Colored stainless steel bonded panel material for automotive door molding, manufactured by bonding stainless steels of different series, and manufacturing method therefor

Abstract

A colored stainless steel bonded panel material for automotive door molding, according to the present invention, comprises: a surface material made of a 300-series stainless steel sheet manufactured to have a predetermined thickness; a base material made of a magnetic 400-series stainless steel sheet and attached in a flat form to the rear surface of the surface material; and an adhesive layer interposed between the surface material and the base material to bond the materials together, wherein the surface material is coated in a predetermined color through surface treatment, and has an elongation greater than that of the base material.

Description

Colored stainless steel bonded steel sheet for automobile door molding manufactured by bonding different types of stainless steel and method for manufacturing the same

[0001] The present invention relates to a color stainless steel bonded steel plate for automobile door molding and a method for manufacturing the same, and more particularly, to a color stainless steel bonded steel plate for automobile door molding manufactured by bonding different series of stainless steels having excellent corrosion resistance and workability by roll bonding, and a method for manufacturing the same.

[0002]

[0003] Typically, stainless steel car door moldings are manufactured by slitting stainless steel materials to specifications, forming, bending, and pressing them into door frames, door belts, and quarter glasses.

[0004] These finishing materials are intended to utilize the unique properties of the material, and as they are directly exposed to people's eyes, they have a great influence not only on durability but also on corrosion resistance, gloss, and the aesthetic appeal of the color.

[0005] Additionally, recently, for automobile door moldings, products with a mirror-finished stainless steel surface, semi-gloss products with an embossed finish, and color products with various coating processes are being applied.

[0006] Stainless steel has various series depending on the manufacturing process, but here, austenitic series with high chromium and nickel content and non-magnetic (hereinafter referred to as 300 series stainless steel) and ferritic series with high chromium content and magnetism (hereinafter referred to as 400 series stainless steel) are mainly used.

[0007] Specifically, 300 series stainless steel has excellent corrosion resistance and workability, but has the problem of having to go through a separate mirror process to achieve a surface gloss, and has the inconvenience of not being able to utilize magnetism when bonding door frames, door belts, PVC, TPC, etc., which are post-processing, or when injecting quarter glass inserts.

[0008] 400 series stainless steel can be used to obtain a desired gloss by adding a skin pass process, and has the advantage of being magnetic, which is advantageous in post-processing. However, it has low tensile strength and elongation, making it vulnerable to processing shock, and has the problem of cracks occurring during forming or bending.

[0009] Furthermore, 400-series stainless steel has poor corrosion resistance, leading to problems such as surface discoloration. Therefore, a method to address these issues is needed.

[0010]

[0011] The present invention is an invention devised to solve the problems of the above-described prior art, and has the purpose of providing a stainless steel bonded steel plate for automobile door molding, which secures corrosion resistance and processability while having magnetism to increase productivity during post-processing by bonding 300 series stainless steel, which has relatively high tensile strength and elongation, as a surface material to the upper surface of a base material made of a preset 400 series stainless steel, thereby taking advantage of both the advantages of 300 series and 400 series stainless steel.

[0012] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0013]

[0014] In order to achieve the above object, the present invention provides a color stainless steel bonding steel plate for automobile door molding, comprising: a surface material made of a 300-series stainless steel plate manufactured to a preset thickness; a base material made of a 400-series stainless steel plate having magnetism and attached to the back surface of the surface material in a flat shape; and an adhesive layer positioned between the surface material and the base material to bond them to each other, wherein the surface material is coated with a preset color through surface treatment, and the surface material has a characteristic of having a relatively greater elongation than the base material.

[0015] In addition, the surface material expands when forming or bending the base material inward, and can maintain the surface condition without damage such as cracking.

[0016] In addition, the surface material may be characterized in that the surface treatment process is performed in a rolled state.

[0017] In addition, the adhesive may be characterized in that it is applied to at least one surface of the base material or the surface material or is attached in the form of a film.

[0018] In addition, the surface material may be made of a material having an elongation of approximately 50% or more and being relatively more resistant to processing impact than the base material.

[0019] In addition, the surface material may be made of any one of the steel grades STS304, STS304L, STS304J1, STS316, or STS316L, and the base material may be made of any one of the steel grades STS409, STS411, STS430, STS436, or STS441.

[0020] Additionally, the thickness of the surface material may be formed to be 0.1 mm to 0.3 mm, and the thickness of the base material may be formed to be 0.3 mm to 0.7 mm.

[0021] Meanwhile, the method for manufacturing a bonded steel plate of the present invention for solving the above-described problem includes a step (a) of manufacturing a base material with a 400 series stainless steel plate, a step (b) of preparing a surface material with a 300 series stainless steel plate, a step (c) of forming an adhesive layer by applying an adhesive to either the back surface of the surface material or the upper surface of the base material, a step (d) of positioning the adhesive layer between the surface material and the base material and bonding them to each other to manufacture a bonded steel plate, and a step (e) of processing the bonded steel plate into a preset size and shape, wherein step (b) performs a coloring process for adjusting the color of the surface material.

[0022] In addition, the bonded steel plates bonded in the above step (d) may be characterized by having a bonding force of 200 N or more.

[0023] In addition, the surface material may be characterized by being applied using any one of a dry coating method using a vacuum deposition process, a wet coating method using wet coating on the surface, or a method of performing dry coating using vacuum deposition followed by wet coating.

