JPH1015489A - Method for coating weld zone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high corrosion preventive effect with simple means by filling the clearances generated in a weld zone, applying a sealer contg. metallic powder having a higher tendency to ionization than an iron material so as to cover the entire part of this weld zone and forming a coating film thereon. SOLUTION: Iron side plates 2 are arranged to a Tee form by bringing their side edges into contact with the surface of an iron bottom plate 1 and welding is executed in such a manner that weld beads 3 are formed intermittently along the end edges of the side plates 2 from both surfaces sides thereof. In the case of coating this weld zone M, the scale on the surfaces of the weld beads 3 are removed and, thereafter, the sealer 4 contg. the metallic powder having the higher tendency to ionization than iron, such as zinc, is applied on the weld zone M including the non-welded parts existing between, for example, the weld beads 3 and the weld beads 3 and the clearance parts where the side plates 2 are not tightly stuck to the surface of the bottom plate 1 so as to cover the entire part of the weld zone. The entire surface of the bottom plate 1 and the side plates 2 including the parts coated with the sealer 4 is then subjected to color coating by known simple means and is coated with the coating film 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for industrial vehicles which are expected to be used outdoors under severe conditions with high humidity, and structures which are installed on the premise of being exposed to rain. The present invention relates to a method for coating a welded part having high corrosion resistance.

[0002]

2. Description of the Related Art When the entire surface including a welded portion is coated, there is a drawback that the paint does not easily adhere to the weld bead and is easily peeled off. If the weld bead is intermittent, or there is a porosity or crack in the bead, As shown in FIGS. 5A and 5B, a cavity 7 is formed in the interior covered with the coating film 5, and when the coating film 5 is cracked or partially peeled, water enters from the crack. Rust is generated in the welded portion M, causing erosion. Therefore, in the prior art, for example,
As described in Japanese Patent Application Laid-Open No. 0-75225, a technique of applying a rust inhibitor solution after coating a rust preventive treatment on a welded part and coating the rust preventive agent solution thereon, or as described in JP-A-58-119382,
Apply a primer to the weld, apply a sealer on it,
Further, a technique of forming a urethane coating film on the sealer and applying an overcoat thereon, and a technique for the purpose of rust prevention treatment, as described in JP-A-59-230671, are disclosed in A technique for welding a hot-melt resin material to a resin is known.

[0003]

The technique of applying a rust inhibitor solution after rust prevention treatment does not guarantee the durability of the rust prevention effect on the exposed surface due to the peeling of the coating, and also requires the undercoating and sealing. In the technique of sequentially performing urethane coating and top coating, the number of steps is increased, the work is complicated, and the cost is increased. Further, in the rust prevention treatment for welding the hot-melt resin material, welding cannot be performed unless the welded portion is heated to a high temperature after the welding operation is completed.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for coating a welded portion which can be expected to have a high rust prevention effect by simple means,
The configuration consists in applying a sealer containing a metal powder having a higher ionization tendency than iron so as to fill gaps generated in the welded portion and cover the entire welded portion, and to provide a coating film thereon. . And the said welding part can be implemented in the form in which the welding bead was formed intermittently.
Incidentally, in the present invention, the weld portion, the weld bead is intermittent,
Alternatively, in the form formed in a spot shape, it means a wide range including a non-welded portion having no weld bead.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a method of coating a weld according to the present invention is applied to a forklift will be described with reference to the drawings. The drawing shows a part of a welded portion in the body of a forklift, and as a first step, as illustrated in FIGS. 1 (a), (b) and (c),
The side edge of the iron side plate 2 is brought into contact with the surface of the iron bottom plate 1 so as to form a T-shape, and the welding beads 3 are intermittently arranged along the edges of the side plate 2 from both sides of the side plate 2. . Is formed so as to be formed. The portion having the weld bead 3 of the welded portion M formed by the above means is completely closed by the weld bead 3, 3 as shown in FIG. In a portion having no bottom plate, the seam between the bottom plate 1 and the side plate 2 is open to the outside as shown in (c) shown in the BB cross section, the side plate 2 does not adhere to the bottom plate 1, and a slight gap exists between them. In some places, p is formed. Next, as a second step, welding beads 3, 3. . After removing the scale on the surface, the gap formed in the welded portion M, for example, the non-welded portion P between the weld bead and the bottom plate 1,
The sealer 4 is applied so as to cover the entirety of the welded portion M, including the portion of the gap p where the side plate 2 is not in close contact with the surface (see FIG. 2). The sealer 4 contains metal powder, such as zinc, having a higher ionization tendency than iron. The sealer 4 penetrates deep into the gap p as shown in FIG. Further, as a third step,
Bottom plate 1 and side plate 2 including the part to which the sealer 4 is applied
Is colored by known means and covered with a coating film 5 (FIG. 3). Thereby, the welded portion M is formed as shown in (b) and (c) of FIG.
The sealer 5 and the coating film 5 are double coated.

