JPS61162281A - Electric resistance welding method making combination use of energy beam - Google Patents

Abstract

PURPOSE:To heat relatively thick sheets as well at a prescribed temp. distribution and to make possible a high welding speed by projecting the respective radiation energy beams of at least two energy beam generator to the welding point. CONSTITUTION:Laser beams LB1, LB2 oscillated by laser oscillators LG1, LG2 are irradiated to mirrors MB1, MB2. The laser beams are projected by the mirrors MB1, MB2 and are further reflected by a synthesizing mirror Mx1 by which the laser beams LB1, LB2 are synthesized. The synthesized beam LBx is projected through a beam guide 29 to a wedge-shaped groove. The relatively thick-walled pipes are thus satisfactorily welded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a combined welding process that uses both electric resistance welding and the projection of an energy beam, such as a laser beam.

[Conventional technology]

Welding objects is required in a wide range of fields, and various methods are used, among which electric resistance welding is one of the most commonly used techniques.

For example, in the field of manufacturing welded pipes, it is generally used as a welding method for pipes called electric resistance welded pipes, which has a high welding speed, that is, has high productivity.

In the manufacturing method of ERW pipes, for example, in the welding pipe manufacturing process using the conventional high frequency contact welding method, first the steel IF is formed by a group of forming rolls.
are formed into a tubular shape, and their edges are butted together using a squeeze roll. As a result, the etched portion takes on a wedge shape with the abutting portion as the apex.

A high-frequency voltage is applied to the contacts placed upstream of the squeeze roll, and a high-frequency current is passed from one contact 4 to the other to form a wedge-shaped edge.
Flow i-frequency current. The edges are heated by this high frequency current, and the apex of the wedge shape, that is, the welding point, reaches the welding temperature and is welded under pressure by the squeeze roll.

The welding quality of ERW pipes is greatly influenced by the magnitude of the welding current, and when the welding power is too low, the edge part will be in a low heat input state and a welding defect called cold welding will occur. If the welding power becomes excessive and the edge portion is in a high heat input state, a welding defect called a penetrator may occur. The main cause of cold welding that occurs during low-heat-input pipe manufacturing is insufficient heating of the edge.In the case of springs 1 to 2, which occur during high-heat-input pipe manufacturing, the edge melts and the molten metal is ejected from the welding surface by electromagnetic force. The main cause is that the welding point repeats periodic positional fluctuations in the tube axis direction.

These conventional problems will be explained in more detail.

Generally, the high frequency power used for ERW welding pipe production is 10
The frequency band of ~500KHz is used, and the
Due to the synergistic effect of two phenomena, the "skin effect" and the "proximity effect," the higher the frequency, the greater the electrical welding effect.

This is the reason why high frequency power is widely used in ERW welding pipe manufacturing.

By the way, at the same time as melting the etched end face by high frequency heating, we used a squeeze roll to make Absen 1-1, which is strong at the joint.
It was thought that welding would be performed by applying force to expel most of the molten metal from the weld together with the oxides generated during heating. The welded portion is deformed by the absorption 1, and metal flow in the heat-affected zone rises as shown in FIG. 8a.

When the metal flow rises, the inclusions contained in the strip also stand up, causing the disadvantage that the inner part, which has inferior mechanical and chemical properties compared to the surface, oozes out to the surface. On the other hand, if Absen 1~ is not added, welding defects will occur frequently. The relationship between the metal flow angle θ and the toughness of the weld is shown in FIG. 8b, and the larger the vertical angle 0, the lower the toughness. Note that the shaded area in FIG. 8b indicates the range of toughness. Toughness varies within the shaded range.

The high-frequency current concentrates on the surfaces of the butt end faces, especially at the corners. Therefore, the amount of melting at the corner portions is greater than at the center portion of the butt end faces. The molten metal generated at the end faces is discharged from the end faces to the outside of the strip plate by the action of electromagnetic pressure induced by currents flowing in opposite directions flowing through the opposing abutting faces.

