JPS59133381A - Production of rust preventive plate-worked parts for automobile - Google Patents

Abstract

PURPOSE:To produce rust preventive plate-worked parts for an automobile which are subjected to a powerful rust preventive treatment in the parts susceptible to corrosion by press forming a steel plate which is a blank material for plate- working in such a way that the thick rust preventive coating part formed on said plate occupies the required joined part of the plate-worked parts. CONSTITUTION:A rust preventive coating layer (c) of a thin single layer of zinc or plural layers of galvanizing is formed on the required one surface of a hood outer 1-o and hood inner 1-i, and a rust preventive coating (a) of thick galvanizing or precoating is formed on a part of such one surface or both surfaces thereof. The outer and inner are then press formed in such a way that the above-mentioned thick rust preventive coating part (a) occupies a joined part (y), thereby producing an engine hood formed with the thick rust preventive treating layer on the joined part susceptible to pitting corrosion and the thin rust preventive treating layer on the other part. It is possible to obtain the rust-preventive plate-worked parts by the press forming similar to the above- mentioned one by using the steel plate formed by butt welding with laser beam the steel plate subjected to thin galvanizing and the steel plate subjected separately to thick galvanizing as the blank material for plate-working.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a manufacturing method suitable for molding sheet metal parts used in a portion of an automobile body, particularly parts that require strong rust prevention, and relates to a manufacturing method suitable for forming sheet metal parts used in a part of an automobile body. ．． -2'o
69AAR Relates to improvements in "Method for manufacturing sheet metal parts for automobile bodies."

In recent years, due to salt damage caused by the spread of snowmelt salt in the so-called Nrutobelt region of North America and Europe, measures to prevent holes caused by rust corrosion in automobiles, especially exported vehicles, have become an important issue.

As a countermeasure against this, the first step is to create a structure that prevents moisture from entering as much as possible and to apply a sealant.However, if there is a partial pressure where water or moisture cannot enter, it is necessary to create a structure that allows water to drain easily and where the electrodeposited coating film easily clings. In addition to this, various types of surface-treated steel sheets injected with anti-rust wax have come to be used.

Surface-treated steel sheets are also called rust-proof steel sheets.

Generally, they are divided into barrier type and sacrificial corrosion type, and the former includes organic coatings, or composite coatings of organic materials such as epoxy resin and inorganic materials such as chromic acid and zinc powder sold under the trademark Synchrometal. This corresponds to so-called pre-coated steel sheets with coatings, the latter being zinc or zinc alloy coated steel sheets (Zn-Fe, Zn-N) by electroplating or hot-dipping.
i, Zn-Al+Zn-Cr, etc.), and the thickness of these anticorrosion coating layers is at most 20 microns or less.

However, in automobiles, there are two places where pitted corrosion parts (χ) occur, for example, as shown in Fig. 1.

These are the inner hemmings and plate joining areas where moisture tends to accumulate.1 Usually near the front end of the engine hood (1) or some rear end corners, near the rear end of the trunk lid (2), and the door (6). ), then concentrate on the bottom part.

In the remaining parts of these parts, even if surface rust called so-called cosmetic corrosion occurs, it rarely progresses to serious pitting corrosion.

In other words, according to the conventional manufacturing method, a steel plate that has been subjected to a thick surface treatment over a wide range of areas including unnecessary parts for rust prevention is used as is. We propose a manufacturing method that uses sheet metal materials with a thick anti-corrosion treatment layer applied to the areas where the plates are easily mated together, and a thin anti-corrosion treatment layer applied to other areas that are subject to cosmetic corrosion. be.

That is, the first invention uses, as a sheet metal material, a surface-treated steel sheet with a thick anti-corrosion coating applied to a portion of one or both sides, and the thick anti-corrosion coating portion is made of sheet metal. This is a method for manufacturing rust-proof sheet metal parts for automobiles, the gist of which is press-forming so as to occupy a required plate-joining area of the parts.

The second invention is a sheet metal material in which one or both sides are plated with a thin zinc-based single layer or multiple layers, and a portion of the one or both sides is further coated with a thick zinc-based plating or pre-coating. This is the manufacturing method described in (1) above, the gist of which is to use a surface-treated steel sheet.

