JPS6149035B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welded can with excellent corrosion resistance and a method for manufacturing the same, and more specifically, the present invention relates to a welded can with excellent corrosion resistance and a manufacturing method thereof. After coating a metal or alloy with excellent weldability, overlap resistance welding is performed.
Regarding the manufacturing method of TFS welded cans. TFS has poor weldability, so in order to make welded cans using this material, for example, the chrome coating on the part to be welded is scraped off (edge cleaning) using a device such as that described in Japanese Patent Publication No. 51-14189. The conventional method is to expose the base steel and perform lap welding. However, in the above conventional method, the steel substrate is exposed at the seam of the product can due to the edge cleaning and cut edges, and if this exposure is on the inner surface of the can, iron elution into the contents and rust. Even if the exposed parts of the steel are coated with an organic film, the exposed parts of the steel will have poor adhesion with the organic film, especially in processed areas. It is difficult to suppress corrosion under the organic coating. In addition, exposed steel on the outside of the can may cause red rust or filamentous rust during storage.
These rust occurrences significantly reduce the commercial value in terms of appearance. Therefore, to date, the use of welded cans has been limited to less corrosive contents. In order to solve the above-mentioned problems of the conventional method, the present inventors conducted various researches, and as a result, coated the edge cleaning part and the cut edge part of the edge-cleaned TFS in advance with a metal or base metal with excellent corrosion resistance and weldability. Later, they discovered that it was possible to manufacture a welded can with excellent corrosion resistance by overlapping resistance welding, and thus arrived at the present invention. That is, the present invention provides a method for manufacturing a welded can, in which the chromium coating on the opposing edges of a can blank made of electrolytic chromic acid treated steel plate is removed, and the chromium coatings are overlapped and electrical resistance welded. This method is characterized in that a metal or alloy coating having corrosion resistance and weldability is previously provided on the exposed base steel surface of the cut edge portion and the portion from which the coating has been removed, and then welding is performed. In the present invention, examples of metals with excellent corrosion resistance and weldability suitable for coating the exposed base steel surface of the TFS material plate are lead, tin, zinc, and nickel, and alloys of these metals may also be used. can. Coating metals or alloys such as those exemplified above onto bare steel surfaces can be achieved by any of the conventional metal coating methods such as electroplating, electroless plating, hot dipping or thermal spraying. method can also be used. Coating thickness for metals and alloys is 0.003μm
~100μm, more preferably 0.005μm ~ 50μm
It is. The edge cleaning department and cut edge department are
Since the clean base steel is usually exposed, the metal or alloy coating described above can be applied to the exposed base steel surface without any pretreatment. However, the above coating may be applied after conventional pre-treatments such as degreasing and pickling. The can body manufactured by the method shown in the present invention can be used unpainted or painted depending on the purpose, so it can be used for all food cans, beverage cans, aerosol cans, and general cans. used for. Next, examples of the present invention will be shown. In each of the Examples and Comparative Examples, weldability was evaluated for each test item using 10 test cans according to the following procedure. Welded part strength: Measured the welded part using a tensile tester. Weld integrity: The weld is cut parallel to the side seam and the cut surface is observed under a 300x optical microscope to evaluate the integrity of the weld. ○: Welding is complete over the entire length of the side seam. ×: There is a welding defect at one or more side seams. Molten metal splatter: Observe and evaluate the presence or absence of molten metal splatter around the weld using a 10x stereo microscope. In the actual can storage test, test cans are tested for each of the following test items.
After storing 10 cans for one year, evaluate them according to the following procedure. Can internal pressure or can vacuum degree: Can internal pressure or can vacuum degree after one year of storage, average value of 10 cans. Amount of hydrogen generated: Amount of hydrogen generated (ml)/can, average value for 10 cans. Dissolved iron: Dissolved iron (mg)/Contents (100g), average value for 10 cans. Perforations: Number of perforations that occurred within one year of storage Changes in contents: Color and other changes in contents Can internal condition: After opening the can, visually evaluate the inside of the can,
(Rust occurrence, changes in paint film, etc.) Can external condition: Visual evaluation of can external surface after 1 year of storage. Example 1 Epoxy-phenol paint was applied to a can body blank (105 mm x 206 mm) made of an electrolytic chromic acid treated steel plate with a thickness of 0.23 mm and a temper of 4, so that the thickness after curing was approximately 5μ, and the weight was applied during welding. It was roll coated except for the joints and baked at 205°C for 10 minutes. After removing the chrome coating on the overlapping parts of the can body blanks using a milling cutter, tin plating is applied under the following conditions, washed with water, dried, and formed into a cylindrical shape with a roll former to a height of 105 mm. death,
Using a regular overlap seam resistance welding machine, overlap width 0.4 mm, feed speed 45 m/min, and current conditions.
