JP3254156B2 - High-speed non-polishing welding method of electrolytic chromated steel sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed non-polishing welding method for manufacturing a can body of a metal container by wire seam welding an electrolytic chromated steel sheet.

[0002]

2. Description of the Related Art When manufacturing a can body of a metal container, the thickness of the can is reduced to 0.
As a method of performing wire seam welding on a thin-plated steel sheet having a thickness of 5 mm or less, a method is known in which a lap width (lap width) of the steel sheet is set wider than a weld bead width (wire width). This method is mainly used in early wire seam welding, in which the inner and outer surfaces of the can body are welded with wires of the same shape. The reason why the lap width of the steel sheet was set wider than the weld bead width by this method was that at the time, the control technology of the weld bead position and the wrap width of the steel sheet was not sufficiently established,
This is because the wrap width could not be reduced.
However, in this method, if the lap width is too large than the weld bead width, the non-welded edges of both edges of the thin plate bend around the welded portion, causing poor repair of the welded portion and deterioration of the corrosion resistance of the can body.

[0003] Further, since the welding conditions could not be stabilized, usable steel sheets have metallic tin on the surface layer,
Tinplate, which had small electric resistance (contact resistance) and was advantageous for fluctuation of welding current, was mainly used. In addition, electrolytic chromate-treated steel sheets such as tin-free steel (TFS) with high contact resistance
When welding at a wire feed speed of m / min or more, remove the insulating film (chromium metal layer and chromium hydrated oxide layer) at the welded part by welding or other method before welding to reduce the contact resistance. Was needed. Further, since a material having a small contact resistance, which is advantageous for the fluctuation of the welding current, is to be welded, if the contact area between the wire and the steel plate is large, a problem arises that the welding current required for proper heat generation becomes too large. In order to avoid such a problem, a wire having an arcuate outer shape in a weld width direction of a portion to be contacted with the steel plate has been used so that the contact area between the wire and the steel plate can be stably and relatively small.

[0004] In contrast to such a conventional wire seam welding method (wide lap welding), a wire seam welding method for a can body, which is currently the mainstream, is a narrow width lap welding as shown in Japanese Patent Publication No. 54-213213. is there. This is a welding method in which the lap width of a steel sheet is reduced to less than half of the welding bead width, and the progress of lap management technology has made such a welding method possible. The advantage of this wire seam welding method is that since the lap width of the steel sheet is smaller than the weld bead width, it is welded including the edges of both edges of the thin plate, so there is no fear of poor repair of the welded part and deterioration of the corrosion resistance of the can body That is the point.
In addition, since the current is effectively concentrated on the plate / plate interface, appropriate heat generation can be obtained with a small current even with a material having a small contact resistance.

[0005] In recent years, regulations on contamination of containers with foreign substances have become strict, and it has become necessary to clean the welding environment. For this reason, there is a growing need to weld an electrolytic chromate-treated steel plate such as TFS, which has been conventionally polished and welded immediately before welding, without welding, and at a high speed in terms of workability.

[0006]

However, when an electrolytic chromate-treated steel plate such as TFS having a high contact resistance is welded at high speed without polishing by narrow lap welding as described above, it is immediately called dust at the plate / plate interface. There is a problem that welding defects occur. In other words, in this welding method, the entire lap portion including the edge portion of the steel plate is welded because the wrap width of the steel plate is small, and the weld portion is mashed with high pressure,
When excessive heat is generated, dust is immediately generated. For this reason, the conventional narrow width lap welding is not suitable for non-polishing high-speed welding of a material having a high contact resistance such as an electrolytic chromated steel sheet.

On the other hand, when the electrolytic chromate-treated steel sheet is welded at high speed without polishing by the conventional wide-width lap welding as described above, under the current conditions that can ensure appropriate heat generation at the plate / plate interface, dust is generated at the wire / plate interface. There is a problem that occurs. This is because in narrow lap welding, the current density at the wire / plate interface is smaller than that at the wire / plate interface, so that the current density at the wire / plate interface can be reduced and heat generation can be suppressed. This is because the current density at the wire / plate interface is increased due to the larger energization area at the plate / plate interface, and excessive heat is generated.

