JPH0735337U - Metal can with a handle - Google Patents

Abstract

(57) [Summary] [Purpose] While maintaining sufficient welding strength by optimizing the material conditions and welding conditions in a metal can in which the washer for the handle is spot-welded to the top plate formed of laminated steel plates. Prevents the occurrence of defective holes in the laminate layer on the inner surface of the nugget. [Structure] The top plate 2 has a laminate layer 15 laminated on the inner surface of a steel plate of 0.24 to 0.40 mm. The laminate layer 15 has a thickness of 45 to 80 μm and a melting point of 120.
It is composed of a polyolefin plastic film having a temperature of up to 150 ° C. And the outer surface of the top plate 2 (non-laminated surface)
When the washer 4 is spot-welded, the welding current per welding point is 1.6 to 2.3 KA. The base end of the handle 3 is attached to a washer 4 welded to the top plate 2 so as to be able to rise and fall.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a metal can in which a washer for a handle is spot-welded to an outer surface of a top plate of a laminated steel plate.

[0002]

[Prior art]

 It is known to form a can body and a top plate by using a laminated steel plate as a material, and it is also known to attach a handle to a top plate of a metal can of this kind through a washer. An example thereof can be found in Japanese Utility Model Laid-Open No. 62-105126. Here, as shown in FIGS. 1 and 2, a washer 4 is formed in an Ω shape in cross section, and a large number of ribs 12 are provided in parallel on the lower surfaces of the left and right seat plates 11, 11. A pair of welding ribs 7 protruding upward is formed on the top plate 2, and after the washer 4 is arranged on the outer surface of the top plate 2 in a state where both ribs 7 and 12 are orthogonal to each other, By pressing the welding electrodes T and T onto the upper surfaces of the seat plates 11 and 11, the contact portions of the ribs 7 and 12 are welded to each other.

[0003]

[Problems to be solved by the device]

 Most of these washers are fixed to the outer surface of the top plate by series current-carrying multi-spot welding.However, when the top plate is a laminated steel plate, the laminating layer on the rib inner surface is melted by the welding heat and the size of the nugget is increased. There is a hole corresponding to that. Since the steel sheet is exposed at the perforated portion, corrosion spreads from there, impairing the corrosion resistance of the metal can. Corrosion that occurs on the inner surface of the can is not visible from the outer surface, so it is absolutely necessary to avoid perforating the laminate layer.

The amount of heat generated during welding is basically determined by the electrical resistance value of the object to be welded, the amount of welding current, and the energization time, and is caused by differences in the thermal conductivity of the object of welding and the electrode material, the contact area between the two, and the like. The difference in the amount of heat dissipated affects the total amount of heat generated. Therefore, when the welding current amount and the energization time are reduced, the amount of heat generated at the welding point can be suppressed and the formation of holes in the laminate layer on the inner surface of the nugget can be prevented. However, in this case, the metal melting amount tends to be insufficient, which makes it difficult to reliably weld the washer with the required strength.

It is also possible to prevent perforation of the laminate layer by changing the material conditions in addition to the welding conditions. For example, increasing the thickness of the laminated film can prevent the formation of holes. However, in this case, it becomes difficult to bend the laminated steel sheet sharply, and there is a problem in performing press working. Incidentally, in Japanese Utility Model Laid-Open No. 62-105126 mentioned above, perforation is prevented by applying a thermosetting powder coating material to the inner surface of a steel sheet by electrostatic coating and thermosetting.

Therefore, an object of the present invention is to optimize the welding conditions and material conditions to prevent the formation of holes in the laminate layer on the inner surface of the nugget while welding the washer to the top plate with sufficient strength. To obtain a metal can with a handle that contributes to improved productivity.

[0007]

[Means for Solving the Problems]

 The present invention has a top plate 2 in which a laminate layer 15 is laminated on the inner surface of a steel plate having a thickness of 0.24 to 0.40 mm, and a washer 4 is spot-welded to the outer surface of the top plate 2, and The target is a metal can whose base end is attached to the washer 4 so that it can be tilted up and down. Further, the laminate layer 15 includes a polyolefin plastic film having a thickness of 30 to 100 μm and a melting point of 110 to 160 ° C. The amount of welding current per melting point is set to 1.6 to 2.3 KA, and the washer 4 is welded to the top plate 2.

[0008]

[Action]

 When the washer 4 is welded to the top plate 2 by setting the welding conditions and material conditions as described above, the laminating layer 15 on the inner surface of the nugget 14 is once melted by the welding heat. However, as the temperature of the nugget 14 decreases, the melted portion solidifies again to form a continuous film at the non-melted portion, covering the inner surface side of the nugget 14 and not forming a hole. When the melting point of the film forming the laminate layer 15 is lower than 110 ° C., the melting range expands beyond the size of the nugget 14, the hole becomes large, and solidification starts from the side separated from the nugget 14, and the melt is It cannot be self-repaired by flowing back to cover the inner surface of the nugget 14 with a solidified film. On the other hand, when the melting point of the film forming the laminate layer 15 exceeds 160 ° C., the viscosity of the melt is high, and once the melted holes are melted, the melt flows back to the solidified film on the inner surface of the nugget 14. It may not be self-repairing by covering with, and it may become a crater and the hole may remain open, and the inner surface of the nugget 14 may be exposed. If the thickness of the laminate layer 15 is less than 30 μm, the holes formed by melting the film cannot be reliably filled with the solidified film. Further, if the layer thickness exceeds 100 μm, it becomes difficult to sharply bend the laminated steel sheet. Therefore, the laminate layer 15 is set to have a thickness of 30 to 100 μm, more preferably 45 to 80 μm, and a melting point of 110 to 160 ° C., further preferably 120 to 150 ° C. In addition, the welding current amount per melting point is specified to be 1.6 to 2.3 KA in order to ensure welding in conformity with the above material conditions.