The direction of this electromagnetic pressure is shown in Figure 9a. Therefore, the butt shape of the end face of the welding surface Mu is as shown in Fig. 9b.
It has a convex shape with a bulging center. The area between the end faces immediately after welding is filled with molten steel. If the molten steel solidifies in this state or with little addition to the absen 1 in the welded part, solidification shrinkage holes will occur near the corners, and this part will become a welding defect. This state is shown in the upper column of FIG. 9c.

If a strong Absen 1- is applied to the welded part, the welded part deforms into a convex or planar shape, and the solidified layer becomes a thin film, so that no shrinkage pores are generated in the plate thickness plane. This state is shown in the lower column of FIG. 9C.

[Problem that the invention seeks to solve]

In conventional high frequency electric resistance welding, as mentioned above, Absen I-
You have to make it stronger, and if you make Absen 1- stronger,
There was a contradictory problem in that the metal flow rise angle θ increased and the toughness of the welded part decreased.

These phenomena are observed not only in electric resistance welding of slate seam electric resistance welded pipes, but also in electric resistance welding of spiral pipes and section steel such as beats.

- On the other hand, there is a welding method that uses energy beams such as lasers and electron beams as a welding method that has less thermal influence during welding and provides excellent welding quality.
0, a welding method was proposed in which the energy beam of this genius was stripped in steps at the apex of the wedge shape to be welded, that is, at the welding point.
Improvements are proposed in issue 1.

For example, to explain the outline of the method disclosed in Japanese Patent Application No. 58-1071.20 with reference to FIG.
(the wedge-shaped welding facing surface) is heated by the high frequency power supplied from the contactor 7 and the Joule heat generated by C, and the laser beam irradiated from the laser irradiation device 4 through the beam guy F 29. -4B uniformly heats the entire thickness to the welding temperature.

The laser beam [, B is a predetermined angular range centered around the apex of the Couli'by shape that forms a predetermined angle, that is, the welding point,
The welding agent facing surface 2 of the tubular body 1 is scanned back and forth in the direction 4J.

The laser beams (1) and (F3) hit one side of the armature surface, are reflected there, are directed to the other side, are reflected at the other side, and hit that side again, repeating the reflection and finally reach the welding point. That is, even if the laser beam 1.13 is not directly irradiated onto the welding point, it is automatically focused on the welding point by reflection and convergence.

Even in such composite welding, there are cases where the welding speed cannot be increased due to insufficient power of the energy beam 11 at the center of the thickness or point-like power distribution, and uniform heating throughout the thickness may not be achieved. In particular, it has been found that there is a problem in that the larger the thickness, the more pronounced the cracking becomes.

The present invention relates to an improvement of this type of composite welding method that uses high-frequency electric resistance welding and an energy beam, and aims to increase the energy beam in order to heat with a predetermined temperature distribution over the entire thickness. Even if the plate is thick, it can be heated with a specified temperature distribution throughout the thickness.
The purpose is to enable even higher welding speeds, that is, to obtain higher productivity.

[Means for solving problems]

In order to achieve the above-mentioned objective 1, in the present invention, electrical energy is supplied to the welded workpiece in which the opposing welding surfaces asymptotically approach and the welding point becomes the apex, forming a rust shape, and from the open side of the wedge shape. In the electric welding method for energy beam cans, in which the apex of the wedge shape is heated to the welding temperature by the Joule heat generated and the projected energy beam by throwing the energy beam 11 at the welding point: at least two energy beam generators Each beam of radiant energy is projected onto the welding point.

[Operation] According to this, it is possible to arbitrarily obtain an energy beam that has the required power as a whole, and therefore, the power of high-frequency resistance welding can be set to the minimum necessary, and the entire thickness of the workpiece can be welded at a uniform temperature. can be heated to shallow depths. Also, the welding speed can be increased. In particular, since the energy beam can be projected in a desired pattern around the center of the thickness,
The humidity distribution can be easily made uniform, and even when the thickness is large, the entire thickness can be heated uniformly and without excess or deficiency. In a preferred embodiment of the present invention, the projection position and power of each energy beam are controlled according to the thickness of the workpiece, and since a large energy power is required at the center of the thickness, the ends of the thickness of the workpiece are removed and the Either the energy beams are projected with some overlap in the center, or one energy beam is projected at the center of the thickness of the workpiece, and another energy beam with a ring-shaped or elliptical energy distribution is projected at the center. Project according to the center of the thickness.