Further, in the wire seam welding method, it is difficult to improve the cooling capacity of the wire / plate interface on the inner surface of the can body due to structural restrictions of the welding machine. Therefore, there is a problem that foreign matter is mixed into the can and a weldable current range cannot be secured due to the generation of dust. As described above, with the conventional wire seam welding method, it was practically difficult to manufacture a can body by performing non-polishing high-speed welding on an electrolytic chromate-treated steel sheet. Therefore, an object of the present invention is to provide a wire seam welding method capable of appropriately performing high-speed welding of a non-polished electrolytic chromate-treated steel sheet without causing a problem such as generation of dust when manufacturing a can body of a metal container by wire seam welding. To provide.

[0009]

In order to solve such problems, the wire seam welding method of the present invention has the following features. (1) In a method of manufacturing a can body by wire seam welding a non-polished electrolytic chromate-treated steel sheet at a wire feed speed of 15 m / min or more, the electrode wire used on the inner side of the can body is perpendicular to its longitudinal direction. The cross-sectional area is 0.
5 to 3.0 mm ² , wherein the outer shape in the width direction of the welded portion of a portion to be brought into contact with the electrolytically chromated steel sheet to be welded has a length of 1.0 to 4.0 times the thickness of the electrolytically chromated steel sheet to be welded. The wire of the electrode used on the outer surface side of the can body has an arc-shaped outer shape in the width direction of the welded portion at a portion to be brought into contact with the steel plate to be subjected to electrolytic chromate treatment. Overlap width W (m
m) satisfies L ≦ W <L + 1.5 in relation to the length L (mm) of the linear portion of the electrode wire used on the inner side of the can body, and the inner side of the can body and the outer side of the can body The pressure between the electrodes is 30-150kgf, and the nugget pitch of the weld is 0.6
A high-speed non-polishing welding method for an electrolytic chromate-treated steel sheet, which has a thickness of about 1.8 mm.

(2) In the welding method of the above (1), the wire of the electrode used on the inner surface side of the can body is attached to both ends of the linear portion in the width direction of the welded portion of the portion to be brought into contact with the electrolytically chromated steel sheet to be welded. A high-speed non-polishing welding method for an electrolytic chromate-treated steel sheet, comprising an arc-shaped portion having a radius of curvature R of 0.1 mm or more.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the optimum width of lapping (lap width) of steel sheets for suppressing the generation of dust at the plate / plate interface during non-polishing high-speed welding of electrolytic chromated steel sheets is studied. As a result, in order to avoid the generation of dust by avoiding the mash at the plate / plate interface, the overlap width of the steel plate is set to the contact width of the wire / plate interface in the weld width direction in relation to the wire used on the inner surface of the can body. Equal or better. However, if the overlap width of the steel sheet is 1.5 mm or more wider than the contact width of the wire / plate interface, a problem of warpage of the steel sheet edge portion occurs, so that repair of the welded portion becomes difficult.
For this reason, it is not preferable to make the overlapping width of the steel sheets 1.5 mm or more larger than the contact width of the wire / plate interface. here,
When the overlap width of the steel plate is equal to or larger than the contact width of the wire / plate interface in the weld width direction as described above, it is difficult to reduce the amount of electricity at the wire / plate interface,
In particular, excessive heat generation at the wire / plate interface on the inner surface side of the can body poses a problem.

Therefore, as a result of a study for optimizing the wire shape in order to reduce the current density at the wire / plate interface, excessive current generation was suppressed by reducing the current density at the wire / plate interface on the inner surface side of the can body. In order to achieve this, a wire having a straight portion in the width direction of the welded portion of the portion to be brought into contact with the steel plate on the inner surface side of the can body, that is, a wire in which the contact portion with the steel plate in the welded width direction is linear Was found to be effective. On the other hand, the use of a wire having the above-described linear portion on the outer surface of the can body has a problem in that the discoloration range due to welding is increased and the appearance of the welded portion is impaired. It is preferable to use a conventionally used wire having an arc shape (convex arc shape) in a width direction of a welded portion of a portion to be brought into contact with a steel plate, so that welding can be performed without impairing the appearance of the welded portion.

