JPS59118294A - Electroslag welding method - Google Patents

Abstract

PURPOSE:To prevent the slag inclusion near the contact point between a base metal and a strap plate and to obtain a defect-less electroslag weld zone by providing a groove which prevents the stagnation of molten slag in the base metal near the part where the angle between the base material and the strap plate is acute. CONSTITUTION:A base metal 102 is installed with the spacing from a base metal 101 and copper strap plates 103, 104 are attahced to enclose the spacing between the two materials, thereby forming a groove part 105. A welding wire 106 urapping a wire 107 is inserted into the part 105, and electroslag welding is performed. A groove 108 having a distance L3 from the plates 103, 104 and having a width L1 and a depth L2 is formed in the position of the part 105 of the material 101 in the weld line direction. The cooling near the end of the groove of the material 101 by the plates 103, 104 is relieved by the groove 108, whereby the stagnation of molten slag 109 is prevented and the transmission efficiency of slag heat is improved.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to consumable and non-consumable electroslag welding methods.

[Technical background of the invention]

The electroslag welding method is a single-layer upward welding method for ultra-thick steel plates, and is classified into consumable and non-consumable nozzle types depending on the shape and role of the welding nozzle. That is, a type in which the welding nozzle melts during welding is called a consumable nozzle type, and a type in which the welding nozzle does not melt is called a non-consumable nozzle type. Therefore, a conventional example will be explained with reference to FIG.

Reference numerals 1 and 2 in the figure indicate base materials. This base material 1 and 2
are installed with a predetermined gap. A pair of copper contact plates 3 and 4 are fixed to the base materials 1 and 2 so as to reduce the gap, and together with the base materials 1 and 2, form a groove portion 5. Cooling water is contained within this copper contact plate 3.
The copper contact plate 3 is cooled by this cooling water. Further, 6 in the figure indicates a welding nozzle. An electrode wire 7 is contained within this welding nozzle 6, and an arc is generated between the tip of the electrode wire 7 and the base metal 1.2, and the electrode wire 7 itself melts due to breakage and welding is performed. This is the configuration that is performed.

Further, the electrode wire 7 is supplied by a pair of rollers 8 and 9. The numbers of the electrode wires 7 and welding nozzles 6 are determined in relation to the wall thicknesses of the base materials 1 and 2. Further, a flux 10 is provided near the welding nozzle 6. That is, the flux 10 is melted by the arc generated between the electrode wire 7 and the base materials 1 and 2, and the groove portion 5 is melted.
It has a structure that improves weldability by coating the steel.

According to the above configuration, when welding is performed, base materials 1 and 2 are first installed with a predetermined gap between them. Then, copper contact plates 3 and 4 are installed to cover this gap to form a groove portion 5. Then, a welding nozzle 6 and a flux 10 are installed, and the rollers 8 and 9 supply the stain electrode wire 7 to the groove 5 through the welding nozzle 6. and electrode wire 7
An arc is generated between the tip of the base metal 1.2 and the flux 10 is melted by this arc, and molten slag 11 is generated. The inside of the groove portion 5 is then filled with molten slag 11. By melting the slack 10, the shear arc disappears and a current flows between the electrode wire 7 and the base materials 1 and 2.

This current generates surface heat iQ as shown in the following equation.

Q-"0.24EI (cat/s) -(
A) However, E; Welding voltage; Welding current Due to this amount of heat Q, the temperature of the above molten slag 1 rises, and the base metal 1,
The base materials 1, 2 and the electrode wire 7, which have a melting point of 2 or higher, are melted. Thereby, the base materials 1.degree. 2 are joined together in a molten pool 12 under a bath of molten slag 11, and then cooled to form a weld metal 13.

