KR101614603B1 - HOT PRESS FORMING METHOD FOR TAILOR WELDED MATERIALS COATED WITH Al-Si - Google Patents

Abstract

The present invention relates to a hot press forming method of an Al-Si plated steel sheet welded to a welded portion of an Al-Si plated steel sheet and a tailor welded blank welded to prevent corrosion and scale from occurring on a cut surface, The hot press forming method of the Al-Si plated steel sheet welded with the Taylor welded blank according to the present invention is a process of removing the plating site layer of the welded area of the Al-Si plated steel sheet; A process of placing a pair of plated steel sheets from which a plating layer has been removed adjacent to each other, and then welding them using a Taylor welded welding (TWB) apparatus; A first metering step of applying oil to the flat and bottom surfaces of the welded portion so as to prevent rust from occurring in the welded portion of the welded steel plate; A hot forming step of heating a bonded steel sheet coated with oil to a molding temperature and molding the hot-pressed steel sheet to form a molded product; A step of cutting the molding into a desired size and shape using a laser cutting device (LCM); And a second metering step of applying oil to the flat surface and the bottom surface of the molded article so as to prevent corrosion and scales from occurring on the cut surfaces and welds of the molded article.

Description

TECHNICAL FIELD [0001] The present invention relates to a hot press forming method of a welded Al-Si plated steel sheet with a Taylor welded blank,

The present invention relates to a hot press forming method for an Al-Si plated steel sheet welded with a Taylor welded blank, and more particularly, to a hot press forming method for a welded portion and a cut surface of an Al- The present invention relates to a hot press forming method for a welded Al-Si plated steel sheet welded with a welded blank.

Recently, the requirements for vehicles have been steadily strengthened due to the strengthening of environmental and safety regulations. That is, the application of high-strength steels including AHSS (Advance High Strength Steel) is expanding in order to respond to the demand for light weight for improving fuel economy and the improvement of collision safety.

In manufacturing the body, high strength parts are applied to reinforce the side collision, and in the case of electric vehicles, the role of the side impact filler is more important than the existing internal combustion engine body for battery protection. To this end, the use of super high strength steels with HPF (Hot Press Forming) technology is expanding.

On the other hand, parts to be applied to the collision member can be roughly divided into two types.

First, it is a member that absorbs external shocks through deformation by an energy absorption part.

Typically, the energy absorbing member includes a front side member, a rear side member, and a bottom side of the B-pillar.

Secondly, it is an anti-intrusion part, which is hardly deformed. For example, since a cabin zone is occupied by a passenger in the event of a collision, the collision member applied to the collision member is mostly a non-penetrating member.

Typically, the rear side of the front side member, the front side of the rear side member, and the upper side of the non-pillar correspond to each other.

In the case of the non-penetrating member, the case where the impact performance is improved by applying the HPF is increasing rapidly, and the impact absorbing member adopts the relatively elongated AHSS.

In the case of a member such as the front side member, the rear side member, and the non-pillar, the energy absorbing member and the non-penetrating member are combined, and the two members are welded and molded.

At this time, the tailor welded blank (TWB), which is mainly used, cuts and welds a different type of steel sheet having different thickness, strength and material, such as cutting clothes, It consists of a cutting process for cutting a steel plate, a welding process for welding the cut steel plate with a laser, and a blanking process for an integrally welded steel plate.

The Taylor Welded Blank method (TWB) can weld different thicknesses and types of steel and can have required properties for each part. It can be manufactured with precise dimensions as well as a harder structure and longer life than steel sheets And is being applied to the production of structures such as automobile body panels such as automobiles and electric trains.

In particular, in the automotive industry where high productivity, low cost, and low weight are required, it is required to reduce the number of parts, reduce the weight of the vehicle body, reduce the weight of the vehicle, and reduce the manufacturing cost compared to the molding method in which the steel sheet is cut, Saving, improving quality, improving crash stability, and simplifying the structure of the vehicle body.

However, in order to weld the coated steel sheet, it is necessary to remove the coated layer of the coated steel sheet, and there is a problem that the quality of the produced product is deteriorated due to the occurrence of rust in the area where the plating layer is removed for welding.

