JPS60111782A - Production of welded can body - Google Patents

Abstract

PURPOSE:To decrease welding resistance and to improve the strength, airtightness and appearance of a weld zone by subjecting the part intended to be overlapped at the side end of a rectangular blank to a specific pressurizing treatment. CONSTITUTION:A rectangular blank is sandwiched between an upper H-shaped roll 2 which is built into a housing 4 and is driven and a lower flat roll 3 and only the part intended to be overlapped at the side end is pressurized under 10- 300kg.f/mm.<2>. The hydrated chromium oxide layer of high resistance and metallic oxide layer of chromium, nickel, tin, etc. which are the locally surface treated layer are thus broken down on the surface of the thin steel sheet by the pressurization and the contact electric resistance is decreased. The surface treated steel sheet for various cans is seam-welded by the above-mentioned method without film removing treatment and the beautiful welded can body having excellent tightness and corrosion resistance is easily produced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a welded can body, and more specifically, the present invention relates to a method for manufacturing a welded can body, and more specifically, the welding resistance is significantly reduced by pressurizing the side end polymerization area of a rectangular blank at room temperature or by heating it. This article relates to a method of manufacturing a welded can body that can be made in a small amount.

Conventionally, one end of a rectangular blank cut from a surface-treated steel sheet for cans having a surface-treated film with relatively high electrical resistance, such as TFS-CT (chromium type tin-free steel, i.e., electrolyzed and acid-treated steel sheet), has been polymerized at one end. When welding parts using the seam welding method without any special welding pretreatment, even if we try to obtain sufficient welding strength, significant splatter will occur and only incomplete welds will be obtained, resulting in incomplete welding of the product can. There was a problem that a good sealing performance was not ensured, and furthermore, there was a problem that the appearance of the welded part after welding was poor (and it was difficult to repair).

As countermeasures to these problems, proposals have been made to remove the height and anti-coating of the side edges of the rectangular blank where polymerization is planned, using milling equipment or ultrasonic equipment, as well as improving welding equipment and welding conditions, and combinations of these. .

However, at present, none of these methods has been used as a practical solution, and the above-mentioned problems have not yet been completely solved.

In other words, the method of removing the coating by grinding has the disadvantage that coating dust after grinding adheres to the area around the welded part, and the welded part, which is the part to be ground, has no surface treatment coating at all (as a result, corrosion resistance is significantly reduced, and repair Furthermore, even if various improvements are made to welding equipment and welding conditions in order to weld without polishing the coating, it tends not to be cost-effective in commercial production, and the quality remains stable. The disadvantage is that it is difficult to obtain welded can bodies.

Therefore, as a result of continuing research on the contact resistance of the blank overlapping area, the present inventors discovered that the electrical resistance could be easily reduced by applying pressure only to the area where the polymerization is to be performed prior to welding, and completed the present invention. reached.

The object of the present invention is to provide a thin steel sheet for cans having a surface-treated film with relatively high electrical resistance so that the welded part has a beautiful appearance and reliable sealing performance without removing the film in the area to be polymerized by polishing. The present invention provides a method for manufacturing a welded can body that can be welded.

Another object of the present invention is to provide a method for manufacturing a welded can body that allows a good welded can body to be obtained without any particular modification of the conventional can body seam welding machine itself.

According to the present invention 1B, in a method for manufacturing a welded can body, in which a rectangular blank made of a thin steel plate is continuously supplied and sequentially rolled by bending to form a side end overlapping part, and the overlapping part is seam welded to form a can body. , a method for producing a welded can body, characterized by using a rectangular blank whose side end polymerization area has been subjected to pressure treatment of 10 to 300 m/f7- in advance, and continuously supplying rectangular blanks made of thin steel plates. In a method for manufacturing a welded can body, in which a side end overlapping part is provided by sequentially rolling it by bending, and the overlapping part is seam welded to form a can body, the side end overlapping part is heated to 100 to 600 ° C. in advance or at the same time. Provided is a method for manufacturing a welded can body, characterized in that a rectangular blank subjected to pressure treatment at 10 to 300 f/mA is used.

