CN109108508B

CN109108508B - Welding method for forming uniform welding bead

Info

Publication number: CN109108508B
Application number: CN201810522324.XA
Authority: CN
Inventors: 金明基
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-06-22
Filing date: 2018-05-28
Publication date: 2020-11-06
Anticipated expiration: 2038-05-28
Also published as: WO2018236035A1; CN109108508A; KR101798091B1

Abstract

The present invention is technically characterized by comprising: a preparation step of placing the first object to be welded and the second object to be welded in contact with each other; a spot welding step of forming a plurality of spot welds at spaced intervals by a welding torch on one surface selected from one side surface or the other side surface of the first object to be welded and the second object to be welded which are in contact with each other; a first normal welding step of performing normal welding along a longitudinal direction of a surface where the first object to be welded and the second object to be welded are in contact with each other, on a surface opposite to a surface where spot welding is performed in the spot welding step; and a second normal welding step of performing normal welding along a longitudinal direction of a surface where the first object and the second object are in contact with each other, on a surface where the spot welding is performed in the spot welding step.

Description

Welding method for forming uniform welding bead

Technical Field

The present invention relates to a welding method that allows a weld bead formed by welding to be formed uniformly.

More specifically, the present invention relates to a welding method in which a first object to be welded and a second object to be welded are placed in contact with each other, and when welding is performed by a welding torch (torch) on a surface where the first object to be welded and the second object to be welded are in contact with each other, welding is performed by swinging in a state where the welding torch is inclined from the first object to be welded or the second object to be welded, so that the length of a weld bead formed by one welding operation is maximally increased, thereby forming a uniform weld bead.

Background

Generally, welding using weaving is a welding method as follows: the welding torch is moved while the electrode rod is alternately moved in both side directions with respect to the welding direction, thereby forming a weld bead.

However, in the conventional technique, welding using weaving has the following problems in the welding process: the movement of the welding torch is out of the range for swinging due to frequent hunting of the welding torch, and therefore a uniform weld bead is not formed.

Further, since welding is performed mainly based on experience of an operator in a state where the torch is not supported, a weld bead having an uneven shape is formed during the oscillation, and further, the length of the weld bead formed by one welding is short, and a plurality of connection points where the weld bead is connected to the weld bead are increased, thereby causing a problem that the shape of the weld bead at the connection points cannot be made uniform.

Accordingly, in order to prevent the above problems, various welding apparatuses for performing welding by automation have been developed, but there is a problem in that a high cost is required to install and maintain the welding apparatuses, and thus there is a problem in that the availability is very low.

Accordingly, the following welding method is required: the length of a weld bead formed by one welding is increased to the maximum, and the weld bead with a uniform shape is formed by moving the supported welding torch.

Prior art documents

[ patent document ]

(patent document 0001) patent publication No. 10-2017 0067346 (2017.06.16)

(patent document 0002) patent publication No. 10-2013 0061297 (2013.06.11)

Disclosure of Invention

The present invention has been made to satisfy the above-described requirements, and an object to be solved by the present invention is to provide a welding method for forming a uniform bead, in which a first object to be welded and a second object to be welded are placed in contact with each other, and when welding is performed by a welding torch on a surface where the first object to be welded and the second object to be welded are in contact with each other, the welding torch is tilted from the first object to be welded or the second object to be welded, and welding is performed by swinging, whereby the length of the bead formed by one welding can be increased to the maximum, and a uniform bead can be formed.

In order to solve the above problem, a welding method for forming a uniform bead according to the present invention provides a welding method for forming a uniform bead, including: a preparation step of placing the first object to be welded and the second object to be welded in contact with each other; a spot welding step of forming a plurality of spot welds at spaced intervals by a welding torch on one surface selected from one side surface or the other side surface of the first object to be welded and the second object to be welded which are in contact with each other; a first normal welding step of performing normal welding along a length direction of a surface where the first object to be welded and the second object to be welded are in contact with each other, on a surface opposite to the surface where spot welding is performed in the spot welding step; and a second normal welding step of performing normal welding along a longitudinal direction of a surface where the first object and the second object are in contact with each other, on a surface where spot welding is performed in the spot welding step, thereby solving a technical problem.