In addition, the third invention provides a sheet metal material in which a steel sheet having a thin zinc-based single-layer or multi-layer plating on one or both sides and a steel sheet having a thick zinc-based plating or pre-coating on one or both sides are processed using a laser beam. The manufacturing method described in (1) above is characterized in that a butt-welded steel plate is used.

The following two inventions will be specifically explained with reference to the drawings.

Embodiment 1: Example of application to an engine hood An engine hood is comprised of an adhesive structure of a 7-tooth 7-outer and a hood inner, and is a case of the present invention.

The hood outer (1-o) is shown in Fig. 2 (A) K, and the hood inner (1-i) is shown in Fig. 2 (B), in the area where there is a possibility of corrosion holes, that is, in Fig. 6. A sheet metal part having a rust-preventive coating part (a) of pre-coated rust or zinc-based plating that sufficiently covers the joining part (y), also called the hemming part, is press-formed, as shown in Fig. 2 (
As shown in the cross section of C), the hood is assembled into one piece.

Here, in the hood outer (1-o), most of the range that requires stretch formability is the bare part (b) or thinned part (c), while in the hood inner (1-i), the area that requires stretch formability is the bare part (b) or the thinned part (c). Since the tough parts and most of the punched parts (γ) are similarly exposed parts (b) or thinned parts (c), the moldability is good, and when using scrap as a return material, it is easy to prevent it from becoming a public prayer. This is advantageous because there are fewer rust-covered parts.

Figure 6 shows a detailed cross-sectional view of the vicinity of the tip of the hood in Figure 2 (C), showing the joining part of the plates (y
) is designed to cover the interior of the area around (a) within a sufficiently safe range.

This hood outer (1-o) and hood inner (1-4)
The sheet metal press forming procedure shown in ) is used to prepare the hood outer blank (1-o') shown in FIG. 4 and the hood inner flank (1-i') shown in FIG. 5, respectively.

In the example shown in Fig. 4, there is a rust-preventing covering part (a) on both sides of the blank.
) is applied to one side, the remaining center is the bare part (b), and the outer surface on the other side is coated with a thinned part (c) of electrolytic zinc to prevent cosmetic corrosion. In particular, the anti-corrosion wrinkle extension part (a) on both sides of the blank is applied to both sides as shown in the figure.

This shows a case in which the inner surface of the remaining surface is bare (b), and the outer surface is thinned with electrolytic zinc (c) to prevent rust on the press punched end surface.

Of these, CB+ in Figure 5 is the hood inner blank (1-i'
), the part corresponding to the rust-proof coating (a) VC is pre-coated or zinc-plated, and in Figure 5 (C), the thick rust-proof coat part (a) is pre-formed. A steel plate is shown in which a steel plate and a steel plate with a thinned portion (C) are integrated by laser beam welding at a butt weld (arrow W).

For example, in order to obtain a hood outer (1-o) of the desired size after press forming, the blank for the hood outer (1-o') is prepared using a thick anti-corrosion coated part (a) and a thinner part (c), and a press mold. Determine the dimensions of the board, taking into consideration the wrinkle presser allowance, etc.

The case of the hood inner blank is similar to the case of the hood outer blank.

If you use the blanks shown in Figures 4 and 5, you will not have to change the press mold or equipment (conventional press procedure).

A desired hood can be obtained as shown in FIG.

Embodiment 2: Trunk lid Trunk lid case 2 Normally, as shown in Figure 6, it consists of an adhesive structure of a sole outer (2-o) and a lid inner (2-i). Since K is likely to occur at the joining part of the end plate (y), use the glue rad outer blank (2-o') shown in Fig. 7 or the glue shown in Fig. A material is prepared like the blank for the outer door (2-i), and the procedure is the same as that for the engine hood.

In the example shown in Figure 8, it is only necessary to apply a rust-preventing coating (a) on one side of the blank, and then apply a thin zinc-based coating (c) on the outer surface of the remaining portion, and a bare portion on the inner surface. (b) - Figure 8 is for inner use.

In order to achieve more preferable rust prevention, thick rust prevention coatings (a) are especially applied to both sides of the blank as shown in the figure.

Of these, Figures 8k) and FB) respectively show the cross-sectional configuration of the lid inner blank (2-i').
In Figure (A), as in the case of an engine hood, the rust-preventive coating part (a) is coated with a thick pre-coat or zinc-based plating, and the remaining part that will become the inner surface is the bare part (b), and the part that will be the outer surface In Fig. 8 (B), a surface-treated steel sheet with a thick anti-rust coating (a) and a single-sided galvanized steel sheet are butt-welded ( Arrow W) indicates an integral steel plate that has been laser beam welded.

Using the blanks shown in FIGS. 7 and 8, the trunk lid shown in FIG. 6 is obtained in the same manner as for the engine hood.

Embodiment 6: In the case of door 7, the door outer (3
-o) and the door inner (3-i), and since pitting corrosion tends to occur near the bottom edge of the plate mating area (y) enclosed in the figure, this area is covered with a thick anti-rust coating (a).
Blanks (not shown) for the outer door 7 and the inner door 7 are prepared so as to sufficiently cover the door 7, and the procedure and molding thereof are the same as those for the trunk lid.

Example 4: In the case of pillars, when a high degree of rust prevention is required for the lower part, surface-treated steel plates were conventionally used for the entire surface, but in the case of two pillars, as shown in Figure 10. The butt welding part (arrow W) is laser beam welded with a rust-proof steel plate applied to the required pressure in advance for the thick and rust-proof coated part (a), and a zinc-based thinned steel plate for the remaining parts. Press-formed from steel plate.

In each of the above embodiments, zinc-based thinning may be applied to either one side or both sides with full or partial coating as appropriate. Furthermore, in the case where a zinc-based thinned part (c) and a thick anti-rust coating part (a) are applied to the same side of the plate, it is preferable to use a steel plate which has been surface-treated by overlapping the two.

In addition, for white body components such as floors and fenders, we use sheet metal material so that thick anti-corrosion coatings are applied near the mating parts of the sheets.

The method of the present invention can be applied using an integral steel plate consisting of a striped pattern of a zinc-based thinned part and a thick anti-rust coating part.

In addition, regarding the sheet metal material used in the present invention.

The basis weight of the zinc-based thinned part is 15 g / rr (
If it is less than 15 g/m at ~7 D g/m, the rust prevention function is insufficient, and if it exceeds -11:70 g/m, the plated part becomes powdery during molding, which is not preferable.
, around 50 g/m''.The area weight of the thick anti-rust coating is 1.5 to 25 times that of other thinned areas.

The maximum basis weight is 150 g/m, and if it exceeds this, it is unfavorable for plating processing, and preferably it is about twice the weight of the thinned part.

In addition, for zinc-based thinning applied in the present invention, double-layer plating of iron and zinc improves adhesion to paint.

This includes not only multilayer plating with two or more layers of zinc, nickel, aluminum, chromium, cobalt, and other various alloys, but also those with chemical conversion treatments such as chromate treatment. Similarly, the pre-coat used for the thick anti-corrosion coating of the present invention includes various resin-based coatings, coatings with conductive or non-conductive additives, and so-called electrodeposition coatings formed by electrophoresis.

Further, the sheet metal materials used in Examples 1 to 6 are as follows.

A copper strip wound with a continuous coil and thinned on one side is pre-coated with a synchronous metal using a roll coater on both ends or near one end to match the required sheet metal parts. .

Alternatively, it is possible to mass-produce coated steel sheets with galvanized or melt-dipped zinc plating applied to one or both sides of the sheet in stripes of a desired width, and then cut and use the blanks as appropriate. It is possible.

In this case 1. A roll coater (not shown) that is usually used
If the transfer roll attached to the step is, in particular, a stepped roll, a precoated steel plate with continuous vertical stripes as shown in FIG. 11(A) can be obtained.

In the case of using a p-rucoater, by devising the roll design or the face plate, it is possible to pre-coat as many parts as necessary, that is, locally, and also to apply the coating in a curved pattern, not just in a straight line. It's easy.

In the case of a steel plate plated with zinc or the like, a partially coated (plated) steel plate can be obtained in the same way as in the case of a pre-coated steel plate by applying an anti-plating coating to the surface of the bare steel plate in advance.

Note that the method of the present invention is applicable not only to the case of a single steel plate as in the above embodiments, but also to lightweight sandwich steel plates with a non-metal such as plastic in the center and steel plates on both sides, steel plates constituting damping steel plates, and other composite steel plates. It can also be applied to the steel plates that make up the steel plates.

