KR100458725B1 - Laser welder and thereof method of formed sheet for pipe manufacturing - Google Patents

Abstract

The present invention relates to a laser welding apparatus for a pipe and a method thereof, comprising: a fixed frame; A mold pipe mount mounted on an upper surface of the fixing frame and installed to be movable along the mold frame; A housing fixed to an upper surface of the fixing frame and provided to allow a roll forming tube mounted on the forming tube mounting bracket to pass therethrough; A pair of upper fixing rolls rotatably fixed in the housing and arranged to contact and pressurize the upper outer circumferential surfaces of both sides of the welding point of the roll forming tube; A pair of lower fixing rolls symmetrical to the upper fixing rolls and supported by the fixed roll driving unit, the lower fixing rolls being arranged to be in contact with the lower outer peripheral surface of the roll forming tube; A welding deformation control roll positioned on the side of the upper fixing roll and rotatably fixed to both upper walls of the housing to press the welding part of the roll forming tube to a constant pressure; A welding head connected to the laser beam oscillator and disposed directly above the welding portion to irradiate a welding portion of the roll forming tube located in the housing between the welding deformation control roll and the upper fixing roll, and according to an initial welding condition. After deciding the moving distance of each fixed roll and the forming pipe mount, it is pressed by the welding deformation control roll while moving it, and irradiated with a laser beam to perform laser welding.

According to the present invention, even if the welding object is variable, it is variable correspondingly so that the welding quality is remarkably improved by keeping the welding gap and the step constant at all times.

Description

LASER WELDER AND THEREOF METHOD OF FORMED SHEET FOR PIPE MANUFACTURING}

The present invention relates to a welding apparatus and method for manufacturing a pipe by cutting a structural steel material to a predetermined length and then performing laser welding on a material processed into a pipe shape through a roll processing apparatus.

As shown in FIG. 1, a pipe manufacturing method using a conventional welding method includes a support roll on a left and a right side of a material 101 processed in a pipe shape by a plurality of forming rolls in an inlet step using an infinitely long steel band as a raw material. Very high heat is generated at the contact point of the welding groove 102 by heating the power applied through the high frequency welding power source 301 to the molding material with the induction electrode 302 while supporting the weld as 201 and 202. The high heat and the pressure of the support rolls 201 and 201 interact to form the weld bead 103 while forming the weld pipe.

However, this method was not suitable for the manufacture of short length pipes, and the inconvenience of having to replace both the support rolls 201 and 202 when the diameter of the pipe was changed.

As another example, as shown in FIG. 2, there is a method of manufacturing a pipe by extracting welding energy from the arc welding power source 303 and the welding torch 304 by cutting the molded material 101 to a predetermined length in advance. In addition, in order to maintain the position and the precision of the joint surface of the weld, it is not only necessary to mount a plurality of support means 203 on the left and right sides of the molded body. Since the contact 104 should be performed, the welding speed is slow, the productivity is very low, and the weld part quality reliability is not excellent.

In order to overcome these examples, a welding method as shown in FIG. 3 has been disclosed in Japanese Patent Laid-Open No. 2000-15469.

According to the present disclosure, as the type of the welding pipe is changed, an optical configuration for setting the initial focus position at the initial welding position is added, and the component is assembled to the welding head 403 to manufacture the pipe of infinite length. Although it was intended to improve the welding quality, this also has a support roll 202 is mounted on the left and right sides of the molded body in order to make the welded joint constant, there is essentially no difference from the method of Figure 1 can be an effective improvement plan There was no.

Recently, a hybrid welding technology such as US Pat. No. 6,140,601 has been disclosed.

According to the disclosure, the welding technique as shown in FIG. 4 improves welding efficiency by supplying a laser 404 to the same structure as that of the conventional high frequency welding method using the high frequency induction power supply device 301. In order to improve the quality of the welded portion by minimizing the step of the joint is configured to mount the fixing roll 502 to the upper left and right of the molding material immediately before the welding point.

However, this welding technique can improve the quality of the welded part, but if the length of the pipe is not constant or the formed diameter is not the same, it is free from the fundamental limitation of replacing all the rolls or changing the welding line. Almost impossible, there is no breakthrough in the application of a laser source of heat, but this method does not deviate from the scope of conventional pipe welding technology, and thus the practicality is very low.

