JPS623877A - Welding method - Google Patents

Abstract

PURPOSE:To enable a deeper penetration and narrower groove area and to make the welding faster by arranging a non-consumbable electrode at the front of the consumable electrode in a butt welding. CONSTITUTION:The welding is performed by arranging as the preceding electrode plural (two pieces for instance) non-consumable electrodes 14, 15 on the base metal 13 providing the groove 12 abutted at a root face 11 and the welding is further performed by arranging as the succeeding electrode plural (three pieces for instance) consumable electrodes 16, 17, 18. Due to the vicinity of the groove 12 being preheated by the welding by the non-consumable electrodes 14, 15, a deeper penetration is obtd. even if the groove 12 of the base metal 13 be narrow in the welding by consumable electrodes 16, 17, 18 and the filling quantity of the welding metal to the groove 12 can be reduced as well, enabling a high speed welding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a welding method, and specifically relates to an improvement in a butt welding method for ships, steel structures, trenches, construction machinery, etc.

[Prior art]

Structures such as ships basically have a plate or frame structure, in which skin materials are joined and assembled by butt welding to a predetermined size. Currently, many butt welding methods have been established, but the most commonly used welding method is submerno arc welding.

FIG. 5 shows the groove shape and electrode arrangement of conventional submerged arc welding, in which the base material IK has a relatively wide groove 2, and the root face 3 is also relatively small. This method is an example of three-electrode welding, and includes 4, 5.
Reference numeral 6 denotes electrodes arranged at appropriate pitches in the welding direction.

FIG. 6 shows a cross section of a welded joint obtained by the above method, and the groove 2 provided in the base material 1 is shown by a dotted line. Also, 4a, 5m.

6a are weld metals formed by the first, second and third electrodes, respectively.

[Problem that the invention seeks to solve]

In the submerged arc welding method, it is possible to increase the welding speed to some extent by increasing the number of electrodes. However, when welding with the first to third electrodes 4 to 6,
When the thermal cycle of these welded parts 4 and 6a is measured using the test piece shown in FIG. 7, the characteristic diagram shown in FIG. 8 is obtained.The penetration is relatively shallow due to the restriction of the energy density of the arc. In addition, 7 in Fig. 7 is a hole provided for measurement, and 8
is a thermocouple. As a result, for example, when performing single-sided welding, it is necessary to make the root 7 and 8 of the groove small, and the groove angle also needs to be selected relatively wide. There was a problem in that it took time to fill with weld metal, and even if there were multiple electrodes, welding had to be performed at a relatively slow speed.

The present invention aims to provide a welding method that makes it possible to narrow the groove area by deepening penetration in metal butt welding, and which achieves a significant increase in speed compared to conventional methods. It is.

[Means for solving problems]

The present invention is characterized in that metal butt welding is performed by arranging a plurality of non-consumable electrodes as leading electrodes and arranging a plurality of consumable electrodes as trailing electrodes.

[Effect]

According to the present invention, a plurality of non-consumable electrodes are arranged in front of a consumable electrode, and the groove portion is heated by the arc heat of the non-consumable electrodes, and then welding is performed using a plurality of consumable electrodes. It is possible to increase the depth of groove and narrow the groove area, which in turn makes it possible to significantly speed up welding.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

First, a base material 13 that is butted at the root face 11 and provided with a groove 12 is prepared. The angle of the groove 12 is narrower than in the conventional method, and the root 7 ace 11 is made larger, and as a result, the area of the groove 12 is narrower. Subsequently, welding is performed by arranging a plurality (for example, two) of non-consumable electrodes 14.15 as leading electrodes, and further arranging a plurality of (for example, three) consumable electrodes 16, 17.18 as trailing electrodes. (as shown in Figure 1). By such welding, the joint shown in FIG. 2 is obtained. In addition, 12 in Figure 2
is the groove provided in the base material 13, 16m, 17h, 18g
is the weld metal formed by the consumable electrodes 16, 17, and 18.

Thus, the non-consumable electrodes 14.15 and the consumable electrodes 16,1
When the thermal cycle of the welded part during welding according to 7.18 is measured using the test piece shown in FIG. 3, the characteristic diagram shown in FIG. 4 is obtained.

Note that 19 in Figure 3 is a hole provided for measurement, and 20
is a thermocouple. For example, two non-consumable electrodes 14.15 are arranged in front of the consumable electrodes 16, 17 and 18, and the non-consumable electrodes 14.1 are placed in front of the consumable electrodes 16, 17 and 18.
By welding at step 5, the vicinity of the groove 12 can be preheated.

Therefore, when welding with the consumable electrodes 16, 17, 18, deep penetration can be obtained even if the groove 12 of the base metal I3 is narrow, and since the amount of weld metal filling the groove 12 can be small, high-speed welding is possible. It becomes possible.

Although two non-consumable electrodes are arranged in the above embodiment, it is of course possible to use more than this.

〔Effect of the invention〕

As detailed above, according to the welding method of the present invention, by placing the non-consumable electrode in front of the consumable electrode and preheating the groove in advance, The angle can be narrowed, and the root face of the groove can be made larger, making it possible to narrow the groove area. It has remarkable effects such as requiring less filling amount and enabling faster welding.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the welding process in an embodiment of the present invention, FIG. 2 is a sectional view of a joint after welding, and FIG. 3 is a sectional view of a test piece for measuring thermal cycles during welding. Figure 4 is a characteristic diagram showing the thermal cycle of each electrode obtained from the test piece in Figure 3, Figure 5 is a perspective view showing welding by the conventional method, and Figure 6 is a cross section of the joint after welding by the conventional method. Figure 7 is a cross-sectional view of a test piece for measuring thermal cycles during welding using the conventional method, and Figure 8 is a characteristic diagram showing the thermal cycles of each electrode determined from the test piece shown in Figure 7. be. 1. Root face, 12. Bevel, 13.
・Base material, 14.15...Non-consumable electrode, 16,17゜1
8-...Consumable electrode, 16 a + 17 a + 1
+! ? a = weld metal, 19... hole, 20...
thermocouple. Applicant's sub-agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 61 Figure 4 Figure 5 @ Figure 6

Claims (1)

[Claims] 1. A welding method for butt welding metals, which comprises arranging a plurality of non-consumable electrodes as leading electrodes and arranging a plurality of consumable electrodes as trailing electrodes.