[0006] The airframe painted in this way has a coating film 5.
, The same beautiful appearance as before is exhibited, and since all of the welded portions M are shielded from the outside by the outermost coating film 5, moisture adhering to the surface of the coating film 5 is shut out. Is done. The coating film 5 is strongly bonded to the sealer 4 and the possibility of peeling is extremely low.
Even if the coating film 5 peels off or is scraped or damaged by contact with a metal object or the like, the layer of the sealer 4 prevents the welded portion M from coming into contact with water. Further, even if the sealer 4 is worn and the welded portion M is exposed, the bottom plate 1 corresponding to the non-welded portion is exposed.
A sealer 4 is provided in a gap p at a part where the
Is filled, so there is no room for water to enter the gap, and no water can enter. Since the sealer 4 contains metal powder having a higher ionization tendency than iron, when the welded portion M comes into contact with water, the metal powder contained in the sealer 4 is oxidized to form a base of the iron portion. Corrosion is prevented.

Further, not only between the weld bead 3 and the weld bead 3 but also as shown in FIG. 4A, for example, the weld bead 3 itself has a void or crack 6 having a depth reaching the side plate 2.
4B, since the voids and cracks 6 are filled with the sealer 4 as shown in FIG. 4B, the inside of the weld bead 3 is not affected by water, and the weld M The whole becomes a corrosion resistant structure. Therefore, it has sufficient durability to work with marine products and landing work at the storage yard.It can be realized only by adding the step of applying the sealer, and the welding bead is intermittently provided. High corrosion resistance is exhibited even in a weld where simplification has been achieved.

In the above embodiment, the T-shaped welded portion has been described. However, the shape of the welded portion such as a butt shape and an overlapped shape is not limited to the embodiment, and the metal contained in the sealer is as follows. Magnesium other than zinc, aluminum, chromium, etc., are appropriately selected from metals having a higher ionization tendency than iron, and the welded portion is provided with a weld bead in a spot or, conversely, a continuous form. No problem.

Although the embodiment has been described with reference to the body of a forklift, the invention is also applied to masts, pillars and the like in addition to the body, and is also applied to industrial vehicles other than forklifts and various structures such as bridges and steel towers.

[0010]

According to the present invention, the cost can be reduced because it can be carried out in a small number of steps, the coating film on the weld bead is hardly peeled off by applying the sealer, the gap is filled with the sealer, and the sealer has Since a metal powder having a high ionization tendency is contained, a high rust prevention effect is exhibited. In addition, the gap between the non-welded portions is filled with the sealer for the welded portion in which the weld bead is formed intermittently and the welded portion is halved, so that the corrosion resistance effect is not deteriorated.

[Brief description of the drawings]

FIG. 1 shows a first step in a method for coating a welded portion according to the present invention, wherein (a) is an external view, (b) is an AA cross section,
(C) is each explanatory drawing which shows BB cross section.

FIG. 2 shows a second step in the method for coating a welded portion according to the present invention, wherein (a) is an external appearance, (b) is a CC cross section,
(C) is an explanatory view showing a DD section.

3A and 3B show a third step in the method for coating a welded portion according to the present invention, in which (a) is an external appearance, (b) is an EE cross section,
(C) is an explanatory view respectively showing the FF cross section.

FIGS. 4A and 4B are explanatory diagrams of a corrosion resistance effect in a weld bead forming portion.

FIG. 5 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1, bottom plate, 2 side plate, 3 weld bead, 4 sealer, 5 coating film, 6 crack, 7 hollow, M
・ Welds, P, p ... gaps.

Claims (2)

[Claims] A sealer containing a metal powder having a higher ionization tendency than an iron material is applied so as to fill gaps formed in a welded portion and to cover the entire welded portion, and to provide a coating film thereon. Characteristic method of painting welds. 2. The method according to claim 1, wherein the weld is formed by forming a weld bead intermittently.