[0009]

[Effect of device]

 According to the metal can of the present invention, the washer 4 is welded to the top plate 2 with sufficient strength by optimizing the material condition of the laminate layer 15 of the laminated steel plate and the welding condition, and the nugget is generated by the welding heat. Since it is possible to prevent the laminated layer 15 on the inner surface of 14 from being punctured, it is possible to reliably produce a metal can with a handle without causing perforation defects or welding defects. Can be improved. Since there is no corrosion on the inner surface of the nugget 14, there is no need to perform a separate corrosion prevention treatment, and a metal can having excellent corrosion resistance can be obtained at a lower cost.

[0010]

【Example】

 1 to 3 show an embodiment of a metal can according to the present invention. In FIG. 3, reference numeral 1 is a can body, 2 is a top plate, and a handle 3 is attached to the center of the top surface of the top plate 2 with a washer 4. Each of the can body 1 and the can lid 2 is formed of a laminated steel plate in which a plastic film is laminated on one surface (inner surface) of a steel plate S having a thickness of 0.24 to 0.40 mm.

On the outer surface of the top plate 2, four petal-shaped reinforcing portions 5 are formed inwardly of the can, and spouts 6 are provided at the corners. A pair of parallel welding ribs 7 are provided on the upper surface so as to project at the center of the cross-shaped unprocessed surface sandwiched by the four reinforcing portions 5. The washer 4 is welded to the welding ribs 7 by the multi-spot welding method of the series energizing method, and the base end of the handle 3 is attached to the washer 4 so as to be tiltable. The handle 3 is formed by bending a steel wire into a D-shaped ring, and a gripping tool 8 is attached to its swinging tip.

In FIG. 1, a washer 4 is made of a press-molded product having an Ω-shaped cross section, and has a U-shaped groove 10 that opens downward and a pair of left and right protruding outward from both lower ends of the groove wall. It is provided with a seat plate 11. Eight V-shaped ribs 12 projecting to the lower surface side are formed in parallel on the plate surface of each seat plate 11 (see FIG. 2). After the top plate 2 is supported by the receiving tool 13, the washer 4 is placed on the welding rib 7 with the lower surface of the rib 12 abutting the welding rib 7, and the left and right seat plates 11 and 11 are paired by welding. The ribs 12 and the welding ribs 7 are spot-welded by pressing the electrodes T 1 and T 2 to energize them.

By performing the above-mentioned welding process, the laminate layer 15 is melted in the inner surface side portion of the nugget 14, and in order to prevent the formation of holes, the laminate layer 15 is made of a polyolefin-based plastic such as polyethylene or polypropylene. It is made of film. Specifically, the laminate layer 15 is formed of a plastic film having a thickness of 30 to 100 μm, more preferably 45 to 80 μm. Further, the melting point of the plastic material is adjusted to 110 to 160 ° C, more preferably 120 to 150 ° C. As the welding conditions, the welding current amount per melting point is set to 1.6 to 2.3 KA. Specifically, since there are 16 melting points, if the welding current amount per point is, for example, 2.0 KA, a total current of 32 KA will be applied between the pair of welding electrodes T and T. .

(Processing Example) A top plate 2 is formed of a laminated steel plate obtained by laminating a polyethylene film having a thickness of 60 μm on one surface of a steel plate S having a thickness of 0.32 mm, and the welding current amount per melting point is The washer 4 was multi-spot welded to the top plate 2 by setting it to 2.0 KA. The melting point of the polyethylene film at this time was 120 ° C. The weld strength of the washer 4 was confirmed for the obtained intermediate product. Furthermore, the state change of the laminate layer 15 inside the nugget 14 was visually confirmed. As a result, no welding defects or perforation defects of the laminate layer 15 were found in any of the intermediate products.

Although the laminate layer 15 is formed of one plastic film in the above embodiment, the laminate layer 15 can be formed of a plurality of plastic films. However, the maximum layer thickness in this case is 100 μm.

[Brief description of drawings]

1 is a cross-sectional view taken along the line AA in FIG.

FIG. 2 is a sectional view taken along line BB in FIG.

FIG. 3 is a plan view of a metal can.

[Explanation of symbols]

 2 Top plate 3 Handle 4 Washer 7 Welding rib 12 Rib 14 Nugget 15 Laminate layer S Steel plate T Welding electrode

Claims (1)

[Scope of utility model registration request] 1. A top plate 2 having a laminate layer 15 laminated on the inner surface of a steel plate having a thickness of 0.24 to 0.40 mm, and a washer 4 spot-welded to the outer surface of the top plate 2. Hand 3
In the metal can whose base end is attached to the washer 4 so as to be tiltable, the laminate layer 15 includes a polyolefin-based plastic film having a thickness of 30 to 100 μm and a melting point of 110 to 160 ° C. A metal can with a handle characterized in that the washer 4 is welded to the top plate 2 by setting the welding current amount per melting point to 1.6 to 2.3 KA.