In the present invention, when welding is performed by a welding torch on a surface of a first object to be welded and a second object to be welded which are placed in contact with each other, the welding torch is tilted from the first object to be welded or the second object to be welded, and welding is performed by swinging, and therefore, the following significant effects are obtained: the length of the weld bead formed by one welding is maximized, thereby forming a uniform weld bead.

Further, the spot welding is performed once on one surface selected from one side surface or the other side surface of the first object to be welded and the second object to be welded, and after the first conventional welding is performed twice on the opposite surface to the surface on which the spot welding is performed, the conventional welding is performed three times on the surface on which the spot welding is performed, thereby having the following remarkable effects: the first and second bodies to be welded are corrected in bending during welding, so that the flat or rectangular shape according to the design can be stably maintained.

In addition, when the first object to be welded and the second object to be welded are in contact with each other at a portion perpendicular to the ground surface, welding is performed while the welding torch is tilted downward and moved upward from the lower side, and the following significant effects are obtained: the bead formed during welding is pushed upward before the molten iron before solidification flows downward, thereby forming a bead of uniform shape.

Further, by being provided in the guide portion of the welding torch, the distance between the portion of the first object to be welded and the second object to be welded, which are in contact with each other, and the electrode rod provided in the welding torch can be maintained at about 1 to 2mm, and the following significant effects are exhibited: the weld bead can be formed uniformly by the interval.

Drawings

Fig. 1 is a flowchart illustrating a welding method of forming a uniform bead according to the present invention.

Fig. 2 is a diagram showing various embodiments of preparation steps in the welding method for forming a uniform bead according to the present invention.

Fig. 3 is an example showing a welding stage fixing step in the welding method for forming a uniform bead according to the present invention.

Fig. 4 is an example illustrating a spot welding step in the welding method for forming a uniform bead according to the present invention.

Fig. 5 is an example showing a first conventional welding step in the welding method for forming a uniform bead according to the present invention.

Fig. 6 is an example showing a second conventional welding step in the welding method for forming a uniform bead according to the present invention.

Fig. 7 is a perspective view showing a welding torch in the welding method for forming a uniform bead according to the present invention.

Fig. 8 is a view showing an example when the first and second welded bodies are formed in a vertical posture in the welding method for forming a uniform bead according to the present invention.

Detailed Description

Advantages and features of embodiments of the present invention, and methods for accomplishing the same, will become apparent from the following detailed description of embodiments of the invention and the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be realized in a plurality of different forms, and the embodiments are provided only for the following purposes: so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art to which the invention pertains, and the present invention will only be defined by the appended claims. Like reference numerals refer to like elements throughout the specification.

In describing the embodiments of the present invention, it is judged that a detailed description of a known function or configuration may unnecessarily obscure the gist of the present invention, and a detailed description thereof will be omitted. Further, the terms and words used in the present specification and claims are defined in consideration of functions in the embodiments of the present invention, and are not to be construed as limited to general or dictionary meanings, and the inventor should only be construed as meanings and concepts conforming to the technical idea of the present invention on the basis of the principle that the concept of the terms can be appropriately defined in order to explain his own invention in the best way.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferable embodiments of the present invention and do not represent all the technical ideas of the present invention, and therefore it should be understood that various equivalents and modifications that can substitute for these embodiments exist in the present application.

In the following, a description will be given of a known configuration that is not necessary for showing the gist of the present invention, and that is obvious to a person having ordinary knowledge, or a specific description will not be given, in order to explain the gist of the present invention.

The welding method for forming a uniform bead according to the present invention relates to a welding method including: the first object 100 and the second object 200 are placed in contact with each other, and when welding is performed by the welding torch 400 on the surface where the first object 100 and the second object 200 are in contact with each other, welding is performed by oscillation in a state where the welding torch 400 is inclined from the first object 100 or the second object 200, so that the length of the weld bead 10 formed by one welding is increased to the maximum, and a uniform weld bead 10 is formed.

