WELDING METHOD FOR PROVIDING SHAPE TO A BASE MATERIAL AND A BASE MATERIAL USED FOR SAME

Abstract

A welding method includes: forming one or more lower plate grooves having a predetermined width and a predetermined depth at one side of an upper surface of a lower plate; forming one or more upper plate grooves having a predetermined width and a predetermined depth at one side of a lower surface of an upper plate; overlapping the lower plate and the upper plate so that the lower plate grooves of the lower plate and the upper plate grooves of the upper plate mesh with one another; and performing welding to form a bead at a welding part.

Claims

1. A welding method of welding base materials comprising a lower plate which is a base material made of metal and positioned at a lower side, and an upper plate which is a base material made of metal, positioned at an upper side of the lower plate, and attached to the lower plate by welding, the welding method comprising: forming one or more lower plate grooves having a predetermined width and a predetermined depth at one side of an upper surface of the lower plate; forming one or more upper plate grooves having a predetermined width and a predetermined depth at one side of a lower surface of the upper plate; overlapping the lower plate and the upper plate so that the lower plate grooves of the lower plate and the upper plate grooves of the upper plate mesh with one another; and performing the welding to form a bead at a welding part.

2. The welding method of claim 1, wherein each of the grooves formed in the lower and upper plates is formed in any one of a serrated shape, a semi-circular shape, an elliptical shape, and a quadrangular shape.

3. The welding method of claim 1, wherein a shape of each of the grooves formed in the lower and upper plates has any one of a simply repeated pattern, an aperiodically repeated pattern, a periodically repeated pattern, and a single pattern.

4. The welding method of claim 1, wherein there is a non-contact portion p2 where at least one pair of grooves, among the grooves formed in the lower and upper plates which mesh with one another, is not in contact with each other.

5. The welding method of claim 1, wherein a thickness t2 of the lower plate is 0.1 to 80.0 mm, and a thickness t1 of the upper plate is 0.1 to 40.0 mm.

6. The welding method of claim 1, wherein an overall length A of the grooves is set within a range defined by an Expression 1,
0.5×t min<A<2.0×t min  (Expression 1) where t min is a thickness of the base material which is the smaller of a thickness t1 of the upper plate and a thickness t2 of the lower plate, and where A is an overall length of the grooves.

7. The welding method of claim 1, wherein a width B of the grooves is set within a range defined by an Expression 2,
B<0.2×t min  (Expression 2) where t min is a thickness of the base material which is the smaller of a thickness t1 of the upper plate and a thickness t2 of the lower plate, and where B is a width of the grooves.

8. A welding method of welding base materials comprising a lower plate which is a base material made of metal and positioned at a lower side, and an upper plate which is a base material made of metal, positioned at an upper side of the lower plate, and attached to the lower plate by welding, the welding method comprising: forming one or more grooves having a predetermined width and a predetermined depth in any one of the lower plate and the upper plate; overlapping the two base materials; and performing the welding to form a bead at a welding part.

9. Base materials comprising: a lower plate made of metal and having one or more lower plate grooves having a predetermined width and a predetermined depth formed at one side of an upper surface of the lower plate; and an upper plate made of metal and having one or more upper plate grooves having a predetermined width and a predetermined depth formed at one side of a lower surface of the upper plate, wherein the lower plate and the upper plate overlap each other so that the lower plate grooves of the lower plate and the upper plate grooves of the upper plate mesh with one another, and wherein welding is performed to form a bead at a welding part.

10. The base material of claim 9, wherein a thickness t2 of the lower plate is 0.1 to 80.0 mm, and a thickness t1 of the upper plate is 0.1 to 40.0 mm.

11. The base material of claim 9, wherein an overall length A of the grooves is set within a range defined by an Expression 1,
0.5×t min<A<2.0×t min  (Expression 1) where t min is a thickness of the base material which is the smaller of a thickness t1 of the upper plate and a thickness t2 of the lower plate, and where A is an overall length of the grooves.

12. The base material of claim 9, wherein a width B of the grooves is set within a range defined by an Expression 2,
B<0.2×t min  (Expression 2) where t min is a thickness of the base material which is the smaller of a thickness t1 of the upper plate and a thickness t2 of the lower plate, and where B is a width of the grooves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a schematic cross-sectional view illustrating a state in which welding is performed by a general welding process.

[0020] FIG. 2 is a schematic cross-sectional view illustrating a state before base materials, which are provided with shapes according to the present disclosure, are welded.

[0021] FIGS. 3A and 3B are enlarged views of an upper plate and a lower plate, which are provided with the shapes according to the present disclosure.

[0022] FIG. 4 is a schematic cross-sectional view illustrating a state after the base materials, which are provided with the shapes according to the present disclosure, are welded.

[0023] FIG. 5 is a detailed view illustrating groove portions formed in the base material.