[0024]

[0025] The present invention, which aims to solve the above-described problem, provides a color stainless steel bonded steel plate for automobile door molding and a method for manufacturing the same, by bonding a base material made of a magnetic 400 series stainless steel plate and a surface material made of a non-magnetic 300 series stainless steel plate to manufacture the bonded steel plate, thereby preventing cracks from occurring on the processed surface through the characteristics of high tensile strength and elongation of the surface material during forming, bending, and press processing of automobile door molding, and at the same time, having the advantage of allowing the manufacturing process of the molding to be easily performed through the magnetic base material.

[0026] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0027]

[0028] FIG. 1 is a drawing showing the structure of a color stainless steel bonded steel plate for an automobile door molding according to one embodiment of the present invention;

[0029] FIG. 2 is a drawing showing a state in which a surface material and a base material of a color stainless steel bonding steel plate for an automobile door molding according to one embodiment of the present invention are bonded with an adhesive;

[0030] FIG. 3 is a drawing showing a state in which a 300 series stainless steel plate is bent in a color stainless steel bonding steel plate for an automobile door molding according to one embodiment of the present invention;

[0031] FIG. 4 is a drawing showing a state in which a 400 series stainless steel plate is bent in a color stainless steel bonding steel plate for an automobile door molding according to one embodiment of the present invention;

[0032] FIG. 5 is a drawing showing the difference between a product made of a color stainless steel bonded steel plate for an automobile door molding according to one embodiment of the present invention and a product made of a conventional 400 series stainless steel single plate, each of which is bent;

[0033] FIG. 6 is a drawing showing a detailed state of deformation during forming or bending of a color stainless steel bonding steel plate for an automobile door molding according to an embodiment of the present invention;

[0034] Fig. 7 is a drawing showing the results of an adhesive strength test of a bonded steel plate according to an embodiment of the present invention;

[0035] FIG. 8 is a drawing sequentially showing the entire manufacturing process of a color stainless steel bonded steel plate for an automobile door molding according to one embodiment of the present invention;

[0036] Fig. 9 is a drawing showing a detailed process for manufacturing a surface material in the manufacturing process of Fig. 8; and

[0037] Fig. 10 is a schematic drawing of a device for manufacturing a color stainless steel bonding steel plate for an automobile door molding of Fig. 9.

[0038]

[0039] In this specification, when it is said that a component (or region, layer, portion, etc.) is “on,” “connected to,” or “coupled to” another component, it means that it can be directly disposed / connected / coupled to the other component, or a third component may be disposed between them.

[0040] Identical drawing numbers indicate identical components. Furthermore, in the drawings, the thicknesses, proportions, and dimensions of components are exaggerated for the purpose of effectively illustrating the technical content.

[0041] “And / or” includes any combination of one or more of the associated constructs that can be defined.

[0042] While terms such as "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a "second component," and similarly, a second component may also be referred to as a "first component." Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0043] Additionally, terms such as "below," "lower," "above," and "upper" are used to describe the relationships between components depicted in the drawings. These terms are relative concepts and are described based on the directions indicated in the drawings.

[0044] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. Furthermore, terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the relevant technical context, and unless interpreted in an idealized or overly formal sense, they are explicitly defined herein.

[0045] Terms such as "include" or "have" should be understood to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0046] Steel sheets for automobile door molding are made of a single stainless steel sheet of 0.4 to 0.7T that can be processed into a desired shape by surface treatment, and are usually made of 400 series stainless steel composed of ferritic series.

[0047] 400-series stainless steel sheets for automotive door moldings offer the advantage of increased gloss through a separate skin-pass process after cold rolling. However, their low tensile strength and elongation can lead to micro-cracks on the machined surface during the forming and bending processes required for automotive door molding, making them susceptible to harsh bending. Furthermore, their low corrosion resistance can lead to numerous issues, including surface discoloration.

[0048] Therefore, in order to solve these problems, the bonded steel plate for automobile door molding according to the present invention can produce a bonded steel plate that utilizes the advantages of two types of steel by bonding stainless steel plates having different characteristics.

[0049] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0050] FIG. 1 is a drawing showing the structure of a color stainless steel bonding steel plate (100) for automobile door molding according to one embodiment of the present invention, and FIG. 2 is a drawing showing a state in which a surface material (110) and a base material (120) of a color stainless steel bonding steel plate (100) for automobile door molding according to one embodiment of the present invention are bonded using an adhesive.

[0051] As illustrated, a color stainless steel bonding steel plate (100) for an automobile door molding according to one embodiment of the present invention includes a surface material (110), a base material (120), and an adhesive layer (130).

[0052] The surface material (110) is formed to have a preset thickness and area, and is made of a non-magnetic stainless steel plate. Specifically, the surface material (110) is made of 300 series stainless steel, which is an austenitic material, and has an elongation above a certain level and is a material with relatively stronger corrosion resistance than the base material (120) described below.

[0053] At this time, the surface material (110) is formed in the form of a thin plate that is bonded to the base material (120) described later, and here, the surface treatment can be performed in a state of being coated with a preset color.

[0054] Specifically, the surface material (110) may additionally undergo a separate coloring process before bonding with the base material (120), and the coloring process may be performed using any one of a dry coating method using a vacuum deposition process, a wet coating method of a wet type, or a method of performing wet coating after dry coating, and accordingly, the surface material (110) is bonded to the base material (120) described below in a colored state.

[0055] And the base material (120) is attached to the back surface of the surface material (110) and is made of a stainless steel plate that has magnetism and has relatively lower corrosion resistance and elongation than the surface material (110).

[0056] Specifically, the base material (120) is made of 400 series stainless steel, which is a ferrite type and has magnetism, unlike the surface material (110), and is formed relatively thicker than the surface material (110).

