JPS6160267A - High speed and continuous tack welding method - Google Patents

Abstract

PURPOSE:To form a stable bead by high speed and continuous tack welding at high speed by entering a weld electrode into a weld start point at a little later speed than the specified weld speed and hasten the weld speed slowly at the same time of welding. CONSTITUTION:In a high speed and continuous tack welding, a molten metal 4 formed with an arc 3 of a proceeding electrode 1 is stopped with an arc 5 of a succeeding electrode 2 that follows it to form a weld bead, and the tack welding of materials is carried out at the specified weld speed. At that time, weld electrodes 1, 2 or materials are moved from the front of the weld start point of a tab plate to enter the weld start point at a little later speed than the specified weld speed, and the weld speed is slowly hastened at the same time of welding. In this way, the occurrence of welding faults is prevented by forming the stable bead with high speed and continuously.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a high-speed continuous tack welding method for continuously performing tack welding at high speed prior to main welding.

(Prior art) When performing tack welding at high speed, a leading electrode 1 and a trailing electrode 2 are used as shown in FIG. 2 to prevent the molten metal 4 generated by the arc 6 of the leading electrode 1 from flowing backward. Trailing electrode 2
This is done by forming a weld bead while blocking the arc 5.

In conventional high-speed tack welding, the welding speed is reduced to O during a short period of time, e.g. 1 to 2 seconds, at the start of welding, as shown in Figure 3.
It is necessary to change the welding speed V1 from n/min to a predetermined welding speed V1 of, for example, 10 m/min. Since the molten metal 4 cannot follow this change in welding speed and the flow of the molten metal 3 becomes unstable, this unstable state is stabilized by the tab plate.

However, if the length of the tab plate is made too long in order to absorb the unstable condition mentioned above, it will take time to attach the tab plate to the base material, and material will be wasted, so the length of the tab plate should be fixed. is limited to the length of

Therefore, a sudden change in welding speed occurs even when the welding electrode enters the base metal, and the weld bead shape of the base metal becomes discontinuous.

During tack welding, the weld bead shape of the base metal becomes discontinuous, and if the throat thickness is not average, there is a problem that when main welding is performed, the penetration depth becomes discontinuous and weld defects occur. .

(Object of the Invention) The object of the present invention is to improve the above-mentioned problems and to propose a high-speed continuous tack welding method that continuously forms stable beads at high speed.

(Summary of the Invention) The high-speed continuous tack welding method of this invention moves the welding electrode or base metal from before the welding start point of the tab plate, and the welding electrode enters the welding start point at a speed slightly slower than a predetermined welding speed. In this method, a continuous weld bead is formed from the edge of the base metal by slowly increasing the welding speed to reach a predetermined welding speed at the same time as welding starts.

(Embodiment of the Invention) FIG. 1 shows welding speed change characteristics in an embodiment of the invention. In the figure, ■ indicates the maximum value of the welding speed set according to the welding conditions, which is about 10 m/min when tack welding is performed at high speed using two electrodes. Vo is the welding speed when both the leading and trailing electrodes enter the welding start point of the tab plate attached to the welding start point of the base metal, and is slightly less than the preset maximum welding speed v1. The speed is slow.

To start welding, after setting the maximum values for the welding current, electrode spacing, and welding speed for the leading and trailing electrodes that match the welding conditions, weld the welding device equipped with the leading and trailing electrodes from the front of the tab plate. Start moving the trolley or the base material carrying the , and make sure that both the leading and trailing electrodes enter the welding start point of the tab plate at a speed slightly slower than the welding speed vl. Welding is started when both electrodes enter the welding start point of this tab plate, and the welding speed is gradually increased from speed v0 to reach a predetermined speed V1 by the time both electrodes reach the end of the base metal. Tack welding of the base metal is performed at this welding speed v1.

As mentioned above, the speed at which the leading and trailing electrodes enter the welding start point of the tab plate is a little slower than the predetermined welding speed, so the welding speed will drop by the time both electrodes reach the end of the base metal. can be easily changed to a predetermined speed v1, and the welding speed within the tab plate can be changed slowly, so the molten metal follows the electrode well and the welding current of the leading electrode can be stabilized quickly. I can do it.

(Effects of the Invention) As explained above, this invention applies a welding electric current to the welding start point of the tab plate at a speed slightly slower than the predetermined welding speed, so that the welding speed within the tab plate reaches the predetermined speed. Since the change can be made slowly to reach It is also possible to prevent defects from occurring.

[Brief explanation of drawings]

Fig. 1 is a welding speed change characteristic diagram of an embodiment of this invention;
The figure is an electrode arrangement diagram for the two-electrode welding method, and FIG. 3 is a conventional welding speed change characteristic diagram. 1... Leading electrode, 2... Trailing electrode, 6, 5... Arc, 4... Molten metal, Vl... Predetermined welding speed. Agent Patent Attorney Sanro Kimura Figure 2

Claims (1)

[Claims] In a welding method in which the welding speed is set to a predetermined speed and tack welding of the base metal is performed, the welding electrode or the base metal is moved from before the welding start point of the tab plate, and the welding electrode is moved at a speed slightly slower than the predetermined welding speed. to enter the welding starting point,
A high-speed continuous tack welding method characterized by performing tack welding by gradually increasing the welding speed at the same time as welding starts.