The present invention has been made in view of the above-mentioned limitations of the conventional welding technology. The present invention has been made to solve this problem, and in any case, the welding quality is improved by adding a means for guiding the step and the butt gap constant. It is an object of the present invention to provide an apparatus and method for laser welding a pipe further improved.

1 to 4 is an exemplary view showing an example of a welding pipe according to the prior art,

5 is a conceptual diagram of the device of the present invention;

6 is a conceptual diagram for explaining a welding method through the apparatus of the present invention;

7 is an external perspective view of the device of the present invention;

8 is a perspective view of an installation state of the device of the present invention;

9 is a conceptual diagram for explaining an operation relationship of the apparatus of the present invention;

10 is a relationship graph between a penetration ratio and a focus control position through the device of the present invention;

11 is a photograph showing a state of the weld bead through the present invention device,

12 is a flow chart showing a laser welding process using the device of the present invention.

Explanation of symbols on the main parts of the drawings

102: welding groove 103: welding bead

401 laser oscillator 403 welding head

501: housing 502,503,504,505: fixed roll

508: welding deformation control roll 509: welding line guide portion

510: linear guide 512: forming pipe mounting

The above object of the present invention is fixed frame; A mold pipe mount mounted on an upper surface of the fixing frame and installed to be movable along the mold frame; A housing fixed to an upper surface of the fixing frame and provided to allow a roll forming tube mounted on the forming tube mounting bracket to pass therethrough; A pair of upper fixing rolls rotatably fixed in the housing and arranged to contact and pressurize the upper outer circumferential surfaces of both sides of the welding point of the roll forming tube; A pair of lower fixing rolls symmetrical to the upper fixing rolls and supported by the fixed roll driving unit, the lower fixing rolls being arranged to be in contact with the lower outer peripheral surface of the roll forming tube; A welding deformation control roll positioned on the side of the upper fixing roll and rotatably fixed to both upper walls of the housing to press the welding part of the roll forming tube to a constant pressure; And a welding head connected to the laser beam oscillator and disposed directly above the welding portion to irradiate the welding portion of the roll forming tube positioned in the housing between the welding deformation control roll and the upper fixing roll. By providing a laser welding device.

In addition, an object of the present invention comprises the first step of determining the focal position after inputting the tensile strength of the material, the diameter of the formed pipe, the wall thickness and the length of the weld line which is the initial condition for pipe welding; Determining a moving distance of the upper and lower fixed rolls after the first process, and waiting for each of the rolls to be driven; A third step of setting the moving distance of the mold pipe mount according to the initial input condition and preparing to move at the welding speed determined by the transfer means at the same time as the second step; A fourth step of determining a reduction force of the welding deformation control roll after the third step and determining a position of the weld line guide part; A fifth process of outputting a predetermined laser beam through a laser oscillator according to a welding start signal and simultaneously starting welding by operating each structure according to a set value; It is achieved by providing a welding method for a pipe, characterized in that it comprises a sixth process, the output of the laser oscillator is stopped with the welding completion signal and fed back to the first process while returning the forming pipe mount to the initial position. .

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

5 is a conceptual diagram for explaining the present invention.

According to FIG. 5, the present invention transmits the energy output from the laser oscillator 401 to the welding head 403 using the optical transmission system 402, and then forms a focused light 404, and forms the focused focused light 404. The welding bead 103 is obtained by spinning and welding the molded material 101 directly.

In this process, to improve the quality of the welded portion, as shown in FIG. 6, the welded part fixing rolls 502, 503, 504 and 505 are arranged to maintain the step and the butt gap at an appropriate value in any case. The fixing rolls 502 and 503 are designed to completely remove the surface step by maintaining the tip of the material to be welded at a constant height at all times, and the lower fixing rolls 504 and 505 are designed to support the formed material at the bottom. In addition, the lower fixing rolls (504, 505) has a structure that can be adjusted up and down in an oblique direction toward the center point of the pipe to be welded by a drive means 515 driven by a hydraulic pressure in accordance with the diameter of the final product, further left In this case, it is configured to have the same function. This configuration is required to completely fix the pipe to be welded. That is, depending on the pipe size, as a configuration for matching a structure capable of varying the position of the lower fixed roll (504 505) so that it can be used to facilitate when various sizes of pipe welding and more encourage its versatility.