First, in the present specification, spot welding and regular welding are performed such that the size of the formed weld bead 10 is different depending on the degree of welding, and specifically, when the length of the portion where the first object 100 and the second object 200 are in contact with each other (the portion where welding is to be performed) is formed long, the weld beads 10 are formed in the form of dots at intervals in the longitudinal direction. In other words, spot welding, which is a prior operation before performing normal welding, means that the first object 100 and the second object 200 are temporarily joined by spot welding.

Further, the conventional welding means that the first object 100 and the second object 200 are completely joined by the conventional welding, and the linear bead 10 is formed along the longitudinal direction in which the first object 100 and the second object 200 are in contact with each other.

Hereinafter, a welding method for forming a uniform bead according to the present invention will be described in detail with reference to the accompanying drawings.

The welding method of forming a uniform bead according to the present invention is to weld the first and second

welded bodies

100 and 200 by welding with weaving, and forms the uniform bead 10, and includes a preparation step S10, a spot welding step S20, a first normal welding step S30, and a second normal welding step S40.

Step S10 is prepared as a step for bonding the first body to be welded 100 and the second body to be welded 200 by welding so that the first body to be welded 100 and the second body to be welded 200 are placed in contact with each other so that the portions to be welded are joined.

In the preparation step S10, it is preferable that the first and second bodies to be welded 100 and 200 be formed in a horizontal form to the ground, or in a vertical form, or in a circular form, so that the portions to be welded are first selected and then placed in a form of being joined to each other in consideration of the form characteristics between the bodies to be welded.

Further, depending on the morphological characteristics of the object to be welded, it should be placed in consideration of the morphology of the object to be welded.

For example, as shown in fig. 2(a), the first and second bodies to be welded 100 and 200 formed in a plate form may be joined to each other in a right-angle form, and as shown in fig. 2(b), may be joined in a form having a flat surface.

In this case, in preparation step S10, when the first object to be welded 100 and the second object to be welded 200 are in a state of being joined to each other, the state of temporary joining can be maintained by a jig or the like.

Thus, in the spot welding step S20, the first normal welding step S30, and the second normal welding step S40, which will be described later, it is possible to prevent the first object 100 and the second object 200 from moving during welding and to perform precise work.

The preparation step S10 may include a welding platform fixing step S11 according to design conditions.

The welding surface plate fixing step S11 will be described in detail below with reference to fig. 3.

The welding stage fixing step S11 is a step of: in the spot welding step S20 and the second conventional welding step S40 described later, the welding table 300 can support the guide portion 420 of the welding torch 400 and can guide the welding bead 10 so as to form a uniform shape.

As shown in fig. 2(a), the welding stage fixing step S11 is a step of: when the first object 100 and the second object 200 in the form of a plate are joined to each other in a right angle, the welding table 300 is disposed adjacent to a selected one of the first object 100 and the second object 200, and then fixed.

In this case, as shown in fig. 3, when the welding stage 300 is disposed under the second body to be welded 200, a part of the welding stage 300 is formed to protrude outward of the second body to be welded 200, and the first body to be welded 100 and the welding stage 300 may be formed in a right angle.

Accordingly, during welding, welding is performed in a state where both side surfaces of the distal end of the guide portion 420 of the welding torch 400 are supported by the first object 100 and the welding surface plate 300, respectively, and the distal end of the electrode rod 430 protruding outward of the guide portion 420 can always maintain the same interval with the portion for performing welding.

For example, as shown in fig. 3, both side surfaces of the distal end of the guide part 420 are supported by the first object 100 and the welding table 300, respectively, so that the distal end of the electrode rod 430 is spaced apart from the portion for realizing welding, so that the portion for realizing welding can realize welding while maintaining a space from the distal end of the electrode rod 430, and the weld bead 10 can be prevented from being formed in various sizes at the time of welding, so that the weld bead 10 is formed in a uniform form.

