JPH0698488B2 - Method of joining strip metal plates - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining metal plates, and more particularly to a method for joining metal plates in which strip-shaped metal plates are butted or partially overlapped and welded.

[Conventional technology]

In addition to the pressure welding method and the brazing method, there is a fusion welding method as a method for welding and joining band-shaped metal plates to each other. This fusion welding method is a method of melting and joining the materials to be welded, and there are gas welding, arc welding, special welding by laser or electron beam, and the like. In these welding methods, the end portions of the band-shaped metal plates to be joined are butted against each other and welded (for example, JP-A-61-276770), or the end portions are overlapped and welded. In particular, for thin strip metal plates, it is effective to superimpose a small amount and weld them.

Further, FIG. 3 is an observation view of a metal structure of a cross section of a welded joint in which an aluminum plate having a thickness of 0.15 mm and an aluminum plate having a thickness of 0.3 mm are overlapped with each other by 1.0 mm and joined by TIG arc welding. As shown in FIG. 3, when the cold-rolled strip-shaped metal plates 67 and 69 are joined by fusion welding, a molten and solidified molten portion 71 is produced at the joining portion and the welding heat is generated around it. The recrystallized portions 73 and 73 which have been recrystallized by receiving for a certain time are generated. That is, the welded joint of the cold-rolled strip-shaped metal plates 67, 69 is composed of a melted and solidified melted portion 71 and a recrystallized portion 73 recrystallized under the influence of heat during welding. Has a base material (original metal plate) 75 in which neither melting, solidification nor recrystallization has occurred, and three kinds of metal structures are formed at the joint portions of the band-shaped metal plates 67 and 69. Also,
Even in welded joints of metal plates that have not been cold rolled,
It can be classified into three types of metal structures, a molten part, a recrystallized part, and a base material.

[Problems to be solved by the invention]

However, when the band-shaped metal plates 67 and 69 are weld-bonded by the conventional weld-bonding method, the welded joint may not match the original thickness of the band-shaped metal plates 67 and 69. Further, in the case of joining thin plates, when welding is performed by overlapping about 2 mm, preferably 0.5 mm to 1.5 mm, the thickness of the welded joint becomes larger than the original plate thickness of the strip-shaped metal plates 67, 69. If the thickness of the welded joint greatly differs from the original thickness of the strip-shaped metal plates 67, 69, when the strip-shaped plate having such welded joints is hung on a number of pass rollers and conveyed, stress is applied to the welded joints. Concentration occurs and breakage easily occurs. In particular, stress concentration becomes remarkable when metal plates 67 and 69 having different plate thicknesses are joined together.

Further, the hardness of the base material 75, the recrystallized portion 73, and the melted portion 71 and the proof stress at break are such that the base material> the recrystallized portion ≧ the melted portion. When a bending stress is applied to the metal plate, the stress is likely to concentrate on the portion where the thickness changes greatly, and a recrystallized portion with poor fracture resistance is located in this portion. Therefore, when the strip-shaped metal plates 67 and 69 having the joints formed by the conventional joining method are rolled and contacted with a large number of pass rolls, there is a problem that they are broken in a short time.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a welding and joining method in which the strength of a welded and joined portion between metal plates is increased and fracture does not occur.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention welds the ends of cold-rolled aluminum metal plates to each other, and melts the welded welded part, and recrystallizes due to a thermal effect at the time of welding. In the method for joining strip-shaped metal plates in which a portion is formed, the thickness difference between the melted portion and the recrystallized portion is
The welded joint is rolled so as to be within 30%, and the thickness difference between the recrystallized portion and the aluminum metal plate portion is 30%.
It is characterized in that the welded joint is rolled so as to be within%.

[Action]

According to the method for joining strip-shaped metal sheets according to the present invention, the recrystallized portion where the fracture of the welded joint is likely to occur has a difference in thickness between the adjacent welded portion and the original metal sheet which is not affected by heat during welding. Since it is within 30%, it is difficult for these stresses to concentrate on the recrystallized portion when a tension or bending stress is applied to the metal plate. Therefore, even when the strip-shaped metal plate having the welded joint portion according to the welding joint method of the present invention is rolled and contacted with a large number of pass rollers while receiving tension, the joint portion increases in strength and does not break.