In particular, the welding deformation control roll 508, the welding line guide portion 509 and the lower fixing rolls (504, 505) are installed symmetrically, including the installation position and angle of the upper fixing rolls (502, 503) among the welding part fixing rolls (502, 503, 504, 505). Regardless of the diameter of the target pipe to be welded, an appropriate weld is always configured.

The molding materials 101, 101a, and 101b each represent pipes of different diameters, and in order to weld such pipes, fixing rolls 502, 503, 504, and 505 are arranged at intervals and distances corresponding to the diameters so that the grooves of the welded portions are less than or equal to a certain distance. A proper gap should be formed.

Therefore, in this invention, the lower left fixed roll 504 and the right fixed roll 505 of a molded object are provided, and it is comprised so that they may linearly move up and down and left and right.

If large diameter pipe welding is required, the lower fixing rolls 504 and 505 are preferably located at the positions indicated by the dotted lines (eg, 504a and 505a).

At this time, these fixing rolls (504a, 505a) is preferably configured to push up the molded body at any position at any time while maintaining a balance of force to form a constant angle (A).

According to the experiment, the angle A is particularly preferably about 120 °.

In addition, the molded body should have a very sophisticated bearing structure in the lower fixing rolls (504, 505) because there should be no vibration in the front and rear direction as the welding proceeds and must move at a constant speed.

On the other hand, the focused light 404 should be incident exactly in the center of the welding groove 102 to be welded, but the actual molded body is a place to be welded even if the molded body proceeds in a constant direction because there is a slight distortion in the inlet stage due to the characteristics of the molding In other words, the center line of the welding groove 102 and the focus of the focused light 404 are often poorly aligned on the plane. As a result, the welding energy is incident on the unnecessary portion, which results in poor welding quality or defects. In order to prevent such a phenomenon from occurring, in the present invention, a welding line guide part 509 having a mechanical structure capable of inducing the welding groove 102 is installed in front of the welding point. In order to effectively remove frictional resistance at the time, it may have a wedge shape having a rotating disk-like structure or suitable for welding thin plate materials.

The tip of the welding line guide portion 509 should be made of a high strength, high hardness, and wear-resistant material having a blade shape, and should have a property that bending does not occur due to a predetermined external force.

In addition, the upper fixing rolls (502, 503) has a plate shape, while balancing the force with the lower fixing rolls (504,505) by applying pressure to the molded material to be welded to reduce the butt gap and to remove the step of the welding site and Since the cold plate should also have an effect after welding, it is preferable to be made of an alloy material having excellent wear resistance and thermal conductivity.

The tip of the formed material becomes a welding groove without post-treatment, so proper welding can be made in this place, so that a pipe without welding defect can be manufactured. Since the joint surface of the laser beam should be perpendicular to the laser focusing light 404 to prevent the opening of the welding groove, the welding groove deformation control roll 508 is inserted in the state where the welding line alignment is completed by the welding line guide part 509. Will be prevented.

Figure 7 is a perspective view of the installation state of the device of the present invention.

Referring to FIG. 7, the molded material 101 guides the welding line to be pulled directly under the focus of the focused light 404 by the welding line inducing unit 509, and welds between the focus of the welding energy and the welding line inducing unit 509. The groove 102 deformation control roll 508 is mounted to make a stable weld.

The upper fixing rolls 502 and 503 are disposed so that the center line is aligned with the focusing point of the focused light 404 to control the step and gap of the welded portion. That is, the upper fixing rolls 502 and 503 always have the tip of the material to be welded. Maintain a constant height to completely remove the surface step, the lower fixing rolls (504,505) is designed to serve to support the molded material at the bottom bar, the top end of the material these upper and lower fixing rolls (502,503,504,505) The material (pipe) entering between these rolls is naturally supported so that the gaps are naturally matched to the position where the focusing light of the focusing light 404 is formed while the steps are removed. This is because the material is pressed naturally.

These various supporting rolls are integrated in a housing 501, which is a single structure, thereby maintaining mechanical rigidity and precision in position control.

