JPH10286678A - Mending method for thin metal sheet coating surface of metal base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely seal and to surely prevent the invasion of oxygen, water, etc., by inserting an insert composed of a metal which has a shape larger than a penetrated hole, which can be welded to a thin metal sheet and which has corrosion resistance or stain resistance, and sealing the lapped part with an indirect seam resistance welding method. SOLUTION: A caking agent or an adhesive material 6 under a thin metal sheet 2 is removed and the area of a removed part is made larger than the face of an insert 5. The insert 5 is shaped into a rectangle whose short side is made shorter than the long diameter of ellipse of a damaged penetrated part after preprocessing of mending and longer than the short diameter, and whose long side is made longer than the long diameter of ellipse of the damaged penetrated part 4. The short side of the insert 5 is made to coincide with the long diameter direction of the ellipse of the damaged penetrated part 4 and inserted, the insert 5 is turned and arranged so that the total face of damaged penetrated part 4 is covered with the insert 5 from the underside of the thin metal sheet 2 and made to be in the positional relation to close the damaged penetrated part 4, and then the lapped part is sealed with a mending resistance welding wire 10a treated with an indirect seam resistance welding method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to corrosion resistance and antifouling applied to the surface of a metal substrate to prevent corrosion of metal structures such as marine structures, bridges and various plants and to prevent adhesion of marine organisms. For repairing partially damaged penetrations of flexible thin metal sheets.

[0002]

2. Description of the Related Art Conventionally, anticorrosion and antifouling of the above-mentioned metal structure have been generally performed by applying an organic / inorganic paint. In this method, repainting is required in several years, so maintenance is complicated, and repainting is dangerous. For this reason, in recent years, metal structures having corrosion resistance and antifouling properties over a long period of time, such as copper, copper alloy, stainless steel, titanium, monel A metal sheet coating method has been used in which a special metal sheet (hereinafter referred to as a metal sheet) such as that described above, or a sheet obtained by cladding with old-fashioned steel, is adhered to the surface of a metal base material.

[0003] Among chemical plants such as heat exchangers for seawater and tanks for chemicals, equipment requiring particularly high corrosion resistance uses clad steel made of a corrosion-resistant metal such as ordinary steel and titanium as a material. A method of forming the same or a method of processing ordinary steel, coating the surface with a corrosion-resistant metal, and partially explosive joining in a linear or dot shape are used. Some roofing materials employ a method (RT method) in which the rising portions of two coated metals whose ends are bent so as to be perpendicular to the coating surface are resistance seam-welded using opposing roller electrodes. is there. These metal sheet coating methods can be expected to have high anticorrosion properties and antifouling properties over a long period of time.

[0004]

The conventional metal sheet coating method has various methods, but has the following problems. (1) In a method in which a single metal sheet is superimposed on a metal substrate and the outer periphery of the metal sheet is joined to the metal substrate by fillet welding, welding of dissimilar metals is difficult, and it is difficult to ensure welding quality. Further, in order to sufficiently dissolve into a metal substrate having a large thickness, it is necessary to increase welding heat input. On the other hand, in order to prevent overmelting of the metal sheet, the thickness must be 1 mm or more. For this reason, the material cost of the expensive special metal sheet is increased, and it becomes heavy, and handling is inconvenient.

(2) In a method in which clad steel is used as a metal sheet, a portion of the ordinary steel of the clad steel is welded to a metal substrate (ordinary steel), and then the coated metals are welded to each other, the same type of metal is used. Although welding was performed and the welding quality could be secured, the metal sheet could not be thinned for the same reason as described above, and the high production cost of clad steel and the inconvenience of handling the metal sheet could not be eliminated. Furthermore, regardless of whether the metal sheet is used alone or clad steel, the metal sheet is thick and stiff when it covers a structure with a complicated shape where the surface of the metal base material changes in a curved shape. However, there is also a quality problem that molding is difficult due to the high hardness and the adhesion between the metal substrate surface and the metal sheet is deteriorated.

(3) When a clad steel is used as a material and formed into a tank for chemicals by forming it, advanced technology and large-scale equipment are required for bending and joining. There was also a limit on the size of the tank that could be made. In addition, after processing ordinary steel, the surface is coated with a corrosion-resistant metal, and in the method of partially explosive joining in the form of a line or a point, the thickness of the corrosion-resistant metal must be thick enough not to be damaged by the impact of the explosion. In addition, the material cost was high, the metal sheet was heavy, and handling was inconvenient. Also, special safety measures were required to handle explosives.

