JPS6012152B2 - Narrow gap MIG welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a steel plate for shielding gas protection in MIG welding of narrow gap multilayer welding of mainly extremely thick workpieces such as press slides, beds, crowns, etc. This article relates to a narrow joint MIG welding method that allows welding from the first layer to the last layer using the same torch without replacing the torch.

Conventionally, when narrow gap MIG welding is used for extremely thick plate joints of about 300 mm, for example, a flat groove internal torch and gas nozzle as shown in Figure 1 and an elliptical type as shown in Figure 2 are used. Two types of tools are used as a set: a mold finishing torch and a gas nozzle.

The purpose of its use is to take into consideration the occurrence of blowholes, and in the stack from the first layer to a position 35 mm below the top surface of the mother village, there is a first layer that allows shielding gas to flow only near the arc.
Using the flat type shown in the figure, from then on until finish welding,
The oval shape shown in Figure 2 is used. Therefore, it is necessary to prepare torches and gas nozzles for use in the dark and for finishing, and the torches and gas nozzles must be replaced during welding work, which greatly reduces work efficiency. In Fig. 1, 1 is a flat gas nozzle, 2 is a gas insertion port, 3 is a water-cooled pipe, 4 is a torch for inside the groove, 5 is a tip, 6 is a water-cooled pipe, and 7 is a cooling water inlet/outlet. be.

In Fig. 2, 8 is an oval gas nozzle, 9 is a gas insertion port, 10 is a water cooling pipe, 11 is a cooling water inlet/outlet, 12 is a surface torch, 13 is a chip, and 14 is a cooling water inlet/outlet. It is.

This invention was made with the above points in mind,
Next, this invention will be explained in detail with reference to the drawings from FIG. 3 onwards showing an embodiment thereof.

In those drawings, 15 is two objects to be welded,
The respective ends are opposed to form a narrow groove groove 6. 17 is a backing material, 18 is on the ends of both objects 15 to be welded,
Each is a copper plate for shielding gas protection that is erected via a flexible tape such as a glass tape 19, and the gap between the opposing surfaces of both steel plates 18 is made almost the same as the gap between the narrow grooves 16,
In addition, the opposing surfaces of both copper plates 18 are located approximately on the same plane as the surface of the narrow junction 16.

It is a magnet attached to the outside of the Nikawa copper plate 18,
The copper plate 18 is fixed at a predetermined position on the workpiece 15 to be welded.

Reference numeral 21 denotes a tapered cutout formed at the lower end of the facing surface of the steel plate 18, and serves to sufficiently store the shielding gas from the gas nozzle and promote the shielding effect during welding.

Reference numeral 22 is a flat-type groove-inside torch and gas nozzle shown in FIG. 1, and 23 is a weld metal. Note that the glass tape 19 facilitates the setting of the copper plate 18 onto the object to be welded 15, and since the upper surface of the object to be welded 15 is not flat,
This prevents shielding gas from leaking and increases shielding effectiveness. Therefore, by using the torch for inside the groove and the gas nozzle 22, it is possible to weld from the first layer to the finish welding of the final layer without replacing the torch, and the work efficiency is greatly improved. Furthermore, as shown in FIG. 4, the length of the steel plate 18 is set to an arbitrary length by appropriately adding copper plate elements 18' according to the welding length. Then, when the steel plate surface body 18' is being joined, as shown in FIG. and the recessed portion 25 of the other steel plate body 18' are joined together. As described above, according to the narrow gap MIG welding method of the present invention, a narrow gap is formed with the ends of two workpieces facing each other, and a flexible groove is placed on the ends of both workpieces, respectively. A steel plate for shielding gas protection is erected with a plastic tape interposed therebetween, and the distance between the opposing surfaces of the copper plates is approximately the same as the gap between the narrow grooves, and the opposing surfaces of the copper plates are aligned with each other between the opposing surfaces of the narrow grooves. A tapered cutout for shielding gas is formed at the lower end of the opposing surface of both the copper plates, and a magnet attached to the outside of both the copper plates connects each steel plate to the covered steel plate. Fix it to the welding object and
Both steel plates are made by joining together the convex and concave parts of a plurality of steel plate bodies, and by welding from the first layer to the final layer with the same torch without changing the torch. , it is possible to perform welding from the first layer to the final layer with one torch, and there is no need to prepare one for inside the groove and one for finishing, unlike in the past.
In addition, there is no need to replace the torch during welding work, which dramatically improves work efficiency.Furthermore, since the steel plate is erected on the workpiece via a flexible tape,
There is no gap between the steel plate and the object to be welded, and the shielding is complete, and no blowhole defects occur due to air entering through the gap.

Moreover, since a tapered cutout is formed at the lower end of the opposing surfaces of both copper plates, a sufficient amount of shielding gas is accumulated, and the amount of shielding gas used is extremely small. Furthermore, since the steel plate is fixed by the magnet, the copper plate can be easily and reliably erected and removed. Further, since the steel plate is constructed by competing and adding convex portions and concave portions of a plurality of copper plate bodies, it is possible to easily adapt to changes in welding length.

[Brief explanation of the drawing]

Figures 1 and 2 show the torch and gas nozzle for use inside the groove and for finishing, respectively; each figure (a) is a front view, and each figure (b) is a front view.
The figure is a side view, FIG. 3 is a cutaway front view of one embodiment of the narrow gap MIG welding method of the present invention, FIG. 4 is a perspective view of the steel plate in FIG. 3, and FIG. 5 is a part of FIG. 4. FIG. 1...Gas nozzle, 4...Torch, 5...Tip "1
5... Work to be welded, i6... Narrow gap, Turtle 8...・
・Steel plate for shielding gas protection. Qin/Zu's Brother 2 Figure 3 Figure 5 Younger Brother Mu's Figure 5

Claims (1)

[Claims] 1 Form a narrow gap with the ends of the two objects to be welded facing each other,
Shielding gas protection copper plates are erected on the ends of both the welded parts via flexible tapes, and the spacing between the opposing surfaces of the copper plates is approximately the same as the spacing between the narrow grooves, Opposing surfaces of the two copper plates are located substantially on the same plane as the narrow groove surfaces, and a tapered cutout for shielding gas is formed at the lower end of the opposing surface of the copper plates, Each of the copper plates is fixed to the object to be welded by a magnet attached to the outside of the copper plate, and each of the copper plates is made up of a plurality of copper plate bodies that are joined by fitting the convex portions and concave portions of each, and A narrow gap MIG welding method characterized by welding from layer to final layer using the same torch without replacing the torch.