JPH1133735A - Thin chrome plating steel plate and its seam weld method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the thin chrome plating steel plate and its seam welding method by which the seam welding of the thin chrome plating steel plate can be carried out without grinding and in a good productivity. SOLUTION: In the seam weld method of a thin chrome steel plate having a metal chromium layer and a chromium oxide layer on the surface, before the seam welding, on the four planes, namely the two junction planes of the welding part and two planes contacting with the electrode or on two planes contacting with the electrode or on two junction planes, the metal tin is adhered at 0.01-0.7 g/m<2> per metal tin adhesion unit area by preferably sliding the metal tin on the thin chrome plating steel plate. Then this steel plate obtains the aforementioned metal chromium layer, chromium oxide layer and linearity or banded metal tin layer formed by the sliding method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a seam welding method for a thin chromium-plated steel sheet and a thin chromium-plated steel sheet.
In particular, the present invention relates to a seam welding method for a thin chromium-plated steel sheet and a thin chrome-plated steel sheet capable of producing a welding can with high productivity without causing environmental pollution due to grinding powder generated during welding.

[0002]

2. Description of the Related Art Thin chromium-plated steel sheets, usually called tin-free steel, in which metal chromium and chromium oxide are plated on steel sheets, are widely used for beverage cans, food cans, 18L cans, and pail cans. When the thin chromium-plated steel sheet is used as a can body, an integral forming method by drawing or a joining method of bonding or welding after rounding is generally used as a method of forming the can body.

[0003] Among the can body forming methods, in the case of a method by welding,
Since chromium oxide such as chromium oxide on the surface is a high electrical resistance material, it is difficult to weld thin chromium-plated steel sheet as it is, and it is possible to grind only the part to be welded and remove most of the chromium plating layer. Generally done.
However, in this method, there is an environmental problem because the grinding powder of Cr is scattered, and there is a possibility of remaining in the can even when trying to remove the scattered grinding powder by suction, so there are environmental and sanitary problems. It is required to weld a thin chromium-plated steel sheet without performing grinding.

In the case of the grinding method, an area larger than the area of the welded portion is often ground in order to stabilize the weldability. Therefore, the ground portion, that is, the chromium plating is cut off around the welded portion, and the ground iron is exposed. There is a problem that rust is generated because this portion is easily corroded. As a technique for improving the weldability of a thin chromium-plated steel sheet and eliminating the need for grinding, a method of reducing the amount of plating on a thin chromium-plated steel sheet is disclosed in JP-A-61-213398. However, it is not stable, and the variation due to the welding machine is large.

Japanese Patent Publication No. Sho 63-26200 discloses a method of improving the weldability by reducing the contact resistance by giving fine chromium or granular morphology to the metal chromium of the thin chromium-plated steel sheet. In the case of the method, the weldability can be considerably improved by controlling the projections and granular forms well, but the color of the steel sheet is dark and the fingerprints are easy to get because of the projections and granular forms. Not accepted.

As another method for improving the weldability of a thin chromium-plated steel sheet, a method of providing a metal Sn plating layer between chromium metal and chromium oxide is disclosed in JP-B-63-35718. According to this method, since the melting point of metal Sn is as low as 232 ° C., it is quickly melted at the time of welding, and the contact surface can be stably reduced by wetting the joint surface, so that good weldability can be obtained.

[0007] However, since the entire surface including the welded portion is plated with Sn, the cost is high, and the tint makes the color tone white, so that there is a problem that it is hardly accepted by can users. Also,
Japanese Patent Publication No. 6-96790 discloses a method in which metal Sn is previously subjected to granular scattered plating and then thin chromium plating is performed thereon. However, even with this method, the weldability is improved by the metal Sn. There is a problem that the cost is high and the color tone becomes whitish because the metal Sn is plated on the entire surface including the metal.

Japanese Patent Application Laid-Open No. 61-213395 discloses a can-plated steel sheet in which metal Sn is plated in a striped form only on a welded portion, and a chromium metal layer and a chromium oxide layer are formed on the plating layer and on the entire surface of the steel strip. This steel plate is to be plated in several stripes for each portion to be welded when forming a can body in a wide steel plate.

[0009] In the case of this steel sheet, it is cut into a can body size after plating. However, since the width of the welded portion is usually about 1 mm, it is difficult to control the plating position accuracy, and it is very difficult to properly align the plating position with the welded position. Difficult. Further, this strip-shaped Sn-plated steel sheet can be used only for a welding can body, and cannot be diverted to a can lid or the like.