The present invention will be explained in detail below.

The thin steel sheet targeted by the present invention is TFS-CT, which was conventionally extremely difficult to weld without edge cleaning.
J! Ti
Contains QV4 board.

After forming the above-mentioned thin steel plate into a rectangular blank using a slitter or the like, pressure treatment, which is a feature of the present invention, is applied to the overlapping portions of the side ends of the rectangular blank.

The pressure treatment can be performed online on the rectangular blank supply side of the can illumination/one-sea welding machine, or can be performed separately in advance off-line.

The simplest method is to perform offline pressure treatment in advance using a device such as that shown in FIGS. 1 and 2.

Here, Fig. 1 is a front view of the pressurizing device, and Fig. 2 is a front view of the pressurizing device.
It is a sectional view taken along line n-n' in the figure.

In FIG. 1, the pressurizing device is a type of rolling mill, and a rectangular blank is sandwiched between an upper H-shaped roll 2 and a lower flat roll 3 that are built into a housing 4 and driven, and the side edges are Only the area to be polymerized is pressurized at a pressure of 10 to 300 wheels/f/i-. In this case, the pressurizing device may be a reciprocating pressurizing device such as a press, and the pressurizing effect can be further improved by using a knurled or roughened rolling roll or a press rad.

In FIG. 2, the rectangular blank 2 is extruded in the direction of arrow RD, and only the side end portions to be overlapped are subjected to pressure treatment.

Let us now consider the reason why the electrical resistance of the polymerized portion is greatly reduced by a simple pressure treatment.

In general, there is a close relationship between the contact electrical resistance (hereinafter abbreviated as Re) of a material and weldability, and the lower the Rc of a material, the better weldability it is, so it is widely used to estimate the weldability of a material from Rc. There is.

Therefore, in order to investigate the relationship between pressing force and Rc, the inventors conducted the following experiment and measured Re.

In other words, two thin steel plates are sandwiched between a pair of L-bottom round rod-shaped electrodes with copper tips at their tips, the electrodes are strongly pressurized from above, and 10 A of direct current is passed between the electrodes.
I got e.

FIG. 3 is a semi-logarithmic graph showing the relationship between pressing force and Re. TFS- has the highest contact electrical resistance among metal can materials.
The relationship between the CT interelectrode pressure and Rc is shown by a solid line.

In this case, Re decreases rapidly as the pressing force increases, but
It can be seen that the higher the pressing force, the lower the rate of decrease (gradient) of Rc.

Here, in the middle of pressurization, -l pressurization is stopped and the pressurizing force is removed,
Broken line B shows the change in Rc when pressure is applied to the same location again. Note that the broken line B arrow indicates the pressure film layer path. As can be seen from the broken line B, the surface of the metal once pressurized remained at the low Rc when the past maximum pressurizing force was applied, even after the pressurization was removed.

In this way, it can be seen that even a material with a high Rc can be made into a material with a low contact electrical resistance if the surface of the material is once subjected to pressure treatment.

There is no need to apply this pressure treatment to the entire surface of the rectangular blank (only the area where end polymerization is planned is sufficient.In fact, if the entire surface of the rectangular blank is subjected to pressure treatment, it will not only significantly deteriorate the corrosion resistance of the board, but also This is because the load required for pressure treatment becomes extremely large, which is inconvenient in terms of equipment.

Therefore, in the present invention, J of the old end polymerization area of the rectangular blank is
It is subjected to intense pressure treatment. The width of the pressure treatment may be at least as short as the width during polymerization during matzo welding, but in view of the precision of the equipment and the rectangular blank, it is desirable that the width be about 1.5 times the width during polymerization [1].

Using the equipment shown in Figures 1 and 2, welding experiments were carried out by pressurizing the side end portions of rectangular blanks to be overlaid. 5
-The weldability of CT was significantly improved. Note that the pressing effect can be increased by applying ultrasonic vibration to the pressing roll or by making the pressing roll inclined with respect to the traveling direction of the plate.

In addition, if pressure is applied using the equipment shown in Figs. It has been found that good weldability can be obtained even if the amount is relatively small.The same effect can be obtained even if the heating is performed simultaneously with the pressure treatment.