According to this, the uneven temperature distribution of high heating at the edge corner and low heating inside the corner due to high frequency resistance welding can be rationally compensated for, and the energy beam power is higher at the center from the center of the thickness to the edge. , the beam is distributed in a low pattern at the corners, making it possible to perform beam heating over a wide range even with a large plate thickness. As a result, the power of high-frequency resistance welding is reduced as much as possible because the energy beam has a small heat-affected zone and the contribution of heating by the energy beam is as large as possible. [7
In addition, welding with fewer heat-affected zones can be achieved.

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an outline of the configuration of a welding device that implements one embodiment of the present invention. Joule heat generated by the high-frequency power supplied from the two contacts 7 at the edge of the tubular body 1 and the L/- laser beam r-B irradiated from the laser IJ device 4 through the beam kite 29 to the entire flesh area. The material is heated uniformly to the welding temperature. This is the previous patent application 1986-1
This is similar to the welding in No. 07120.

Welding conditions and process-related data regarding the tubular body 1 are provided to a welding data processor 13 . The data processor 13 is connected to the melting depth and the heat-affected zone width.

Power data processor 15 converts welding data such as vertical angle θ
niU, get it.

The power data processor 15 converts the heat input rate (welding power) data from the tubular body data processor 12 and the welding data from the welding data processor 13 into actual data (experiments) obtained from the obtained data and operational results. The heating pattern by high-frequency power (heating temperature distribution in the plate thickness direction) and the heating pattern by laser beam (heating temperature distribution in the plate thickness direction) are calculated, and the high-frequency heating pattern data is converted into a high-frequency power calculator. Give to 16. Further, the power data processor 15 calculates each beam power of a beam profile described later and a composite beam described later from the laser beam heating pattern, and transmits the profile data to the optical system controller 17.
In addition, each beam power data is given to the laser controller 18.

The high-frequency power calculator 16 calculates the high-frequency frequency and applied voltage from the high-frequency heating pattern data, and provides data instructing these to the high-frequency power controller 19. The high frequency power control 19 sets the oscillation frequency and output voltage of the high frequency power source to the specified values.

1./-The irradiation device 4 has the configuration shown in FIG. In FIG. 2, T-G 1 + LG 2 are laser oscillators, each with a laser beam LBI.

1. Irradiate the mirror MBIIMT32 with I-32.

It is reflected by mirror M +3 + + M B 2,
The laser beam 1. is further reflected by the combining mirror Mx. B,
, LB2 are combined, and the combined beam LBx is beam guy 1.
~29 into the wedge-shaped bevel. In addition, if a larger beam power is required, or if a larger spread of the laser beam is required, four (or three) laser oscillators ■, G, as shown in Figure 3.
1-LG4, Mi"7 MB 1-MB4 + composite mirror Mx1, MX2, mirror MB5゜MB61
Four combined beams T using a combining mirror Mx3,
B X3 may be obtained. Similarly 8 pieces, 16 pieces
Beams from a large number of laser oscillators may be combined. Combined beam 1 in the manner shown in FIG. Bx
(L B + + I, B2 +LB3+r-B4) is jointly controlled as a composite beam bundle by a mirror or lens system in the beam shape control unit 29 and projected onto the welding point as shown in FIG.

In the figure, hp indicates the heating temperature distribution due to electric resistance welding (high frequency welding), and hl and h4 are h2. Higher than h3. In this embodiment, I', than T-B 1rLB4,
+32 + I-B Increase the power of a to make the heating temperature distribution uniform as shown by the dotted line.

With reference to FIGS. 5a, 5b, and 5c, the control mode of the laser beam 11 profile by the combination shown in No. 21\1 used in the laser irradiation device 4 shown in FIG. 1 will be explained. Mx composite angle 02 is 90°
When the laser beam L 13 + +L B 2 is projected in parallel, benzointamira M B 4 +MB
If the bend angle o1 of 2 is 90' or less, 03 becomes 0°
The following results, and L T3 and LB2 are separated (does not intersect)
For example, these projected images may be separated or slightly intersect as shown in FIG. 5b. ol 90
If it is 2, then 1. ,B.

and L +32 intersect, for example, these projected images are the fifth
It becomes a wrap type as shown in figure c. Like this-11
The position can also be adjusted by adjusting the composite angle θ2 of the composite mirror Mx.

