speed was 35 cm / min, and the conditions of the rotating arc were that the rotating diameter of the arc was 2 mm and the rotating speed was 50 Hz.

According to the non-rotating arc welding in which the arc is not rotated, the surface of the bead 16a becomes convex and the penetration depth Ha becomes large and concentrated. Therefore, in the second pass, a fusion defect is likely to occur at the location 17a. On the other hand, according to the high speed rotary arc welding, the arc force and the arc heat are dispersed by the rotation of the arc, so that the bead 1
The surface of No. 6 is smooth, the penetration depth H is small, and the shape is swollen to the groove wall side, and the effect of improving the penetration shape is remarkable. Of course, no defective fusion occurs at 17 points.

Macro-sections of lateral weld joints according to the present invention are shown in FIGS. 4 (a) -4 (d). (A) is G = 3 mm,
(B) G = 6 mm, (c) G = 9 mm, (d) G = 1
It is the case of 2 mm. As is clear from the figure, extremely good lateral welded joints were obtained regardless of the size of the root gap.

[0018]

As described above, according to the present invention, horizontal multilayer welding can be continuously and automatically performed by high-speed rotary arc welding, and a very good horizontal welded joint can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a horizontal multilayer welding method according to the present invention.

FIG. 2 is a schematic diagram of an automatic welding machine used in the present invention.

FIG. 3 is a cross-sectional view of a first layer bead.

FIG. 4 is a macro sectional view of a horizontal welded joint according to the present invention.

[Explanation of symbols]

 20 Re-shaped groove 21 Electrode nozzle 22 Welding wire

Claims (1)

[Claims] 1. In the horizontal multi-layer arc welding, when welding a pass in contact with the groove wall, the welding is performed under high-speed rotary arc welding under the control of the groove profile control of the arc sensor method, and the intermediate is not in contact with the groove wall. When welding a pass, the horizontal multi-pass welding method is characterized in that the copying control data in the previous pass is reproduced to perform welding.