JPS59191577A - Electric resistance welding method using energy beam in combination - Google Patents

Abstract

PURPOSE:To prevent generation of a cold junction, penetrator, etc. and to perform sure welding in the stage of using a high-frequency voltage and a laser beam in combination in welding wedge shaped welding surfaces by controlling the incident angle, beam diameter, diverging angle, etc. of the laser beam. CONSTITUTION:The wedge shaped ends 2 of a tubular body 1 formed by forming a steel plate into a pipe shape are heated by the current conducted to contactors 4a, 4b from a high-frequency power source 4. On the other hand, a laser beam LB is radiated from a laser oscillator to said part to heat and melt the ends thereby welding the same. When the beam LB adjusted in a beam diameter D and a diverging angle alpha by beam shape converters 6, 7 and an objective mirror 8 is projected toward the single Vee groove, the laser beam is multiple-reflected by PL1-PR1 to form a final heating zone Hz and a melt zone Mz. The projecting angle between the beam LB and the inside surface of the single V groove increases sharply when the number of reflection increases. The position of the zone Hz and the zone Mz is thus controlled by changing the angle alpha.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite welding method characterized in that an electric resistance welding method is used in combination with the projection of an energy beam, such as a laser beam.

Electric resistance welding (hereinafter abbreviated as ERW) is one of the most commonly used welding techniques. For example, in the field of manufacturing welded steel pipes, a method for manufacturing pipes generally called electric resistance welded pipes is widely used as a welding method with high welding speed, that is, with high productivity.

Figure 1 shows a conventional pipe-making method using high-frequency contact type electric resistance welding, in which a copper strip is formed into a tubular shape by a group of forming rolls (not shown), and then the copper strip (hereinafter referred to as a tubular body )■ end 2.2 with squeeze roll 3,
3 to form a wedge shape with the abutted portion as the apex. Furthermore, a high frequency voltage is applied from the high frequency power supply 4 to the contacts 4a and 4b arranged upstream of the squeeze rolls 3 and 3, and one contact 4a is applied to the other contact 4b (or from the contact 4b to the contact 4b). A high frequency current circuit (to 4a) is formed along the wedge-shaped ends 2, 2, and the ends 2, 2 are heated by this high frequency current. As a result, the welding temperature is reached at the apex of the wedge shape, and pressure welding is performed by the squeeze roll 3.

However, this ERW also has problems when the welded object becomes thick or when an attempt is made to increase the welding speed.

For example, when the wall is thick, the high frequency current density at the corner portions 2a and 2b of the end portion 2 is lower than the center portion 2c of the thickness, as shown in Fig. 2a.
As a result, the temperature distribution produces a low temperature region in the center of the plate thickness as shown by Ha2, and cold welding defects occur. Furthermore, if a high heat input state is created to eliminate cold welding, the temperature distribution will become as shown in Hal, and a penetrator defect will occur.

The present invention was made with the aim of solving the problems of Σ and RW as described above. In the voltage resistance welding method in which energy is supplied and the generated Joule heat is used to heat the apex of the wedge shape to the welding temperature and weld; An energy beam whose incident angle, beam diameter, divergence angle, and energy output are controlled according to the heating temperature distribution is projected to control the heating and melting part by the energy beam.

Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings.

FIG. 3 is an explanatory diagram showing an embodiment in which the present invention is applied to the manufacture of ERW steel pipes and a laser beam is used as the energy beam, in which 1 is a tubular body formed from a steel strip, and 2 is the tubular body. Wedge shaped end. 4 is a high frequency power supply, 4a
,4. b is a contact.

5 is a laser oscillator, 51 and 52 are resonant mirrors provided therein, 6 and 7 are beam shape converters, 8 is an objective mirror, 9 is a beam duct through which the laser beam LB passes, and 1o is a gas supply pipe for preventing oxidation. , 10a is a nozzle portion at the tip thereof. Further, 2a is the upper end of the contact end, 2b is the lower end, and 2C is the center part.

To perform welding according to the present invention, as in the case of FIG. It flows through the wedge-shaped ends 2, 2 of the tubular body 1 and heats these parts.

On the other hand, from the laser oscillator 5, the built-in resonant mirror 51
．． 52 emits a laser beam L B whose shape is controlled as shown in FIG. 7a or FIG. Adjust the divergence angle α, make the light incident on the objective mirror 8, and the mirror 8
By this, the ends 2, 2 of the tubular body 1 can be heated and melted together with the high frequency current.