[0057] That is, the surface material (110) is bonded to the base material (120) to form a thin surface, thereby forming a stainless steel bonding steel plate (100) for automobile door molding.

[0058] Meanwhile, the adhesive layer (130) is positioned between the surface material (110) and the base material (120), and serves to adhere the base material (120) to the surface material (110).

[0059] In this embodiment, the adhesive layer (130) can be directly applied to one surface of either the base material (120) or the surface material (110) or attached in the form of a film to mutually adhere to each other, and the base material (120) and the surface material (110) can be stably bonded by pressure and heat in a laminated state.

[0060] Typically, when bonding a surface material (110) with a conventional adhesive, peeling occurs after a certain period of time, and thus, there is a problem in that it is difficult to maintain stable bonding.

[0061] However, in the present invention, the adhesive layer (130) can suppress problems such as peeling during forming or bending by using an adhesive having a bonding strength of 200 N or more in a bonding strength test (Peel Test), and it is preferable to produce it so as to maintain an adhesive strength of 300 N or more so as to withstand even harsher processing such as reverse bending.

[0062] The overall process of bonding the surface material (110) and the base material (120) by the adhesive layer (130) will be described later.

[0063] The color stainless steel bonded steel plate (100) for automobile door molding according to the present invention configured as described above is further processed to change its shape in a bonded state as described above, and can be stably processed by bending the surface material into a shape forming an outer surface.

[0064] In particular, in the color stainless steel bonding steel plate (100) for automobile door molding according to the present invention, the surface material (110) has a characteristic of having a relatively greater elongation than the base material (120), and when bent in a direction toward the inside of the base material (120), it expands together and can maintain the surface condition without being damaged.

[0065] The bonded steel plate of the present invention configured in this manner is formed in a state in which the base material (120) and the surface material (110) are bonded, unlike a steel plate made of a single material, 400 series stainless steel, which is a form mainly used in the past, and thus can have both the characteristics of 300 series stainless steel and 400 series stainless steel.

[0066] In particular, the bonding steel plate (100) according to the present invention is configured such that the base material (120) is made of a 400 series stainless steel plate, thereby maintaining the characteristics of a single 400 series stainless steel plate used in the past, while the surface material (110) is made of a 300 series stainless steel plate, thereby having relatively high elongation and tensile strength.

[0067] That is, the present invention is configured to have both the characteristics of 300 series stainless steel and the characteristics of 400 series stainless steel.

[0068] As described above, the bonded steel plate according to the present invention is not simply made of one type of steel plate, but is formed by bonding a 300 series stainless steel plate and a 400 series stainless steel plate to form a single steel plate, so that it has a relatively low processing cost compared to the 400 series stainless steel plate for automobiles that has undergone several skin pass processes in the past, and at the same time, it has the advantage of being able to be stably processed due to high elongation and tensile strength when processed into a desired shape, and having excellent corrosion resistance.

[0069] Next, with reference to FIGS. 3 and 4, the characteristics of each of the 300 series stainless steel sheet and the 400 series stainless steel sheet according to the present invention will be independently examined.

[0070] FIG. 3 is a drawing showing a state in which a 300 series stainless steel plate is bent in a color stainless steel bonding steel plate (100) for an automobile door molding according to one embodiment of the present invention, and FIG. 4 is a drawing showing a state in which a 400 series stainless steel plate is bent in a color stainless steel bonding steel plate (100) for an automobile door molding according to one embodiment of the present invention.

[0071] First, looking at Figure 3, a 300 series stainless steel plate is bent, and corresponds to the surface material (110) in the present invention.

[0072] The above surface material (110) has an elongation of approximately 50% and has a relatively higher elongation and tensile strength than the base material (120) and is resistant to processing shock. In particular, 300 series stainless steel has strong corrosion resistance and is relatively resistant to damage or corrosion from the outside, making it a suitable material for exterior use.

[0073] Accordingly, as shown in the figure, in the case of the 300 stainless steel plate, even if it is processed with zero bending and bent into a completely folded shape, it expands at the location and maintains the surface condition without causing damage.

[0074] The above surface material (110) is preferably made of one of the steel grades STS304, STS30L, STS304J1, or STS316L, and in this embodiment, STS304L, which is relatively inexpensive and contains Ti (titanium), is used.

[0075] In addition, the thickness of the surface material (110) can be formed to be 0.1 mm to 0.3 mm. This is to have a thinner thickness than the base material (120) described later, to minimize the manufacturing cost of the color stainless steel bonding steel plate (100) for automobile door molding according to the present invention, and to position the surface material (110) at a location where deformation occurs a lot during subsequent processing.

[0076] Additionally, a hairline may be processed on the surface of the surface material (110), or various surface finishing treatments such as vibration, beadblast, and embossing may be performed.

[0077] In this way, in the case of the surface material (110) illustrated in FIG. 3, it is relatively easy to process due to the characteristics of the material, and the surface can be processed later.

[0078] Meanwhile, looking at Figure 4, a 400 series stainless steel plate is bent, and corresponds to the base material (120) in the present invention.

[0079] The above base material (120) is attached to the back surface of the surface material (110) and has a relatively low elongation of about 20 to 30% compared to the surface material (110) and is weak against processing shock, but has the advantages of being magnetic and inexpensive. In particular, in the case of 400 series stainless steel, the elongation is low, so it is advantageous to form a framework internally rather than being arranged on the surface.

[0080] However, in the case of 400 series stainless steel plates, since they are magnetic materials, they have the advantage of being advantageous for positioning using magnetism during additional post-processing, and they have the advantage of having a certain level of strength, but they have the disadvantage of being weak to processing shock due to low elongation.

