KR20210061206A - Electro gas welding apparatus and heat input control method thereof - Google Patents

Abstract

The present invention relates to an electro gas welding apparatus and a method for controlling heat input capacity thereof. The electro gas welding apparatus comprises a welding torch with a welding wire mounted at a tip, a wire supply unit for supplying a welding wire to the welding torch, a weaving unit for weaving the welding torch in a thickness direction of a welding base material to be butt welded vertically, a driving unit for driving the welding torch to move in a vertical direction to perform upward welding, and a control unit for controlling heat input capacity by adjusting the welding current and voltage condition according to the welding site's location. Therefore, the heat input capacity can be controlled by adjusting the welding current and voltage condition according to the welding site's location during electro gas welding.

Description

Electro gas welding device and its heat input control method {ELECTRO GAS WELDING APPARATUS AND HEAT INPUT CONTROL METHOD THEREOF}

The present invention relates to an electrogas welding apparatus, and more particularly, to an electrogas welding apparatus for controlling the heat input of electrogas welding of a vertical butt joint generated during a block assembly process during ship construction, and a heat input control method thereof. .

In general, vertical butt welding is indispensable when manufacturing large structures such as commercial ships and offshore structures.

The thickness of the steel plate applied to the manufacture of such large structures is generally increasing from 15 tons to 95 tons in recent years.

For example, the thickness of the steel plate applied to the box-shaped oil tanker, bulk carrier, and LNG carrier is about 15 mm to 30 mm, and the upper steel plate of the container ship is very thick, reaching about 100 mm.

_{In the case of manual CO 2} welding of a steel plate having a thickness of about 20 mm, multi-layer welding of about 10 passes should be performed.

In order to improve productivity when manufacturing large structures such as ships or offshore structures as described above, an electro gas welding (EGW) technique capable of welding vertical butt joints at once is mainly used.

The electrogas welding is one of the upper welding methods in which the end of the base material and the water-cooled copper wall surround the molten paper, wrap it with carbon dioxide, etc., and then cause an arc to weld.It is developed to increase the welding productivity of the thick plate when building a ship. Is being applied.

For example, in Patent Documents 1 to 2 below, electrogas welding apparatus and method technology according to the prior art are disclosed.

In the case of applying the electrogas welding technique, it is possible to weld up to about 50t of the steel plate at a time.

And when the thickness of the steel plate exceeds about 50t, a combined tandem electrogas welding using two torches and single electrogas welding and _{manual CO 2} welding are performed on both sides of the X-improved steel plate at the same time. ) Electrogas welding method is applied.

The following patent document 3 discloses a tandem electro-gas welding technique.

As described above, the electrogas welding technique mainly uses carbon dioxide as a protective gas to generate an arc in a carbon dioxide atmosphere, and the arc heat is used to melt and join the base material. , The thicker the plate, the more economical it is.

That is, in electrogas welding, when a single electrode is used, a steel plate having a thickness of about 50 mm can be welded by weaving at one time.

1 is a view illustrating a welding area in electrogas welding according to the prior art, and FIGS. 2 and 3 are diagrams illustrating a structure of a heat-affected area with high heat input and low heat input.

1 is a plan view of the welded portion viewed from the top, and the portion indicated by the dotted line in FIG. 1 is an improved shape before the steel plate is welded.

Electrogas welding improved shape is set by international standards, and is constructed in accordance with the regulations of the world's leading classification society.

In the electrogas welding apparatus according to the prior art, as shown in FIG. 1, since the width of the face portion corresponding to the surface of the welding portion is wider than the width of the root portion corresponding to the rear surface of the welding portion, the face portion As a standard, the welding current and voltage conditions are set identically.

Therefore, the electrogas welding apparatus according to the prior art was welded while weaving under the same set welding current and voltage conditions irrespective of the welding part.

In this way, since the welding current and voltage conditions for melting the face portion are equally applied to the center portion and the root portion, penetration of the center portion and the root portion increases.