Figure 4 shows the wedge-shaped ends 2, 2 (hereinafter referred to as V-bevel).
This shows details of laser beam LB irradiation for
O is the open angle of the groove, and δ is the butt angle of the tubular body 1. 2
a-3a is a welding line, and 2a-2b is a welding point. Also,
FO+F1 is the input direction of the laser beam LB, γ is the input angle, α is the divergence angle, and D r 1 is the horizontal beam diameter of the laser beam at 21 points. In addition, Dr2 is the beam diameter in the horizontal direction of the laser beam at 22 points,
D z 2 is also the beam diameter in the vertical direction. Q is 2
This is the distance between point 1 and point 22.

The present invention is characterized by controlling the heating position, melting area, etc. of the joint surface within the groove shape by controlling the output of the energy beam such as the laser beam LB, the beam diameter, the divergence angle, and the injection angle. In a preferred embodiment of the present invention, the laser beam determines (1) the position and heating distribution of the heated part in the direction of the welding line;

(2) Selection of heating area and heating distribution in the plate thickness direction.

(3) Electric resistance welding is reliably performed by controlling external scattered light and the like with respect to the butt angle δ of the butt surfaces.

Specifically, the present invention uses an energy beam, such as a laser beam, in combination with the electric resistance welding method as described above to (1) control the heating position, melting area, etc. within the groove. First, control in the weld line direction will be explained.

Figure 5 shows the actual situation, in which the laser beam LB is adjusted from the laser oscillator 5 to the beam shape converters 6 and 7 and the objective mirror 8 to have a beam diameter of 2 and a divergence angle of α.
When projected into the groove, the left and right outermost ends of the laser beam LB are ■P L 1 + ...PR inside the groove
As a result, a final heating zone Hz and a melting zone Mz are formed as shown in the figure. In addition, ρm
is the distance from the junction point to the melting point, and wh is the width of the heating section.

In this case, the entrance angle β between the laser beam LB and the inner surface of the groove increases rapidly as the number of reflections increases (βn = (2n -1-1) β0 + n: number of reflections).

Therefore, by changing the divergence angle α, the convergence point changes, so the positions of the final heating zone Hz and the melting zone Mz can be controlled.

Figures 6a and 6b show the details, and
When the opening angle θ of the groove is constant, as shown in FIG. It is further away from the junction point CP compared to the final convergence position P3 (indicated by B in the middle). Also, as shown in Figure 6b, the divergence angle α
When is negative (indicated by B' in the figure), the final convergence position P3' of the laser beam is closer to the junction point CP than that of the parallel beam (indicated by B in the figure). Therefore, by adjusting the divergence angle α, the heating area can be controlled. Next, a method of adjusting the divergence angle α will be explained.

FIGS. 7a and 7b show the configuration of built-in resonant mirrors 51 and 52 of the laser oscillator 5, and the divergence angle α of the laser beam can be controlled by the configuration of this mirror. That is, the rear mirror 51 is configured to have a concave surface,
When the mirror 52 on the output window side is configured to be flat, the divergence angle α1 of the output laser beam becomes negative (Fig. 7a),
Conversely, if the rear mirror 51 is made flat and the mirror 52 on the output window side is made concave, the divergence angle α2 of the output laser beam becomes positive (FIG. 7b). Note that the same effect can also be achieved by providing an uneven mirror on the outside.

Further, as shown in FIG. 4, in order to abut the ends 2 of the steel strip 1 and make a perfect circle at the abutting portion, it is necessary to create an abutting angle δ at the opening (■ groove). In this case, the laser beam is reflected and scattered at the edge, and ■ outside the groove (above).
However, the projection angle γ of the laser beam
By adjusting , such escape of the laser beam can be prevented.

That is, as shown in FIG. 8, when a laser beam is introduced into the V groove from the upper angle at an injection angle γ1 from the horizontal direction (injection direction Fl), the laser beam will be applied at A, B,
It is projected onto the area surrounded by C and D, and scattering outside the groove is eliminated. Incidentally, this injection angle can be adjusted by changing the angle of the objective mirror 8.

Further, in the present invention, as shown in FIG. 3, an anti-oxidant gas is sprayed from an anti-oxidant gas supply pipe 10 over the entire heating section after the power supply point to prevent oxidation, thereby preventing the laser beam from being caused by the oxide film. Beam control can be stabilized without deteriorating the reflection characteristics on the steel plate surface.