Preferably, if the guide part 420 contacts and is supported by the first body to be welded 100 and the welding stage 300, the tip of the electrode rod 430 and the portion for performing welding, i.e., the portion where the first body to be welded 100 and the second body to be welded 200 contact, may be configured to be spaced apart by about 1 to 2 mm.

In this case, if the distance between the portion for welding and the end of the electrode rod 430 is greater than 2mm, the size of the weld bead 10 becomes large, and the weld bead 10 cannot be formed in a uniform shape, and if the distance is less than 1mm, the bonding force by welding is reduced, and the first object 100 and the second object 200 cannot be firmly bonded to each other.

Accordingly, in the process of welding the welding torch 400 while moving in the longitudinal direction of the first body to be welded 100 and the second body to be welded 200, the guide portion 420 of the welding torch 400 is supported by the second body to be welded 200 and the welding table 300, and even if the welding torch 400 is repeatedly engaged with the second body to be welded 200 and the welding table 300 or disengaged from the second body to be welded 200 and the welding table 300, the electrode rod 430 having a shape protruding outward of the guide portion 420 is kept in contact with the first body to be welded 100 and the second body to be welded 200 and a portion to be welded is kept spaced apart, so that the thickness of the formed weld bead 10 is kept constant, and the welding torch 400 is stably supported while moving during welding, so that the shape of the weld bead 10 has a uniform shape.

After the welding stage 300 is disposed according to the design conditions, the welding stage 300 may be temporarily fixed to the first object 100 or the second object 200 by using a jig or the like.

The spot welding step S20 is a step of: in preparation step S10, a plurality of spot welds are performed by the welding torch 400 at spaced intervals on one surface selected from one side surface or the other side surface of the first object to be welded 100 and the second object to be welded 200.

In other words, as shown in fig. 4, the spot welding step S20 is a step of: after spot welding is performed so as to form a small number of weld beads 10 along the longitudinal direction in which the first object 100 and the second object 200 are in contact with each other, the welding torch 400 is moved so as to perform spot welding so as to form another weld bead 10, and the process is repeated to temporarily join the first object 100 and the second object 200.

In addition, in the present specification, spot welding is performed without immediately welding one side and the other side of the first object to be welded 100 and the second object to be welded 200 by the first normal welding step S30 and the second normal welding step S40 described later, and it is an object that, after the first object to be welded 100 and the second object to be welded 200 are joined in the preparation step S10, if normal welding is immediately performed, the first object to be welded 100 and the second object to be welded 200 are inclined to the side where normal welding is performed, and therefore, it can be prevented from happening in the future.

In other words, the spot welding is performed such that the first to-be-welded body 100 and the second to-be-welded body 200 are temporarily joined, and only a small number of weld beads 10 formed by the spot welding are formed, thereby minimizing the degree of inclination of the first to-be-welded body 100 and the second to-be-welded body 200, and in the first conventional welding step S30 described later, the conventional welding is performed on the opposite side where the spot welding is performed, so that the degree of inclination can be corrected at the time of spot welding.

At this time, the face where the spot welding is achieved in the spot welding step S20 is achieved on the same face as the face where the normal welding is achieved in the second normal welding step S40 described later, and on the opposite face where the spot welding step S20 and the second normal welding step S40 are achieved, the first normal welding step S30 described later may be performed.

The first conventional welding step S30 is the following step: the opposite side to the spot welding performed in the spot welding step S20 is subjected to normal welding along the longitudinal direction of the contact surface between the first object to be welded 100 and the second object to be welded 200.

Referring to fig. 5, the first normal welding step S30 will be described, in which normal welding is performed on the opposite surfaces of the first body to be welded 100 and the second body to be welded 200, which are inclined to the side where spot welding is performed in the spot welding step S20, so that the first body to be welded 100 and the second body to be welded 200 are again inclined in the direction where normal welding is performed, and can be restored to the original form, thereby correcting the degree of inclination at the time of spot welding.

At this time, as shown in fig. 5, in the first normal welding step S30, normal welding is performed, and the welding torch 400 is moved while being swung in a state where both side surfaces of the tip of the guide part 420 of the welding torch 400 are respectively supported between the first object to be welded 100 and the second object to be welded 200, which are formed in a right-angled state, in a joined manner, whereby normal welding can be performed.

The second conventional welding step S40 is the following step: the surface where spot welding is performed in the spot welding step S20 is subjected to normal welding along the longitudinal direction of the surface where the first object 100 and the second object 200 are in contact.

The second conventional welding step S40 is performed at a portion where the weld bead 10 is formed by spot welding of the spot welding step S20 as a step of performing conventional welding on the opposite side of the side where the conventional welding is achieved at the first conventional welding step S30.

Here, it is preferable that the second conventional welding step S40 is performed in the same manner as the conventional welding of the first conventional welding step S30, such that both side surfaces of the tip end of the guide part 420 of the welding torch 400 are respectively brought into contact with and supported by the first object 100 and the welding stage 300.

At this time, it is preferable that the welding torch 400 is placed and implemented in a form of being inclined at the time of welding in the spot welding step S20, the first regular welding step S30, and the second regular welding step S40.

In more detail, the welding torch 400 may be inclined at an angle of about 45 ° to 75 ° with respect to the first welded body 100 or the second welded body 200.

Here, if the inclination angle at which welding torch 400 is inclined is smaller than 45 °, the following problem occurs: the welding torch 400 is excessively inclined from the first welded body 100 and the second welded body 200, so that the tip of the electrode rod 430 formed at the tip of the welding torch 400 is not abutted to a portion where welding is intended to be performed, and thus welding is not performed, and if the inclination angle is greater than 75 °, there are problems in that: similarly to the state where the welding torch 400 is perpendicular to the portion to be welded, it is difficult to maintain the inclination angle of the welding torch 400 during the movement of the welding torch 400 during welding, and the welding bead 10 having a uniform shape cannot be formed due to the movement of the welding torch 400.

Further, it is preferable that the direction in which the welding torch 400 is placed in an inclined form is formed in the opposite direction to the direction in which the welding torch 400 travels for welding.

In other words, the operator can perform welding by holding welding torch 400 and tilting it toward the operator, and then moving welding torch 400 away from the operator.

The object is to minimize the dispersion of the form of the weld bead 10 and to obtain a uniform form by dispersing the form of the weld bead 10 and solidifying the weld bead in a fluid state before the molten iron is solidified, by utilizing the principle that the molten iron is pushed in the longitudinal direction of the portion where the first body 100 and the second body 200 are joined while the welding torch 400 is moving during welding.

According to design conditions, the torch 400 performing the conventional welding using the weaving may be formed with the chamfered part 421 at the tip of the guide part 420 in the first and second conventional welding steps S30 and S40.

The torch 400 is described in detail with reference to FIG. 7.

First, the welding torch 400 includes: a main body 410; a guide part 420 provided at one side of the body 410; and an electrode rod 430 provided on the body 410 and formed to protrude outward of the guide part 420.

At this time, it is preferable that the length of the electrode rod 430 protruding to the outside of the guide part 420 is formed to have a length spaced apart from the corner part forming the right angle by about 1 to 2mm if the outer side surface of the tip of the guide part 420 is in contact with the surface forming the right angle.

The guide part 420 may be formed at a distal end thereof with a chamfered part 421 having an outer diameter gradually decreasing from the main body 410 side toward the outer side according to design conditions.

In the chamfered portion 421, when the welding torch 400 is positioned between the first body to be welded 100 and the second body to be welded 200 or between the first body to be welded 100 and the welding surface plate 300 during welding, the tip of the guide portion 420, that is, the outer peripheral surface on which the chamfered portion 421 is formed, is supported by the first body to be welded 100, the second body to be welded 200, or the welding surface plate 300 in surface contact therewith, and in this case, even if the operator does not arbitrarily manipulate the inclination angle of the welding torch 400, the chamfered portion 421 in the inclined form is inclined, and the inclined state can be easily maintained.

The chamfered portion 421 may include a first chamfered portion 421a, a second chamfered portion 421b, and a third chamfered portion 421c having different inclination angles from each other, as described with reference to fig. 7.