And although it does not melt by heat, the range of the heat-affected zone (HAZ) in which the structure by heat is changed is very wide compared to manual welding.

Therefore, when a large heat input is applied by increasing the heat input of the welding as shown in FIG. 2, the structure becomes coarse and the impact toughness decreases compared to the case where the low heat input shown in FIG. 3 is applied.

Accordingly, in order to secure the impact toughness of the heat-affected zone to which the high heat input is applied, when an alloy element is added or a complex heat treatment process is performed when manufacturing a steel sheet, the manufacturing cost of the steel sheet is increased.

Therefore, in the case of using a high heat input steel plate or a super heat input steel plate to use electrogas welding, which is essential for mass production of ships, etc., there is a problem in that the cost of materials such as ships increases.

For reference, the high heat input standard is 100kJ/cm or more and 350kJ/cm or less, and the superheat input is 350kJ/cm to 750kJ/cm.

Korean Patent Registration No. 10-1253858 (announced on April 12, 2013) Korean Patent Publication No. 10-2012-0097165 (published on September 3, 2012) Korean Patent Registration No. 10-0651783 (announced on December 1, 2006)

However, the electro-gas welding technique according to the prior art is continuously used even though there is a problem in the welding construction as described above.

In particular, when the thickness of the steel plate is 20 mm or more, a weaving operation is required, and the flux of the filler material melts due to excessive penetration of the center and the root, thereby increasing the amount of slag floating in the molten part.

As the slag increases, the electrical conductivity decreases, the arc becomes unstable, and the slag starts to burst in all directions. And the increased slag and spatter adhere to the welding tip, and the wire feeding performance is deteriorated.

Therefore, if the welding work is stopped due to excessive slag and spatter generated during the welding work, solidification cracks may occur in the part where it was stopped, and correction work must be performed again after the welding work.

In particular, in the case of thick plates, the heat treatment work and separate processing work of the base metal must be performed for the correction welding, resulting in a delay in the work process due to the slow working speed, and the production cost due to the increase in the amount and number of materials required for welding. Caused to increase.

In addition, the electrogas welding according to the prior art has a problem of increasing the manufacturing cost by increasing the amount of heat input to the welding as heat input under the same conditions is applied to the root part, the center part, and the face part.

An object of the present invention is to solve the above-described problems, and an electrogas welding apparatus capable of controlling the amount of heat input by adjusting the welding current and voltage conditions according to the position of the welding site during electrogas welding operation, and the amount of heat input thereof It is to provide a control method.

Another object of the present invention is an electrogas welding device that sets the weaving width and welding conditions according to the thickness of the welding base material, and controls the amount of heat input by welding with the weaving width and welding conditions set based on the location of the welding site, and the heat input thereof It is to provide a control method.

In order to achieve the above object, the electrogas welding apparatus according to the present invention includes a welding torch having a welding wire mounted at the tip, a wire feeding unit supplying a welding wire to the welding torch, and vertical butt welding the welding torch. A weaving unit that weaves in the thickness direction of the welding base material, a driving unit that moves the welding torch in an up-down direction to drive upward welding, and a control unit that controls the amount of heat input by adjusting welding current and voltage conditions according to the location of the welded part. It characterized in that it comprises a.

The weaving unit is provided with an encoder pulse control type servo motor, a DC motor equipped with an encoder, or a DC motor equipped with a tachometer, so that the weaving unit can control the weaving speed and position, and the control unit is recognized through the weaving unit. It is characterized in that the welding current and voltage conditions are adjusted based on the weaving position.

A start point and a rear end point corresponding to a preset maximum weaving width are set in the face portion and the root portion of the welding base material, and at least one intermediate point is set between the start point and the rear end point, and the control unit It is characterized in that the welding current and current conditions are controlled to decrease or increase for each movement section.

The present invention further includes an input unit receiving the welding current and voltage conditions and the weaving width set, and a power supply unit for supplying power to each device, wherein the control unit is welded according to the welding current and voltage conditions and the weaving width set through the input unit. A start point and a rear end point of a portion, and one or more intermediate points are set, and the welding current and current conditions are controlled to decrease or increase for each moving section between the set points.

In addition, in order to achieve the above object, the method for controlling the amount of heat input of the electrogas welding apparatus according to the present invention is a part to be welded by weaving along the thickness direction of the welding base material during vertical butt welding using the electrogas welding technique. It is characterized in that the amount of heat input is controlled by adjusting the welding current and voltage conditions based on the position of.

The present invention includes the steps of (a) moving the welding torch disposed at the welding part of the welding base material in the direction of the rear end point from the start point set on the face part by using a weaving unit, (b) the center set between the starting point and the rear end point in the control unit. Controlling to weld in a face condition of a preset welding current and voltage level in the first moving section to the point, (c) the current and voltage levels in the face condition in the second moving section from the center point to the rear end point. Controlling to weld with a central condition reduced by a preset first set ratio, (d) again, in the third moving section from the rear end to the center point, the current and voltage levels in the face condition are higher than the first set ratio. And (e) controlling welding to the central condition in a fourth moving section from the center point to the start point, and (e) controlling the welding to the central condition in a route condition reduced by a largely set second set ratio.

When the weaving operation of reciprocating from the starting point to the rear end point through the steps (a) to (e) is completed, the welding torch is increased by a predetermined interval, and the (a) to (e) steps. It is characterized in that step e) is repeatedly performed.

When the welding part reaches the starting point, the center point, and the rear end point, the control unit controls the amount of heat input by welding the welding device in a state in which the weaving operation is stopped for a preset time.

As described above, according to the electrogas welding apparatus and the heat input amount control method thereof according to the present invention, there is an effect that the heat input amount can be controlled by adjusting the welding current and voltage conditions according to the position of the welding site during the electrogas welding operation. Is obtained.

In addition, according to the present invention, the welding current and voltage conditions can be reduced or increased by a certain ratio according to the recognized weaving position during the weaving operation to obtain an appropriate penetration shape for each welding position, and the heat input amount can be effectively controlled. Is obtained.

In addition, according to the present invention, when welding under the same conditions irrespective of the location of the welding site in the related art, it is possible to prevent the impact toughness of the root portion from being deteriorated due to excessive penetration, and at the same time, increase the impact toughness of the root portion. By making the toughness uniform, the effect of reducing the risk of fatigue failure during the operation of the ship is obtained.

For this reason, according to the present invention, in order to secure the impact toughness of the heat-affected zone, there is no need to use a high heat-input iron plate or a super heat-input iron plate, thereby obtaining an effect of reducing the manufacturing cost.

In addition, according to the present invention, the effect of reducing slag and spatter through proper penetration into the welding site and stabilizing the molten pool and arc is obtained.

In addition, according to the present invention, it is possible to prevent the interruption of the welding operation due to excessive generation of slag and spatter in the related art, and to minimize the welding operation modification operation to improve workability and quality.

1 is a view illustrating a welding area in electrogas welding according to the prior art, FIGS. 2 and 3 are diagrams illustrating a structure of a heat-affected area with high heat input and low heat input,
4 is a block diagram of an electrogas welding apparatus according to a preferred embodiment of the present invention,
5 is a configuration diagram of the electrogas welding apparatus shown in FIG. 4;
6 is a view illustrating a state welded by the electrogas welding apparatus shown in FIG. 4;
7 is a step-by-step process diagram illustrating a method of controlling the amount of heat input of an electrogas welding apparatus according to a preferred embodiment of the present invention.

Hereinafter, an electrogas welding apparatus and a method for controlling the amount of heat input thereof according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is a block diagram of an electrogas welding apparatus according to a preferred embodiment of the present invention, and FIG. 5 is a block diagram of the electrogas welding apparatus shown in FIG. 4.

And FIG. 6 is a diagram illustrating a state of being welded by the electrogas welding apparatus shown in FIG. 4.

Hereinafter, terms indicating directions such as'left','right','front','rear','upward' and'downward' are defined as indicating each direction based on the state shown in each drawing. do.

Electrogas welding apparatus 10 according to a preferred embodiment of the present invention, as shown in Figs. 4 and 5, the welding torch 20 on which the welding wire is mounted at the tip, the welding wire is supplied to the welding torch 20 A weaving unit 40 for weaving the wire feeding unit 30, the welding torch 20 in the thickness direction of the welding base material to be vertically butt-welded, and driving to move the welding torch 20 in the up-down direction to drive upward welding. It includes a control unit 60 that controls the driving of the unit 50 and each device, and controls the amount of heat input by adjusting the welding current and voltage conditions according to the position of the welded portion.

In addition, the electrogas welding apparatus 10 according to a preferred embodiment of the present invention includes an input unit 70 that receives welding current and voltage conditions and a weaving width set by an operator's operation, and a power supply unit 80 that supplies power to each device. It may further include.

The welding torch 20 is a torch used in an electro-gas welding technique, and functions to supply and energize a welding wire.

For example, the welding base material is provided as a vertical steel plate having a thickness of about 11t to 100t, as shown in FIG. 6, and has an improved shape of an approximately'V' shape when viewed from the top.

The backing material 11 is installed on the rear surface of the welding base material, and the copper danggeum 12 is installed on the front surface of the welding base material.

The backing material 11 may support and cool a molten metal during a welding process to form a welding bead.

The copper sugar 12 supports the molten metal and may function to supply a cooling function and a protective gas by a water cooling hose (not shown). The copper danggeum 12 may be moved up and down by the driving unit 20 together with the welding torch 20.

The weaving unit 40 functions to weave the welding torch 20 in the thickness direction of the welding base material, that is, the steel plate.

In this embodiment, the weaving unit 40 may be provided with an encoder pulse control type servo motor, a DC motor equipped with an encoder, or a DC motor equipped with a tachometer so as to control the weaving speed and position.

Therefore, the control unit 60 receives the distance between the starting point (S) and the rear end point (B), that is, the weaving width, from the operator through the input unit 70 before starting the welding or during the welding operation, and the set weaving width and the weaving unit 40 It is possible to control the welding current and voltage condition to be adjusted while weaving the welding torch 20 according to the weaving position recognized through ).

And the control unit 60 receives the welding current and voltage conditions for each section moving between the start point (S) and the rear end point, and the welding current and voltage conditions set according to whether the position of the welding area is a root part, a center part, or a face part. You can control the amount of heat input by adjusting.

That is, the control unit 60 controls the driving of the weaving unit 40 to move the welding torch 20 from the face to the root through the central part and weld it, and then move the welding torch 20 back and forth from the root through the central part to the face part. do.

In addition, the control unit 60 controls to decrease and increase the welding current and voltage conditions for each movement section.

In FIG. 6, the maximum weaving width of the welded portion when welding a 30t-thick steel plate should be weaved in a space excluding about 3 to 5 mm from the front and rear surfaces of the steel plate in order to prevent damage or damage to the weld base material.

For example, in this embodiment, the maximum weaving width may be set to about 24 mm.

Therefore, the starting point (S) is installed at a position separated by about 3 mm from the front to the rear of the welding base material corresponding to the face part, and the rear end point (B) is about 3 mm from the rear to the front of the welding base material corresponding to the root part. Can be set as spaced apart.

And between the start point (S) and the rear end point (B), a center point C may be set at a position of about 12 mm, which is the middle of the maximum weaving width.

Therefore, the control unit 60 controls to weld in the first moving section R1 from the start point S to the center point C with a preset welding current and voltage condition (hereinafter referred to as'face condition'), and the center point In the second movement section (R2) from (C) to the rear end (B), the current and voltage levels are reduced by a first set ratio, e.g., about 10%, compared to the phase condition. ) Can be controlled to weld.

In addition, the control unit 60 reduces the current and voltage level to a second set ratio, for example 20%, compared to the face condition in the third moving section R3 from the rear end point B to the center point C. Welding is controlled to be welded under conditions (hereinafter referred to as'root condition'), and welding by increasing the welding current and voltage according to the central condition in the fourth moving section (R4) from the center point (C) to the starting point (S). Can be controlled to do.

Here, the control unit 60 controls the amount of heat input by welding at the start point (S), the center point (C), and the rear end point (B) in a state in which the weaving operation is stopped for a predetermined time, for example, about 0.1 to 0.5 ms. can do.

As described above, the present invention can control the amount of heat input by adjusting the welding current and voltage conditions according to the position of the welding portion during the electrogas welding operation.

Next, a method of controlling the amount of heat input of the electrogas welding apparatus according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 6 and 7.

7 is a flowchart illustrating step-by-step a method of controlling the amount of heat input of an electrogas welding apparatus according to an exemplary embodiment of the present invention.

In step S10 of FIG. 7, the welding torch 20 is disposed on the welding part of the welding base material to be vertically butt-welded.

At this time, the backing material 11 and the copper danggeum 12 are installed on the rear and front surfaces of the welding base material, respectively.

The welding torch 20 supplies a wire from the wire supply unit 30 and generates an arc in a carbon dioxide atmosphere using a protective gas such as carbon dioxide.

Then, the control unit 60 controls the driving of the weaving unit 40 to weave in the thickness direction of the welding base material, and adjusts the welding current and voltage conditions according to the position of the welding part recognized through the weaving unit 40 Control the amount of heat input.

That is, the control unit controls the welding in the first movement section R1 from the start point S to the center point C in a preset face condition (S12).

In step S14, the control unit welds to the central condition in which the current and voltage levels are reduced by a first set ratio, e.g., about 10%, compared to the face condition in the second movement section (R2) from the center point (C) to the rear end point (B). Control to do it.

In step S16, the control unit 60 reduces the current and voltage levels by a second set ratio, for example, 20%, compared to the phase condition in the third movement section R3 from the rear end point B to the center point C. Controlled to weld.

In step S18, the controller 60 controls the welding by increasing the welding current and voltage according to the central condition in the fourth moving section R4 from the center point C to the starting point S.

At this time, when the weaving position reaches the starting point (S), the center point (C), and the rear end point (B), the control unit 60 stops the weaving operation for a preset time, for example, about 0.1 to 0.5 ms. You can control the amount of heat.

When the weaving operation of reciprocating the starting point (S) and the rear end point (B) is completed through this process, the control unit 60 moves the welding torch 20 and the copper danggeum 12 upward by a preset height. Controls the driving of the drive unit 50.

Subsequently, the control unit 60 controls to weld the entire improved portion of the vertical steel plate provided with the welding base material by repeatedly performing steps S10 to S20 described above.

Through the above-described process, the present invention can control the amount of heat input by adjusting the welding current and voltage conditions according to the position of the welding portion during the electrogas welding operation.

In addition, according to the present invention, the welding current and voltage conditions can be reduced or increased by a certain ratio according to the recognized weaving position during the weaving operation to obtain an appropriate penetration shape for each welding position, and the amount of heat input can be effectively controlled.

In addition, the present invention prevents the impact toughness of the root portion from deteriorating due to excessive penetration when welding under the same conditions regardless of the location of the welding site in the related art, and at the same time, it is possible to increase the impact toughness of the root portion.

For this reason, the present invention eliminates the need to use a high heat input iron plate or a super heat input iron plate in order to secure the impact toughness of the heat-affected zone, thereby reducing manufacturing cost.

In addition, the present invention can reduce slag and spatter through proper penetration into the welding area, and stabilize the molten pool and arc.

In addition, according to the present invention, it is possible to improve workability and quality by preventing the conventional welding operation from being interrupted due to excessive generation of slag and spatter, and minimizing the welding operation modification operation.

Although the invention made by the present inventor has been described in detail according to the above embodiment, the invention is not limited to the above embodiment, and it goes without saying that the invention can be changed in various ways without departing from the gist of the invention.