The can body was manufactured by seam welding with 7.3KA. Tin plating coating conditions Bath composition (aqueous solution) Stannous sulfate 80g/ Phenol sulfonic acid 80g/ Gelatin 2g/ β-naphthol 1g/ Bath temperature 50℃ Current density 30A/dm ³ plating time 4 seconds Using this can body , weld strength, weld integrity and molten metal splatter were evaluated. The results are shown in Table 1. Using another can body, apply epoxy-phenol paint around the weld on the inside of the can,
After baking at ℃ for 2.5 minutes, flanging was performed using the usual method, and the can can was double-sealed to form a can body. This can body is filled with tuna dressing or meat sauce, and the can lid is double-sealed.
It was retorted at ℃ for 90 minutes and subjected to a real can storage test. The results are shown in Table 1. Example 2 A can body blank (105 mm x 206 mm) made of electrolytic chromic acid treated steel plate with a thickness of 0.17 mm and tempered DR8 was coated with epoxy-phenol paint to a thickness of approximately 5 μm after curing.
The parts were roll coated except for the overlapping parts during welding, and baked at 205°C for 10 minutes. After removing the chrome coating on the overlapping parts of the can body blanks with a milling cutter, nickel plating is applied under the following conditions, washed with water, dried, and formed into a cylindrical shape with a roll former to a height of 105 mm. Then, a can body was manufactured by seam welding using a regular lap seam resistance welding machine with a lap width of 0.4 mm, a feed rate of 45 m/min, and a current condition of 6.5 KA. Nickel plating coating conditions Bath composition (aqueous solution) Nickel sulfate 220g / Nickel chloride 40g / Boric acid 30g / Bath temperature 55℃ Current density 15A/dm ² Plating time 10 seconds Using this can body, weld strength and weld integrity The properties and molten metal scattering were evaluated. The results are shown in Table 1. Using another can body, apply epoxy-phenol paint around the weld on the inside of the can,
After baking at ℃ for 2.5 minutes, flanging was performed using the usual method, and the can can was double-sealed to form a can body. Add consommé soup or vegetable juice to this can.
The can was heated and filled at 93°C, and the can lid was double-sealed. For cans filled with consommé soup, at 116°C.
The cans that were retorted for 90 minutes and filled with vegetable juices were subjected to a real can storage test. The results are shown in Table 1. Example 3 Epoxy-urea paint was applied to a can body blank (125 mm x 206 mm) made of electrolytic chromic acid treated steel sheet with a thickness of 0.24 mm and a temper of 4, so that the thickness after curing was approximately 3 μm, and the layer was overlapped during welding. All but one part was roll coated and baked at 205°C for 10 minutes. After removing the chrome coating on the overlapping parts of the can body blanks using a milling cutter, nickel-phosphor coating was applied under the following conditions, washed with water, dried, and shaped into a cylinder with a height of 125 mm using a roll former. Using a normal overlapping seam resistance welding machine, overlap width 0.4 mm, feed speed 35 m/min, and current conditions.
The can body was manufactured by seam welding with 6.2KA. Nickel-phosphorus alloy plating coating conditions Bath composition (aqueous solution) Nickel chloride 35g/ Sodium acetate 12g/ Sodium hypophosphite 10g/ Bath temperature 95℃ Plating time 60 seconds Using this can body, welded part strength and welding perfection The properties and molten metal scattering were evaluated. The results are shown in Table 1. Using another can body, apply epoxy-urea paint around the welds on the inside of the can, bake it at 200℃ for 2 minutes, then process the flange using the usual method, and double-wrap the canopy and eyelid. It was tightened and made into a can body. This can body was filled with glass cleaner or shaving cream together with an aerosol propellant, clinched with mountain cups, and subjected to a real can storage test. The results are shown in Table 1. Example 4 Epoxy-phenol paint was applied to a can body blank (105 mm x 206 mm) of an electrolytic chromic acid treated steel plate with a thickness of 0.23 mm and a temper of 4 so that the thickness after curing was approximately 5 μm.