[0081] In the case of the above-mentioned base material (120), when the deformation exceeds a certain level, breakage occurs due to low elongation, and in particular, when it is processed with zero bending as shown and folded in a completely folded form, cracks occur on the surface.

[0082] The above base material (120) is preferably made of one of the steel grades STS409, STS430, STS436, or STS441, and in this embodiment, STS409 is used.

[0083] In addition, the thickness of the base material (120) may be formed to be 0.3 mm to 0.7 mm. This is to have a thicker thickness than the surface material (110), and to maintain a certain level of rigidity while ensuring that the surface material (110) is positioned at a location where harsh processing occurs during the subsequent processing of the bonded steel plate (100).

[0084] In this way, the 300 series stainless steel plate and the 400 series stainless steel plate each have different characteristics, and by bonding them as the surface material (110) and the base material (120), the bonded steel plate (100) of the present invention is formed.

[0085] In this embodiment, as described above, the surface material (110) may be made of STS304L, and the base material (120) may be made of STS409. These may be selected by considering the yield strength, tensile strength, and elongation based on the table derived through the Posco Mill Test Certificate as shown in Table 1 below.

[0086] ClassificationAusteniticFerrite304304L316L409430430J1LYield Strength298287272243326319Tensile Strength668628578394504463Elongation525258372734

[0087] Based on the above-described Table 1, the surface material (110) and the base material (120) according to the present invention may be made of stainless steel having different thicknesses and properties.

[0088] Next, referring to FIGS. 5 and 6, the bonded steel plate (100) for automobile door molding according to the present invention, in which the base material (120) and the surface material (110) are bonded, will be examined as follows.

[0089] FIG. 5 is a drawing showing the difference between a product made of a color stainless steel bonded steel plate for automobile door molding according to an embodiment of the present invention and a product made of a conventional 400 series stainless steel single plate, each of which is bent, and FIG. 6 is a drawing showing a detailed state of deformation during bending of a color stainless steel bonded steel plate (100) for automobile door molding according to an embodiment of the present invention.

[0090] Looking at the drawing shown, the color stainless steel bonding steel plate (100) for automobile door molding is a photograph of a single steel plate made of a 400 series stainless steel plate and a bonding steel plate according to the present invention, each bent. In the case of a single steel plate, cracks occur on the surface when bent to a certain level or higher.

[0091] Specifically, Fig. 5 (a) is a photograph of a bent stainless steel for an automobile door molding made of a 400 series stainless steel plate, in which cracks or breakage occur on the surface when deformation exceeding the elongation occurs.

[0092] At this time, the 400 series stainless steel plate is magnetic and has a hardness above a certain level, so it is suitable as a material for positioning or maintaining a shape during processing, but there is a problem that processing is difficult due to low elongation during additional processing.

[0093] In addition, in the case of automobile door moldings that are usually made only of 400-series stainless steel plates, STS430J1L is mainly used, and although the cost itself is cheaper than 300-series stainless steel plates, in order to actually use it as automobile door moldings, the skin pass process to adjust the gloss of the surface must be performed 3 to 5 times additionally, which causes the actual cost to increase significantly.

[0094] In contrast, as shown in (b) of FIG. 5, the color stainless steel bonding steel plate (100) for automobile door molding according to the present invention has all of the material properties of the surface material (110) and the base material (120) when they are made of bonding steel plates.

[0095] In particular, when the base material (120) is bent inward, the surface material (110) expands and can maintain its surface condition without being damaged.

[0096] Specifically, as shown in FIG. 6, the surface material (110) is bonded to the upper portion of the base material (120), and the base material (120) is formed relatively thick, so that the center line of the bonding steel plate is positioned on the base material (120).

[0097] And, the distance d at which the surface material (110) is positioned from the center line is controlled by the difference in thickness between the surface material (110) and the base material (120), and the surface material (110) is positioned at a position where relatively large expansion occurs.

[0098] That is, since the surface material (110) is positioned on the surface at a distance d apart from the center line of the bonded steel plate, even if a relatively large amount of expansion occurs, it can be deformed by a high elongation and maintain the surface state.

[0099] In this way, the color stainless steel bonded steel plate (100) for automobile door molding according to the present invention is relatively easier to process than a single steel plate made only of the 400 series stainless steel plate, and can have excellent corrosion resistance due to the characteristics of the 300 series stainless steel plate.

[0100] In particular, the color stainless steel bonding steel plate (100) for automobile door molding according to the present invention is processed into a desired shape through a process in a manufactured state.

[0101] The color stainless steel bonding steel plate (100) for automobile door molding according to the present invention is used in various types of products when manufacturing automobile moldings, and a door belt method or a door frame method can be used.

[0102] In this method, a color stainless steel bonding steel plate (100) for automobile door molding is roll-formed, and a separate thermoplastic plastic (polyvinyl chloride, PVC) or thermoplastic elastomer (thermoplastic elastomer, TPE) is bonded through high-frequency induction heating, and then processes such as shearing, bending, and notching are performed.

[0103] In addition, a method of processing using the insert injection method of Quarter Glass is used. This is a method of inserting a color stainless steel bonding plate (100) for automobile door molding processed by pressing into a mold and then injecting thermoplastic plastic (PVC) to bond them, and a magnet is embedded inside the mold to fix the position of the bonding plate (100).

[0104] Accordingly, when manufacturing vehicle moldings using the above method, it is relatively easy to manufacture using a magnetic material, but there is a problem that the 400 series stainless steel, which is magnetic, has relatively poorer processability than the 300 series stainless steel.

