JPH0623573A - Electroslag welding device - Google Patents

Abstract

PURPOSE:To increase a welding speed, to improve the efficiency, to decrease a welding heat input amount and to improve the joint strength. CONSTITUTION:A main wire 6a and an auxiliary wire 6b are arranged in a V-type or X-type groove 3 enclosed by base materials 1, 2 and a fixed water cooling plate 4 and a sliding water cooling plate 5. The auxiliary wire 6b is finer in diameter than the main wire 6a. A wire supplying device and welding electric sources 9a, 9b are equipped respectively to the main wire 6a and the auxiliary wire 6b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroslag welding apparatus used for butt vertical welding of thick steel plates.

[0002]

2. Description of the Related Art As shown in FIG. 3, a work procedure for performing butt upright welding of thick steel plates using electroslag welding is a groove formed between upright base materials 1 and 2. 3 is surrounded by a fixed water cooling plate 4 and a sliding water cooling plate 5, and an electrode wire 6 is fed into the groove 3 by a feeding roller 7 through a non-consumable nozzle 8 while the base material 1 and the electrode wire 6 are fed.
A welding power source 9 connected between the molten metal 1 and the molten metal 10 energizes the molten metal 10 in a pool of the molten slag 11 to melt the electrode wire 6 by its resistance heat generation.
A weld metal 12 is obtained by solidification of 0, so that a joint 13 is formed by one welding.

However, in the case of the electroslag welding method, since it is a large heat input welding method utilizing the resistance heat generation of the molten slag having conductivity, the welding speed is slow and
When the amount of heat input is large, there is a problem in strength of the welded joint such as cracking in the bending test, and there is a problem that a large strain occurs due to the wide groove.

Therefore, in order to solve the above problems,
As shown in (a) of FIG. 4, a method of welding the groove 3 formed between the base materials 1 and 2 into a V shape, or as shown in (b) of FIG. (JP-A-5
No. 1-92545, No. 54-2947, etc.), and a single-sided slide-type vertical welding device for use in the groove of V type, X type, etc. has been developed (Japanese Patent Laid-Open No. 58-6849).
No. 6).

[0005]

However, when electroslag welding is performed using the above V-type or X-type groove,
Since the groove cross-sectional area is small, the welding speed can be increased and high efficiency and low heat input can be achieved to some extent, but the improvement effect is limited only by devising the groove shape. For this reason, it is required to further increase the welding speed to achieve high efficiency and also to achieve low heat input.

The welding heat input is J = 60 · E · I /
It is given by the formula of v. Where J is the welding heat input (Jou
le / cm), v is the welding speed (cm / min), E is the welding voltage (V), and I is the welding current (A). The welding heat input is proportional to the welding current and welding voltage and inversely proportional to the welding speed.
Therefore, the welding heat input amount can be reduced by increasing the welding speed, and the welding heat input amount can be reduced by lowering the welding current and welding voltage.

However, if the welding current and the welding voltage are reduced, the heat of fusion of the electrode wire is reduced, so that the amount of wire fusion is reduced and the welding speed becomes slow. Therefore, although the welding heat input amount becomes small, high efficiency cannot be achieved.

Therefore, the present invention focuses on further increasing the welding speed, and aims to provide an electroslag welding apparatus capable of reducing the heat input of welding at the same time while improving the efficiency. .

[0009]

In order to solve the above problems, the present invention provides a V-shaped or X-shaped groove formed between base materials and surrounded by a fixed water cooling plate and a sliding water cooling plate. Electroslag welding apparatus in which electrode wires are continuously fed to the base metal and the electrode wires are melted by using resistance heating of the molten slag by a welding power source connected between the base material and the electrode wires. In the above, the main wire and the auxiliary wire having a diameter smaller than that of the main wire are arranged in the groove at a predetermined distance or more, and each wire is equipped with a wire feeder and a welding power source. The configuration.

[0010]

When the auxiliary wire is fed and melted together with the main wire in the groove at a predetermined distance or more, the melting amount corresponding to the feeding amount of the auxiliary wire is increased, and as a result, the welding speed is increased. The amount of heat is reduced.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention, which is a V-shaped member formed between upright base materials 1 and 2 and surrounded by a fixed water cooling plate 4 and a sliding water cooling plate 5. The electrode wire is continuously fed into the groove 3, and the molten slag 11 is generated by the welding power source connected between the base material 1 (or 2) and the electrode wire.
In the non-consumable electroslag welding apparatus in which the electrode wire is melted as the molten metal 10 by utilizing the resistance heat generation of No. 1, and the joint 13 is formed by the weld metal 12 obtained by solidifying the molten metal 10. As the wire, in addition to the main wire 6a having a normal diameter (for example, φ2.4 mm), a diameter smaller than the main wire 6a (for example,
φ1.6 mm) auxiliary wires 6b, each of which can be fed separately by wire feeding rollers 7a and 7b as wire feeding devices, and the main wire 6
The main wire 6 is arranged so that the position where the molten slag 11 a is fed into the pool is guided to a relatively wide position in the center of the groove 3.
The position of the non-consumable nozzle 8a through which a is passed is set, and the auxiliary wire 6 is guided so that the feeding position of the auxiliary wire 6b into the pool of the molten slag 11 is guided to the narrow portion of the groove 3.
b, set the position of the consumable nozzle 8b,
Arrange a and 6b in a well-balanced manner so that both wires 6a and 6b do not come into contact with each other. Incidentally, the distance between the main wire 6a and the auxiliary wire 6b needs to be 10 to 15 mm. Further, between the base material 1 (or 2) and the main wire 6a and the base material 1
The welding power sources 9a and 9b are connected between (or 2) and the auxiliary wire 6b, respectively.