[Problems with background technology]

Generally, when welding is performed using the above-described method, approximately 82% of the heat generated by resistance is consumed in melting the base materials 1 and 2 and the electrode wire 7. However, as shown in Figure 3, in the case of irregular joints such as so-called T-joints in which the base metal 2A is installed perpendicularly to the base metal IA, the heat transfer efficiency to the base metal IA is poor, and Material IA and copper backing plates 3A and 4A
The molten slag 11 may accumulate in a part of the corner of the molten slag, and the molten slag 11 may not be heated or cooled by convection. Then, before the base metal IA melts, the molten slag 11 in a part of the corner is cooled and solidified by the base metal IA and the copper contact plates 3A and 4A, and becomes solidified slag 14 between the weld metal 14 and the base metal IA. This causes slag entrainment. If such slag entrainment occurs, the area must be repaired after welding.
It requires work such as scraping, inspection, and repair using other welding methods, and is not desirable in terms of cost.

[Purpose of the invention]

The purpose of the present invention is to prevent the occurrence of welding defects such as a part of the corner between the base material and the plate, eliminate the need for repair work due to the occurrence of welding defects, and ``improve weldability and widen the area. The object of the present invention is to provide an electroslag welding method that can be applied to a wide range of areas.

=5- [Summary of the Invention] The electroslag welding method according to the present invention includes the steps of: positioning opposing base materials with a predetermined gap; installing a cooling plate to cover the gap; In the electroslag welding method, which includes the step of installing a welding nozzle containing an electrode wire in the gap covered by the backing plate, the base material near the part where the included angle between the base metal and the backing plate forms an acute angle. In this structure, retention prevention grooves are formed in advance to prevent retention of molten slag.

In other words, by forming a retention prevention groove in the base material near the part where the included angle between the base material and the cooling plate forms an acute angle, the cooling by the cooling plate is alleviated, and the contact point between the base material and the cooling plate is This structure prevents slag W from stagnant molten slag in the vicinity and further improves slag heat transfer efficiency.

Therefore, it is possible to prevent slag entrainment near the contact point between the base metal and the cooling plate, suppressing the occurrence of weld defects, and obtaining a high-quality weld.

6- [Embodiment of the Invention] 3 A first embodiment of the present invention will be described with reference to Fig. ψ. In the figure, 101 and 102 indicate base materials.

The base material 102 is installed perpendicularly to the surface of the base material 101 with a gap (groove portion) therebetween. Copper contact plates 103 and 104 are attached to surround the gap to form a groove 105. A welding nozzle 106 is inserted into this groove 105, and an electrode wire 07 is wired inside this welding nozzle 106. Grooves 10B having a width Ll and a depth L2 are formed in the weld line direction at the groove portion 105 of the base material 101 at a distance L3 from the copper contact plates 103 and 104, respectively. By forming this groove 108, cooling of the vicinity of the open end of the base material 101 by the copper contact plates 103 and 104 is alleviated, and stagnation of the molten slag 109 is prevented, and the slag heat transfer efficiency is improved. This is a configuration that improves.

According to the above configuration, first, the electrode wire 07 and the base material 101
．． An arc occurs between the 102 and the flux (not shown) →
The molten slag 109 is melted and filled in the groove 105. Then, a current flows between the electrode wire 107 and the base material 101, 102, thereby causing the molten slag 109
The resistance heats up and the temperature rises. As the temperature of the molten slag 109 rises, the stain electrode wire 107 and the base metals 101 and 102 are melted and deposited under the column of the molten slag 109, bonded together in a molten pool, and then cooled to form weld metal. At this time, a groove 1 of medium L1 + depth L2 is placed at the groove 105 position of the base material 101.
08 is formed in the direction of the welding line, so the copper contact plate 103
The cooling of the vicinity of the open end of the base material 101 by the base material 104 is relaxed, and the stagnation of the molten slag 109 in the vicinity is suppressed. Furthermore, since the slag heat transfer efficiency is improved, it is possible to prevent the slag entrainment phenomenon that conventionally occurs near the contact points between the base material 101 and the copper contact plates 103 and 104.

This is illustrated with reference to FIG. FIG. 4 is a photographic representation of a welded part welded by the conventional method (left side in the figure) and a welded part welded by the method according to the present embodiment (right side in the figure). As is clear from this, the slag entrapment part B occurs on the left side, while it does not occur on the right side. In this way, the quality of the welded part can be significantly improved, and there is no need to carry out repair work for welding defects as in the past, and costs can also be reduced.

Next, a second embodiment will be described with reference to FIG.

That is, grooves 110° 111 are formed in the welding line direction near the contact points between the base material 101 and the copper contact plates 103 and 104, respectively. Therefore, the base material 101 and the copper backing plate 103
It is possible to achieve the same effects as in the first embodiment, such as cooling relaxation in the vicinity of the contact point with molten slag 104, prevention of retention of molten slag 109, and improvement in slag heat transfer efficiency.

Next, a third embodiment will be described with reference to FIG.
That is, it has a configuration in which a surface 112 or a rounded surface 113 is provided on the base material 102 side.

-9= When the leg length L4 of the fillet is larger than the groove Ls due to cracking, cooling relaxation near the contact point between the base material 102 and the copper contact plates 103 and 104, prevention of retention of molten slag 109, and slag heat transfer efficiency This is a configuration that aims to improve the performance. Further, on the base material 101 side, there are grooves 110 having the same structure as in the second embodiment.
111 is formed.

Therefore, it is possible to prevent slag from being caught in the vicinity of the contact points between the base material 101 and the copper contact plates 103 and 104, as well as prevent the base material 10
It is also possible to improve the slag heat transfer efficiency on the second side, and it is possible to obtain a high quality welded joint.

Note that in the second and third embodiments, the same parts as those in the first embodiment are denoted by the same reference numerals, and explanations of the same constituent parts are omitted.

〔Effect of the invention〕

The electroslag welding method according to the present invention includes a step of positioning opposing base materials with a predetermined gap, a step of installing a cooling plate to cover the gap, and a gap created by the plate. −10= In an electroslag welding method comprising a step of installing a welding nozzle containing an electrode wire at the base metal, the molten slag is prevented from accumulating in the base metal near the part where the included angle between the base metal and the plate is an acute angle. This is a configuration in which retention prevention grooves are formed in advance.

In other words, a retention prevention groove is formed in the base material near the part where the included angle between the base material and the cooling plate forms an acute angle, which alleviates the cooling caused by the cooling plate and also prevents the contact between the base material and the cooling plate. This structure prevents molten slag from staying near the contact point and further improves the efficiency of slag heat transfer.

Therefore, it is possible to prevent slag entrainment in the vicinity of the contact point between the base material and the cooling plate, suppressing the occurrence of weld defects, and obtaining a high-quality weld.

[Brief explanation of drawings]

Fig. 1 is a perspective view for explaining the conventional electroslag welding method, Fig. 2 is a perspective view showing welding of a T-joint, Fig. 3-7 is a sectional view near the groove, and Fig. 4 is a perspective view for explaining the conventional electroslag welding method. 5 and 6 are cross-sectional views of welded parts according to the conventional method and this embodiment, respectively.
FIG. 101.102... Base material, 103, 104... Copper backing plate, 106... Welding nozzle, 107... Electrode wire, 10B... Retention prevention groove. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) The process of positioning the opposing base materials with a predetermined gap, the process of installing a cooling plate to cover the gap, and the process of inserting the electrode wire into the gap covered by this plate. In the electroslag welding method, which includes a step of installing an enclosed welding nozzle, a retention prevention groove is preliminarily formed in the base material near the part where the included angle between the mother plate and the plate is an acute angle to prevent retention of molten slag. An electroslag welding method characterized by forming. (2) The electroslag welding method according to claim 1, wherein the retention prevention groove is formed with a predetermined distance from the backing plate.