[0105] However, by manufacturing the bonded steel plate (100) of the present invention by bonding the surface material (110) of the 300 series and the base material (120) of the 400 series, as in the present invention, the metal finishing material has a certain level of magnetism and can be fixed in position by a magnet during additional processing.

[0106] In addition, when bending or pressing is performed at a certain level or higher, a surface material (110) with a relatively high elongation is positioned on the outside to prevent cracks from occurring on the surface.

[0107] That is, the present invention is a bonded steel plate (100) in which a base material (120) made of a magnetic 400 series stainless steel plate and a surface material (110) made of a non-magnetic 300 series stainless steel plate are bonded, so that when manufacturing an automobile door molding, cracks are prevented from occurring on the surface through the high elongation of the surface material (110), and at the same time, the molding processing process can be easily performed through the magnetic base material (120).

[0108] Next, referring to FIG. 7, it can be seen that the bonded steel plate according to the present invention has an adhesive strength higher than a preset level.

[0109] Fig. 7 is a drawing showing the results of an adhesive strength test of a bonded steel plate according to an embodiment of the present invention.

[0110] The bonding steel plate (100) according to the present invention is configured to be bonded by including a separate adhesive layer (130) between the surface material (110) and the base material (120), but can have durability comparable to a single 400 series stainless steel plate by maintaining a bonding strength of a certain level or higher.

[0111] Specifically, looking at the drawing illustrated in Fig. 7, it can be confirmed that the peak load value of the measured value exceeds 200 [N] as a result of the joint strength test (Peel Test) of the joint steel plate of the present invention.

[0112] This shows that even if the base material (120) and the surface material (110) of the present invention are formed in the form of a bonded steel plate (100) joined by the adhesive layer (130), it has a strength similar to that of a steel plate made of a single material, and accordingly, it can be seen that there is no problem with the durability of the bonded steel plate.

[0113] As described above, the bonded steel plate according to the present invention has been examined, and such a bonded steel plate has superior workability than the single steel plate used in the past, and can stably maintain durability due to high elongation and tensile strength.

[0114] Additionally, for steel sheets used in door moldings for automobiles, an additional gloss control process and a coloring process for controlling color can be performed, and in these processes, the bonded steel sheet according to the present invention can be performed relatively cheaply and quickly compared to the 400 series stainless steel sheet that is commonly used.

[0115] First, looking at the gloss control process, in the case of the 400 series stainless steel single steel plate used in the past, the skin pass process must be additionally performed based on STS430J1L to obtain the desired gloss.

[0116] In particular, for 400 series stainless steel, although there is a skin pass process in the production process, a high-gloss surface can be obtained by performing an additional 3 to 5 processes.

[0117] In contrast, in the case of the bonded steel plate (100) of the present invention, the surface material (110) itself is made of STS304, a 300 series thin plate stainless steel, and can be made glossy through a simple heat treatment process after rolling. Of course, an additional polishing process can be performed if desired, but a certain level of gloss can be achieved through simple heat treatment alone.

[0118] That is, a bonded steel plate (100) using 300 series stainless steel as a surface material (110) and 400 series stainless steel as a base material (120) as in the present invention can have a gloss level of a certain level or higher even without performing a separate polishing process.

[0119] Next, the differences between the bonded steel plate (100) of the present invention and the existing 400 series single steel plate with respect to the coloring process will be examined.

[0120] At this time, the color is implemented by depositing titanium ions or chromium ions according to the color during the coloring process of the surface material (110), and the surface material (110) uses a 300 series stainless steel plate.

[0121] For example, if the color of the surface material (110) is gold, it is deposited using nitrogen gas and titanium in a closed space, black uses carbon gas and chromium, and bronze color uses a mixed gas of carbon and nitrogen and titanium to realize the color.

[0122] In this way, the color stainless steel bonding steel plate (100) for automobile door molding of the present invention can implement color through a separate coloring process on the surface material (110).

[0123] In general, the coloring process is carried out using a vacuum deposition method (PVD: Physical vapor deposition) that involves placing a steel plate in a closed space and depositing the material, or a nanoceramic coating method (NCC: Nano Ceramic Coating).

[0124] First, when the coloring process is performed using a vacuum deposition method, the object is placed inside a vacuum chamber of a preset size, a high vacuum state is created, and then coloring is performed through a deposition process.

[0125] At this time, in the present invention, by winding the steel plate into a coil shape and loading it into the vacuum chamber, a relatively large amount of steel plate can be colored compared to its volume.

[0126] Here, in the case of the present invention, rather than loading the entire bonding steel plate, only the surface material (110) is wound and injected, so that a length of up to 2500 m (based on 0.15 t) or more can be colored at once.

[0127] In contrast, in the case of a single steel plate of 400 series stainless steel, there is a problem in that it is difficult to roll and load it due to the thickness of the steel plate itself, and even if rolled, the overall length itself is short, so coloring can only be performed for a relatively short length compared to the method of coloring only the surface material (110) as in the present invention.

[0128] Specifically, when the coloring process through vacuum deposition of the surface material (110) according to the present invention and a general 400 series stainless steel single plate is performed once, the production volumes are compared, and the results shown in Table 2 below can be derived.

[0129] First, looking at the penetration amount inside the vacuum chamber, in the case of a single steel plate, it is made of a thickness of 0.5 t and can penetrate up to a length of about 750 m inside the limited vacuum chamber. In contrast, in the case of the surface material (110) according to the present invention, it is possible to penetrate up to a length of about 2,500 m under the same conditions with a thickness of 0.15 t.