In the combination shown in FIG. 2 used in the apparatus shown in FIG.
=92° and 02=90°, and the beam guide 29 produces the laser beam projection images shown in FIGS. 5b and 5c, as well as the distance between the projection points of both beams in the embodiment of FIG. 5b. Further, in the embodiment shown in FIG. 5c, the overlapping distance of both beams is continuously set to various values. 5th c
According to the embodiment shown in the figure, when the power of both beads 11 is fixed to be the same, the temperature distribution is made uniform as shown by the dotted line, corresponding to the temperature distribution 111 of electric resistance heating shown in FIG. 4b, for example. Noza heating is possible. Beam guide 29
The structure and beam profile adjustment control will be described later with reference to FIG.

The laser irradiation device 4 may be a combination shown in FIG.

In FIG. 6, JE, laser oscillator LG, and LG
2 emits a laser beam L B 1+ I-82 having approximately the same diameter and a small ring-shaped energy distribution.

The laser beam L B is directly reflected by the pendulous mirror Mb and is projected through the central hole M D of the composite mirror MD, but the laser beam L B 2 is reflected by the lens system T.
, c, T, ν and is converted into a composite mirror M1 having a ring-shaped energy distribution with a large diameter. )
6M1] It is projected by hitting the surrounding area of 1. As a result, a composite beam LBx in which a small cylindrical beam LB2 passes through the center of the large cylindrical beams T, , B2 is projected onto the welding point. This composite beam r,, B x is also
As shown in FIG. 4, the high frequency 41 (corresponding to the non-uniform temperature distribution hp due to anti-welding, is an energy distribution that makes the temperature distribution uniform. Note that the laser beam L B is not ring-shaped (cylindrical) but , may be rod-shaped (linear) or bispherical (solid).

Next, the configuration of the beam guide 29 will be explained with reference to FIG. This beam guy 1 is equipped with a laser beam condensing lens FL and a transport mirror M1°M2te. Laser beam LB (LB x = r-B shown in Fig. 2)
I0L B 2 ) is set so as to always pass through the center of the condenser lens F■ and the transport mirrors M1+M2. The walls of the beam guide include a base portion 29d and an intermediate portion 29b.
and the tip 29c.

The tip 29 (which is dogleg-shaped and emits a laser beam and non-oxidizing gas) has a diagonal shape in appearance and has the same angle as the opening angle of the wedge shape of the tubular body 1.
It has a cylindrical shape, and its inner surface has a mirror finish. A mirror M2 is attached to the bent part of the dogleg shape.

The distal end of the intermediate portion 29b is inserted into the rear end of the distal end portion 29c, and the distal end portion 29c can rotate around this distal end and can also slide in the -] two vertical direction arrows AD3).

The intermediate portion 29b has a dogleg shape, and a mirror M1 is attached to the bent portion. The inside surface is finished with a mirror surface. The rear end of the intermediate portion 29b is inserted into the tip of the base portion 29a,
It can slide in the left and right directions (arrows A, D,).

A condensing lens FL is attached to the rear end of the base 29a whose inner surface is mirror-finished. Further, the rear end of the base 29a is attached to a beam sending guide 29o of the laser irradiation device 4 so as to be slidable in the left-right direction (arrow AD4). A branch pipe 29F for introducing non-oxidizing gas G is integrally formed in the base 29a, and inert gas,
Preferably, helium (tIl:l) gas at a predetermined pressure is supplied.

The He gas passes through the inner spaces of the base 29a, intermediate portion 29b, and tip 29c and reaches the tip 29F.
It ejects toward the welding point. This gas flow cools the beam guides 1 to 29, blows out dust inside the beam guide 11, and prevents dust from entering the beam guide. Furthermore, T-1e has an ionization voltage of 24.6V, which is higher than the ionization voltage of argon (Ar), which is 15.76V, and suppresses the generation of plasma due to the laser beam emitted coaxially with the I-Te gas. However, the absorption of beam energy is low. In addition, He flows along the laser beam path from the tip 29F across the welding point and heads toward the welding point,
It covers the facing surface of the tubular body I before welding (edge 2: Fig. 1) and the welding point to prevent oxidation of the welding surface. Since this He flow is constantly flowing, the temperature distribution in the beam path between the tip 29F and the welding point is uniform, the beam is not bent, and the beam hits the intended position.