That is, in the above embodiment, it has been described that a center point is set between the start point and the rear end point, and the welding current and voltage conditions are adjusted for each section moving between each point, but the present invention provides a plurality of intermediate points between the start point and the rear end point. It can be changed to subdivide and set the points, and to further subdivide and control the welding current and voltage conditions for each moving section between each point.

In addition, the present invention may be set by variously changing the rate at which the welding current and voltage level for each face condition, the central condition, and the root condition are adjusted, such as 5 to 30%.

Further, according to the present invention, the welding conditions can be set by changing the current and voltage levels together, or by changing only the current level or voltage level.

The present invention is applied to electrogas welding and a method of controlling the amount of heat input thereof by controlling the amount of heat input by adjusting the welding current and voltage conditions according to the position of the welding part during the electrogas welding operation.

10: Electrogas welding device
11: Backing material
12: Dongdam Geum
20: welding torch
30: electrode wire supply unit
40: weaving unit
50: drive unit
60: control unit
70: input
80: power supply

Claims (8)

Welding torch with welding wire mounted on the tip,
A wire supply unit for supplying a welding wire to the welding torch,
Weaving unit for weaving the welding torch in the thickness direction of the welding base material to be vertically butt-welded,
A driving unit that moves the welding torch in an up-down direction to drive the welding torch up and down, and
Electrogas welding apparatus, characterized in that it comprises a control unit for controlling the amount of heat input by adjusting the welding current and voltage conditions according to the position of the welded portion. The method of claim 1,
The weaving unit is provided with an encoder pulse control type servo motor, a DC motor equipped with an encoder, or a DC motor equipped with a tachometer so as to control the weaving speed and position,
The control unit is an electrogas welding apparatus, characterized in that to adjust the welding current and voltage conditions based on the weaving position recognized through the weaving unit. The method of claim 2,
A start point and a rear end point corresponding to a preset maximum weaving width are set in the face portion and the root portion of the welding base material, respectively,
One or more intermediate points are set between the starting point and the trailing end point,
The control unit is an electrogas welding apparatus, characterized in that for controlling to decrease or increase the welding current and current conditions for each movement section between the set points. The method of claim 2,
An input unit configured to set the welding current and voltage conditions and the weaving width, and
Further comprising a power supply for supplying power to each device,
The control unit sets the starting point and the rear end point and one or more intermediate points of the welding area according to the welding current and voltage conditions and the weaving width set through the input unit, and reduces the welding current and current conditions for each moving section between the set points or Electrogas welding apparatus, characterized in that the control to increase. An electrogas welding device characterized in that when vertical butt welding using an electrogas welding technique, the amount of heat input is controlled by controlling the welding current and voltage conditions based on the position of the welded part by weaving along the thickness direction of the welding base material. How to control the amount of heat input of The method of claim 5,
(a) using a weaving unit to move the welding torch disposed on the welding part of the welding base material from the starting point set on the face part to the rear end point,
(b) controlling, by a control unit, to weld in a first moving section to a center point set between the start point and the rear end point in a phase condition of a preset welding current and voltage level,
(c) controlling the welding to a central condition in which the current and voltage levels are reduced by a preset first set ratio in the face condition in the second moving section from the center point to the rear end point,
(d) again controlling the welding in the third moving section from the rear end point to the center point under a root condition in which the current and voltage levels in the face condition are reduced by a second set ratio set greater than the first set ratio, and
(e) controlling the welding to the central condition in a fourth moving section from the center point to the start point. The method of claim 6,
When the weaving operation of reciprocating from the start point to the rear end point through the steps (a) to (e) is completed, the welding torch is raised by a predetermined interval, and the steps (a) to ( The method of controlling the amount of heat input of an electrogas welding apparatus, characterized in that repeating step e). The method of claim 6,
When the welding part reaches the starting point, the center point, and the rear end point, the control unit welds the welding device in a state in which the weaving operation is stopped for a preset time to control the amount of heat input. Calorie control method.

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