[0024] FIGS. 6A-6D and 7A-7D are cross-sectional views of embodiments of the base material provided with the shape according to the present disclosure, in which FIGS. 6A-6D illustrate cross sections of the base materials according to the embodiments having various shapes and in which FIGS. 7A-7D illustrate cross sections of the base materials according to the embodiments in which different shapes are periodically formed.

[0025] FIG. 8 is an enlarged view illustrating a state in which the upper plate and the lower plate according to the present disclosure engage with each other.

[0026] FIG. 9 is a graph illustrating widths of the groove portions with respect to thicknesses of the base materials.

[0027] FIGS. 10A-10C are photographs illustrating cross sections in which the shape according to the present disclosure is provided only to the upper plate, in which FIG. 10A is a photograph illustrating the cross section before welding, FIG. 10B is a photograph illustrating the cross section in a state after welding, and FIG. 10C is a photograph illustrating the cross section in a state after welding base materials in the related art.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Hereinafter, a welding method of providing a shape to a base material and a base material used for the same according to the present disclosure are described in detail with reference to the drawings.

[0029] However, the disclosed drawings are provided as an example for fully transferring the spirit of the present disclosure to those having ordinary in the art. Therefore, the present disclosure is not limited to the drawings disclosed below and may be specified as other aspects.

[0030] Unless otherwise defined, the terminologies used in the specification of the present disclosure have the meanings that those having ordinary skill in the technical field to which the present disclosure pertains typically understand. In the following description and the accompanying drawings, a detailed description of publicly known functions and configurations has been omitted so as to avoid unnecessarily obscuring the subject matter of the present disclosure.

[0031] FIG. 2 is a schematic cross-sectional view illustrating a state before base materials, which are provided with shapes according to the present disclosure, are welded. FIGS. 3A and 3B are enlarged views of an upper plate and a lower plate, which are provided with the shapes according to the present disclosure.

[0032] First, referring to FIG. 2, base materials are used for a welding method of providing a shape to a base material according to the present disclosure. The base materials include a lower plate 10, which is a base material made of metal and positioned at a lower side, and an upper plate 20, which is a base material made of metal, positioned at an upper side of the lower plate 10, and attached to the lower plate 10 by welding.

[0033] In addition, as illustrated in FIGS. 3A and 3B, the base materials according to the present disclosure include the lower plate 10 having one or more lower plate grooves 11 having a predetermined width and a predetermined depth and formed at one side of an upper surface of the lower plate 10, and the upper plate 20 having one or more upper plate grooves 21 having a predetermined width and a predetermined depth and formed at one side of a lower surface of the upper plate 20.

[0034] In this embodiment, the lower plate grooves 11 of the lower plate 10 and the upper plate grooves 21 of the upper plate 20 may be formed to mesh with one another.

[0035] FIG. 4 is a schematic cross-sectional view illustrating a state after a welding process is performed by using the lower plate 10 and the upper plate 20 according to the present disclosure configured as described above. When the welding is performed about a root R, which is an outermost point of a lower edge of the upper plate 20 placed on the upper surface of the lower plate 10, welding parts of the base materials are melted, and molten metal from a welding rod is added to the welding parts. The welding process is performed in a state in which the upper plate 20 is mounted on the lower plate 10 so that the lower plate grooves 11 formed in the lower plate 10 and the upper plate grooves 21 formed in the upper plate 20 mesh with one another. Thus, a bead 30 having a predetermined volume is formed about the root R over an upper space portion of the lower plate 10 and a lateral space portion of the upper plate 20, as illustrated.

[0036] In this embodiment, as illustrated in FIG. 5, an overall length A and an overall width B of the grooves 11 or 21 formed in the lower plate 10 or the upper plate 20 according to the present disclosure should be apparent, and a thickness t of the base material should be apparent. As illustrated in FIG. 4, an overall length and an overall width of the grooves 11 or 21 remaining without being covered by the bead 30 are measured when the bead 30 is formed after welding. The bead 30 is observed from a lateral side of the welding part, and the overall length and the overall width are compared with an overall length A and an overall width B before welding. Thus, it is possible to accurately recognize the position of the root R when the two base materials 10 and 20 are joined by welding. A throat thickness W and a leg length L of the bead 30 are easily calculated based on the recognized position of the root R. Thus, the uniformity of the entire shape of the bead 30 on the structure may be ascertained. Further, with the presence of the grooves 11 and 21, the amount of weld penetration of the molten materials to be inputted to the bead 30 is increased.

[0037] The grooves 11 and 21 formed in the lower plate 10 and the upper plate 20 according to the present disclosure may be formed to have various shapes and periodically repeated patterns. For example, as illustrated in FIGS. 6A-6D and 7A-7D, the groove 21 formed in the upper plate 20 is formed in a serrated shape, a semi-circular shape, an elliptical shape, or a quadrangular shape. The grooves 21 may be formed to have various repeated patterns such as simply repeated patterns, aperiodically repeated patterns, periodically repeated patterns, and a single pattern. The shape or the pattern may also be identically applied to the groove 11 formed in the lower plate 10.

