JPS63215379A - Manufacture of thin can shell body - Google Patents

Abstract

PURPOSE:To prevent a burn through and thermal deformation at welding time by forming the superposing allowance in the dimension of specific times a plate thickness at the side edge of a thin Al or Al alloy plate and effecting a fillet TIG arc welding without using filler rod. CONSTITUTION:A superposing allowance is formed in advance in the dimension of 0.5-20 times a plate thickness at both side edges of the plate consisting of a thin Al or Al alloy and a fillet TIG arc welding is effected at the superposing part directly without using a filler rod. The weld zone is hardened with roll rolling method, if necessary. The welding is stabilized because of the superposing allowance being >=0.5 times the plate thickness and the deterioration in the formability is prevented because of the superposing allowance being set <=20 times the plate thickness. A burn through and the thermal deformation at welding time are thus prevented in the case of the fillet welding performing the TIG welding without using a filler rod.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a thin-walled can body, and more particularly to a method for manufacturing a thin-walled can body by TIG arc welding aluminum plates or aluminum alloy plates.

[Prior Art] (Background) The mainstream manufacturing method for thin-walled can bodies is the seamless can body manufacturing method (DI method), which is made by ironing. When producing in small quantities, it becomes necessary to frequently replace the press mold.
Productivity is extremely low and becomes a problem.

Therefore, in order to increase productivity, a method is used in which a thin plate (including a hoop) of aluminum or aluminum alloy is formed to have a circular cross section, and both edges of the plate are joined.

(Structure of Prior Art) By the way, the following technology is known as a manufacturing technology for a thin-walled can body in which thin plates are joined at both side edges.

■Method of butt welding with both edges facing each other (Figure 3).

■A method in which both edges are bent to form an L-shaped standing edge, and the standing edges are brought into contact with each other to perform welding (Fig. 4) (Unexamined Japanese Patent Publication No. 58
-25893).

[Problems to be Solved by the Invention] However, such a method has the following problems.

■In butt welding, where both edges face each other, butt precision is very important, and if there is even a slight gap in the butt part, burn-through (molten metal burns down to the opposite side) will occur.

In addition, deformation is likely to occur during welding, and it is highly conceivable that the butt accuracy will decrease during welding. Therefore, in order to prevent deformation during welding, it is necessary to use a plasma power source or a high frequency power source that can suppress the spread of the arc and reduce thermal deformation, and there are restrictions on the power source that can be used.

Furthermore, it is difficult to insert the -1 filler metal into the abutting portion due to its short arc length, so welding is usually performed without using the filler metal. However, when welding without using a filler rod, the plate thickness is thin (usually about 0.1 to 1.0 mm thick).
As a result, the amount of welded metal is insufficient, and as shown in FIG. 5, the welded metal portion becomes concave, and constrictions are likely to occur when forming a can.

■The method of bringing the L-shaped vertical edges into contact with each other is the above-mentioned butt welding method. It is similar to

The present invention aims to solve the above-mentioned problems and provide a welding method having good formability.

[Means for Solving the Problem] The above problem is solved in a method for manufacturing a thin can body in which a can body is formed by joining rolled aluminum plates or aluminum alloy plates at both side edges. Overlap the chain plates at 15 to 20 times the thickness to form an overlap, then fillet TIG the overlap without using a filler rod.
The problem is solved by a method of manufacturing a thin-walled fuselage characterized by performing arc welding.

In the present invention, a thin aluminum plate or an aluminum alloy plate is used as the material.

Here, the thin plate preferably has a thickness of 0.1 to 1.0 mm, for example.

As an aluminum alloy, for example, 1100°3003
．． 3004, 5052, 5082°5182, etc., but of course other aluminum alloys may be used.

In addition, cans to which the present invention is applied include, for example, food cans,
Examples include beverage cans and general cans.

In the present invention, the both side edges of the plate are 0.5 to 20 times the thickness of the chain plate.
Overlap by double to form an overlap margin.

In the present invention, the overlapping margin is set to 0.00% of the thickness of the plate that is the material to be welded.
The reason why it is set at 5 to 20 times is to prevent burn-through and obtain a welded part with a good appearance.

If the overlap allowance is less than 0.5 times the thickness of the material to be welded,
The same problem as welding occurs during butt, and weldability becomes unstable.

If it exceeds 20 times, the end face before welding will remain as shown in FIG. 6, which will easily result in notches during forming, which will significantly deteriorate formability. Furthermore, when considering the breadth of the range of appropriate welding conditions, a more preferable range for the overlap is 1-is times the thickness of the material to be welded.