Thus, the welded steel sheet is usually formed using a hot press forming (HPF) method capable of forming a component having a high strength of 1500 MPa or higher, and then the product is produced by a laser cutting device (LCM).

However, since the plating layer is removed from the cut surface of the produced product, corrosion and scale are generated on the cut surface, and the product quality is deteriorated.

Conventionally, as a method for improving the corrosion resistance of hot-pressed products by adjusting the deposition amount of the plating layer and the occupation rate of the compound layer (Fe ₃ Al + FeAl) relative to the plating layer, there has been known a method called "an aluminum- Product and its manufacturing method (10-2010-0082537) ".

However, there is a problem in that corrosion and scale are generated at the cut surface of the product cut at the welded portion and the laser cutting equipment (LCM) in which the plating layer is removed to use the Taylor Welded Blank method (TWB) Respectively.

Korean Patent Publication No. 10-2010-0082537 (Jul. 19, 2010)

The present invention relates to a method of manufacturing a hot press forming (HPF) product by using a coated steel sheet, a method of manufacturing a hot-welded blank by welding a welded portion and a cut surface to prevent defects such as corrosion and scale from occurring, The present invention also provides a hot press forming method of an Al-Si plated steel sheet.

A hot press forming method of an Al-Si plated steel sheet welded with Taylor welded blank according to an embodiment of the present invention is a process of removing a welded site plating layer of an Al-Si plated steel sheet; A process of preparing a bonded steel plate by arranging one or more plated steel plates from which a plating layer has been removed adjacent to each other and welding them using a Taylor welded welding (TWB) apparatus; A first metering process of applying oil to the flat and bottom surfaces of the welded portion so as to prevent rust from occurring in the welded portion of the welded steel strip; A hot forming step of heating the bonded steel sheet to which the oil has been applied at a forming temperature to form a hot press to produce a formed product; A step of cutting the molding into a desired size and shape using a laser cutting device (LCM); And a second metering step of applying oil to the flat surface and the bottom surface of the molded article so as to prevent corrosion and scales from occurring on the cut surfaces and welds of the molded article.

Wherein the first metering step includes a pair of oiling rolls vertically spaced apart from each other on a moving line of the welded portion of the welded steel plate at the tail end of the Taylor welded welding device and a pair of oiling rolls coupled to outer circumferential surfaces of the oiling rolls, It is preferable to use the first metatail member accommodated.

It is preferable that the first metathesis member is formed of a sponge material so as to apply oil to the welded portion without damaging the surface of the welded steel plate.

The second metering process may include a jig body provided at a rear end of the laser cutting device and bent in a shape corresponding to a shape of a flat surface and a bottom surface of the molded article and a sponge material having an annular tubular shape provided to surround the outer surface of the jig body It is preferable to use a pair of the oiling jigs including the second metathesis member.

Preferably, the oiling jig is provided so as to be able to move up and down in the direction of the molding so as to correspond to a curved plane and an upper surface of the molding.

In the first and second metering processes, the oil to be applied is preferably grease.

According to the embodiment of the present invention, it is possible to prevent the occurrence of corrosion in the welded portion by applying oil to the welded portion from which the plating layer is removed during welding, thereby minimizing the defective rate of the produced product and improving the quality.

Further, it is possible to prevent corrosion and scale from being generated on the cut surface by applying oil to the cut surface from which the plating layer is removed in the process of forming the product after molding, thereby minimizing the defective rate of the produced product and improving the quality.

1 is a flowchart for explaining a hot press forming method of an Al-Si plated steel sheet welded with Taylor welded blank according to an embodiment of the present invention,
2 is a view for explaining a first metering process according to an embodiment of the present invention,
3 is a view showing a first opposed member according to an embodiment of the present invention,
4 is a view for explaining a molded article manufactured according to an embodiment of the present invention,
5 is a cross-sectional view illustrating an oil jig according to an embodiment of the present invention,
6 is a view for explaining a second metering process according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments. For reference, the same numbers in this description refer to substantially the same elements and can be described with reference to the contents described in the other drawings under these rules, and the contents which are judged to be obvious to the person skilled in the art or repeated can be omitted.

