Welding device

Abstract

The invention provides a carbon dioxide gas electric arc welding method and a welding device for reducing splashing and improving welding quality. The welding device comprises a power supply circuit for supplying voltage between a welding torch and a base material, and a power supply control device for controlling the voltage of the power supply circuit. The power supply control device controls the power supply circuit in a manner that a high level current superimposed with a wave form which increases and decreases with a specified period and has an gradually increasing amplitude is outputted in a first electric arc period Ta1 in the early stage of an electric arc period following a short circuit period Ts, and constant voltage control is performed in a second electric arc period Ta2 in the later stage of the electric arc period. Through the superimposing of the wave form with the amplitude increasing as a molten drop grows, the intumesce of the molten drop caused by counter-acting force of the electric arc is prevented, and the stable formation of the molten drop and the improvement of the growing speed of the molten drop are realized.

Description

technical field [0001] The invention relates to a welding device, in particular to a welding device for carbon dioxide gas arc welding. Background technique [0002] Japanese Patent Application Publication No. 4-4074 (Patent Document 1) discloses a consumable-electrode arc welding method in which short-circuiting and arc generation are repeated between a consumable electrode and a base material. The consumable electrode arc welding method repeats the formation process of the droplet and the transition process of the droplet to the base metal. [0003] Figure 10 It is a diagram for explaining a consumable-electrode arc welding method in which short-circuiting and arc generation are repeated. [0004] refer to Figure 10 , in the consumable-electrode arc welding method in which short-circuiting and arc generation are repeated, the processes (a) to (f) described below are repeatedly performed sequentially. (a) The initial state of short circuit when the droplet is in contact...

AI Technical Summary

Problems solved by technology

However, in the case of welding with a high current (a current exceeding 200 A when the diameter of the welding wire is 1.2 mm) by the carbon dioxide gas arc welding method, in the droplet transfer accompanied by a short circuit, the droplet is caused by the reaction force of the arc. The bulge (せり上がゐ) is on the top of the welding wire, so the arc time is prolonged and it is difficult to produce periodic short circuits, and arcs and short circuits will occur irregularly

[0007] In this way, if the cycle of short circuit and arc fluctuates irregularly, the droplet size at the time of short circuit will become unstable, and the overall bead portion of the weld bead will deteriorate.

[0008] In addition, because the high current exerts excessive arc force at irregular positions relative to the weld pool, the weld pool becomes large and vibrates irregularly, especially by pushing the weld pool to the side opposite to the welding direction, then Prone to humping weld bead

[0009] In particular, the welding speed is required to be set at a high speed in order to increase productivity, but the deterioration of the welding quality due to the influence of the above-mentioned problems is remarkably manifested in high-speed welding

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