FIG. 4 is a front view of a pressurizing device equipped with a preheating device,
FIG. 5 is a sectional view taken along the line V-'V'. In FIGS. 4 and 5, 10.10 is a high-frequency induction heating electrode,
12.12 indicates a water-cooled electrical conductor. Reference numeral 13 denotes an H-shaped cooling roll for pressure treatment, and has a structure in which a passage 15.15 is opened in the center, through which liquid for cooling the roll flows. The same applies to the lower flat cooling roll 14.

In this embodiment, the overlapping portions of the side ends of the rectangular blank are heated by high-frequency induction heating, but it goes without saying that heating may be performed using a contact heat exchanger plate, a heating roll, electrical heating, or direct flame.

Note that if these series of heating and pressure treatments are performed in a non-oxidizing or reducing atmosphere, weldability is further improved.

The reason why weldability is improved by the combined use of heat treatment will be discussed based on the following experimental results.

That is, the present inventors conducted the following experiment to investigate the relationship between temperature and Re. First, two IIN steel plate blanks are stacked one on top of the other, and the central part is shaped like a round bar with a pair of copper chips at the tips in the thickness direction. 1 was sandwiched between poles, then sandwiched between heating electrodes on opposite ends of a thin steel plate, and resistance heating was performed by passing an alternating current between the heating electrodes. The plate temperature was measured with a thermocouple welded to a part of the thin steel plate in advance. Next, a direct current of 10 A was passed between the round rod-shaped electrodes, and Re was determined from the voltage drop between the electrodes at each pressing force and each plate temperature.

FIG. 6 is a semi-log graph showing the relationship between plate temperature and Rc. In Fig. 6, the relationship between the TFS-CT temperature and Re when the electrode pressure is 101 marks and f74-constant is the solid line C.
is shown. According to this, it can be seen that Re increases (decreases) as the temperature increases.

Here, the broken line shows Re when the heating is temporarily stopped and the material is naturally cooled to room temperature while being pressurized by the electrode.

Note that the dashed arrow indicates the heating history path. As can be seen from the dashed line 4, the resistance of the heated material does not return to its original high resistance value even when it is cooled, and the low R at the past maximum temperature
It showed c. In this way, it can be seen that even a material with a high Rc can be made into a material with a low contact electrical resistance if the material is heat-treated under pressure. That is, the same phenomenon as in the pressure treatment was observed.

Pressure treatment reduces the contact electrical resistance of a 2-kilometre-long thin steel plate (it means that the contact electrical resistance between the electrode and the thin steel plate is measured together with the resistance between the plates) as follows: It seems to be based on the reason.

In other words, fl The metal oxide layer of nickel, tin, etc. will be destroyed, and the electrical contact resistance will decrease.

It is thought that not only pressurization but also further heating softens the steel base material itself and softens the surface treatment layer as well, which promotes the above-mentioned tendency to reduce resistance.

Once the surface high-resistance layer is destroyed, the steel base is exposed at the peaks as described above, so unless it is oxidized again, the overall resistance will remain low.

The reasons for limiting the pressing force and heating temperature in the present invention are as follows.

If the pressurizing force is less than 101y-f/mff1, the effect of the present invention will not be recognized, and if it exceeds 3001cr・f/mA, the effect of the present invention will be saturated. Since there is no pressure, please set the pressure range to 10~
It was set to 300 kg·f/mA.

When the heating temperature is less than 100℃, it is the same as normal temperature pressurization, and 6
If the temperature exceeds 00°C, although it is local heating, the surface treatment area near the polymerization area tends to deteriorate due to thermal effects, and the polymerization area itself tends to re-oxidize, so the heating temperature range should be kept at 100℃ or higher.
The temperature was 600°C. In addition, in the case of a surface-treated steel sheet that is easily affected by heat, the heating temperature range is preferably 100 to 250°C.

By carrying out the present invention, all of the above objects can be achieved. That is, it is possible to reliably seam-weld various surface-treated steel plates for cans without performing film removal treatment, and easily produce welded can bodies that are beautiful, have excellent sealing properties, and are excellent in corrosion resistance.