(4) RT used for processing roofing materials
In the construction method, since the end of the coated metal is bent so as to be perpendicular to the coated surface, linear projections are formed at a constant width, so that the appearance is impaired and the projections become obstacles to other work There were challenges. For this reason, after the resistance seam welding, a step of further bending the projection was required.

(5) Recently, a method has been proposed in which a metal sheet is adhered to the surface of a metal base material with only the adhesive or the adhesive to improve the performance of the adhesive or the adhesive. Because this method does not have the problem of overmelting of the metal sheet by welding,
There is an advantage that the thickness of the metal sheet can be reduced, but since the pressure-sensitive adhesive or adhesive on the outer peripheral portion of the metal sheet comes into contact with light, outside air, water, and the like, deterioration proceeds from this portion, and the metal sheet is easily peeled. There was a problem that.

The present inventors have previously proposed means described in Japanese Patent Application Laid-Open Nos. 7-155961 and 7-204868 as means for solving some of these problems. As shown in FIG. 8, after attaching a metal sheet 13 to the surface of the metal substrate 1 with an adhesive or an adhesive 6, a local vacuum device 14 is attached to the end and the outer periphery of the metal sheet explodes. This is a method of hermetically sealing by joining.

Japanese Patent Application Laid-Open No. Hei 8-71763 discloses that a metal sheet frame 3 having a thickness that can be welded to a metal substrate 1 is fixed to a metal substrate 1 by welding, as shown in FIG. 2 has been proposed, and a method of hermetically sealing the lap portion by indirect resistance seam welding is proposed. The method is intended for combinations of metals that cannot be directly welded, such as when coating titanium on plain steel. In this case, a titanium clad steel which can be welded to ordinary steel is used for the metal sheet frame 3, a titanium sheet corresponding to the thin metal sheet 2 is overlapped on the titanium clad steel, and the lap portion is hermetically sealed by indirect resistance seam welding. Will do.

By using these means, expensive metal sheets can be stored, so that material costs can be reduced, and the outer peripheral portion and the wrap portion of the metal sheet can be securely hermetically sealed. Can be maintained. However, in both cases, a hard foreign material or the like collides with the thin metal sheet 2 and the impact force is reduced.
When the thin metal sheet 2 is damaged so as to exceed the impact strength of the thin metal sheet 2 and break (hereinafter referred to as a damage penetrating portion), oxygen, moisture and the like enter under the thin metal sheet coating. .

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and repairs a damaged penetration portion of a thin metal sheet easily and reliably by using a metal having corrosion resistance or antifouling property equivalent to that of a thin metal sheet. It is intended to provide a method for doing so.

[0013]

The gist of the present invention to achieve the above object is as follows. In a method for repairing a damaged portion of a thin metal sheet having corrosion resistance or antifouling properties overlaid on the surface of a metal substrate, after performing a pretreatment on the damaged portion,
An indirect resistance seam welding method in which the overlapping portion is inserted by inserting an insert made of a metal having corrosion resistance or antifouling property that can be welded to the thin metal sheet having a shape larger than the through hole from the thin metal sheet through hole at the damaged portion. A method for repairing a thin metal sheet coated on the surface of a metal substrate, wherein the thin metal sheet is sealed and welded. Removing the filler in the gap between the damaged metal base material and the thin metal sheet, and performing a pre-treatment of providing a through hole in which the damaged part of the thin metal sheet is opened in a specific shape; Repair method for thin metal sheet on the surface. The method for repairing a thin metal sheet coated on the surface of a metal substrate as described above, wherein the through-hole opened in the damaged portion of the thin metal sheet is formed into an elliptical, square or rectangular shape. Insert the insert material divided into multiple parts from the damaged penetration part of the thin metal sheet, butt-weld the insert material into a shape larger than the through hole, and seal weld the overlapping part with the thin metal sheet by indirect resistance seam welding A method for repairing a thin metal sheet coated on the surface of a metal substrate as described above.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The material of the insert used in the present invention has corrosion resistance or antifouling property, and can be welded to a thin metal sheet to be repaired, for example, a titanium plate when the thin metal sheet is titanium. Alternatively, titanium clad steel is used. When the thin metal sheet is made of stainless steel, the insert is made of stainless steel, a stainless steel alloy, or a clad steel thereof. Similarly, in the case of other thin metal sheets, the same metal or clad steel is used. This insert material has a larger area than the damaged penetration portion of the thin metal sheet or the penetration portion opened for repair, and is inserted into the penetration portion of the thin metal sheet to insert the overlapping portion between the insertion material and the thin metal sheet. It is repaired by sealing welding with direct resistance seam welding. As a result, it is possible to obtain the same performance as that of the existing thin metal sheet in terms of the anticorrosion property or antifouling property of the repaired portion. Further, since the repaired portion and the existing covering portion do not become dissimilar metals, there is no potential difference, and dissimilar metal contact corrosion occurs in which either the repaired portion or the existing thin metal sheet around the repaired portion is selectively corroded. Not even. In addition, the repair work can be easily performed, a reliable sealing can be performed by the welding sealing means, and the invasion of oxygen, moisture, and the like from the damaged penetration portion can be reliably prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an example of repairing a damaged portion of a coated thin metal sheet according to the present invention, FIG. 2 is a detail of the repaired portion, and FIG. 3 is AA of FIG.
The situation of the indirect resistance seam welding of the repaired part in the cross section is shown.

As shown in FIG. 1, an insertion material 5 having an area on one surface larger than that of the damage penetrating part 4 and having a thickness equal to that of the adhesive or the adhesive 6 is applied to the damage penetrating part 4. The overlapping portion between the thin metal sheet 2 and the insert 5 is hermetically sealed by indirect resistance seam welding.

FIG. 2 shows an example of a method for inserting the insertion member 5 into the damage penetrating portion 4. First, as a pre-repair treatment, a damaged penetration portion 4 of a shape and a size that facilitates insertion work and welding work of the damaged penetration portion of the thin metal sheet 2 is obtained. The adhesive or the adhesive 6 is removed by using a tool such as an ice pick or the like so that the area of the adhesive or the adhesive removing portion 7 is larger than the area of one surface of the insert 5. FIG. 2 shows an example in which the pre-repair treatment is performed so that the damage penetrating portion has a substantially elliptical shape and the pressure-sensitive adhesive or adhesive removing portion has a substantially circular shape.

Next, the insert 5 has a shorter side than the major axis of the damaged through-hole 4 after the pre-repair treatment, has a shorter side than the minor axis, and has a longer side as the major axis of the damaged through-hole 4. To a longer rectangle. Next, the short side of the shaped insert 5 is inserted in accordance with the major axis direction of the oval of the damage penetrating portion 4, and after the insert 5 is entirely inserted under the thin metal sheet 2, the insert 5 is rotated. Then, the entire surface of the damaged penetrating portion 4 is covered with the insert 5 from below the thin metal sheet 2, and the damaged penetrating portion 4 is disposed so as to close the damaged penetrating portion 4, thereby completing the insertion. After insertion,
As shown in FIG. 2, the overlapping portion between the thin metal sheet 2 and the insert 5 is hermetically sealed with a resistance welding line 10a constructed by an indirect resistance seam welding method.

In order to perform indirect resistance seam welding of the overlapping portion between the thin metal sheet 2 and the insert 5 as shown in FIG. 3, one of the roller electrodes 9 of the resistance welding machine having two roller electrodes is connected to the thin metal sheet. 2 and the other roller electrode 9 is moved in the welding direction while being energized while being in contact with the insert 5. The welding conditions are the material of the thin metal sheet 2,
It is necessary to select an appropriate value according to the plate thickness.

Although the insert 5 may be non-adhesive to the metal substrate, as shown in FIG. 3, before the insert 5 is inserted in advance, the metal substrate under the insert 5 or under the damage penetrating portion 4 may be used. By applying an adhesive 8 for bonding an insert to the surface of the base material 1, the insert 5 can be fixed to the metal substrate 1, and the indirect seam welding work after the insertion can be facilitated. It is possible to prevent the weight of the insert 5 from being applied to the resistance welding line 10 a of the insert 2 and the insert 5.

The combination of the shapes of the shaped damaged penetrating portion 4 and the insert 5 after the pre-repair treatment can be an ellipse and a rectangle, an ellipse and an ellipse, a rectangle and a rectangle, and the like, in addition to the ellipse and the rectangle illustrated here.
FIG. 4 shows an example of insertion in the case where the shaped damage penetrating portion 4 and the insert 5 are both square in shape after the pre-repair treatment, and an example of hermetic sealing by resistance welding thereafter. In this case, the length B of one side of the insertion member 5 is shaped such that A <B <√2A with respect to one side A of the square of the shaped damaged through portion 4 after the pre-repair treatment.

