JPH0866772A - Method for automatically welding bent plate - Google Patents

Abstract

PURPOSE: To provide an automatic welding method for joining bent plates which can obtain a stable quality without depending on the ability of a welding worker, improves remarkably the welding working efficiency, further does not require a large-scale device to regulate an inclining angle of a welding surface plate. CONSTITUTION: In a one-side welding method using an inert gas welding for joining bent plates, the angle of the bent plate is detected with an angle sensor 40 installed on an automatic welding carriage 10, and the welding current I and the welding speed v are controlled automatically to the most suitable welding current and welding speed corresponding to the bent angle of steel plates 70a, 70b to be welded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an automatic welding method for bent plate joints at the bow or stern.

[0002]

2. Description of the Related Art Conventionally, bending plate joints at the bow or stern have been performed by a semi-automatic carbon dioxide welding method. They were working while adjusting the welding current and welding speed. Specifically, as the plate bending angle increases, the weld metal tends to flow down behind the weld, the amount of weld pool directly under the welding wire decreases, and the back bead tends to become excessive. Adjusted the welding current by slowing down the welding torch while observing the state of the molten pool to slow down the welding torch (to reduce the welding speed) and to generate a constant backwater.

[0003]

As described above, since the conventional method is semi-automatic welding, the quality depends on the skill of the operator, but the welding work efficiency is poor. Further, in order to reduce the burden on the welding operator, a large-scale device such as hydraulically adjusting the inclination angle of the welding surface plate on which the bending plate is placed is required so that the welding can be performed in a horizontal downward position as much as possible.

The present invention has been made in order to overcome the above-mentioned conventional problems, and its purpose is to obtain stable quality without being influenced by the skill of the welding operator and to significantly improve the welding operation efficiency. Another object of the present invention is to provide an improved automatic welding method for bent plate joints which does not require a large-scale device for adjusting the inclination angle of the welding platen.

[0005]

That is, an automatic welding method for bending plate joints according to the present invention is a method for determining a bending angle of a plate by an angle sensor provided on an automatic welding carriage in the side welding by an inert gas welding method for bending plate joining. Detected, welding current I,
It is characterized in that the welding speed v is automatically controlled to the optimum welding current and welding speed according to the bending angle.

[0006]

As described above, the plate bending angle is detected by the angle sensor provided on the automatic welding carriage, and the elution current I and the welding speed v are automatically controlled to the optimum welding current and welding speed according to the bending angle. As a result, stable quality can be obtained without being affected by the skill of the welding operator. Also, the welding work efficiency is significantly improved. Furthermore, no large-scale device for adjusting the inclination angle of the welding platen is required.

Next, the automatic carbon dioxide welding carriage used when carrying out the method of the present invention will be described. In FIG. 1, 10 is an automatic carbon dioxide welding carriage, and three automatic carbon dioxide welding torches 11, 12, 13 are provided on the side of the carriage 10. The leading welding torch 11 is provided with the welding wire 21 as a leading electrode dedicated to the back wave, the central welding torch 12 is provided with the welding wire 22, and the rear welding torch 13 is provided with the welding wire 23. It is like this.

In FIG. 3, reference numerals 24, 25 and 26 denote welding wire feeding devices. The trolley | bogie 10 can hold | maintain the trolley | bogie 10 horizontally by the means which is not shown in figure. Further, the carriage 10 is provided with a welding operation panel 30, a control device 50 and an angle sensor 40.

The control block diagram of the control device 50 is as shown in FIG. 2. The angle sensor 40 is a type that outputs a voltage change of the capacitance due to the fluctuation of the liquid level between the electrodes, and is proportional to the tilt angle. The voltage output (100 mV / 1 °) can be obtained. In addition, the comparator unit 54
_{In 1} and 54 ₂ , the voltage corresponding to the preset angle and the output voltage from the angle sensor 40 are compared and calculated,
It outputs a pulse voltage signal for relay operation when the voltage is higher than the set voltage.