Japanese Patent Application Laid-Open No. 62-274091 discloses a method of forming a heat diffusion layer by Cr or Cr alloy plating and forming a Sn plating layer of 0.15 to 1.0 mg / m ² on the heat diffusion layer. Is disclosed. However, in this method, the annealing conditions for thermally diffusing Cr and obtaining excellent steel quality are extremely narrow, and the entire surface is metallized by conventional wet electroplating.
There is a problem that the cost is high because the Sn is plated.

[0011]

As described above, in the prior art, there are various problems in making a thin chromium-plated steel sheet into a welding can body without grinding, and there have been recent demands for using a thin chromium-plated steel sheet. It is difficult to produce clean welding cans. The present invention solves these problems and provides a seam welding method for a thin chromium-plated steel sheet and a thin chromium-plated steel sheet that can seam-weld a thin chromium-plated steel sheet without grinding and with excellent productivity. The purpose is to do.

[0012]

According to a first aspect of the present invention, there is provided a method for electric resistance seam welding of a thin chromium-plated steel sheet having a chromium metal layer on the surface of a steel sheet and a chromium oxide layer on the chromium metal layer. Before seam welding, a thin chromium-plated steel sheet seam characterized in that metal tin is applied to both joint surfaces of a welded portion and / or both surfaces in contact with an electrode, in a range of 0.01 to 0.7 g / m ² per unit area of metal tin adhesion. It is a welding method.

In the first invention, it is preferable that the method of attaching the metal tin is a method of pressing and sliding the metal tin on a thin chromium-plated steel sheet.
Further, in the first invention, the method for adhering the metal tin is as follows: the metal tin is applied to the thin chromium-plated steel sheet at a relative speed of 0.1 to 100 m / min and a pressure of 0.1 to 100 kgf / mm ² . It is preferable to use a method of pressing and sliding a thin chromium-plated steel sheet.

In the first aspect of the present invention, the method for adhering the metallic tin includes the steps of:
It is preferable to use a method in which the thin chrome-plated steel sheet is pressed and slid while being rotated under the condition of rotation / minute. In the first invention, the method of adhering the metal tin may be a method of pressing and sliding the metal tin on a thin chromium-plated steel sheet while vibrating the metal tin under the condition of a frequency of 1 to 100000 Hz. preferable.

Further, in the first invention, the method for adhering the metal tin includes the step of:
It is preferable to use a method in which the thin chrome-plated steel sheet is pressed and slid while rotating under the condition of rotation / minute and vibrating under the condition of a frequency of 1 to 100,000 Hz. Further, in the first invention, the method of adhering the metal tin includes pressing and sliding the metal tin on a thin chromium-plated steel sheet at a temperature of 5 ° C. or more and less than 232 ° C. It is preferable that the method is a squeezing method.

According to a second aspect of the present invention, there is provided a metal chromium layer on the surface of a steel sheet, and a chromium oxide layer on the metal chromium layer. A thin chromium-plated steel sheet having a linear or band-shaped metal tin layer having an adhesion amount per unit area of metal tin adhesion of 0.01 to 0.7 g / m ² formed by the method described above. The seam welding method according to the first aspect of the present invention relates to a lap seam welding,
It is more preferably applied, and the thin chromium-plated steel sheet of the second invention is more suitably used as a steel sheet to be subjected to lap seam welding.

In the first and second inventions, chromium oxide means both chromium oxide and chromium hydrated oxide. The total amount of chromium hydrated oxide is shown.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The present invention relates to a method for electrical resistance seam welding of a thin chromium-plated steel sheet having a chromium metal layer on the surface of a steel sheet and a chromium oxide layer formed on the chromium metal layer, wherein the seam welding is performed in advance. This is a seam welding method for a thin chromium-plated steel sheet in which metal tin is adhered to both the joining surfaces of both portions and both surfaces in contact with the electrodes, only both surfaces in contact with the electrodes, or only both joining surfaces.

Here, the two joint surfaces of the welded portion are the two surfaces of the lap seam welded portion where the steel plates are directly joined.
Further, the two surfaces in contact with the electrodes are two surfaces of a portion in contact with the upper and lower electrodes in the lap seam welded portion. Further, the present invention improves the weldability of a thin chromium-plated steel sheet by mechanically adhering metallic tin only to a portion to be welded from above the thin chromium-plated steel sheet before welding.

Further, the present invention has a metal chromium layer and a chromium oxide layer formed on the metal chromium layer on the surface of the steel sheet, and further, as an upper layer, metal tin and the chromium oxide layer And a thin chromium-plated steel sheet having a linear or band-shaped metal tin layer formed by sliding with the above. The above-described seam welding method of the present invention is more preferably applied to lap seam welding, and the thin chromium-plated steel sheet of the present invention described above is more suitably used as a steel sheet provided for lap seam welding.