The lower fixing rolls 503 and 504 are disposed to be inclined by about 120 ° with respect to the center of the forming pipe to be welded by the fixed roll driving units 506 and 507, and are installed to enable vertical movement in up and down precision.

The fixed roll driving unit (506, 507) is preferably such as a hydraulic cylinder, pneumatic cylinder that can be rotated in the horizontal direction.

At this time, the angle change and the shandong is made by each driving means 515, the amount of movement is determined by the command value instructed from the up and down position controller (not shown) of the fixed roll.

The magnitude of the position control signal utilizes a part of the signal output from the welding position signal generator (not shown), which includes the diameter of the pipe to be welded and the distance between the tip of the upper fixing rolls 502 and 503 and the welding point. have.

According to FIG. 8, the forming pipe is fixed to the forming pipe mounts 511 and 512 along its length, which is operated by the mounting drive unit 513 which drives it according to the length of the welding line.

The linear guide 510 is installed at both sides of the lower part of the fixed frame 500 so that the housing 501 can start welding and move at a predetermined speed by the transfer means 517.

Mounting unit driving unit 513 for moving the forming pipe mounts (511,512) is not shown with the linear guide 510 formed on the fixed frame 500, but is installed so as to be mutually movable by having a coupling relationship of the rack and pinion, The mounting drive unit 513 is preferably a means such as a motor.

The operation relationship of the apparatus of the present invention having such a configuration will be described with reference to FIGS. 8 and 9.

First, if the diameter, wall thickness, and weld line length of the forming pipe are input before welding, the upper fixing rolls 502 and 503 may have a predetermined width L and height F according to appropriate welding conditions preset based on the values. ) Is moved to a predetermined position to apply pressure to the material 101.

At this time, the upper fixing rolls (502, 503) to open the angle (R) formed by the plate-like processing surface to about 60 ~ 90 ° according to the diameter of the molding material 101 to machine with the laser welding head 403 or other accessories It is desirable not to cause any interference.

The outer periphery of the upper fixing rolls (502, 503) can be effectively applied to the molding material 101 during welding, and in order to reduce the change in the diameter due to wear it is preferable to perform a chamfering of about 10mm radius of curvature.

Either of the upper fixing rolls 502 and 503 electrically detects and outputs the advancing position of the fixing roll through means for knowing the position in the vertical direction, for example, the above-described welding position signal transmitter (not shown).

This electrical signal is also used as an element to determine the driving distance of the lower fixing rolls 504 and 505, and it operates so that the forming pipe 101 can always be fixed at an appropriate pressure in accordance with the diameter, tensile strength and focus position setting value during welding. do.

The upper fixing rolls 502 and 503 can be moved slightly from side to side on the basis of the welding line so that they are formed at a position equal to the width d of the welding bead 103 when the thickness of the material is thin or the pipe diameter is large and small. By applying pressure to the material 101, it is possible to simultaneously achieve the reduction effect and the rapid removal of surplus energy after welding.

As the welding proceeds, the welding line guide part 509 induces the laser focused light 404 to be incident at the center of the position where the welding groove 102 is to be welded at all times, so that the width d of the welding part is the center of the welding groove 102. It can be formed in the to make a full penetration weld.

FIG. 10 is a graph showing the limits of focus position (F) control as one of the examples for the basic data of proper welding condition setting.

According to the above graph, full penetration welding should be performed in the joint condition such as laser welding of the pipe, and in this case, the control of the focal position should be very important because it is directly related to the maximum penetration depth.

That is, in the upper region and lower region can be seen, when the value of the penetration ratio does not form a full penetration weld less than 1.0. However, setting the focusing of light on the focus F _o F ~ _-2 hayeoteul intervals and subjected to welding full penetration It can be confirmed that a penetration ratio of 1.0 is obtained.

However, since the optimum focal position is also related to the wall thickness or surface condition of the material to be welded, it is necessary to flexibly select it according to the conditions of the material when manufacturing the forming pipe using a laser.

11 shows an example of a weld defect formed when the butt gap G and the offset distance D of the material to be welded are out of the control range even when the focal position F and the welding heat input amount are properly set. It is a photograph shown.