Next, one side of the shaped insert 5 is inserted along the diagonal direction of the square of the damage penetrating portion 4 and inserted, and after all the inserts 5 are inserted under the thin metal sheet 2, the insert 5 is inserted.
Is rotated so that the entire surface of the shaped damaged penetration portion 4 is
The thin metal sheet 2 is covered from below, and is arranged so as to have a positional relationship of closing the damaged through portion 4, and the insertion is completed. After the insertion, the overlapping portion between the thin metal sheet 2 and the insert 5 is hermetically sealed with a resistance welding wire 10a constructed by an indirect resistance seam welding method.

FIG. 5 shows an example of insertion when the shaped damage penetrating portion 4 and the insert 5 are both rectangular combinations after the pre-repair treatment, and an example of hermetic sealing by resistance welding thereafter. In this case, the length B2 of the long side of the insert 5 is A with respect to the long side A2 of the rectangular shape of the damaged penetrating portion 4 after the pre-repair treatment.
2 <B2, and the length B1 of the short side of the insertion member 5 is the short side A1 of the rectangular shape of the damaged penetrating portion 4 after the pre-repair treatment.
And the long side A2 is shaped so that A1 <B1 <A2.

Next, the short side of the shaped insert 5 is inserted along the long side of the rectangle of the damage penetrating portion 4 and inserted.
Are inserted under the thin metal sheet 2 and then the insert 5 is rotated so that the entire surface of the shaped damaged through portion 4 is covered by the insert 5 from beneath the thin metal sheet 2. And complete the insertion. After insertion, thin metal sheet 2
And the insert 5 are hermetically sealed with a resistance welding wire 10a constructed by an indirect resistance seam welding method.

FIG. 6 shows an example in which the insert 5 divided into a plurality of pieces is used. The size of each piece of the insertion member 5 is formed to a size that allows insertion from the damage penetrating portion 4 as described above. These pieces are inserted one by one from the damage penetrating part 4 in the same manner as described above, and after inserting all the pieces, the respective pieces of the insertion material 5 are abutted, and the entire surface of the damage penetrating part 4 is thin metal by the insertion material 5. The sheet 2 is covered so as to be covered from below, and is arranged so as to have a positional relationship to close the damage penetrating portion 4, and the insertion is completed. In this case, since the insertion material is divided into a plurality of pieces, one piece of the insertion material becomes small, and insertion from the damage penetrating portion 4 becomes easy.

After the insertion, the overlapping portion between the thin metal sheet 2 and the insert 5 is applied by indirect resistance seam welding to obtain a resistance welding wire 10a. Next, at this stage, of the parts where the pieces of the insert 5 that are not hermetically sealed are abutted, the part protruding from the damaged penetration part 4 to the outer surface is welded and sealed by TIG welding or the like. Further, the portions where the respective pieces of the insertion staff 5 where the resistance welding lines 10a are discontinuous butted each other are also welded by TIG welding or the like and sealed, thereby completing the hermetic sealing.

FIG. 7 shows an example in which an insert 5 to which a metal rod 12 for grounding is previously attached by spot welding 11 is used. As described above, the shape of the insertion member 5 is shaped so that it can be inserted from the damaged penetration portion 4. After inserting the same through the damage penetrating part 4 in the same manner as described above, the ground metal part 12 is gripped, rotated and moved, and the entire surface of the damage penetrating part 4 is covered with the insert 5 from below the thin metal sheet 2, It is arranged so as to have a positional relationship to close the damage penetrating portion 4, and the insertion is completed. By attaching the metal bar 12 for earthing, the rotation and movement of the insertion material 5 after insertion become easy.

After the insertion, the overlapping portion between the thin metal sheet 2 and the insert 5 is hermetically sealed with a resistance welding wire 10a constructed by an indirect resistance seam welding method. that time,
Although indirect resistance seam welding may be performed using two parallel roller electrodes as described above, it is possible to obtain the resistance welding wire 10a with one roller electrode 9 by grounding the ground metal rod 12. Become. The use of one roller electrode 9 makes the welding machine smaller and easy to handle.

The damaged penetration portion of the thin metal sheet coated on the surface of the metal substrate by the above method is completely hermetically sealed,
It can be repaired. Furthermore, if the thin metal sheet 2 at the portion corresponding to the end of the damage penetrating portion 4 is turned up or bent, the appearance of the thin metal sheet 2 is poor, or if the thin metal sheet 2 is caught by another person or object, and there is a risk of damaging them. After the end of the thin metal sheet 2 that has been turned up or bent is pressed so as to have no gap with the insert 5, the end of the thin metal sheet 2 and the insert 5 are joined by TIG welding or filler metal. None (licking)
It is possible to improve the shape of the end of the thin metal sheet 2 by welding.

