JPS62183965A - High speed welding method - Google Patents

Abstract

PURPOSE:To eliminate the need to execute an adjustment and an attachment of a tab plate, and to easily execute a high speed welding, by executing the welding for a prescribed time by the welding start voltage, current and speed whose values are smaller than stationary welding voltage, current and speed at the time of start of welding. CONSTITUTION:An arc is started by impressing a hot voltage whose voltage is higher than a stationary welding voltage. As soon as the arc is started, the voltage is controlled to a welding start voltage whose voltage is lower than the stationary welding voltage, and also a welding start current is controlled to a smaller value than that of a stationary welding current. Also, a moving speed of a truck is increased slowly, and controlled so that a small welding start speed is obtained. After welding has been executed for a prescribed time by said welding start voltage and welding start current, and thereafter, the voltage and the current are raised gradually, and set to a stationary welding voltage and a stationary welding current. As for a welding speed, the rise start time is delayed from the voltage and the current, and the rise time for obtaining the stationary welding speed is shortened. In the welding terminal part, said voltage and current are dropped to a little smaller values than those of the stationary welding voltage and current.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a welding method suitable for high-speed welding performed using so-called MIG welding or MAG welding.

[Prior art]

In the process of manufacturing UOE steel pipes by bending steel plates into a cylindrical shape and welding the joints, when welding the joints, 'I4
After bending the plate into a cylindrical shape, the beveled ends are butted together, temporarily attached using MIG or MAG welding from the outside, and then finished by welding from the inside. In this tack welding, as shown in FIG. 6, at the time of starting the arc of welding, a pressure Vo of a higher voltage than the steady welding voltage v2 is applied to facilitate the start of the arc. When the arc starts, the voltage is set to a steady welding voltage V2, the alpha solder is controlled to a steady welding speed 2, and the cart is moved at a predetermined steady welding speed S2.

[Problem that the invention seeks to solve]

However, in the conventional bath welding method described above.

When performing high-speed welding with a welding speed of 4 m/min or more.

Arc sometimes fails to start. If the arc start fails, as shown in FIG. 7, the initial bead 14 of the weld applied to the groove portion 12 of the steel pipe 10 is not continuous and becomes scattered, resulting in insufficient extra welding. Furthermore, even if the arc start is successful, as shown in FIGS. 7 and 8, the start portion will be larger than the normal bead 16 and the % groove portion 1
A protrusion 18 is formed that protrudes from 2. These protrusions 1
8, as shown in FIG. 9, when the steel pipes 10 collide with each other, the other steel pipe 10 is damaged.

In addition, as shown in FIG. 7, if the initial bead 14 is not continuous, there will be insufficient extra welding, and when welding from the inner surface like the welding part 20 in the later process, as shown in FIG. 10(B)K, The meltdown fell and 22 occurred.

This will result in a welding defect. In addition, FIG. 10(A) shows the state when welding is performed from the inner surface when the normal bead 16 is tacked.

Therefore, conventionally, in order to compensate for the above-mentioned drawbacks, bead defects at arc start were repaired after tacking. In addition, in order to avoid bead defects at the time of arc starting, as shown in FIG.
0 was being tacked on. This makes welding work complicated.

Production efficiency had to decline.

The present invention has been made to eliminate the drawbacks of the prior art, and an object of the present invention is to provide a high-speed welding method that can simplify welding work.

[Means to resolve the gap]

In the present invention, after starting the arc by applying a hot voltage of 1 pressure higher than the steady welding voltage, the steady laminar liquid voltage,
In a high-speed welding method that performs welding with a welding flow and a welding speed, when the arc is started by applying pressure to the hot ' This is a high-speed welding method characterized by welding at a steady welding voltage, welding current, and welding speed after bath welding.

[Effect]

By virtue of the above-described configuration, the present invention enables a normal bead to be obtained from the start of the arc, and eliminates complicated work such as temporary fixing work and tab plate attachment work.

〔Example〕

A preferred embodiment of the high-speed welding method according to the present invention will be described in detail with reference to the accompanying drawings. Note that the same reference numerals are given to the parts corresponding to the parts explained in the prior art, and the explanation thereof will be omitted.

FIG. 2 is a block diagram schematically showing a welding apparatus for carrying out the high-speed welding method according to the present invention.

In FIG. 2, reference numeral 30 denotes an operating desk that can set welding ridge pressure, welding current, and welding speed. code 3
2 is a sequence controller, and f# contacts 34, 36.3
8 and the trolleys 40, 42, and 44, and manages the presence or absence of failures. Reference numeral 46 is a copying control panel, and the trolley 4
Performs feeding control and copying control of 0.42.44. code 48
The welding conditions can be easily set on a setting panel provided separately from the operating desk 30 so that there is no time delay in control. That is, #i is set on the setting table 48, and the welding start voltage of each welding machine 34, 36, 38 is set.

Voltage, welding speed (moving speed of carts 40, 42, 44) 9
It is possible to set the time, voltage for crater treatment, 'itL time, and switch welding patterns.