Using the electroslag welding apparatus having the above construction, as shown in FIG. 1, the main wires 6a and the auxiliary wires 6b are fed into the pool of the molten slag 11 to weld the base materials 1 and 2. And, the welding speed is increased by feeding the auxiliary wire 6b, and the welding heat input amount can be reduced.

More specifically, the auxiliary wire 6b is a hot wire which is energized by the welding power source 9b. For example, when a cold wire which is not energized is used, J = 60 · E which represents the welding heat input amount. In the formula of I / v, the welding current and welding voltage, which are the numerator, do not change, and the welding speed in the denominator increases. On the other hand, the auxiliary wire 6b
In the case of a hot wire, the total amount of heat input is the amount of heat input by the main wire 6a plus the amount of heat input by the auxiliary wire 6b. The amount of heat will decrease. According to the experiments by the present inventors, a main wire having a diameter of 2.4 mm was used, and welding was performed under the conditions of a current of 500 A and a voltage of 48 V.
At the same time, a wire with a diameter of 1.6 mm was used as an auxiliary wire, and the result of welding under conditions of a current of 170 A and a voltage of 28 V,
The welding speed was 2.0 cm / min. It was found that the welding speed was higher than the welding speed of 1.4 cm / min when only one main wire was used. Since the increase of the welding speed means the shortening of the welding time, the reduction of the welding heat input amount plays an important role in securing the strength of the welded portion. Incidentally, in the case of a cold wire as well, the amount of heat input for welding can be reduced as described above, but since the cold wire takes a long time to be melted as long as no current is applied, a hot wire that can obtain a higher melting amount is preferable.

In the above description, the current value of the auxiliary wire 6b is determined by the state of the molten pool. However, if the current is high, the molten pool will be in a boiling state and the pool will become unstable. When it is set to 480A, the current value of the auxiliary wire 6b is appropriately set to 180A or less. Further, if the current is the same, the smaller the wire diameter is, the higher the current density is, and the faster the wire melting rate is, so that the efficiency can be improved. Furthermore, in this case, selecting a wire having a small diameter is also advantageous in terms of downsizing the device and facilitating its handling. It should be noted that, if too low heat input is attempted during welding work, it may cause fusion failure, but it is necessary to adjust the feed rate of the auxiliary wire 6b to select the melting rate. Furthermore, as shown in FIG. Since the auxiliary wire 6b is fed to the narrow portion of the groove 3 to balance the melting with respect to the main wire 6a, the state of the molten pool can be properly maintained, and the problem of fusion failure can be eliminated. . In addition, when performing long welding, the welding may be interrupted and the wire reel (not shown) may be replaced. However, if the interruption time is long, the molten pool will cool and restart will be difficult. There is. Even in this case, in the present invention, since the power can be supplied from either the main wire 6a or the auxiliary wire 6b, it is possible to reduce the cooling of the molten pool and perform the replacement work of the wire reel with a margin. There is also an advantage that you can.

In the above embodiment, an example of application to a V-shaped groove is shown, but it can be applied to an X-shaped groove, and various other variations are possible without departing from the scope of the present invention. Of course, changes can be made.

[0017]

As described above, according to the electroslag welding apparatus of the present invention, in addition to the main wire, an auxiliary wire having a diameter smaller than that of the main wire is used, and the wire feeding is performed in correspondence with each wire. Since it has a structure equipped with a feeder and a power source for welding, it exhibits the following excellent effects. (1) Since the auxiliary wire can be fed as a hot wire together with the main wire into the pool of molten slag, the amount of fusion of the auxiliary wire can be increased and the welding speed can be increased. Can be reduced and the strength of the welded joint can be improved. (2) By adjusting the feeding speed of the auxiliary wire, the state of the molten pool can be properly maintained, and fusion failure can be prevented. (3) Since the auxiliary wire having a small diameter is used, it is easy to handle, the device can be prevented from increasing in size, and work can be performed without increasing the number of operating personnel. (4) Since the power supply state can be maintained for either the main wire or the auxiliary wire, even if the welding operation is interrupted once, the slag pool will be cooled to such a degree that restart becomes difficult. Can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an electroslag welding apparatus of the present invention.

FIG. 2 is a view taken along the line II-II of FIG.

FIG. 3 is a schematic diagram showing a welding work procedure by an electroslag welding method.

FIG. 4 shows an example of a groove shape, (a) showing a V-shaped groove and (b) showing an X-shaped groove.

[Explanation of symbols]

 1, 2 Base material 3 Bevel 4 Fixed water cooling plate 5 Sliding water cooling plate 6a Main wire 6b Auxiliary wire 7a, 7b Wire feeding roller (wire feeding device) 9a, 9b Welding power source 10 Molten metal 11 Molten slag

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kiyotaka Oe, Inventor Kiyotaka Oe, 59, Nakahara, Tobata-ku, Kitakyushu, Fukuoka 59, Nippon Steel Co., Ltd. (72) Riki Kuno 46, Nakahara, Tobata-ku, Kitakyushu, Fukuoka Of 59 Nippon Steel Corporation

Claims (1)

[Claims] 1. An electrode wire is continuously fed into a V-shaped or X-shaped groove formed between a base material and surrounded by a fixed water cooling plate and a sliding water cooling plate, and the base material and the electrode. In an electroslag welding apparatus in which the above-mentioned electrode wire is melted by using resistance heating of molten slag by a welding power source connected between the main wire and an auxiliary wire having a diameter smaller than that of the main wire. An electroslag welding apparatus, wherein the electroslag welding apparatus is arranged in the groove at a predetermined distance or more, and each wire is equipped with a wire feeding device and a welding power source.