〔Example〕

Hereinafter, preferred embodiments of a method for joining strip-shaped metal plates according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an explanatory view of a method for joining strip-shaped metal plates according to the present invention. As shown in FIG. 1, the thin strip metal plate 10 is a roll 12
It is rewound from the roll, rolled on the pass roller 14, and conveyed to the joining device 16. The pre-cut device 18 of the joining device 16 is a cutter 20,
Composed of 20. The tip portion 10A of the thin strip-shaped metal plate 10 is
It is cut by the precut device 18 and is formed so that it can be accurately abutted or superposed by a small amount on the rear end portion 22A of the thick metal strip 22 to be joined.

The pre-cutting device 18 is not used when the front end portion 10A of the strip-shaped metal plate 10 to be rewound can be directly abutted or directly superposed on the rear end portion 22A of the strip-shaped metal plate 22.

A welding device 24 is provided downstream of the precut device 18, and the welding device 24 includes clamps 26 and 28 and a welding torch 30. The clamp 26 holds the front end 10A of the thin strip metal plate 10, and the clamp 28 holds the rear end 22A of the thick strip metal plate 22.
Is held, and the thin strip metal plate 10 and the thick strip metal plate 22 are butted or overlapped with each other by a small amount. When superimposing a small amount, it is desirable to weld the strip-shaped metal plates 10 and 22 with each other by about 2 mm, preferably about 0.5 mm to 1 mm. Especially the thickness of the strip metal plates 10 and 22
If it is less than 0.3mm, blowholes and holes will be prevented by overlapping and welding.

Further, the welding is performed from above the abutting portion, and the welded joint portion 40 is formed on the strip-shaped metal plates 10 and 22 as shown in FIG.

Welding methods include TIG arc welding and MIG arc welding,
There are gas welding, laser welding of CO ₂ , YAG, etc., which are selected and used according to the type of strip metal.

A rolling device 32 is provided at the subsequent stage of the welding device 24, and the welded joint 40 between the strip-shaped metal plate end portions 10A and 22A is rolled.

As shown in FIG. 2, the joints at the ends of the strip-shaped metal plates 10 and 22 are completely melted during welding, and a molten portion 42 different from the original crystal structure of the metal plate is formed. The molten portion 42 is flattened at the time of rolling, and when the strip-shaped metal plates 10 and 22 have different thicknesses, a step 42A may be formed in the substantially central portion.

Further, recrystallized portions 44, 44 due to the influence of heat during welding are formed adjacent to the molten portion 42. The recrystallized portion 44 is rolled and formed to have substantially the same thickness as the molten portion 42 and the base material (the original metal portion which is not affected by heat during welding) 46. The thickness of the recrystallized portion 44 is ±
It is rolled so as to fall within the range of 30%, preferably ± 15%, and within the range of ± 30%, preferably ± 15% with respect to the thickness of the base material 46.

According to the method for joining strip-shaped metal plates of the present invention configured as described above, the melted portion 42 and the recrystallized portion 44 are generated in the welded joint 40 between the strip-shaped metal plates 10 and 20. Since the thickness of the recrystallized portion 44 is substantially equal to the thickness of the molten portion 42 and the original strip-shaped metal plate (base material), when the strip-shaped metal plates 10 and 22 are applied with tension and bending stress on a pass roll or the like and rolled. However, stress is not concentrated on the recrystallized portion 44. Therefore, the strip metal plates 10 and 22
The joint strength between the welded joints 40 between them is increased, and troubles in a process of carrying a complicated strip-shaped metal plate, for example, a surface treatment process of a lithographic printing plate and a coating / drying process are reduced.

Next, a strength test was performed on the welded portion of the strip-shaped metal plates joined by the joining method for strip-shaped metal plates according to the present invention.

The experimental sample of this example has a thickness of the thin strip-shaped metal plate 10;
0.15 mm, width: 200 mm aluminum plate, thick band metal plate 22 0.3 mm thickness, width: 200 mm aluminum plate, TIG with each band metal plate 10 and 22 overlapping 1.0 mm Arc welding is performed, and the thickness B of the recrystallized portion 44 is rolled to be 1.14 times the thickness A of the original thin strip metal plate 10 (the portion that is not affected by the cold-rolled fusion welding). At the same time, the thickness C of the molten portion 42 is rolled 0.98 times (FIG. 2).

In the conventional comparative sample, the thickness before and after the recrystallized portion 44 was not adjusted by rolling (Fig. 3).