Figure 1 shows the welding process performed using the welding equipment shown in Figure 2.
1 is a time chart showing an embodiment of the welding method of the present invention. In the embodiment shown in Fig. 1, the S contact speed is 4 m/min.
It is particularly preferable to apply the method to the above cases.

In this embodiment, a hot voltage vot higher than the steady welding voltage v2 is first applied to start the arc. At the same time as the arc starts, the voltage is changed to the steady welding voltage V! Welding start voltage V1 of lower voltage (for example, 17
V), and at the same time, the welding start '4 flow rate 1 is controlled to a value smaller than the steady welding voltage level 2 (for example, 170 A). Then, the moving speed of the cart was slowly increased to a steady welding speed of S! a smaller welding start speed Sl (for example 1
m/m1n). This welding starting voltage Vim and welding starting current 11 are applied for a predetermined time (for example, 1
．． 5sec) After welding, gradually increase the voltage and current,
Set the steady welding voltage V2e to the steady welding current 2 (for example *
V over 1.5-2 sec = 25v, Is =
500AK]. In addition, the welding speed should be set to a slightly slower startup time than the voltage and current (for example, 0.5 seconds).
% Shorten the start-up time to obtain a steady welding speed Ss (for example, 4 m/5 ec) At the welding end, reduce the crater treatment voltage V3 + crater treatment area RIs, which is a value slightly smaller than the steady welding voltage and current. , perform crater treatment.

The tacking results obtained in the above example were very good as shown in FIG. That is, there was no arc start failure, and it was possible to prevent the occurrence of protrusions that occur at the time of arc start. Therefore, there is no need for conventional rework or installation of tab plates, and high-speed welding can be performed reliably.
It can be done easily.

FIG. 4 is a time chart showing another embodiment according to the present invention. The embodiment shown in FIG. 4 is particularly suitable for welding at a welding speed of 2 m/min or less.

In this embodiment, welding start voltage v1. The ramp-up from the welding starting current 11 to the steady welding voltage 11 to the steady welding voltage KI2 is performed at one time. Also, the welding speed (
The trolley ($ moving speed) is immediately after the start of @ contact.

The steady welding speed e82 is raised from a stopped state at once.

The time when welding start voltage v1 was applied was 0.2 seconds, and the fourth
FIG. 5 shows the welding results when ts to seC,sl = 2 m/min. As in the previous example, there was no arc start failure, the overlay was properly applied, and good tacking was achieved.

In addition, each of the above examples OVI * It # Be
11 #1, and rising gradient (LADv, LADt
.

LADs) etc. are appropriately determined based on the material of the material to be welded (base metal), the thickness of the base metal, welding conditions, etc.

[Effects of the Invention] As explained above, according to the present invention, at the start of welding, a steady welding voltage, 1t15!, a welding start core pressure, a torrent flow, and a welding iron welded at a speed for a predetermined period of time are smaller than the speed. By making the welding state as follows, there is no need for rework or attachment of the tab plate, and high-speed welding can be easily performed.

[Brief explanation of drawings]

Fig. 1 is a time chart showing an example of the high-speed welding method according to the present invention, Fig. 2 is a schematic block diagram showing an example of a welding device for implementing the welding method shown in Fig. 1, and Fig. 3 is a FIG. 2 is an explanatory diagram of welding results according to the example shown in FIG. 1,
FIG. 3(A) is a front view. Figure 3 (B) is a plan view % Figure 3 (C) tj: Figure 3 (A
4 is a time chart showing another embodiment of the present invention, and FIG. 5 is a welding result according to the embodiment of FIG. 4. Figure 6 is a time chart of the conventional high-speed welding method, Figures 7 and 8 are explanatory diagrams similar to Figure 3 of the welding start part by the conventional high-speed welding method, and Figure 9 is the bead excess. Fig. 10 is an explanatory diagram of defects caused by insufficient excess, and Fig. 11 is an explanatory diagram of defects caused by insufficient excess material. 3 mouth (/'I) (15) (
C) 7th figure 1f, s mouth (A) ”) (C) 3rd mouth Haruma is) YJ9 mouth

Claims (1)

[Scope of Claims] 1. A high-speed welding method in which an arc is started by applying a hot voltage higher than a steady welding voltage, and then welding is carried out at a steady welding voltage, welding current, and welding speed. When the arc is started by hot voltage,
After welding with a welding start voltage lower than the steady welding voltage for a predetermined time, a small welding start current and a welding start speed,
A high-speed welding method characterized by welding at a steady welding voltage, welding current, and welding speed. 2. A high-speed welding method according to claim 1, characterized in that the transition from welding start voltage, welding start current, and welding start speed to steady welding voltage, welding current, and welding speed is performed gradually. 3. In claim 1, the welding start speed is set to zero, and the transition from the welding start voltage, welding start current, and welding start speed to the steady welding voltage, welding current, and welding speed occurs all at once. A high-speed welding method characterized by: