JPS6160222A - Press forming article made of steel plate - Google Patents

Abstract

PURPOSE:To obtain a press forming article made of an ordinary steel plate enabling to secure the necessary intensity with thin thickness even without using a high tensile steel plate by forming a molten bead with high hardness on the part where the intensity of an ordinary steel plate made press forming article is necessary. CONSTITUTION:Several pieces of linear molten beads 12 with high hardness are formed in parallel on the outer side face zones 10A, 10C of the front side member of an automobile which is formed with a press by a thin mild steel plate, for instance. In this instance the bead 12 is formed nearly on the while and the total buckling strength of a press forming article 10 is elevated and the buckling is made difficult. There is no formation of the bead on the outer side face zone 10B and the buckling strength is lowered so much compared to the zones 10A, 10C forming the bead 12. In case of the buckling load being functioned, therefore, it is made to be buckled at the zone 10B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a structure of a press-formed product made of a steel plate, particularly a thin steel plate.

[Conventional technology]

Thin steel sheet press-formed products used for automobile bodies and the like need to be made as thin as possible from the viewpoint of weight reduction. However, ordinary steel plates are inferior in terms of strength, so high-strength steel plates have traditionally been used.

[Problem that the invention seeks to solve]

However, high-strength steel sheets have problems such as poor press formability, cracking during press forming, and poor shape fixability due to springback.

An object of the present invention is to provide a press-formed product made of ordinary steel plate that can be made thin and secure the necessary strength without using a high-tensile steel plate.

[Means and effects for solving the problems] The present invention has been made by focusing on the above-mentioned problems of the conventional art. The purpose is to secure the necessary strength and solve the above-mentioned problems.

The press-formed steel plate product according to the present invention is a press-formed product made of ordinary steel plate, in which a linear high-hardness melt and a single wire are applied to predetermined areas where various strengths such as tensile rigidity, tensile strength, and buckling strength are required. It is characterized by being formed.

To form a highly hard molten bead on a press-molded product, it is done by irradiating it with a laser beam, electron beam, plasma beam, etc. When using a plasma beam,
It is desirable to forcibly cool the irradiation section rapidly by means of air cooling, water cooling, or the like.

Note that the molten bead can be further hardened by applying a hardening member such as carbon or manganese to the surface of the press-formed product and then melting it.

Molten beads are easiest to process if they are formed into a linear shape.
A plurality of linear molten beads are formed in parallel at predetermined intervals at predetermined locations, and the tensile rigidity, tensile strength, buckling strength, etc. of the area where these linear molten beads are formed (hereinafter referred to as
(simply referred to as strength), which in turn increases the strength of press-formed products.

In addition, the strength of the area where a molten bead is formed (hereinafter referred to as a bead formation area) and the area where a molten bead is not formed (hereinafter referred to as a non-bead formation area) is different, υ, and the bead formation area. By forming it at an arbitrary position, the strength distribution of the press-formed product can be arbitrarily designed. For example, if the present invention is applied to an automobile body, it will be possible to arbitrarily control the crash form at the time of a collision.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows the present invention applied to a front side member of an automobile.

In this figure, a number of linear high-hardness molten beads 12 are formed in parallel on the outer surface area 10A, IOC, of a front side member 10 formed by press-forming a thin mild steel plate. As described above, in this embodiment, the highly hard molten bead 12 is formed over the entire dowel, increasing the overall buckling strength of the press-formed product 10 and making it less likely to buckle.

Moreover, the molten bead 12 is not formed in the outer surface area 10B, and the area 10A where the molten bead 12 is formed.
, 10C, the buckling strength is correspondingly lower.

Therefore, when a buckling load is applied, buckling occurs in the region 10B.

In this way, the front side member 3 in the event of a collision
The buckling form of the bar 10 can be controlled from aspects other than the shape of the press-formed product.

FIG. 2 shows another embodiment in which the present invention is applied to a front side member.

In this figure, outer surface areas 20B, 20D of a front side member 20 formed by press-forming a thin mild steel plate,
A plurality of high-hardness molten beads 22 are formed in parallel in each region of 20F, and the remaining outer surface regions 2OA,
No molten bead 22 is formed in 20C, 20E, and 20G.

In this embodiment, the buckling strength of the regions 20B, 26D, and 20F is higher than that of the regions 20A, 20C, 120E, and 20G. , 20G
The buckling pattern is controlled to maximize the amount of impact force absorption against impact force (buckling load), with areas that are easy to buckle and areas that are difficult to buckle formed alternately. It is now possible.

3 to 5 show an embodiment in which the present invention is applied to a side impact par for an automobile.

In these figures, the side impact bar 30 is attached to the outer panel of the front door 31, and the thin steel plate has a corrugated cross-sectional shape so as to resist collision force from the side, that is, to increase bending strength. It is press-molded. Furthermore, this side impact par 30
On the mountain side 30A and the valley side 30B of the cross-sectional wave-shaped part,
A plurality of high-hardness molten beads 32 are formed with a predetermined width along the longitudinal direction of the bar, further increasing the bending strength against impact force from the side (side impact force).

In the above embodiment, a linear molten bead 32 was formed over the entire waveform forming part of the side impact parr 30, but the position where the maximum bending stress occurs in response to the impact force from the side is at the center of the bar 30. Therefore, forming a molten bead only near the center of the bar is also effective in increasing the bending strength.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, high-hardness molten beads are formed in the areas where strength is required in press-formed products made of ordinary steel sheets, thereby ensuring the necessary strength. , it is possible to form a press-molded product that much thinner.

In addition, by appropriately selecting the high-hardness molten bead formation region, it is possible to obtain even better strength and to have the effect that the deformation form of the press-formed product can be set arbitrarily.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a first embodiment of the invention, FIG. 2 is a perspective view showing a second embodiment of the invention, and FIGS. 3 to 5 are a third embodiment of the invention. 3 is a front view of the front door, and FIG. 4 is a perspective view of a side impact bar to which the present invention is applied. FIG. 5 is a sectional view taken along the line ↓nier shown in FIG. 4. 10.20...Front side member, 12.22.
32... Molten bead, 30... Side impact bar, 30A... Mountain side of side impact bar, 30B...
- Valley side of side impact bar.

Claims (1)

[Claims] (1) It is a press-formed product made of ordinary steel plate, with tensile rigidity,
A press-formed steel plate product characterized by forming linear high-hardness molten beads at predetermined locations where various strengths such as tensile strength and buckling strength are required.