According to the above picture, the laser focusing light 404 must be aligned with the welding center line C to melt both walls of the molding material 101 to form a predetermined weld, but the focused light 404 is offset distance D. It is found that the welding portion is not balanced as a result of melting too much on only one side of the material 101 because it is deviated by).

Therefore, the offset distance D should be able to maintain within 15% of the material thickness in any case. Otherwise, the size and shape of the weld is appropriate, and even if a full penetration weld of the same depth as the material thickness T is made, there is a high possibility that a weld defect W is formed below the weld bead 103.

This weld defect is a very harmful defect because it not only lowers the mechanical strength of the weld pipe but also causes leakage of the fluid flowing in the pipe.

The laser welding process through the apparatus of the present invention will be described with reference to the flowchart of FIG.

First, in the step of performing the welding, the tensile strength of the material, the diameter of the formed pipe, the wall thickness, and the length of the weld line, which are the initial conditions, are then subjected to the first process of determining the focal position (S11).

When the initial condition and the focal position are determined in the first process, a feed distance determination signal of the upper and lower fixing rolls 502, 503, 504, and 505 is formed, and a second process is performed in which each of the rolls can be driven according to the signal (S12). .

At the same time, the moving distance of the mold pipe mounts 511 and 512 is also subjected to a third process prepared to move at a welding speed determined by the transfer means 517 by the value set according to the initial input condition (S13).

Then, the reduction force of the welding deformation control roll 508 is determined, and also undergoes a fourth process of determining the position of the welding line guide portion 509 (S14).

Upon completion of the fourth process, the laser oscillator 401 transmits a predetermined laser output according to the welding start signal, and performs a fifth process of starting welding by operating each structure according to a set value (S15). .

At the end of the welding line, with the welding completion signal, the output of the laser oscillator 401 is stopped and the forming pipe mounts 511 and 512 are returned to their initial positions, thereby performing a sixth process to be fed back to the first process. (S16).

As described in detail above, the present invention provides the following effects.

First, even though the welding object is variable, the welding object is variable to correspond to the welding object, and thus the welding quality is remarkably improved by keeping the welding gap and the step constant at all times.

Second, by forming a welding bead of fast welding speed and constant size, it is possible to produce high quality welded products with improved welding reliability.

Claims (6)

A fixed frame; A mold pipe mount mounted on an upper surface of the fixing frame and installed to be movable along the mold frame; A housing fixed to an upper surface of the fixing frame and provided to allow a roll forming tube mounted on the forming tube mounting bracket to pass therethrough; A pair of upper fixing rolls rotatably fixed in the housing and arranged to contact and pressurize the upper outer circumferential surfaces of both sides of the welding point of the roll forming tube; A pair of lower fixing rolls arranged in contact with a lower outer circumferential surface of the roll forming tube while being vertically symmetric about the upper fixing roll and the raw material; A fixed roll driving part configured to fix the lower fixing roll at 120 ° intervals with respect to the center of the material and to be rotated forward and backward and up and down; A welding deformation control roll positioned on the side of the upper fixing roll and rotatably fixed to both upper walls of the housing to press the welding part of the roll forming tube to a constant pressure; And a welding head connected to the laser beam oscillator and disposed directly above the welding portion to irradiate the welding portion of the roll forming tube located in the housing between the welding deformation control roll and the upper fixing roll. Laser welding device. delete delete delete The apparatus of claim 1, wherein the forming pipe mount is installed on the upper surface of the fixed frame to be movable in combination with the rack and pinion along a pair of linear guides formed in the longitudinal direction thereof. A first step of inputting the tensile strength of the material, the diameter of the formed pipe, the wall thickness, and the weld line length, which are initial conditions for the pipe welding, and then determining the focal position; Determining a moving distance of the upper and lower fixed rolls after the first process, and waiting for each of the rolls to be driven; A third step of setting the moving distance of the mold pipe mount according to the initial input condition and preparing to move at the welding speed determined by the transfer means at the same time as the second step; A fourth step of determining a reduction force of the welding deformation control roll after the third step and determining a position of the weld line guide part; A fifth process of outputting a predetermined laser beam through a laser oscillator according to a welding start signal and simultaneously starting welding by operating each structure according to a set value; And a sixth step of feeding back to the first step while the output of the laser oscillator is stopped with the welding completion signal and the mold pipe mount is returned to the initial position.