In the present invention, TIG arc welding is performed without using a filler metal.
The IG arc welding method was adopted because lap fillet welding is essential to achieving the purpose of the present invention.
This is because it was concluded that TIG welding, which does not use filler metal, is optimal in order to avoid burn-through and obtain a good welded part appearance in the lap fillet welding.

[Description of embodiments] (Second claim) The workability of the joint welded by the method of the present invention is improved due to the reinforcement of the wall thickness of the weld metal part. By further work hardening the joint part by rolling, the workability of the joint part becomes even better.

Work-hardened materials are often used as materials for cans from the viewpoint of handling and strength, but the heat-affected zone and weld metal part after welding are softer than the base metal, so they are more likely to be constricted during the forming process. <,,*The upper limit of the shape limit is suppressed. Therefore, by work-hardening this softened part by roll rolling, the hardness difference is reduced and the formability is improved.

(Third Claim) The present invention uses TIG welding without using filler metal, but by using DC-5P (direct current positive polarity) TIG welding, the effect of preventing burn-through is even more remarkable,
Wider suitability 1'l! flow range can be obtained.

(Fourth Claim) In addition, by increasing the speed to In/min or higher, the arc is stabilized at a high current, and there is an effect of further preventing the occurrence of melt dripping and the like. On the other hand, if it exceeds 8 m/min, the so-called humping phenomenon tends to occur, which is not preferable.

[Embodiment J of the invention Examples of the present invention will be described below.

According to the welding conditions shown in Table 1, an aluminum or aluminum alloy plate was formed into a cylindrical body with a diameter of 100 mm, an overlap margin was formed as shown in FIG. 1, and TIG welding was performed. Figure 2 shows the state after welding.

The current was varied in the range of 10 A to 10 OA, and the occurrence of melt drop, appearance of the welded part, etc. were investigated.

The test results are shown in Table 2.

Test N011~No, 11. No, 18~No, 22
shows an example of the present invention.

Test No. 12 to No. 17 show comparative examples.

In No. 12, the overlap allowance/board thickness was less than 0.5, and burn-through occurred. In addition, the welded metal part became concave.

No, 13. In No. 14, the overlapping allowance/board thickness exceeded 20, so the moldability was poor.

No. 15 is an example using a filler metal, but in this example, the appearance of the welded part is poor.

Nos. 16, 17, and 17 were made by the conventional method, and burn-through occurred and the appearance was poor.

On the other hand, Examples of the present invention (No. 1 to No. 11 and No. 18 to No. 22) are as follows.

In all cases, burn-through did not occur, and the appearance and formability of the welded parts were extremely good or good.

Among them, those that were rolled after welding (NO,
No. 18, No. 19) had much improved moldability.

In addition, the welding speed is in/min ~ 8 m/yl i
H (No, 1”No, 11.No.

18, No, 19. No. 21) showed no handling phenomenon and no burn-through.

Furthermore, the polarity is DC-5P (No.

1-No, 11. No', 18. No, 19°No, 2
1. No. 22) did not cause melt drop and was able to obtain a wide appropriate current range.

[Effects of the Invention] Since the present invention is configured as described above, it has the following numerous effects.

■No burn-through occurs during welding.

■No thermal deformation occurs during welding.

■Not restricted by power supply.

■No concave parts are formed in the welded metal part, and no constrictions occur when forming a can.

[Brief explanation of the drawing]

1 and 2 are side views showing an embodiment of the present invention. 3 to 6 are side views showing conventional examples. Figure 2 22yoko Figure 3 222 Figure 6: Teyoko

Claims (4)

[Claims] (1) In a method for manufacturing a thin can body, in which thin aluminum plates or aluminum alloy plates are joined at both side edges to form a can body, the side edges are bonded together at 0.5 to 0.5 times the thickness of the plates.
A method for manufacturing a thin-walled fuselage, characterized by forming an overlapping margin by overlapping at a magnification of 20 times, and then performing fillet TIG arc welding on the overlapping margin without using a filler rod. (2) The method for manufacturing a thin-walled can body according to claim (1), wherein after the fillet TIG arc welding, the welded portion is further work-hardened by roll rolling. (3) The method for manufacturing a thin-walled can body according to claim (1) or (2), in which the current characteristic is DC-SP (direct current positive polarity). (4) The method for manufacturing a thin-walled can body according to any one of claims (1) to (3), wherein welding is performed at a welding speed of 1 m/min to 8 m/min.