[0038] Meanwhile, FIG. 8 is an enlarged view illustrating a state in which the upper plate 20 and the lower plate 10 according to the present disclosure are engaged with each other. According to the embodiment of the present disclosure, there may be a non-contact portion p2 where at least one pair of grooves, among the grooves 11 and 21 formed in the lower and upper plates 10 and 20, which mesh with one another, is not in contact with each other. Therefore, except for the non-contact portion p2 (as shown in FIG. 5), there are contact portions p1 (as shown in FIG. 5) where the other pairs of grooves are in contact with one another.

[0039] According to the embodiment of the present disclosure, as illustrated in FIG. 2, a thickness t2 of the lower plate 10 may be 0.1 to 80.0 mm, and a thickness t1 of the upper plate 20 may be 0.1 to 40.0 mm. As illustrated in FIG. 5, an overall length A of the grooves 11 and 21 may be set within a range defined by the following Expression 1.

0.5×t min<A<2.0×t min  (Expression 1)

[0040] *t min: a thickness of the base material which is the smaller of a thickness t1 of the upper plate 20 and a thickness t2 of the lower plate 10

[0041] *A: an overall length of the grooves

[0042] A width B of the grooves 11 and 21 may be set within a range defined by the following Expression 2.

B<0.2×t min  (Expression 2)

[0043] *t min: a thickness of the base material which is the smaller of a thickness t1 of the upper plate 20 and a thickness t2 of the lower plate 10

[0044] *B: a width of the grooves

[0045] That is because the leg length L of the bead 30 needs to be equal to or larger than 1.0×t min with respect to the thickness of the base material when the bead 30 is formed by welding so that the lower plate 10 and the upper plate 20 according to the present disclosure overlap each other. Thus, the overall length A of the grooves 11 and 21 and the width B of the grooves 11 and 21 according to the present disclosure are limited within a range equal to or smaller than twice the general leg length. In this manner, the grooves 11 and 21 may be formed to a minimum extent without being excessively formed. Further, the width B of the grooves 11 and 21 is equal to or smaller than at most 20% of the thickness of the upper plate 20 or the lower plate 10 and equal to or larger than at least 0.1 mm. If the width B of the grooves 11 and 21 is smaller than 0.1 mm, the grooves 11 and 21 cannot be recognized with the naked eye, and as a result, there is a drawback in that the grooves 11 and 21 cannot be immediately recognized in situ.

[0046] FIG. 9 is a graph illustrating widths of the groove portions with respect to thicknesses of the base materials.

[0047] Referring to the graph, in a case in which there is a gap of 20% of the thickness of the base material, the base material has excellent fatigue properties in comparison with a specimen having no gap (0%). This is because the gap reduces and restricts deformation caused by a load applied during a fatigue test.

[0048] In contrast, in a case in which there is a gap of 33% or more of the thickness, fatigue strength is reduced due to bending stress to the specimen and to concentration of stress to the shape during the fatigue test.

[0049] Therefore, the width B of the grooves 11 and 21 according to the present disclosure may be equal to or smaller than at most 20% of the thickness of the upper plate 20 or the lower plate 10.

[0050] FIGS. 10A-10C are photographs illustrating cross sections in which the shape according to the present disclosure is provided only to the upper plate 20. FIG. 10A illustrates a cross section before welding, FIG. 10B illustrates a cross section after welding, and FIG. 10C illustrates a cross section after welding base materials in the related art.

[0051] FIGS. 10A-10C illustrate another embodiment according to the present disclosure in which the grooves 21 are formed only in the upper plate 20, and the lower plate 10 has no groove.

[0052] In this embodiment, as illustrated in FIG. 10A, an overall length of the four grooves 21 formed in the upper plate 20 is 4.2 mm obtained by 1.5 mm+2.7 mm, and as illustrated in FIG. 10B, 0.7 mm is indicated from the end of the upper plate 20 to the portion where the groove 21 is formed after welding. As a result, it is possible to easily ascertain with the naked eye that a length of the upper plate 20 melted by welding is 0.8 mm made by subtracting 0.7 mm from 1.5 mm. Therefore, the position of the root R of the bead 30 may be accurately recognized, such that the leg length L and the throat thickness W of the bead 30 may also be easily ascertained.

[0053] Further, as illustrated in FIG. 10B, it may be ascertained that the amount of weld penetration of the lower plate 10 is 2.5 mm. Therefore, it may be ascertained that the amount of weld penetration according to the present disclosure is further increased and the welding part becomes more rigid because of the increase in the amount of weld penetration. By comparison, the amount of weld penetration of the lower plate is 1.65 mm as illustrated in FIG. 10C, in a case in which the welding is performed by using base materials having no grooves in the related art.