Using such a sample, load two rubber rolls (φ600) and rubber rolls (φ20) while applying a tension of 75 kg.
0) Circulate between 22 rolls and 2 rolls of rubber (φ180)
A pass roller passing test was performed by examining the number of times of surroundings until cutting. The results are shown in Table 1.

As shown in Table 1, the joining portion using the joining method of the strip-shaped metal plate according to the present invention is less likely to be broken than the joining portion according to the conventional method even when transferred to a large number of pass rollers. The test sample stopped the pass roller pass test 202 laps, but
No breaks or cracks were found. Also, the test sample was selectively rolled in the vicinity of the recrystallized portion 44 on the thin side in FIG. 2, and at that time, a step 42A of about 0.1 mm was formed in the molten portion 42 as shown in FIG. However, the step 42A was not broken or cracked.

Next, the fact that the tensile strength increases when the thickness difference is within 30% will be described with the data in Tables 2 and 3. The sample material is a TIG with a thickness of 0.15 mm and a width of 200 mm (band-shaped metal plate 10) and an aluminum plate with a plate thickness of 0.30 mm and a width of 200 mm (band-shaped metal plate 22), with 1.0 mm of the ends overlapping each other. It was created by performing arc welding and rolling the welded joint with a stepped roller. Further, the sample material was prepared by changing the shape of the stepped roller so that the thickness difference could be 8 kinds within the range of 14% to 50% (see Table 1). Then, the base material thickness A, the recrystallized portion thickness B, and the melted portion thickness C of each sample material are measured, the difference between A and B and the difference between B and C are obtained, and the larger value is taken as the sample. The difference in thickness between the materials was expressed in%.

The following pass roller passing tests were performed on these sample materials. That is, while applying a tension of 75 kg to the sample material, the sample material was placed on a rubber roll (2 mm
), A rubber roll with a diameter of 200 mm (22 pcs), and a diameter of 180 mm
It was made to circulate between the rubber rolls (2). Then, the number of turns until the sample material was cut was obtained. The results are shown in Table 3.
Shown in.

As shown in Table 3, when the thickness difference is suppressed to 30% or less by the method for welding and joining metal plates according to the present invention, the number of revolutions increases to 20 or more when rolling with a large number of pass rollers. Further, in the case of the sample material (No. 1) having a thickness difference of 14%, the pass roller passage test was interrupted after 202 laps, but no fracture or crack occurred in the welded joint. In addition, in the case of other sample materials, cracks occurred in the recrystallized portion of the aluminum plate 10. This is because when the thickness difference between the recrystallized portion and the adjacent portion (base material or molten portion) is large, stress concentration is likely to occur in the recrystallized portion when transferred to the pass roller.

Further, although the recrystallized portion 44 is rolled in the above embodiment, the present invention is not limited to this.
The recrystallized portion 44 may be melted by applying heat to 44 again to form a new recrystallized portion when stress concentration is unlikely to occur.

〔The invention's effect〕

As described above, according to the method for joining strip-shaped metal sheets according to the present invention, the thickness of the recrystallized portion of the welded joint between the metal sheets is adjacent to the molten portion and the original metal sheet portion that is not affected during welding. Since it is formed so as not to cause a difference in thickness between the metal plate and the metal plate, the strength of the welded joint between the metal plates is increased, and no fracture occurs.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for joining strip-shaped metal plates according to the present invention,
FIG. 2 is an observation view of a metal structure of a cross section of a welded joint between strip-shaped metal plates joined together by the strip-shaped metal plate joining method according to the present invention, and FIG. 3 shows between strip-shaped metal plates joined together by a conventional joining method. It is a metallographic observation view of a cross section of a welded joint. 10, 22 …… Band-shaped metal plate, 16 …… Joining device, 18 …… Precutting device, 24 …… Welding device, 30 …… Welding torch, 32 ……
Rolling equipment, 40 …… Welding joints, 42 …… Melting parts, 44 ……
Recrystallized part, 46 ... Base material.

Claims (1)

[Claims] 1. A cold-rolled aluminum metal sheet is welded to each other at its end portions, and a melted portion and a recrystallized portion caused by a thermal effect at the time of welding are formed at the welded welded portion. In the method of joining strip-shaped metal sheets, the welded joint after welding is rolled so that the difference in thickness between the molten portion and the recrystallized portion is within 30%, and the recrystallized portion and the aluminum metal are rolled. A method for joining strip-shaped metal plates, which comprises rolling the welded joint so that the difference in thickness from the plate portion is within 30%.