According to the present invention, a thin chromium-plated steel sheet is
Welding without grinding has made it possible to manufacture welded can bodies. According to the present invention, after cutting a large plate of thin chromium-plated steel sheet to the size of a welding can body, after painting and printing as necessary, before welding, metal tin is applied only to the portion to be welded. Thereby, excellent weldability can be obtained.

The metal tin may be applied at any time before welding, and there is no limitation, but the metal tin is conveyed to the welding machine immediately before or after painting / printing. In some cases, it is most convenient to attach the grinder at a place where the grinder has been removed if the production line used to use the grinder. According to the present invention, there is an advantage that a conventional thin chromium-plated steel sheet can be used as it is. Therefore, the thin chromium-plated steel sheet can be used for a can body or a can lid, and can be used freely as before.

Further, according to the present invention, there is no problem caused by the above-described conventional color tone difference. As means for attaching metal tin in the present invention, metal tin,
Pressing and sliding on the weld of the thin chromium-plated steel sheet causes friction between the metal tin and the chromium oxide layer on the surface of the thin chrome-plated steel sheet by mechanical energy, and the friction causes the metal tin to solidify on the steel sheet. The method of attaching is more preferably used.

The present inventors have newly found that the above-described method of the present invention can directly attach metal tin to a conventionally used thin chromium-plated steel sheet and obtain good weldability. It has been reached. In the present invention, the method of applying metallic tin to the welded portion of the thin chromium-plated steel sheet by the sliding of the metallic tin is easy to control the location and width of the metallic tin to be applied, and the conventional tin-based plating method. Since a plating solution using various industrial chemicals is not used, there is an advantage that there is no problem of a waste solution, the environment is friendly, and the equipment for depositing metal tin can be made relatively compact.

In the present invention, the metallic tin is mainly deposited on the projections of the unevenness which is the surface roughness of the steel sheet having the chromium oxide layer on the outermost surface, and the surface where the metallic tin and the steel sheet are rubbed with each other. The metal tin is not uniformly adhered to the whole. As a result, at the time of welding, first, the convex portion to which the metallic tin is attached comes into contact, and current flows.However, since the metallic tin is soft and has a low melting point, the contact area increases due to the melting of the metallic tin, and the resistance at the beginning of welding is reduced. And this has the effect of improving weldability.

The metal tin adhered to the projections spreads from the projections to the recesses when the temperature rises and melts due to energization,
Excellent weldability is obtained because the resistance of the entire weld is stabilized. Thin chromium plated steel sheet of the present invention, on one side or both sides of the steel sheet, the amount of deposition of chromium metal per metallic chromium coating unit area has a metal chromium layer of 30~150mg / m ^2, on which, chromium oxide It is preferable to have a chromium oxide layer in which the amount of chromium oxide deposited per unit area of the coating is 3 to 30 mg / m ^{2 in} terms of metal chromium.

When the amount of the deposited metal chromium is less than 30 mg / m ² , the corrosion resistance is insufficient and rust easily occurs. On the other hand, when the amount exceeds 150 mg / m ² , the corrosion resistance is sufficient, Adhesion of metallic chromium is not only a problem from the economic point of view, but also reduces the productivity of the thin chromium-plated steel sheet. If the amount of chromium oxide is less than 3 mg / m ^{2 in} terms of metallic chromium,
Corrosion, is insufficient paint adhesion, the case of 30 mg / m ² exceeds the contrary, not only appearance occurs interference colors on the surface of the steel sheet deteriorates, chromium oxides such as chromium oxide has a high electrical resistance material Therefore, even if metallic tin is adhered, the weldability is not improved.

More preferably, the adhesion amount of chromium metal per unit area of chromium metal coating is 50 to 120 mg / m ² , and the adhesion amount of chromium oxide per unit area of chromium oxide coating is 5 to 20 mg / m ² in terms of chromium metal. m ² , more preferably, the adhesion amount of chromium metal is 70 to 110 mg / m ² , and the adhesion amount of chromium oxide is 8 to 18 mg / m ² in terms of chromium metal. In the present invention, the adhesion of the metallic tin to the welded portion is performed on the four surfaces, both the contact surfaces of the weld portion and the two surfaces in contact with the electrode, or both surfaces in contact with the electrode, or on both the joint surfaces.

In the present invention, it is not common in the field of steel plates to express the amount of metal tin deposited on the surface of the steel plate by the number of deposited metals on the convex portions of the steel plate surface.
It was defined by the conventionally used amount of adhesion per unit area. That is, in the present invention, the adhesion amount of metal tin is
0.01 per unit area of tin deposit on the deposit surface of the weld
0.70.7 g / m ² .