Next, to show the results of implementing the present invention, the opening angle θ of the V groove is 3°.
, butt angle δ = 0°, beam radius of laser beam = 3 mm, beam divergence angle α -1, 5°, 0°, +1.
When the heating point and heating area were measured when the temperature was controlled at 5°, the results shown in FIG. 9 were obtained. As is clear from this result, as the divergence angle α increases, the focus of the beam (
The heating point) moves toward the opening side, and the heating area wh expands accordingly.

As explained above, according to the present invention, an energy beam such as a laser beam is used in the electric 4J welding method, and by controlling the energy beam, cold welding, penetrator, etc. It is possible to prevent this from occurring and perform reliable welding. Furthermore, although the above description has been made regarding the case where a laser beam is used as the energy beam, it goes without saying that electron beams or other beams can also be used as the energy beam.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an outline of the pipe manufacturing process using the conventional high-frequency contact electric resistance welding method, and Figs. 2a and 2b show temperature fluctuations at the end of the pipe body using the conventional method. FIG. 3 is a block diagram schematically showing the configuration of an apparatus for implementing the method of the present invention in one embodiment, FIG. 4 is a perspective view showing an energy beam irradiation mode in one embodiment of the present invention, and FIG. 5 6A and 6B are explanatory diagrams showing the final convergence position of the energy beam, and FIGS. 7A and 7
Figure b is an explanatory diagram showing the mode of controlling the shape of the energy beam, Figure 8 is an explanatory diagram showing the state of the heating area by controlling the projection angle of the energy beam, and Figure 9 is an explanatory diagram showing the state of the heating area by controlling the projection angle of the energy beam. and a graph showing the distribution of melted parts. 1: Tubular body 2: End portion 3 squeeze roll 4a, 4b: Contact 5: Laser oscillator 51, 52: Resonance mirror 6.7: Beam shape converter 8: Objective mirror 9: Beam duct L
B: Laser double beam 10: Gas supply pipe 10a:
Nozzle part addition 6a" Diagram pot 7th tank 6b One death 7b Proceedings amendment (method) Commissioner of the Patent Office Wakasugi Wainu 1, Indication of case 1981 Patent Application No. 065973 2
, Title of the invention Electric resistance welding method in combination with energy beam 3, Relationship to the case of the person making the amendment Patent applicant address 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (665) Representative of the Nippon Steel stock bid Takeshi 1
) Yutaka 4, Agent 103 Phone: 03-864-60
52 Address: 2-27-6-5 Higashi Nihonbashi, Chuo-ku, Tokyo Date of amendment order 7 Contents of amendment (1) "What distance is..." on page 6, line 7 of the specification. Then insert the following sentence: ``The temperature distribution caused by this laser beam irradiation produces a high temperature area at the center of the plate thickness at the end 2, as shown by Hb in Figure 2b, and compensates for the low temperature at the center of the plate thickness due to the high frequency current (Figure 2a). However, due to heating by high-frequency current, He as shown in Fig. 2C
As shown in , the temperature distribution is uniform throughout. (2) The sentences in lines 6 and 7 of page 11 of the specification are corrected as follows. The parent diagram, Figure 2a, is an explanatory diagram showing the temperature distribution at the end of the tube according to the conventional method, and Figure 2b shows the temperature distribution at the end of the tube only by the laser beam in one embodiment of the present invention. An explanatory diagram, Figure 2C is an explanatory diagram of closing the temperature distribution at the end of the tube body by a laser beam and high-frequency current in one embodiment of the present invention, and Figure 3 is an explanatory diagram of closing the temperature distribution at the end of the tube body by a laser beam and high-frequency current in one embodiment of the present invention.

Claims (2)

[Claims] (1) Electrical energy is supplied to the welded workpiece, which has a wedge shape with opposing welding surfaces asymptotic and the welding point as the apex, and the Joule heat generated heats the apex of the wedge shape to the welding temperature and welds. In the electric resistance welding method: An energy beam is sent from the open side of the wedge shape to the welding point, with the incident angle, beam diameter, divergence angle, and energy output controlled according to the wedge shape and the heating temperature distribution due to the electric resistance welding method. An electric resistance welding method using an energy beam, which is characterized by controlling heating and melting by an energy beam. (2) The energy beam combined electric resistance welding method according to claim (1), which blows an inert gas onto the heated surface to prevent the formation of an oxide film on the heated surface and maintain the surface reflection characteristics. .