The use of the above-mentioned arcuate wire on the outer surface of the can body increases the current density at the wire / plate interface on the outer surface of the can body. Along with using a wire with a shape with
According to the conventional method, the effect of improving the balance of heat generation on the inner and outer surfaces of the can, which tends to cause the heat generation center to be biased toward the inner surface of the can, can also be obtained. Furthermore, when using a wire having a linear portion in the width direction of the welded portion on both the inner surface of the can body and the outer surface of the can body, the steel plate and the wire do not uniformly hit unless the positions of the electrodes and the like are strictly adjusted. This may cause cracking during can molding. On the other hand, by using a combination of a wire having a linear portion and a wire having an outer shape in the welded portion width direction on the inner and outer surfaces of the can body in combination with the arc-shaped wire, the above-described non-uniform contact of the wire is also prevented. Can be.

When a high contact resistance material having a chromium hydrated oxide layer such as an electrolytic chromated steel sheet is subjected to wire seam welding, the length L of the linear portion in the width direction of the welded portion of the wire used on the inner surface side of the can body is determined. If the thickness is less than 1.0 times the thickness of the steel sheet, the width of the formed nugget is narrow, and the welding strength required for an actual can cannot be sufficiently obtained. On the other hand, if the length L of the linear portion exceeds 4.0 times the thickness of the steel sheet, the effect of expanding the nugget width is not only saturated, but also the pressing force and current required for welding become unnecessarily large. Not preferred.

Therefore, in the welding method of the present invention, regarding the electrode wire used on the inner surface side of the can body, the outer shape in the width direction of the welded portion of the portion to be brought into contact with the steel plate to be subjected to electrolytic chromate treatment is the plate of the steel plate to be subjected to electrolytic chromate treatment. 1.0 ~ of thickness
On the condition that it has a linear portion having a length of 4.0 times, the overlap width W (mm) of the electrolytically chromated steel sheet to be welded at the welded portion is determined by the straight line of the electrode wire used on the inner surface side of the can body. The condition is that L ≦ W <L + 1.5 is satisfied in relation to the length L (mm) of the shape portion. Also, regarding the wire of the electrode used on the outer surface side of the can body, the outer shape in the width direction of the welded portion at the portion to be brought into contact with the electrolytically chromated steel plate to be welded is assumed to be an arc shape (convex arc shape) such as an arc shape. .

FIG. 1 shows an example of a welding situation according to the method of the present invention in a state where a welded portion is cross-sectionally shown.
Is a wire of an electrode (upper electrode wheel) on the inner surface side of the can body, and 2 is a wire of an electrode (lower electrode wheel) on the outer surface side of the can body.
The outer shape of the portion in contact with the steel plate in the width direction of the welded portion has a linear portion 3. On the other hand, the outer shape of the portion of the wire 2 that should come into contact with the steel plate in the weld width direction is arc-shaped. For comparison, FIG. 3 shows a welding situation (cross section of a welded portion) according to the conventional method. In FIG. 3, reference numeral 5 denotes a wire of an electrode (upper electrode wheel) on the inner surface of the can body, and 6 denotes a wire of an electrode (lower electrode wheel) on the outer surface of the can body. Are all arcuate in the weld width direction.

It is preferable that arc-shaped portions (convex portions) such as arcs are formed at both ends of the linear portion in the width direction of the welded portion of the wire on the inner surface of the can body. FIG. 2 shows an example of a welding situation according to the method of the present invention using a wire having such an arc-shaped portion in a state where a welded portion is cross-sectionally shown.
Reference numeral 4 denotes arc-shaped portions formed at both ends of the linear portion 3 of the wire 1. If such an arc-shaped portion 4 is not provided in the wire 1, if the vertical axes of the upper and lower electrode rings are displaced, the end of the weld bead is flawed, and the flaw is formed when the flange is formed after welding. There is a risk of cracking from the part. In particular, when the electrolytically chromated steel sheet to be welded is a thin material having a thickness of 0.5 mm or less, such cracks are likely to occur. Therefore, it is preferable to form the arc-shaped portions 4 at both ends of the linear portion 3.
Further, it is preferable that the radius of curvature R of the arc-shaped portion is 0.1 mm or more in order to obtain the above-described effect.