The parts were roll coated except for the overlapping parts during welding, and baked at 205°C for 10 minutes. After removing the chromium coating on the overlapping portions of the can body blanks using a milling cutter, flux was applied thereto, the blanks were immersed in molten tin for 1 second, and immediately passed through a squeeze roll for tin coating. Form it into a cylindrical shape with a roll former to a height of 105 mm, and use a regular overlap seam resistance welding machine to perform seam welding with an overlap width of 0.4 mm, a feed rate of 45 m/min, and a current condition of 7.5 KA. Manufactured can bodies. Using this can body, weld strength, weld integrity, and molten metal splatter were evaluated. The results are shown in Table 1. Using another can body, apply epoxy-phenol paint around the weld on the inside of the can,
After baking at ℃ for 2.5 minutes, flanges were processed in the usual manner, and the canopy was double-sealed to form a can body. This can body was filled with seasoned bonito or boiled tuna, double-sealed with a can lid, retorted at 116°C for 90 minutes, and subjected to a real can storage test. The results are shown in Table 1. Comparative Example 1 A can body blank (105 mm x 206 mm) made of electrolytic chromic acid treated steel plate with a thickness of 0.23 mm and a temper of 4 was coated with epoxy.
A phenol-based paint was roll-coated to a thickness of about 5 μm after curing, except for the overlapping portion during welding, and baked at 205° C. for 10 minutes. After removing the chrome coating on the overlapping parts of this can body blank using a milling cutter, it was formed into a cylindrical shape with a height of 105 mm using a roll former, and the current conditions were changed to 5.6 KA. Seam welding was performed under the same welding conditions as in Example 1 to produce a can body. Using this can body, weld strength, weld integrity, and molten metal splatter were evaluated. The results are shown in Table 1. Using another copper can, paint around the weld, bake, flange, and seam the can body under the same conditions as Example 1, fill it with contents, and retort it under the same conditions as Example 1. , and was subjected to a real can storage test.
The results are shown in Table 1. Comparative Example 2 A can body blank (105 mm x 206 mm) made of electrolytic chromic acid treated steel sheet with a thickness of 0.23 mm and a temper of 4 was coated with epoxy.
A phenol-based paint was roll-coated to a thickness of approximately 5 μm after curing, except for the overlapping portion during welding, and baked at 205° C. for 10 minutes. The height of this can body blank is adjusted using a roll former.
A can body was manufactured by seam welding under the same welding conditions as in Example 1, except that the can body was formed to have a diameter of 105 mm and the electrolytic conditions were changed to 3.6 KA. Using this can body, weld strength, weld integrity, and molten metal splatter were evaluated. The results are shown in Table 1. Using another copper can, a can body was prepared under the same conditions as in Example 1, filled with contents under the same conditions as in Example 1, retorted, and subjected to an actual can storage test. The results are shown in Table 1. The can body of Example 1, in which the part from which the chromium coating was removed, was coated with tin by electroplating, had an excellent welding condition, and no abnormality was observed even after being stored for one year after being filled with tuna dressing and meat sauce. On the other hand, in the case of Comparative Example 1, where the chrome coating was removed and the part of the can body was not coated with metal, perforation occurred within one year after filling, rust on the inside of the can,
Rust was observed on the outside of the can. The can body of Comparative Example 2 in which the chromium coating was not removed did not have sufficient welding strength, and some welding defects were present.
There was a lot of molten metal splattering, and the welding condition was unsatisfactory for the can. Additionally, after filling with tuna dressing and meat sauce, perforated cans occurred within one year, leakage from poor welding, rust on the inside of the can, and rust on the outside of the can were observed. As is clear from Example 1 and Comparative Examples 1 and 2, the can bodies of the present invention both exhibited extremely excellent effects in the comparative tests. In addition, from Examples 2, 3, and 4, the can body of the present invention obtained by applying electroless plating coating, electroless nickel-phosphorus alloy coating, or molten tin plating coating to the part from which the chromium coating was removed was welded. It is clear that it is in excellent condition and exhibits extremely excellent effects on all kinds of contents such as foods, beverages, and aerosol products. 【table】

Claims (1)

[Scope of Claims] 1. A method for manufacturing a welded can, in which the chromium coating on opposing edges of a can blank made of electrolytic chromic acid treated steel plate is removed, and the parts are overlapped and electrically resistance welded. A method characterized in that a metal or alloy coating having corrosion resistance and weldability is previously provided on the exposed base steel surface of the cut edge portion and the portion from which the chromium coating has been removed, and then welding is performed. 2. The method according to claim 1, wherein the metal or alloy having corrosion resistance and weldability is a metal of the group consisting of lead, tin, zinc, and nickel, or an alloy thereof.