The operation of the beam guide explained below-1- can be summarized as follows.

Adjustment of O-beam projection profile.

○ Dustproofing of optical systems such as mirrors and lenses.

○ Maintaining the multiple reflection effect of the laser beam on the opposing surface before welding by preventing oxidation of the welding surface etch.

○Remove dust and moisture from Laserbee 11 input channel.

Reduce power loss.

Although not shown, the beam guide 29 described above is equipped with a position control mechanism for each of the four directions ΔD and -AD, and can perform the following injection position and profile adjustment/setting.

○Beam position adjustment in welding line direction (AD+) (X Φ mountain)
.

O Horizontal direction (AD2) beam position adjustment (Y axis).

○Vertical direction (ADa) beam position adjustment (2ψ mountain)
.

○Adjustment of projection pattern (ADa) (L T3, and■,
B2 distance adjustment in the X-axis direction (double adjustment).

Next, beam position control in these three directions and projection pattern control will be explained with reference to FIG.

1) Welding line direction (X-axis) This is used to adjust the focus position and guide tip position.
The intermediate portion 29b is adjusted in the direction AD with respect to the base portion 29a. Intermediate portion 29b (mirror M+) with respect to base portion 29a
Since the tip portion 29c (mirror M2) and the tip portion 29c (mirror M2) move together, the position of the guide tip portion 29F may be adjusted.
The distance between the focusing lens FL and its mirrors Ml and M changes to determine the characteristics of the composite focusing system (beam 11 at the projection point).
image) or change. That is, changes in the focal position of the beam and changes in the position of the condensing system (Bee 11 image at the projection point)
becomes. This makes it possible to control the nine positions of the shape of the bead 11 to be placed at the irradiation position, so the shape of the irradiation beam can be controlled in the thickness direction of the plate, and the melting shape can be controlled.

2) By rotating the tip 29c in the horizontal direction (Y The irradiation position of the laser beam passing through the center can be adjusted horizontally.As a result, uneven melting on only one side of the welding surface (edge 2; facing surface) can be prevented.9゜3) Vertical direction (two axes) By moving the tip end 29c up and down in the AD direction, the beam can be controlled to move up and down to the center of the plate thickness and in accordance with the heating distribution of electric resistance welding.

4) Responding to changes in plate thickness Is it necessary to change the injection position of the laser beam 11 in response to changes in the thickness of the raw steel plate of the tubular body, or changes in the thickness? In this case, the bottom surface of the steel plate is in a fixed position,
As the thickness increases, the north face (and the center of the thickness) of the steel plate
This is because it moves to one side.

Along with this, it is necessary to move the laser beam input position to the negative side. When the thickness changes, the tip 29
Adjust c in 3 directions (ΔF) to align the beam injection position with the center of the thickness. The change in optical path length associated with this is calculated by the intermediate portion 29b.
A1] by moving in one direction.

5) L B = r-B x = T-'B 1+
T-, B 2 (Fig. 5a.

The intersection point of l-1B1 and LB2 (see Fig. 7) is located approximately at the welding point, but by moving the base 2'9a in the ADd direction, the intersection point moves to the front and back of the welding point, and the welding point is adjusted. 1. The overlapping length of B1 and L B 2 changes. Therefore, the base portion 29a is moved in the AD4 direction to set the city radius (projection pattern setting).