The cross-sectional area of the wire used on the inner surface side of the can body (cross-sectional area in a cross section perpendicular to the longitudinal direction of the wire) is 0.5 to
3.0 mm ² . The cross-sectional area of this wire is 0.5 mm ²
If it is less than 1, the heat capacity is small and the wire / plate interface cannot be sufficiently cooled. On the other hand, the cross-sectional area of the wire is 3.0
If the thickness exceeds mm ² , the cooling effect from the viewpoint of heat conduction is not only saturated, but also an expensive copper wire is unnecessarily used, which impairs economic efficiency. The wire is preferably composed mainly of copper from the viewpoint of heat conduction. In the present invention, the cross-sectional shape of the wire used for the electrode on the inner surface of the can body,
Any shape is possible as long as the above conditions are satisfied. For example, a cross-sectional shape as shown in FIG. 4 (a cross-sectional shape perpendicular to the longitudinal direction of the wire) can be used. Among these, (a) and (b) are modified examples of the wire cross-sectional shape shown in FIG. 1, and (c) and (d) are modified examples of the wire cross-sectional shape shown in FIG.

The nugget pitch is an important factor that affects the airtightness of the container. In the case of a material having a low contact resistance and a good pressure contact property, such as an abrasive of an electrolytic chromate-treated steel sheet, energization is started at a low pressing force, so that an energization heat generation area is wide, and a weldable nugget pitch is set to a wide range of, for example, 2 mm or more. be able to. In addition, since the polishing is performed immediately before welding, the distribution of resistance on the surface of the steel sheet is also stable, and non-uniform heat generation hardly occurs even when the nugget pitch is reduced. On the other hand, when a high contact resistance material having a chromium hydrated oxide layer is subjected to non-polishing welding, the energization heat generation area is narrow because the energization only starts at a high pressing force, and the nugget pitch is increased to more than 1.8 mm. As a result, unheated portions are generated, so that appropriate airtightness cannot be obtained. Further, in the case of non-polishing welding, an insulating foreign matter or the like is inevitably present on the steel sheet surface.
If it is less than 6 mm, the current flow between the nuggets tends to be non-uniform, and even if the wire shape is optimized, the appropriate welding conditions cannot be obtained.

In the case of a material having a high contact resistance or a material having a poor pressure contact property, by increasing the pressure applied to the upper and lower electrodes, the destruction and pressure contact of the film are promoted, and it is possible to secure a stable current path and improve the welding strength. . Even if the wire shape is optimized, when the pressing force applied between the upper and lower electrodes is less than 30 kgf, the amount of the chromium hydrated oxide layer generally used is about 5 to 10 mg / m ^{2 in} terms of metal chromium. Even with materials, the pressure welding becomes insufficient, so that ACR cannot be properly obtained and sufficient welding strength cannot be obtained. On the other hand, if the pressing force applied between the upper and lower electrodes exceeds 150 kgf, the steel sheet will not be smoothly bitten between the electrodes, and excessive heat will be generated at the start end of welding due to a change in welding speed.

For the above reasons, the present invention is based on the condition that the nugget pitch is 0.6 to 1.8 mm and the pressure between the electrodes on the inner surface of the can body and the outer surface of the can body is 30 to 150 kgf. In carrying out the wire seam welding method of the present invention, considering that tinplate welding and electrolytic chromate-treated steel plate polishing welding are also performed using the same welding machine from the viewpoint of operability, the can body inner surface side electrode A plurality of separate wire forming rolls are arranged immediately before the can body outer surface side electrode and the wire can be appropriately switched, or a forming roll having a plurality of grooves can be formed by a can body inner side electrode and a can body outer surface. It is desirable to arrange them immediately before the side electrodes.