[0130] Single plate 0.5T Surface material for bonded plate 0.15T ① Immersion amount 750M (2.5 tons) 2500M (2.5 tons) ② Vacuum / exhaust time approx. 300 minutes approx. 300 minutes ③ Film time 1.5M / min (approx. 500 minutes) 2.0M / min (approx. 250 minutes)

[0131]

[0132] And, while the single steel plate and the surface material (110) are each independently inserted inside the vacuum chamber, the air inside is discharged for a preset period of time to create a vacuum state. At this time, the size of the vacuum chamber is the same, and accordingly, it takes about 300 minutes to create a vacuum state.

[0133] Afterwards, a deposition process is carried out on each of the single steel plate and the surface material (110) inside the vacuum chamber, and when a single steel plate is inserted, it takes about 500 minutes to form a coating film of about 750 m. In addition, when only the surface material (110) of the thin plate is inserted as in the present invention, it takes about 1,250 minutes to form a coating film of about 2,500 m.

[0134] At this time, the time required for coating after the vacuum atmosphere of the vacuum chamber is formed may be relatively short when a single steel plate is used, but the length of the surface material (110) actually penetrated into the vacuum chamber is much longer, and a large amount can be coated at one time.

[0135] Accordingly, in the case of the single steel plate, when the color coating is performed on a 750 m length using the vacuum deposition method, it takes 800 (300 + 500) minutes and can color a length of about 0.94 m per minute, whereas in the case of the bonded steel plate (100) of the present invention, when the color coating is performed on the surface material (110) using the vacuum deposition method, it takes 1550 (300 + 1250) minutes and can color a length of about 1.6 m per minute.

[0136] In this way, since the exhaust time for vacuuming the inside of the vacuum chamber during the vacuum deposition process is substantially the same and accordingly, a difference in the length that can be colored during the same time occurs, the method of coloring only the surface material (110) can proceed in a greater amount than the method of coloring a single steel plate.

[0137] That is, when the coloring process of coating the surface using the vacuum deposition method described above is performed, unlike the conventional technology consisting of a single steel plate, the present invention can color a relatively large amount at once by immersing only the relatively thin surface material (110) into the vacuum chamber, thereby increasing the productivity of the bonded steel plate (100) according to the present invention.

[0138] Meanwhile, when the coloring process is carried out using a wet method, the surface material (110) is relatively thinner than when coloring a single 400 series stainless steel plate, so energy consumption is reduced and production speed is increased accordingly.

[0139] Specifically, when the coloring process is carried out in a wet manner, drying is required after coating, and when it is made of a single steel plate, the thickness is thick, so the drying time increases compared to the method of coating only the surface material (110) as in the present invention.

[0140] That is, in the case of a bonded steel plate (100) in which the surface material (110) and the base material (120) are bonded as in the present invention, a coloring process can be performed by surface-treating the thin plate of the surface material (110) before bonding, and thus, by coloring the surface material (110), which is relatively thin compared to a conventional single steel plate, drying can be performed relatively quickly.

[0141] Accordingly, the surface material (110) to be colored and the 400 series stainless steel single plate are fundamentally different in thickness, and accordingly, a difference in productivity occurs in the coloring process.

[0142] In addition, since coating using a slot die is possible when only the surface material (110) is coated, high-quality coating can be performed with a productivity more than four times higher than the currently used spray coating.

[0143] The geometric structure and properties of the color stainless steel bonded steel plate (100) for automobile door molding according to one embodiment of the present invention have been described above, and the process for manufacturing the bonded steel plate (100) as described above will be described below.

[0144] FIG. 8 is a drawing sequentially showing the entire manufacturing process of a color stainless steel bonded steel plate (100) for automobile door molding according to one embodiment of the present invention, FIG. 9 is a drawing showing a detailed process of manufacturing a surface material (110) in the manufacturing process of FIG. 8, and FIG. 10 is a drawing briefly showing an apparatus for manufacturing the color stainless steel bonded steel plate (100) for automobile door molding of FIG. 9.

[0145] Looking at the overall manufacturing process of the color stainless steel bonding steel plate (100) for automobile door molding according to the present invention, first, step (a) of manufacturing a base material (120) using a 400 series stainless steel plate, which is a ferrite type, is performed.

[0146] The above base material (120) is manufactured in the form of a flat plate of a preset thickness using a 400 series stainless steel plate. Here, the base material (120) has a thickness of 0.3 mm to 0.7 mm and is manufactured in an extruded state and wound by a separate roller.

[0147] That is, the base material (120) is manufactured in the form of a flat plate with a preset thickness as described above and wound along the longitudinal direction.

[0148] And, the base material (120) is transported along a preset transport path by a separate heating roller (12) in a wound state as illustrated in Fig. 10. At this time, the heating roller (12) heats the base material (120) to a temperature above a certain level so that it can be stably bonded by the adhesive layer (130) when bonded to the surface material (110) later.

[0149] Next, step (b) of preparing a surface material (110) using a 300 series stainless steel plate, which is an austenitic series, is performed.

[0150] The surface material (110) is made of a steel plate having a certain thickness, similar to the base material (120), but unlike the base material (120), it is made of a 300 series stainless steel plate.

[0151] Specifically, the surface material (110) is formed to have a thickness of 0.1 mm to 0.3 mm, has an elongation of about 50%, and may be made of any one of the steel grades STS304, STS304L, STS304J1, STS316, or STS316L.

[0152] In this embodiment, the surface material (110) is manufactured in the form of a thin sheet, similar to the base material (120), and stored in a rolled state. Thereafter, the rolled portion is recoiled and transported so that it can be bonded to the base material (120).