Referring again to FIG. 1, the power data processor 15 calculates the
The high-frequency heating pattern and heating power are adjusted according to the power distribution and heating pattern classification that uses laser beam heating in the widest range, minimizes high-frequency resistance welding heating, and makes the temperature distribution uniform in the thickness direction and minimizes absorption. The pattern and power distribution of the laser beam LBx (LBt +r, B2) are set, the high frequency power calculator 16 sets the frequency and voltage of the high frequency power supply 20, and the optical system controller 17 sets the pattern and power distribution of the laser beam LBx ([, +31
+LB2) The adjustment mechanism of the beam guy 1-29 is controlled according to the pattern of the projection beam position (thickness center) and the projection beam image (pattern or profile: Fig.
(Fig. c), and the laser controller 18 controls the laser oscillators L G 1 and 1 . G
2. Set the oscillation power for each. As a result, the heating temperature distribution is uniform in the thickness direction, the spread of the heat-affected zone is the smallest, there are no welding defects, and welding is performed with high toughness. Furthermore, since the laser beam power is large, high-speed welding is possible.

〔Example〕

5 KW, round beef 1. Beam diameter 50 m +n,
As shown in Figure 2, two CO2 laser oscillators are used,
Bee 11 was synthesized to Ben 1 with fQ O, = 92° 2 joint angle 02 = 90°, and composite welding was performed using a high frequency electric resistance welding method and Inno 1 with a 1.0KWl nozzle welding machine. .

Table 1 The projected beam image is shown in Figure 5C, which is 4mm wide and 8n1m long.The results of 33 welding into a J-4fi circular shape are shown in Table 1. was completed.

〔Effect of the invention〕

As described below, relatively thick pipes can be welded well in the present invention. As the minimum power required for high frequency resistance welding, the entire thickness of the welded object can be heated to a uniform dl and to a uniform, relatively shallow depth at once.

Therefore, welding with a small heat affected zone is possible.

Also, the welding speed can be increased. In particular, since the energy beam can be projected in a desired pattern around the center of the thickness, the temperature distribution can be easily made uniform, and even if the thickness is small, the entire thickness can be heated uniformly and without excess or deficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a general configuration of a welding apparatus that embodies one embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a welding apparatus 4 shown in FIG. 1. FIG. 3 is a block diagram showing another example of the configuration of the laser irradiation device 4, and FIG. 4 shows the laser beam 1 obtained with the configuration shown in FIG.
FIG. 1 is an explanatory diagram showing a projection position onto a workpiece to be welded. 5a is a block diagram showing an enlarged part of FIG. 2, and parts 5b and 5c are enlarged plan views showing projected beam images obtained by the configuration shown in FIG. 2. FIG. 6 is a block diagram showing another example of the configuration of the laser irradiation device 4. As shown in FIG. FIG. 7 is a longitudinal sectional view showing the main part of the beam guide 29 shown in FIG. 1. FIG. 8a is an enlarged sectional view of a joint made by conventional high-frequency electric resistance welding, and FIG. 8h is a graph showing the relationship between the rise angle and toughness of the joint. Figure 9a is a sectional view showing the molten state of the weld edge and electromagnetic force in conventional high frequency electric resistance welding, Figure 9b is a sectional view showing the molten state of the weld edge in conventional high frequency electric resistance welding, and Figure 9c is 1 is a cross-sectional view showing a cooling state of a welding edge portion after upsetting 1 in conventional high-frequency electric resistance welding. 1: Tubular body 2: Esoshi (opposite surface before welding) 3;
Squeeze roll 4: Laser irradiation device 7: Contact
29: Beam guide U)

Claims (4)

[Claims] (1) Electrical energy is supplied to the welded workpiece, which has a wedge shape in which opposing welding surfaces asymptotically approach and the welding point is the apex, and an energy beam is projected from the open side of the wedge shape to the welding point. In the energy beam combined electric resistance welding method in which the apex of a wedge shape is heated to a welding temperature by Joule heat and a projected energy beam, each radiant energy beam of at least two energy beam generators is projected to the welding point. Electric resistance welding method using energy beam. (2) The energy beam combined electric resistance welding method according to claim (1), wherein the projection position and power of each energy beam are controlled depending on the thickness of the workpiece. (3) Energy beam combination electricity according to claim (1) or (2), in which the energy beams are projected by removing the ends of the thickness of the workpiece and partially overlapping each other at the center of the thickness of the workpiece. Resistance welding method. (4) One energy beam is projected onto the center of the thickness of the workpiece, and another energy beam having a ring-shaped or elliptical energy distribution is projected with its center aligned with the center of the thickness. Paragraph 1) or Paragraph (2)
Electric resistance welding method using energy beam as described in section.