At this time, the end of the thin metal sheet 2 and the insert 5 are fixed to the end of the thin metal sheet 2 and the insert 5 immediately after the insertion of the insert 5 is completed without performing indirect resistance seam welding between the thin metal sheet 2 and the insert 5.
Welding by G welding or welding without filler material is also conceivable, but in this case, excessive heat input to the thin metal sheet 2 having a small thickness before the insertion material 5 is not melted causes the thin metal sheet to be welded. Only 2 melts excessively, so that the damage penetrating portion 4 is likely to expand and become larger than the insert 5. By applying the resistance welding wire 10a by indirect resistance seam welding in advance, the heat conduction between the thin metal sheet 2 and the insert 5 is improved, and the end of the thin metal sheet 2 and the insert 5 Problems caused by overmelting of only the thin metal sheet 2 during TIG welding or welding without a filler material are suppressed.

[0031]

According to the present invention, according to the shape of the thin metal sheet through hole at the damaged portion, an insert having a specific shape larger than the through hole is inserted to easily form the overlapping portion, and the thin metal sheet is formed. Since the same kind of metal as the thin metal sheet comes to the surface in the damage penetration part of the sheet as an insert, it is easy to perform indirect resistance seam welding at the overlapping part of the insert and the thin metal sheet Thus, reliable sealing can be achieved, and intrusion of oxygen, moisture, and the like from the damaged penetration portion can be reliably prevented. In addition, the corrosion resistance or antifouling property of the repaired portion can be equal to that of an existing thin metal sheet. Furthermore, since the repaired part and the existing part do not become dissimilar metals, there is no potential difference, thereby preventing the occurrence of dissimilar metal contact corrosion in which either the repaired part or the existing thin metal sheet around the repaired part is selectively corroded. You can also.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of repairing a damaged portion of a coated thin metal sheet according to the present invention.

FIG. 2 is a detailed view of a repair unit in FIG. 1;

FIG. 3 is a view for explaining the situation of indirect resistance seam welding of the repaired part in the section AA in FIG. 1;

FIG. 4 is an explanatory view of a situation of insertion of an insertion material (square) into a thin metal sheet repair target portion according to the present invention.

FIG. 5 shows a thin metal sheet and an insert according to the present invention (rectangular).
FIG.

FIG. 6 is an explanatory view of a state of insertion of an insertion material (two pieces) into a thin metal sheet repair target portion according to the present invention.

FIG. 7 is a schematic diagram showing a repairing method using an insert having a metal rod for grounding according to the present invention.

FIG. 8 is a diagram showing an example of a method of coating a thin metal sheet by explosive bonding.

FIG. 9 is a view showing an example of a method of coating a thin metal sheet with a metal sheet frame.

[Explanation of symbols]

 0 Damage hole 1 Metal substrate 2 Thin metal sheet 3 Metal sheet frame 4 Damage penetrating part 5 Insert material 6 Adhesive or adhesive 7 Adhesive or adhesive removing part 8 Insert material bonding surface 9 Roller electrode 10 Resistance welding 10a Repair resistance Welding line 11 Fillet welding or spot welding 12 Metal rod for ground 13 Metal sheet 14 Local vacuum device A Buffer material B Explosives C Detonator

Claims (4)

[Claims] In a method for repairing a damaged portion of a thin metal sheet having a corrosion resistance or an antifouling property coated on a surface of a metal substrate, the damaged portion is subjected to a pretreatment, and then the thin metal sheet through-hole is formed in the damaged portion. Inserting an insert made of a metal that is weldable to a thin metal sheet having a shape larger than the through hole and that has corrosion resistance or antifouling property, and hermetically welds the overlapping portion by indirect resistance seam welding. A method for repairing a thin metal sheet coated on the surface of a metal substrate. 2. A pre-treatment for removing a filler in a gap between a metal substrate and a thin metal sheet at a damaged portion, and providing a through-hole opening a damaged portion of the thin metal sheet in a specific shape. Item 1. The method for repairing a thin metal sheet coated on the surface of a metal substrate according to Item 1. 3. The repair of a thin metal sheet coated on the surface of a metal substrate according to claim 2, wherein the damaged portion of the thin metal sheet is a through hole having an elliptical, square or rectangular opening. Method. 4. An insert material divided into a plurality of portions from a damaged penetration portion of a thin metal sheet is inserted, and the insert material is butt-welded to have a shape larger than the through hole, and an overlapping portion with the thin metal sheet is indirect resistance seam welding. 4. The method for repairing a thin metal sheet coated on a surface of a metal substrate according to claim 1, wherein the metal sheet is hermetically welded.