Further, the welding current I is controlled by controlling the wire feeding speed, specifically, by setting the variable resistance for controlling the operation phase of the thyristor for controlling the rotation speed of the wire feeding motor. It is like this. Similarly, with respect to the welding speed v, the motor rotation speed of the carriage is controlled. The optimum welding current and speed for each set angle are obtained in advance by experiments, and the variable resistance values VR'2, VR1; VR'2, VR2 are adjusted so as to be the respective values.
Is set. When the angle of the carriage 10 reaches the set angle, the relays R1 and R2 are actuated and are connected to the respective set resistors so that the welding current I and the welding speed v can be switched.

In FIG. 2, reference numeral 55 indicates a timer and a logic circuit. As shown in FIG. 3, when joining the steel plates 70a and 70b placed on the welding surface plate 60 by welding, the welding power source 80 and the carbon dioxide gas cylinder 90 are connected to the automatic carbon dioxide welding carriage 10 placed on the steel plate 70a. To do. Next, the automatic carbon dioxide welding carriage 10 is held horizontally by the digital angle meter 52 provided in the carriage 10, and the cancel amplifier 51 adjusts the zero point of the angle sensor 40 during this time.

When the zero adjustment of the angle sensor 40 is completed,
The output voltage from the angle sensor 40, which is proportional to the tilt angle, is amplified ten times by the amplifier 53. When the above adjustment is completed, the automatic carbon dioxide welding vehicle 10 is run along the welding line 71. Then, the comparators 54 ₁ and 54 ₂ of the automatic carbon dioxide welding vehicle 10 perform comparison calculation between the inclination of the vehicle and the preset changing angles of the welding current I and the welding speed v.

The inclination of the carriage 10 is the first welding condition angle 0-
When reaching 4 °, the relay R1 is activated and connected to the variable resistors VR1 and VR'1 set to have the predetermined welding current I ₁ and welding speed v ₁ , respectively, and the welding current I ₁
And the welding speed v ₁ . Further, the relay R2 operates at the next change angle of 4 to 8 °, and the variable resistors VR2, V
R'2 is connected and the welding current and welding speed are
It is switched to a predetermined value, that is, a welding current I ₂ and a welding speed v ₂ .

[0014]

[Example] A welding current and welding speed control device by the angle sensor of the present invention was installed on a three-electrode carbon dioxide welding trolley, which was applied to a curved plate joint with a plate thickness of 16 to 23 mm, and welding of the backside with a good welding line was performed. I got a part. One example is shown below. Angle of bent plate: 0 to 10 ° Plate thickness of bent plate: 17 to 18.5 mm Welding current, welding speed switching angle; 4 °, 8 ° Welding current control; Leading electrode only Welding conditions; Table 1 Table 1 conditions Butt welding of curved plates with a maximum inclination angle of 10 ° by setting welding current and welding speed beforehand (V groove)
I went. The welding current and welding speed were switched to the values shown in Table 1 at the predetermined angles of 4 ° and 8 °, and no significant change was observed in the condition change part in both the backside and surface appearance of the welding bead, which was good. .

[0015]

[Table 1]

[0016]

As described above, according to the present invention, the following effects can be obtained. That is, it has become possible to automate bending plate joints that were conventionally performed by semi-automatic welding. For bending angles of 0 to 10 °, the welding platen can be fixed and used, and it is not necessary to move a large-scale hydraulic device for adjusting the angle of the platen. The automation stabilizes the quality, and the work efficiency is more than doubled.

[Brief description of drawings]

FIG. 1 is a side view of an automatic carbon dioxide gas welding carriage used for carrying out the method of the present invention.

FIG. 2 is a control block diagram applied to the method of the present invention.

FIG. 3 is an explanatory view showing a welding operation according to the method of the present invention.

[Explanation of symbols]

 10 Automatic welding cart 40 Angle sensor

Front page continuation (72) Inventor Kenji Ito 1 Yawata Kaigan Dori, Ichihara, Chiba Mitsui Engineering & Shipbuilding Co., Ltd. Chiba Works

Claims (1)

[Claims] 1. In the side welding of the curved plate joint by the inert gas welding method, the plate bending angle is detected by an angle sensor provided on the automatic welding carriage, and the welding current I and the welding speed v are optimized according to the bending angle. An automatic welding method for bent plate joints that automatically controls the welding current and welding speed.