Furthermore, the steel plates to which the present invention is applied are not limited to flat plates, but include steel plates such as embossed steel plates and corrugated plates, and are qualitatively not limited to mild steel, but also include high-strength steel plates, weather-resistant steel plates, composite steel plates, and the like.

As described above, according to the present invention, a sufficiently thick anti-corrosion coating layer is applied to areas at risk of perforated corrosion, and a thin enough layer is applied to other areas to avoid so-called cosmetic corrosion. The present invention provides an extremely rational method for producing rust-proof sheet metal parts for automobiles, which has good formability and reduces pollution problems during scrap recycling, since the applied surface-treated steel sheet can be applied.

[Brief explanation of the drawing]

Figure 1: An explanatory diagram of typical areas at risk of corrosion holes in an automobile body. Figure 2: Example of the present invention applied to an engine hood. Figure 3:
Figure 2: Detailed partial cross-sectional view of the embodiment Figure 4 (A): Plan view of the sheet metal material for the hood outer Figure 4 (B):
Side view of tt Figure 5 (A) Plan view of the sheet metal material for the second hood inner Figure 5 FB):
Side view of u Fig. 5 (C): /l
FIG. 6 is a cross-sectional view showing the same side view, especially when integrated by laser beam welding, as shown in FIG. Figure 7 (A) Plan view of sheet metal material for rank lid outer Figure 7 FBl:) Side view of sheet metal material for rank lid outer Figure 8 (A):) Side view of sheet metal material for rank lid inner Figure 8 (B) Side view of the sheet metal material for the Nidoran lid inner, especially when integrated by laser welding No. 9N: Cross-sectional view showing an embodiment of the present invention on the outer and inner parts of the door FIG. 10: The present invention on the pillar Example of FIG. 11 (A
), fBI An explanatory diagram of manufacturing a copper strip of a sheet metal material used for carrying out the present invention, one side of which is thinned with zinc, and the other side of which is a vertically striped pre-coated steel plate and a horizontally striped pre-coated steel plate (11 engine hood, (2)) rankrid. (ro) Door, (4) Pillar, (1-o)
Hood 7 outer, (2-o') lid outer,
(Ro-〇) Door outer, (1-i) Hood inner. (2-4) Lid inner, (3-i) Door inner 2. ,, (1-o") Blank for hood outer. (2-o') Lid outer, (1-i') Blank for hood inner, (2-i') Lid inner, (a) Thick anti-rust coating, (b ) Bare part. (c) Thinned part, (γ) Punched part, (χ
) Perforated corrosion-hazardous area, (y) Plate mating area, Figure j, Figure 2. Figure (, 4) 455 Figure 4 (A) Figure 5 (A) (B) Figure 6 (A) (B) Figure 9 Figure 10 Figure 11 Procedural amendment (method) Showa G and 4 1981 Patent Application No. 7695
Name of the No. Invention Relationship with the Case of Person Amending the Manufacturing Method of Rust-proof Sheet Metal Parts for Automobiles Patent Applicant Address 5-33-8 Shiba, Minato-ku, Tokyo Name (628) Mitsubishi Motors Corporation Agent The 2nd line of page 15 of the specification, column 1, ``Explanation of 1 meter length of 1 section of Akiri 1t11F'' is corrected as follows. "Figure 4 (B): Side view of sheet metal cable cage for food actor" 2
Lines 4 and 5 of page 15 of the specification are corrected as follows.

Claims (1)

[Claims] 6゜(1) When manufacturing sheet metal parts that constitute an automobile body, a thin anti-rust coating layer is applied to one or both sides of the sheet metal material, and a thick anti-rust coating is further applied to a portion of the one or both sides. 1. A method for manufacturing rust-proof sheet metal parts for automobiles, characterized in that the surface-treated steel sheet is press-formed so that the thick rust-proof coating portion occupies a required plate joining area of the sheet metal part. (2) A surface-treated steel sheet with a thin zinc-based single-layer or multi-layer plating applied to one or both sides as a sheet metal material, and a thick zinc-based plating or pre-coating applied to a portion of the one or both sides? The manufacturing method according to (1) above. (b) As a sheet metal material, a steel plate with a thin zinc-based single J finish or multi-layer plating on one or both sides, and a steel plate with a thick ℃ / zinc-based plating or pre-coating on one or both sides are laser beamed. The manufacturing method according to (1) above, using a butt-welded steel plate.