[0153] Here, the surface material (110) may additionally undergo a coloring process to add color through a separate surface treatment before bonding with the base material (120).

[0154] Afterwards, step (c) of forming an adhesive layer (130) to adhere the surface material (110) and the base material (120) is performed.

[0155] In the above step (c), the adhesive layer (130) is formed between the surface material (110) and the base material (120) and is configured to be mutually adhered, so it is formed by being applied to at least one of the back surface of the surface material (110) or the upper surface of the base material (120).

[0156] In this embodiment, as shown in FIG. 10, the adhesive layer (130) is formed by applying it to the lower surface of the surface material (110) and then drying it.

[0157] Here, the adhesive layer (130) is formed in a form in which it is applied to the lower surface via a separate application facility (11) provided on the transport path of the surface material (110), and is then transported and bonded to the base material (110). At this time, the surface material (110) may pass through a separate drying furnace (13) provided on the transport path, and may be transported while undergoing an additional drying process in which the adhesive layer (130) is applied.

[0158] After step (c) of forming the adhesive layer (130) on the upper surface of the base material (120), step (d) of bonding the base material (120) and the adhesive layer (130) is performed.

[0159] The above step (d) positions the adhesive layer (130) between the surface material (110) and the base material (120) and bonds them together to manufacture a bonded steel plate (100).

[0160] Specifically, in the above step (d), as illustrated in FIG. 10, the base material (120) and the surface material (110) are mutually bonded and transported through a separate bonding roller (14) provided downstream of the heating roller (12) on the transport path.

[0161] At this time, the surface material (110) is transported independently from the base material (120), and is transported so as to be connected and combined on the transport path of the base material (120) at a downstream portion according to the transport direction.

[0162] In this embodiment, the surface material (110) is independently transported after the adhesive layer (130) is formed on the lower surface and is laminated on top of the backing material (120).

[0163] That is, the surface material (110) and the base material (120) are transported by a plurality of rollers while being wound in a roll type as described above, and a portion of the transport path is integrated and laminated. Then, the surface material (110) is laminated on top of the base material (120), and transport and bonding are performed simultaneously via the bonding roller (14).

[0164] Here, the above-mentioned bonding roller (14) can be heated to a certain temperature, and heating and pressurization can be performed simultaneously when bonding the base material (120) and the surface material (110).

[0165] In this way, the base material (120) and the surface material (110) are transferred to the bonded steel plate (100) in a laminated state via the bonding roller (14) and are pressurized via the pressure roller (16) to be bonded to each other.

[0166] Afterwards, the base material (120) and the surface material (110) are bonded together via the pressure roller (16) and are transported in a completely bonded state via a separate cooling zone (18), and are recoiled and received again.

[0167] Next, step (e) of processing the bonded steel plate to which the base material (120) and the surface material (110) are bonded into a preset shape is performed.

[0168] The above step (e) is a process of cutting the above-mentioned joint steel plate according to its intended use, and slitting is performed according to the preset size and specifications.

[0169] The bonding steel plate (100) according to the present invention is used for automobile door molding, and can be used by cutting it into a shape and specification suitable for its size.

[0170] In particular, after the bonding steel plate (100) according to the present invention is slit into an automobile door molding, various methods are used during actual molding processing, and the door belt method, the door frame method, or the insert injection method of quarter glass can be used.

[0171] In this method, a bonding steel plate (100) is bonded to a separate thermoplastic plastic (polyvinyl chloride, PVC) or thermoplastic elastomer (thermoplastic elastomer, TPE) using high-frequency induction heating, and then processes such as shearing, bending, and notching are performed, and after press processing, a process such as insert injection is performed using a mold.

[0172] Accordingly, when manufacturing a vehicle molding using the above method, even if the surface material (110) is deformed, the surface can be maintained in a stable state, and at the same time, the position can be stably fixed during molding processing through the magnetic properties of the base material (120).

[0173] The color stainless steel bonding steel plate (100) for automobile door molding of the present invention manufactured according to the above process can exhibit the characteristics of excellent durability, elongation, and tensile strength, which are characteristics of 300 series stainless steel materials, as well as magnetism, which is a characteristic of 400 series stainless steel materials, and relatively low production cost, as a result of mutual bonding of a surface material (110) having a preset area and a base material (120) attached to the back surface of the surface material (110).

[0174] Additionally, the step (b) according to the present invention may perform at least one of a gloss control process for controlling the gloss of the surface material (110) and a coloring process for controlling the color of the surface material (110).

[0175] Referring to FIG. 9, the gloss control process can adjust the gloss by performing a mirror processing on the surface through an additional process in advance during the processing of the surface material (110) or by a process such as bead blasting, and in this embodiment, the gloss is processed to have a gloss of about 200 to 300 at a 60 degree angle.

[0176] Specifically, the gloss control process for the surface material (110) is as follows.

[0177] First, a process (b-1) for preparing a 300 series stainless steel plate is performed. Then, a heat treatment process is performed on the stainless steel plate. At this time, a selection process for selecting the gloss level of the stainless steel plate is performed (b-2).

[0178] In particular, the gloss level of the surface material (110) is selected to be general gloss, semi-gloss, or to adjust the gloss level itself to some extent, and the subsequent process is performed.

[0179] Here, the surface material (100) can generally have a gloss level higher than a certain level with only simple heat treatment in the case of a 300 series stainless steel plate, and if a high gloss level is required depending on the situation, a mirror process is performed (B-3).

[0180] That is, when the surface material (100) is manufactured to a glossy finish, heat treatment and an additional mirror process are performed.