The pressurization and heat treatment of the present invention can also be carried out by attaching an adapter to -Kl of a conventional wire seam welding machine.

The present invention will be explained in more detail below by way of examples.

〔Example〕

Table 1 is a table showing the conditions and effects of the embodiments of the present invention.

The samples used in this example were TFS-CT, which has the highest Rc and is difficult to weld among existing can materials, and Ni-plated steel sheet, which has the highest Re among the currently used welded can materials. and ultra-thin iron-tin plated steel plate with relatively high Re,
We selected Ni-based tin-plated steel sheet, which has a lower Re than the above-mentioned materials (has good weldability but is inferior to the #25 electric tin plate currently in general use). Tinplate was added to the sample as a comparative example.

In Table 1, as an example of 2g et al., the Rc of a rectangular blank was subjected to pressure treatment at a pressure of 100 mm/f/J using the pressure treatment apparatus shown in Figures 1 and 2. The welding results are shown, and the Rc of the rectangular blank was pressurized and heat treated using the pressure and heat treatment equipment N shown in Figures 4 and 5 at 20 kg f/mA and 200°C. and the welding results are shown in comparison.

Note that Rc Comparative Examples 1 to 4 in the same table are cases where no treatment was performed, and conventionally welding was performed in this state.

Among the examples of the present invention, Rc in the case of only pressure treatment is shown in Examples 1 to 4 of the present invention, and Re in the case of pressure treatment and heat treatment is shown in Examples 6 to 9 of the present invention. Both are thicker (it can be seen that Rc is lower) than the comparative example. Incidentally, Re is expressed in logarithm.

The weldability of the rectangular blank processed by the present invention is extremely good, and TFS, which was conventionally considered to be the most difficult to weld,
Even with -CT, the welded part had good strength, airtightness, and appearance.

The strength of the welded part was determined by a shear tear test (Tearin test).
g Te5t ). In other words, welds with broken welds are unacceptable, and welds that do not break are acceptable.
Others were evaluated according to degree.

In addition, airtightness was evaluated by penetrant testing.

The evaluation of welded parts made of other materials, such as Ni-plated steel plates, was also extremely good compared to the conventional untreated case.

In addition, in this evaluation method, even those whose welded portions were evaluated as acceptable (△ mark) had sufficient quality to withstand commercial use.

[Brief explanation of drawings]