FIG. 1 is a flowchart for explaining a hot press forming method of an Al-Si plated steel sheet welded with Taylor welded blank according to an embodiment of the present invention. FIG. 2 is a view showing a first casting process according to an embodiment of the present invention Fig.

As shown in Figs. 1 and 2, a hot press forming method of a Taylor welded blank welded Al-Si plated steel sheet according to an embodiment of the present invention includes a step of removing a plating layer at a welded portion in an Al-Si plated steel sheet A process of welding with a laser after arranging one or more plated steel sheets having the plated layer removed thereon, a first metering process of applying the flat and bottom surface oil of the welded portion of the welded welded steel plate 110, A process of hot press forming the bonded steel plate 110, a process of cutting the formed product 120, and a second casting process of applying oil to the flat and bottom surfaces of the formed product 120.

When Al-Si coated steel sheet is welded using a Taylor World Welding (TWB) device, the aluminum of the plating layer has a higher electrical conductivity than iron or zinc, and therefore, the welding energy due to the joule heat is lowered. Since welding defects can be caused, the plating layer on the welded portion is removed to improve the weldability, and then welding is performed using a Taylor welded blank welding apparatus.

In the first metering process, it is preferable to apply oil to the welded portion of the joined steel plate 110 after the welding is completed. This is because the corrosion of the welded portion can be prevented by coating the welded portion of the welded steel plate 110, which is likely to be rusted by removing the plating layer, with oil.

3 is a view showing a first opposed member according to an embodiment of the present invention.

As shown in FIGS. 2 and 3, in the first metering process, the welded portion of the welded steel plate 110 is placed on the trailing end of the Taylor welded blank welding apparatus, Oil is applied to the welded portion of the bonded steel sheet by using a pair of oiled rolls 210 and a first oiling member 220 installed to surround the outer circumferential surfaces of the oiled rolls 210.

At this time, it is preferable that a pair of oil rolls 210 are installed so as to be able to move up and down in the direction of the bonded steel plate 110. Accordingly, even if the thickness of the jointed steel plate 110 to be produced is changed, a certain amount of oil is coated on the welded portion to prevent corrosion in the welded portion.

The first metering member 220 may be formed in a donut shape so as to surround the outer circumferential surface of the metering roll 210, and the material may be formed of a sponge material. This is because it is possible to prevent the occurrence of defects such as scratches on the surface of the bonded steel plate 110 during the first metering process by coating the welded portion by contacting the welded portion of the welded steel plate 110 by receiving the oil therein Because.

In addition, the first metaphorical member 220 is preferably detachably coupled to the metering roll 210 so that the first metaphorical member 220 can be easily replaced. Accordingly, when the first metrology member 220 is worn or otherwise damaged, the maintenance and repair time is shortened, thereby improving the productivity.

4 is a view for explaining a molded article manufactured according to an embodiment of the present invention.

As shown in FIG. 4, the bonded steel plate 110 coated with oil in the first metering process is heated to a predetermined temperature, moved to the hot press at the subsequent stage, and is formed into a molded product 120 having various curved surfaces during the hot forming process. do.

The manufactured molded product 120 is moved to a laser cutting device (LCM) provided at the rear end of the hot press, and an unnecessary portion is cut using a laser.

FIG. 5 is a cross-sectional view illustrating an oil jig according to an embodiment of the present invention, and FIG. 6 is a view for explaining a second metering process according to an embodiment of the present invention.

5 to 6, the shaped article 120, which has been finished, is moved to a pair of oil jigs 300 provided at the rear end of the laser cutting apparatus to apply oil to the flat surface and the bottom surface of the molded article 120 By performing the second metering process, it is possible to prevent the occurrence of corrosion and scales in the cut surface and the welded portion of the molded product 120, thereby improving the quality of the produced product and minimizing the occurrence of defects.