[0022]

EXAMPLE A steel body was subjected to wire seam welding using an electrolytic chromate-treated steel sheet shown in Table 9 as a raw material and a Fuji welder type welding machine having a large overlap width of the steel sheet as compared with the welding wire width. In this embodiment, 4 to 100 cans were continuously manufactured at a welding speed of 10 to 30 m / min, and the weldable current range (A
CR), the corrosion resistance of the obtained can body and the appearance of the welded part were evaluated. In the evaluation of the cans, the cans whose current was not stable (can bodies made first and last when the can bodies were continuously made) were excluded from the evaluation.

The wire of each electrode was provided with a plurality of grooves on a wire forming roll immediately before the wire was supplied to the electrode so as to have a desired sectional shape. FIG. 5 shows a cross-sectional shape (a cross-sectional shape at a cross-section perpendicular to the longitudinal direction of the wire) of the wire used in this example. Of these, A is a wire having a sectional shape used in the conventional method, and B and C are
Is a wire having a sectional shape used in the method of the present invention. In the example of the present invention, these wires A to C were used in a combination as shown in FIGS.

The ACR is a current range between the lower limit of the current at which an appropriate welding strength cannot be obtained and the upper limit of the current at which excessive heat is generated. The lower limit current is evaluated by a tear test and the upper limit current is evaluated based on the presence or absence of splash or dust. And evaluated according to the following. ○: Sufficient weldable current range is available △: Weldable current range is available but narrow ×: No weldable current range

The corrosion resistance can be measured at room temperature by adding a water-soluble content to a container manufactured based on each can body except the can at all times.
The rusting state of the weld repaired part after storage for months was evaluated by the following. ：: no rusting ×: rusting occurred Note that in Examples where there was no weldable current range, the corrosion resistance could not be evaluated because substantial canning could not be performed. The appearance of the weld was visually observed and evaluated as follows. ：: No color unevenness of welded portion ×: Color unevenness of welded portion Table 1 to Table 8 show the results of evaluating the ACR and corrosion resistance together with the type of material steel plate and welding conditions.

As shown in Tables 1 to 8, all of the examples of the present invention have a sufficient welding current range, and the manufactured can bodies have excellent corrosion resistance. On the other hand, a comparative example 10 to a comparative example 16 in which a wire (wire A) having an arcuate outer shape in a welded portion width direction of a portion to be brought into contact with a steel plate was used for both the inner and outer electrodes of the can body. Is the wire /
ACR is not properly obtained because excessive heat is generated at the plate interface. Comparative Example 1 to Comparative Example 8 used a wire having an outer shape in a width direction of a welded portion of a portion to be brought into contact with a steel plate as a wire of an electrode on the inner surface side of the can body, and an electrode on an outer surface side of the can body. As the wire, a wire having an arcuate outer shape in a weld width direction of a portion to be in contact with a steel sheet is used, but the effect of the present invention is sufficiently obtained because other conditions do not satisfy the scope of the present invention. Not been.

In Comparative Example 2, the length L (mm) of the linear portion of the wire on the inner surface side of the can body and the overlap width W (mm) of the steel plate were used.
Is W> L + 1.5, the edge of the steel plate at the welded portion rises up, causing a problem in the sealability of the welded portion, resulting in poor corrosion resistance. In Comparative Examples 1 and 3, since the cross-sectional area of the wire on the inner surface side of the can body is less than 0.5 mm ² , the cooling capacity of the wire / plate interface is insufficient, and dust is generated. Therefore, an appropriate ACR has not been obtained. Further, in Comparative Example 3, since the length L of the linear portion of the wire on the inner surface side of the can body is less than 1.0 times the thickness of the steel plate, sufficient welding strength required as an actual can cannot be obtained. Further, in Comparative Example 3, the relationship between the length L (mm) of the linear portion of the wire on the inner surface side of the can body and the overlap width W (mm) of the steel plate is W> L + 1.5, which is outside the range of the present invention. .

In Comparative Example 4, the pressure between both electrodes was 30 kgf.
Since it is less than the above, ACR cannot be appropriately obtained due to insufficient pressurization, and welding strength becomes insufficient. Comparative Example 7 and Comparative Example 8
Since the pressure between both electrodes exceeds 150 kgf,
Excessive heat generation at the welding start end occurs due to fluctuations in the welding speed due to poor plate biting between the two electrodes, and thus the appearance of the welded portion is poor. In Comparative Example 5, since the nugget pitch exceeded 1.8 mm, an unwelded portion was formed between the nugget pitches, so that an appropriate welding strength could not be obtained. In addition, discoloration unevenness occurs in the appearance. In Comparative Example 6, since the nugget pitch was less than 0.6 mm, heat generation was uneven and dust was likely to occur. In addition, discoloration unevenness occurs in the appearance.