Figure 1 is a front view of the pressurizing device, and Figure 852 is the front view of the pressurizing device.
3 is a graph showing the relationship between pressing force and contact electrical resistance Re, FIG. 4 is a front view of a pressurizing device equipped with a heating device, and FIG. 5 is a sectional view taken along the line VW in FIG. 4. Figure 6 shows plate temperature and R
This is a graph showing the relationship between e and 1). 1... Rectangular blank 2... Curved H-shaped roll 3...
・・・・・・Flat roll 4・Song・Housing 10・
...High frequency heating type 4fi 13...-H type cooling roll 14...Flat cooling roll. Patent Applicant Toyo Kohan Co., Ltd. Figure 1 Figure 2 Figure 3 Pressure force (wa, fi butt mri) Figure 4 - Drawing rate 6 Illustration Shigeru (°C) Procedural amendment (voluntary) 1981 October January 1st, 2017, Patent Application No. 58-220294 2. Title of the invention: Process for manufacturing welded can bodies 3. Person making the amendment. Relationship with the case. Patent applicant address: 4-3 Kasumigaseki-chome, Chiyoda-ku, Tokyo. Name
Toyo Kohan Co., Ltd. Representative Kozo Yoshizaki 4, Agent postal code 744 Address 1302-6 Higashitoyoi, Kudamatsu City, Yamaguchi Prefecture, ``Detailed description of the invention'', ``Simplified drawings 7,'' of the specification subject to amendment Contents of amendment [1] Column for detailed description of the invention (1) On page 6, line 13 of the specification, "Rectangular blank 2" should be corrected to "Rectangular blank 1." (2) On the 8th page, lines 4 to 3 from the bottom: “...
...improved significantly. In addition, pressure roll...
・" has been changed to "......Remarkably improved.In addition, the pressure treatment does not necessarily have to be applied to the areas where both end faces of the rectangular blank are to be polymerized. Even if only one end of the rectangular blank, which should be the inner surface, is welded, it shows the same or better weldability than when both ends are pressure treated.In addition, the pressure roll...・・・
” he corrected. (3) Insert the following sentence between the bottom line of page 8 and the first line of page 9. ``Furthermore, rather than having the upper and lower pressure rolls have a flat cylindrical shape, it is preferable that either one or both of them be tapered rolls so that the thickness becomes thinner as it approaches the edge of the rectangular blank. By using a tapered pressure roll, the difference in plate thickness between the pressure-treated part and the non-pressure-treated part of the rectangular blank can be reduced or eliminated2, resulting in a stronger welded can. (4) Insert the following sentence between lines 3 and 4 on page 13. 7 and 8 are front views of a device used in another embodiment of the present invention for pressurizing only one side edge of a rectangular blank that will become the inner surface of the can when rolled into a can body. 7 is a diagram and a plan view. In FIG. 7, 20 indicates the main body frame of the pressure processing apparatus, and two people are pressurized by a hydraulic cylinder 22 with a partially tapered upper roll. 2B is a flat cylindrical In this example, only the lower roll 2B is driven by the drive device 24.One side edge IA of the rectangular blank 1 is pressurized with the roll 2A and 2B for one month. 21.21 is a pair of upper and lower thin film rolls that feed the rectangular blank 1 and also grip the blank 1 during pressure processing.As is clear in FIG.
B is arranged at an angle with respect to the traveling direction of the plate. FIG. 9 is a sectional view of a can body seam welding machine head during welding of a pressurized rectangular blank using the apparatus shown in FIGS. 7 and 8. FIG. Outer electrode roll 30 and inner electrode roll 3
1, the overlapping part of the end face of the rectangular blank 1 rolled into the can body is held between the flat copper wire electrodes 32 and 33, and welding is performed by applying current. The pressure-treated side edge IA is the inner surface of the can (1
It appears that he is playing iH. (5) Column 1 of Table 1, page 14 [Zanbururuwo, r
Sn Ni Cr'Cr” J. [2] Brief explanation of drawings (1) Specification, page 17, lines 6 to 7 g-“...
...This is a graph showing. "..."
7N and 8 are respectively a front view and a plan view of a device that pressurizes only one side, and FIG. 9 is a sectional view showing a state during welding of a blank subjected to pressure treatment on one side. ” he corrected. [3] Attached drawing □ - Attachment - Figures 7, 8, and 9 are added. 8. List of attached documents (1) Drawings (Figure 7, Figure 8, Figure 9)...
...2 leaves.

Claims (4)

[Claims] (1) A method for manufacturing a welded can body, in which a rectangular blank made of a thin steel plate is continuously supplied and sequentially rolled by bending to form a side end overlapping part, and the overlapping part is seam welded to form a can body,
A method for manufacturing a welded can body, characterized by using a rectangular blank whose side end polymerization portions have been subjected to pressure treatment of 10 to 300 ky·f/mA in advance. (2) The manufacturing method according to claim 1, wherein the thin steel sheet is an ultra-thin tin-plated steel sheet, and the TFS-CT or at least IM is a surface-treated steel sheet for cans having a Ni plating layer. (3) A method for manufacturing a welded can body in which a rectangular blank made of a thin steel plate is continuously supplied and sequentially rolled by bending to form a side end overlapping part, and the overlapping part is seam welded to form a can body,
The side end polymerization planned area is heated to 100 to 6 oo℃ in advance or simultaneously.
Heat to low to 3o. A method for manufacturing a welded can body characterized by using a rectangular blank subjected to positive/f/Ij pressure treatment. (4) The manufacturing method according to claim 3, wherein the thin steel sheet is an ultra-thin tin-plated steel sheet, TFS-CT, or a surface-treated steel sheet for cans having at least one Ni plating layer.