The first chamfered portion 421a is formed at a part of the tip of the guide portion 420, is formed to be inclined outward from the main body 410, and is formed to have an inclination angle of 45 ° with respect to the outer peripheral surface of the guide portion 420, and is configured to maintain the inclination angle of the welding torch 400 at 45 ° when the welding torch 400 is in surface contact with the

object

100, 200 or the welding table 300 when the welding torch 400 is positioned in contact with the

object

100, 200 or the welding table 300.

The second chamfered portion 421b is formed at a part of the distal end of the guide portion 420, is formed to be inclined outward from the main body 410, and is formed to have an inclination angle of 60 ° with respect to the outer peripheral surface of the guide portion 420, and is configured to be in surface contact with the

object

100, 200 or the welding table 300, so that the inclination angle of the welding torch 400 can be maintained at 60 °.

The third chamfered portion 421c is formed at a part of the distal end of the guide portion 420, is formed to be inclined outward from the main body 410, and is formed to have an inclination angle of 75 ° with respect to the outer peripheral surface of the guide portion 420, and is configured to maintain the inclination angle of the welding torch 400 at 75 ° when the welding torch 400 is brought into contact with the

object

100, 200 or the welding table 300 and is brought into surface contact with the

object

100, 200 or the welding table 300.

Thus, the first, second, or third

chamfered portion

421a, 421b, 421c is selectively brought into surface contact with the objects to be welded 100, 200, or the welding table 300, whereby the inclination angle of the welding torch 400 can be maintained more effectively and stably.

Further, when the first body to be welded 100 and the second body to be welded 200 are formed in the vertical state, it is preferable that the welding torch 400 is moved from the lower side to the upper side while being tilted downward, and welding is performed.

In other words, in the process of welding the first and second objects to be welded 100 and 200 formed in the vertical form, the first and second objects to be welded 100 and 200 are placed in contact by the preparation step S10, after spot welding is performed on one side surface, conventional welding is performed by the first conventional welding step S30 on the other side surface, and conventional welding is performed by the second conventional welding step S40 on the side surface on which spot welding is performed, all welding processes being performed while moving the welding torch 400 from the lower side to the upper side, so that the weld bead 10 of the uniform form can be formed.

Welding is performed while the welding torch 400 is moved from the lower side to the upper side after being inclined to the lower side, so that the formed weld bead 10 is pushed up to the upper side before the molten iron before solidification flows down to the lower side at the time of welding, and the weld bead 10 having a uniform shape can be formed.

According to the method, according to the welding method for forming a uniform bead of the present invention, when the first body to be welded 100 and the second body to be welded 200 are placed in contact with each other and welding is performed by the welding torch 400 on the surface where the first body to be welded 100 and the second body to be welded 200 are in contact with each other, welding is performed by swinging in a state where the welding torch 400 is inclined from the first body to be welded 100 or the second body to be welded 200, so that the length of the bead formed by one welding can be increased to the maximum, and further, the uniform bead can be formed.

Further, by performing the spot welding once on one surface selected from one side surface or the other side surface of the first object to be welded 100 and the second object to be welded 200, which are in contact with each other, and performing the regular welding twice on the opposite surface to the spot welding, and then performing the regular welding three times on the surface on which the spot welding is formed, the bending of the first object to be welded 100 and the second object to be welded 200 is corrected at the time of welding, and thus, the flat shape or the right-angled shape according to the design can be stably maintained.

In addition, when the portion of the first object to be welded 100 and the second object to be welded 200 that are in contact with each other is formed in a shape perpendicular to the ground, the welding torch 400 is tilted downward and moved upward from the lower side to weld the objects, so that the bead formed during welding is pushed upward before the molten iron before solidification flows downward, and a bead of uniform shape can be formed.

Further, the gap between the portion of the first object 100 and the second object 200 that are in contact with each other and the electrode rod 430 provided to the welding torch 400 can be maintained at about 1 to 2mm by the guide portion 420 provided to the welding torch 400, so that the weld bead 10 can be uniformly formed by the gap.