In Comparative Example 9, as the electrode wire on the inner surface of the can body, a wire having an arcuate outer shape in the width direction of the welded portion at the portion to be brought into contact with the steel plate was used. This is an example in which a wire having a straight portion is used in the welded portion in the width direction of the portion to be contacted. In this comparative example, the tendency of excessive heat generation on the inner surface side of the can is promoted.
Is not obtained properly. Note that the conventional example is an example in which wire seam welding was performed at a low welding speed of 15 m / min or less. When the welding speed is low as described above, the discoloration unevenness of the appearance occurs even in the conventional technology, but the electrolytic chromate-treated steel sheet is not used. This indicates that polishing welding is possible.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

[0034]

[Table 5]

[0035]

[Table 6]

[0036]

[Table 7]

[0037]

[Table 8]

[0038]

[Table 9]

[0039]

As described above, according to the present invention, when producing a can body of a metal container by wire seam welding using an electrolytic chromate-treated steel sheet as a raw material, non-polishing electrolysis is performed without causing problems such as generation of dust. Chromate treated steel plate can be appropriately welded at high speed.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a welding situation according to the method of the present invention in a state where a welded portion is cross-sectionally shown.

FIG. 2 is an explanatory view showing another example of a welding situation according to the method of the present invention in a state in which a welded portion is sectioned.

FIG. 3 is an explanatory view showing a welding state according to a conventional method in a state where a welded portion is sectioned.

FIG. 4 is an explanatory view showing an example of a cross-sectional shape of a wire used on the inner surface side of a can body in the method of the present invention.

FIG. 5 is an explanatory diagram showing a cross-sectional shape of a wire used in an example.

[Explanation of symbols]

 1, 2, wire, 3 linear part, 4 arc part

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-122036 (JP, A) JP-A-7-164163 (JP, A) JP-A-57-72781 (JP, A) 91364 (JP, U) JP-B 54-4686 (JP, B2) JP-B 61-50074 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 11/08 B21D 51 / 26 B23K 11/16 B23K 35/02 C25D 11/38

Claims (2)

(57) [Claims] 1. An unpolished electrolytic chromate treated steel sheet
In a method of manufacturing a can body by wire seam welding at a wire feed speed of at least m / min, a cross-sectional area of a wire of an electrode used on the inner surface side of the can body in a cross section perpendicular to the longitudinal direction is 0.5 to 3 mm. a .0mm ^2,
The outer shape of the portion to be brought into contact with the electrolytically chromate-treated steel sheet to be welded has a linear portion having a length of 1.0 to 4.0 times the thickness of the electrolytically chromated steel sheet to be welded, The wire of the electrode used on the outer surface side has an arc-shaped outer shape in a welded portion width direction at a portion to be brought into contact with the electrolytically chromated steel sheet to be welded, and the overlap width W (mm) of the electrolytically chromated steel sheet at the welded portion is In relation to the length L (mm) of the linear portion of the wire of the electrode used on the inner surface of the can body, the following condition is satisfied: L ≦ W <L + 1.5, and the distance between the electrodes on the inner surface side of the can body and the outer surface side of the can body is satisfied. Pressure is 30-150kgf, nugget pitch of weld is 0.6
A high-speed non-polishing welding method for an electrolytic chromate-treated steel sheet, which has a thickness of about 1.8 mm. 2. A wire of an electrode used on the inner surface side of the can body has a radius of curvature R of 0.2 at both ends of a linear portion in a width direction of a welded portion of a portion to be brought into contact with the electrolytically chromated steel sheet to be welded.
2. The method according to claim 1, wherein the arc-shaped portion has a length of 1 mm or more.
2. A high-speed non-polishing welding method for an electrolytic chromate-treated steel sheet according to item 1.