At this time, it is preferable that the pair of the oiling jigs 300 are installed vertically spaced apart from each other about the molded product 120, and can be elevated in the direction of the molded product 120. This is because it is necessary to apply the oil to the flat surface and the bottom surface of the molding 120 while the molded article 120 is bent so as to have various curved surfaces in the hot press.

The oedometer jig 300 has a bar shaped jig body 310 bent in a shape corresponding to a plane and a bottom surface of a molded product 120 formed in various shapes and a jig body 310 in contact with a plane and a bottom surface of the molded product 120, And an annular tubular second metrology member 320 installed on the outer periphery of the jig body 310 so as to apply oil to the cut surface and the welded portion of the jig body 310.

In this case, the jig body 310 is preferably provided so as to be able to move up and down so as to apply oil evenly on the flat surface and the bottom surface of the molding 120 in correspondence with various curved surfaces of the molding 120. As the jig body 310 is lifted and lowered in correspondence with the curved surface that changes as the workpiece 120 moves, the oil surface is evenly coated on the flat surface and the bottom surface of the workpiece 120, It is possible to prevent defects such as corrosion and scale from being generated.

In addition, the second metrology member 320 is preferably formed of a sponge material so as to apply oil without causing defects on the surface of the molding 120.

The oil applied to the flat and the underside of the bonded steel plate 110 or the molded product 120 in the first heating process and the second heating process uses grease having a degree of driving of 2 to 4 in the National Lubricating Grease Institute (NLGI) .

This is because, when grease or oil of less than NLGI 2 is used, it can easily be removed from the bonded steel plate 110 or the molded product 120 to cause defects such as corrosion and scale on the cut surface and the welded portion from which the plated layer has been removed, There is a problem in that the first and second metamorphic members 220 and 320 which are in contact with the bonded steel plate and the molded product in the first and second metering processes are worn or damaged, This is because the maintenance time for replacement is increased and the productivity is lowered.

Although the present invention has been described with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the following claims. It can be understood that

110: bonded steel plate 120: molded article
210: Stacking roll 220: First metatool member
300: oil jig 310: jig body
320: second opposed member

Claims (6)

A process of removing the plating site of the welded portion of the Al-Si plated steel sheet;
Preparing a bonded steel plate by arranging one or more plated steel plates from which the plated layer has been removed adjacent to each other and then welding them using a Taylor welded welding (TWB) apparatus;
A first metering process of applying oil to the flat and bottom surfaces of the welded portion so as to prevent rust from occurring in the welded portion of the welded steel strip;
A hot forming step of heating the bonded steel sheet to which the oil has been applied at a forming temperature to form a hot press to produce a formed product;
A step of cutting the molding into a desired size and shape using a laser cutting device (LCM); And
And a second metering process of applying oil to the flat surface and the bottom surface of the molded article so as to prevent corrosion and scale from occurring on the cut surface and the welded portion of the molded article,
The second metering process may include a jig body provided at a rear end of the laser cutting device and bent in a shape corresponding to a shape of a flat surface and a bottom surface of the molded article and a sponge material having an annular tubular shape provided to surround the outer surface of the jig body Wherein the oil is applied while raising and lowering a pair of oiling jigs including the second metathesis member of the second metering member in the direction of the mold so as to correspond to the curved plane and the upper surface of the mold, Hot press forming method of steel sheet.
The method according to claim 1,
In the first deriving process,
A pair of oiling rolls disposed up and down on the moving line of the welded portion of the welded steel plate at the tail end of the Taylor welded welding device and a pair of oiling rolls coupled to the outer circumferential surfaces of the oiling rolls respectively and containing oil therein A method of hot-pressing a Al-Si-plated steel sheet welded with a Taylor welded blank.
The method of claim 2,
The first meta-
Wherein the welded portion is formed of a sponge material so as to apply oil to the welded portion without damaging the surface of the welded steel plate.
delete delete The method according to claim 1,
In the first and second metering processes,
A method for hot-pressing a Al-Si coated steel sheet welded with a Taylor-welded blank, characterized in that the applied oil is grease.

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