While various embodiments of the present invention have been described in the foregoing, it is to be understood that the present invention is not necessarily limited thereto, and various substitutions, modifications and changes may be made by those having ordinary knowledge in the art to which the present invention pertains without departing from the technical spirit of the present invention.

Description of the reference symbols

10, weld bead 100: first welded body

200: second soldered body 300: welding platform

400: the welding torch 410: main body

420: the guide portion 421: chamfered part

421 a: first chamfered portion 421 b: second chamfered part

421 c: third chamfered portion 430: electrode bar

Claims

1. A welding method for forming a uniform bead, comprising:

a preparation step (S10) of placing the first body to be welded (100) and the second body to be welded (200) in contact;

a spot welding step (S20) of forming a plurality of spot welds at spaced intervals by a welding torch (400) on one surface selected from one side surface or the other side surfaces of the first object (100) and the second object (200) that are in contact with each other;

a first normal welding step (S30) of performing normal welding along a longitudinal direction of a surface of the first object (100) and the second object (200) in contact with each other, on a surface opposite to a surface where spot welding is performed in the spot welding step (S20); and

a second normal welding step (S40) of performing normal welding along a longitudinal direction of a surface where the first object to be welded (100) and the second object to be welded (200) are in contact with each other, on a surface where spot welding is performed in the spot welding step (S20),

the preparing step (S10) includes: a welding stage fixing step (S11) of disposing and fixing a welding stage (300) in such a manner as to be adjacent to a selected one of the first body to be welded (100) and the second body to be welded (200),

the welding-stage fixing step (S11) is characterized in that,

in the spot welding step (S20), a guide portion (420) of a welding torch (400) is caused to abut between a welding platform (300) and a selected one of a first object to be welded (100) or a second object to be welded (200) disposed apart from the welding platform (300),

the welding torch (400) comprises:

a body (410);

a guide part (420) provided at one side of the body (410); and

an electrode rod (430) provided on the body (410) and formed in a protruding manner to the outside of the guide part (420),

a chamfered part (421) having an outer diameter gradually decreasing from the main body (410) side toward the outer side is formed at the end of the guide part (420),

the chamfered section (421) comprises:

a first chamfered portion (421a) which is formed partially at the end of the guide portion (420), is formed so as to be inclined from the main body (410) side to the outer side, and is formed so as to have an inclination angle of 45 DEG with respect to the outer peripheral surface of the guide portion (420);

a second chamfered portion (421b) which is formed partially at the end of the guide portion (420), is formed so as to be inclined from the main body (410) side to the outer side, and is formed so as to have an inclination angle of 60 degrees with respect to the outer peripheral surface of the guide portion (420);

a third chamfered portion 421c formed at a part thereof at the end of the guide portion 420 so as to be inclined outward from the main body 410 and formed at an inclination angle of 75 DEG with respect to the outer peripheral surface of the guide portion 420,

selectively causing one of the first chamfer (421a), the second chamfer (421b) and the third chamfer (421c) to be in surface contact with the first body to be welded (100), the second body to be welded (200) or the welding platform (300).

2. The welding method for forming a uniform bead according to claim 1,

the guide part (420) is in contact with the first object (100) or the second object (200) in an inclined manner,

if the guide part (420) is in contact with the first body to be welded (100) or the second body to be welded (200), the tip of the electrode rod (430) is spaced from the portion of the first body to be welded (100) and the portion of the second body to be welded (200) in contact with each other by 1-2 mm.

3. The welding method for forming a uniform bead according to claim 1,

in the spot welding step (S20), the first normal welding step (S30), and the second normal welding step (S40), the welding torch (400) and the first object (100) or the second object (200) are inclined at an angle of 45 DEG to 75 deg.

4. The welding method for forming a uniform bead according to claim 1,

in the case where the first body to be welded (100) and the second body to be welded (200) are formed in a vertical form, the welding torch (400) is moved from the lower side to the upper side while being tilted downward, and welding is performed in the spot welding step (S20), the first normal welding step (S30), and the second normal welding step (S40).