The above-mentioned adhesion amount indicates an adhesion amount per unit area of metal tin adhesion on the surface of the welded portion where the metal tin adheres. When the adhesion amount of metal tin is less than 0.01 g / m ² , the improvement of the weldability is insufficient, and when it exceeds 0.7 g / m ² , the effect of improving the weldability is sufficient, but the amount is more than necessary. Adhesion of metallic tin is a problem from the viewpoint of economy.

More preferably, the amount of deposited metal tin is from 0.05 to 0.05 per unit area of deposited metal tin on the surface of the welded portion where the metal tin is deposited.
0.55 g / m ² . Adhesion of metal tin only needs to be performed on the welded portion of the thin chrome plated steel sheet cut out to the size of the can body,
Before seam welding, metallic tin may be attached to the four surfaces of both the welding surfaces and both surfaces in contact with the electrodes, or both surfaces in contact with the electrodes, or both the bonding surfaces.

The width of the metal tin adhesion is not particularly limited, but may be the same as or larger than the width of the welded portion. Since it is uneconomical if the width of metal tin deposition is too wide, the width of metal tin deposition is
A width of 0.4 to 4 mm is preferred. The method of adhering the metal tin may be a method of rubbing (rubbing) the thin chrome-plated steel sheet with the metal tin. The relative speed of the metal tin and the thin chrome-plated steel sheet is 0.1 to 100 m / min, and the pressing force is 0.1 to 100 kgf. / mm ²
It is preferable to use a method of sliding while pressing against each other under the conditions described above.

Normally, in a welding can manufacturing facility, the sheets are transported one by one from a piler having piled plates to a welding machine by a conveyor or the like, so that the adhesion of metal tin can be carried out during this transport. In addition, the metal tin may be moved while the plate is fixed. The sliding speed is preferably 0.1 to 100 m / min in relative speed as described above.

When the relative speed is less than 0.1 m / min, the frictional energy generated at the time of rubbing is small, and it is difficult to uniformly adhere the required amount of metallic tin. Conversely, when the relative speed exceeds 100 m / min. Slip occurs, and similarly, it becomes difficult to uniformly deposit the required amount of metallic tin. More preferably,
The relative speed is between 1 and 70 m / min.

The pressure for depositing metallic tin is 0.1
100100 kgf / mm ² is preferred. If pressure is less than 0.1 kgf / mm ^2, it is difficult to perform the deposition of the required amount of metallic tin, 10 to reverse
If it exceeds 0 kgf / mm ² , not only is a strong force required for relative movement, but also the plate is deformed by the pressing pressure, which is not preferable. More preferably, the pressure is 0.
5 is a ~75kgf / mm ^2.

The shape of the metal tin used for sliding adhesion of the metal tin may be a round bar, as long as the Sn adhesion width is equal to or greater than the width of the welded portion.
It is not particularly limited, such as a band, a disk, or a plate. In order to attach the metallic tin, the metallic tin and the thin chromium-plated steel sheet may be relatively moved while pressing each other to cause friction, but at this time, the metallic tin is rotated, and the friction caused by the rotation is added. Tin can be efficiently attached.

In this case, the shape of the metal tin used for the sliding adhesion of the metal tin may be a round bar shape, a band shape, a disk shape or a plate shape, while rotating at a rotation speed of 1 to 3000 revolutions / minute. It may be rubbed. If the number of rotations is less than 1 rotation / minute, the effect of increasing the friction due to rotation cannot be obtained.
When the rotation speed exceeds 00 rotations / minute, the vehicle slips, and similarly, the effect of increasing the friction by rotation cannot be obtained.

More preferably, the number of revolutions is 5 to 2500 revolutions /
Min, more preferably 10 to 2000 revolutions / min.
In the present invention, as a method of sliding adhesion of the metal tin, in addition to rotation, friction can be applied by vibration to apply the metal tin. In this case, the shape of the metal tin used for sliding adhesion of the metal tin may be a round bar, a band, a disk, or a plate.

The above-mentioned method of applying friction by vibrating to deposit metallic tin has an advantage that it is hardly affected by the shape of metallic tin. When using vibration, the frequency is preferably 1 to 100000 Hz. If the frequency is less than 1 Hz, the effect of increasing friction by vibration cannot be obtained. Conversely, if the frequency exceeds 100,000 Hz, slip occurs, and the effect of increasing friction by vibration cannot be obtained.