[0181] In contrast, if the surface material (110) needs to be surface-treated to a semi-gloss finish, an additional bead blasting process or a process using an amboroll is additionally performed (b-4).

[0182] In this way, in the present invention, the surface material (110) undergoes the gloss adjustment process before bonding with the base material (120), and can be adjusted to gloss or semi-gloss during the gloss adjustment process.

[0183] For example, in the present invention, if the surface material (110) has a glossy finish, it is made of STS304 or STS316 with a thickness of 0.1 to 0.2 t and a separate mirror treatment is applied to one side. In addition, the base material (120) is made of STS409, 411, 430, etc. with a thickness of 0.3 to 0.6 t and no separate surface treatment process is performed.

[0184] In addition, in the present invention, when the surface material (110) is to have a semi-gloss, the surface is treated through a pressing process using an additional embossing roll and a bead blasting process to have the desired gloss.

[0185] In this way, in the present invention, the surface material (110) can undergo a gloss control process to have a desired level of gloss.

[0186] Afterwards, the gloss control process is performed and the surface material (110) is manufactured to be glossy or semi-glossy, and then the coloring process is performed (b-5).

[0187] Specifically, the coloring process is a process of coloring the surface material (110) using at least one inorganic material, and in the present invention, it is performed through vacuum deposition and wet coating using the PVD (Physical vapor deposition) method.

[0188] At this time, the color is implemented by depositing titanium ions or chromium ions according to the color during the coloring process of the surface material (110), and at this time, a 300 series stainless steel plate is used as the surface material (110).

[0189] Here, if the color of the surface material (110) is gold, it is deposited using nitrogen gas and titanium in a closed space, black uses carbon gas and chromium, and bronze color uses a mixed gas of carbon and nitrogen and titanium to implement the color.

[0190] Next, the surface material (110) on which the coloring process has been performed can undergo additional nanoceramic wet coating (b-6).

[0191] By performing the above nanoceramic wet coating, the surface of the surface material can be prevented from becoming contaminated, and it can greatly help maintain the durability and gloss of the surface.

[0192] In this way, the stainless steel bonding steel plate (100) for automobile door molding of the present invention can have a color implemented through a separate coloring process on the surface material (110).

[0193] As described above, preferred embodiments of the present invention have been described. It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms, in addition to the embodiments described above, without departing from the spirit or scope thereof. Therefore, the above-described embodiments should be considered illustrative rather than restrictive, and accordingly, the present invention is not limited to the above description, but may be modified within the scope of the appended claims and their equivalents.

[0194]

[0195] (Explanation of symbols)

[0196] 100: Bonded steel plate

[0197] 110: Stainless steel plate

[0198] 120: Base material

[0199] 130: Adhesive layer

[0200] 12: Heating roller

[0201] 14: Joint roller

[0202] 16: Pressure roller

Claims

1. Surface material made of 300 series stainless steel plate manufactured to a preset thickness; A base material made of a 400 series stainless steel plate having magnetism and attached to the back surface of the surface material in the form of a flat plate; and An adhesive layer positioned between the surface material and the base material to bond them together; The above surface material is made by coating with a preset color through surface treatment, A color stainless steel bonding steel sheet for automobile door molding, characterized in that the surface material has a relatively greater elongation than the base material.

2. In paragraph 1, The thickness of the above surface material is 0.1 mm to 0.3 mm, The thickness of the above base material is formed to be 0.3 mm to 0.7 mm. Colored stainless steel bonding sheet for automotive door molding.

3. In paragraph 1, The above surface material is made of any one of the steel grades STS304, STS304L, STS304J1, STS316 or STS316L, The above base material is a color stainless steel bonded steel plate for automobile door molding made of any one of the steel grades STS409, STS411, STS430, STS436 or STS441.

4. In paragraph 1, The above surface material is, A color stainless steel bonding steel sheet for automobile door molding that expands when forming or bending the base material inward and maintains the surface condition without damage such as cracking.

5. In paragraph 1, The above adhesive, A colored stainless steel bonding steel sheet for automobile door molding, characterized in that it is applied to at least one surface of the base material or the surface material or is attached in the form of a film.

6. In paragraph 1, The above surface material is, Stainless steel bonding steel sheet for automobile door molding made of a material having an elongation of approximately 50% or more and being relatively resistant to processing impact compared to the above-mentioned base material.

7. In paragraph 1, The above surface material is, Color stainless steel bonding steel sheet for automobile door molding characterized in that the surface treatment process is carried out in a roll-type state. Step (a) of manufacturing a base material using 8.400 series stainless steel plate; Step (b) of preparing a surface material using 300 series stainless steel plate; (c) step of forming an adhesive layer by applying an adhesive to either the back surface of the surface material or the upper surface of the base material; (d) step of manufacturing a bonded steel plate by positioning the adhesive layer between the surface material and the base material and bonding them together; and (e) step of processing the above-mentioned bonding steel plate into a preset size and shape; including; The above step (b) is a method for manufacturing a stainless steel bonded steel plate for automobile door molding, which performs a coloring process to adjust the color of the surface material.

9. In paragraph 8, A method for manufacturing a stainless steel bonded steel plate for an automobile door molding, characterized in that the bonded steel plate bonded in the above step (d) has a bonding force of 200 N or more.

10. In paragraph 8, The above surface material is, A method for manufacturing a stainless steel bonded steel sheet for automobile door molding, characterized in that the method comprises performing any one of a dry coating method using a vacuum deposition process, a wet coating method using wet coating on a surface, or a dry coating method using vacuum deposition followed by wet coating.

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