More preferably, the frequency is between 10 and 50,000 Hz. The temperature of metallic tin when attaching metallic tin is 5 ° C
As described above, it is desirable that the temperature be lower than 232 ° C. When the temperature of the metal tin is lower than 5 ° C., transformation from α to β occurs, which is not preferable because the metal tin becomes brittle and the metal tin is damaged during tin adhesion.

Conversely, the temperature of metallic tin is the melting point of metallic tin.
If the temperature is higher than 232 ° C, the temperature of the metallic tin needs to be lower than 232 ° C because melting will occur and tin adhesion becomes impossible.
On the other hand, the higher the temperature of the metal tin, the softer it becomes, so that it is easier to rub (rub), so that the temperature of the metal tin is preferably higher, and the temperature of the metal tin is more preferably 10 to 231 ° C.
More preferably, the temperature is 20 to 150 ° C.

The purity of metallic tin used for tin deposition is 9
9.9 wt% or more is preferable.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. By subjecting a cold-rolled steel sheet to a cathodic treatment in an aqueous solution containing Cr ⁶⁺ and sulfuric acid, the steel sheet has a chromium metal layer and a chromium oxide layer as an upper layer on both surfaces of the steel sheet.
The three (A, B, C) thin chromium-plated steel sheets shown in FIG.

Using the obtained thin chromium-plated steel sheet, metal tin was adhered to the position of the welded portion of the lap seam welding shown in FIG. 1 by the tin adhesion method shown in FIG. Next, a thin chromium-plated steel sheet to which metal tin is adhered is subjected to lap seam welding under the welding conditions shown in Table 2, and a primary current range (appropriate welding current range) having sufficient welding strength and no welding dust is determined. ,
The weldability was evaluated.

Table 3 shows the results of the weldability evaluation together with the test conditions.
Shown in As shown in Table 3, it can be seen that the welding method and the thin chromium-plated steel sheet of the present invention have excellent weldability.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

According to the present invention, a commercially available thin chromium-plated steel sheet can be welded without grinding, and therefore has a great industrial significance in the can manufacturing industry. In addition, since no industrial chemicals are used to deposit tin, there is no problem such as generation of waste liquid, and it is environmentally friendly.In addition, tin can be securely adhered only to necessary parts and welding can be performed. Resources are attainable and industrially excellent.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a position where metal tin adheres to a welded portion.

FIG. 2 is an explanatory view showing a method for attaching metal tin.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuyuki Kato 10 Shimogida, Aramaki character, Itami-shi, Hyogo Prefecture Inside Kawatetsu Container Co., Ltd. In company

Claims (7)

[Claims] 1. A method for seam welding a thin chromium-plated steel sheet having a chromium metal layer on the surface of a steel sheet and a chromium oxide layer on the chromium metal layer, the method comprising the steps of: Alternatively, a seam welding method for a thin chromium-plated steel sheet, wherein metal tin is applied to both surfaces in contact with an electrode in an amount of 0.01 to 0.7 g / m ² per unit area of metal tin adhesion. 2. The seam welding method for a thin chromium-plated steel sheet according to claim 1, wherein the method of attaching the metal tin is a method of sliding the metal tin on a thin chromium-plated steel sheet. 3. The method for adhering metallic tin includes the steps of: applying metallic tin at a relative speed of 0.1 to 100 m to a thin chromium-plated steel sheet;
/ Min under the conditions of pressure 0.1 ~100kgf / mm ^2, the seam welding method of a thin chromium-plated steel sheet according to claim 1, characterized in that it is a method in which slides a thin chromium-plated steel sheet. 4. The method of attaching metal tin according to claim 1, wherein the metal tin is slid on a thin chromium-plated steel sheet while rotating at a rotation speed of 1 to 3000 revolutions / minute. Item 4. A seam welding method for a thin chromium-plated steel sheet according to item 2 or 3. 5. The method of attaching metal tin according to claim 2, wherein the metal tin is slid on a thin chromium-plated steel sheet while vibrating at a frequency of 1 to 100000 Hz. 4. The method for seam welding thin chromium-plated steel sheet according to any one of 4. 6. The method of depositing metallic tin is a method of sliding metallic tin on a thin chromium-plated steel sheet under the condition that the temperature of the metallic tin is 5 ° C. or more and less than 232 ° C. The seam welding method for a thin chromium-plated steel sheet according to claim 2. 7. A metal formed by a metal chromium layer on the surface of a steel sheet and a chromium oxide layer on the metal chromium layer, and further formed by sliding between metal tin and the chromium oxide layer as an upper layer. Tin adhesion amount per unit area is 0.01-0.7g
A thin chromium-plated steel sheet having a linear or band-shaped metal tin layer of / m ² .