TWI615207B - Coated steel plate with oxidation resistance at high temperature and method of manufacturing the same and application thereof - Google Patents

Abstract

The invention relates to a high temperature oxidation resistant coated steel plate and a manufacturing method thereof, which are provided with a composite protective layer composed of a nickel plating layer and a high temperature resistant oxidation coating layer on at least one surface of the steel substrate, and the obtained high temperature oxidation resistance is obtained. After the coated steel sheet is applied to the subsequent hot stamping forming treatment, the obtained hot stamped steel sheet has better resistance to high temperature oxidation, spot weldability and paintability.

Description

High temperature oxidation coated steel plate and its manufacturing method and application use

The present invention relates to a coated steel sheet and a method for producing the same, and more particularly to a high temperature oxidation resistant coated steel sheet having a composite coating layer and a method for producing the same, and an application thereof to hot stamping.

The hot stamping technology of the automotive industry mainly heats the manganese-boron steel sheet to the state of ironation of Vostian, and then quickly transfers it to the high-speed hot stamping in the mold. Under the condition of ensuring a certain pressure, the manganese-boron steel plate is quenched in a mold body at a cooling rate of more than 27 ° C (° C / s) per second, and is subjected to pressure quenching for a period of time to obtain a uniform ram field iron structure. Steel plate.

At present, the hot stamped steel sheet can be classified into a manganese boron steel sheet (or bare steel) having no aluminum ruthenium plating layer and a manganese boron steel sheet having an aluminum ruthenium plating layer. When bare steel is heated before hot stamping, it needs to be carried out in the presence of protective gas. After hot stamping, it is necessary to perform blasting treatment such as sand blasting to eliminate high temperature oxidized scale on the surface to ensure subsequent spot welding and coating. The work was carried out.

After the manganese-boron steel plate is hot-dip galvannealed, a manganese-boron steel plate having an aluminum-bismuth plating layer can be formed, and the manganese-boron steel plate is provided with high-temperature oxidation resistance, and the subsequent blasting treatment such as blasting can be omitted. However, the aluminum-iridium coating does not provide the sacrificial protection of the manganese-boron steel substrate.

The prior art proposes a steel sheet having a zinc-nickel alloy coating which can be applied to hot stamping and provides a sacrificial protection function for the manganese-boron steel substrate. However, the electroplated zinc-nickel layer of the steel plate with zinc-nickel alloy coating does not have high-temperature oxidation resistance. After hot stamping and forming, the surface forms a zinc oxide layer, which causes an increase in interface resistance, and the interface generates a great heat during spot welding. It is easy to cause flying explosion, and also affects the quality of the welding core and the life of the welding head.

In summary, conventional alloy coatings lack the disadvantages of sacrificial protection, poor resistance to high temperature oxidation, or poor weldability. In view of the above, there is an urgent need to develop a high temperature oxidation resistant coated steel sheet and a method for manufacturing the same, thereby overcoming various problems in the conventional hot stamping and spot welding of the alloyed manganese bronze steel sheet.

Accordingly, an aspect of the present invention provides a method for producing a high temperature oxidation resistant coated steel sheet which is provided with a composite protective layer composed of a nickel plating layer and a high temperature resistant oxidation coating on at least one surface of the steel substrate.

Another aspect of the present invention provides a high temperature oxidation resistant coated steel sheet which is obtained by the above method.

Still another aspect of the present invention provides a hot stamping forming method for a high temperature oxidation resistant coated steel sheet which is subjected to a heating step and a hot stamping step of the above-mentioned high temperature resistant oxide coated steel sheet to form a hot stamped steel sheet.

Still another aspect of the present invention provides a hot stamped steel sheet which is produced by the above-described hot stamping forming method.

According to the above aspect of the invention, a method for producing a high temperature oxidation resistant coated steel sheet is proposed. In one embodiment, the steel is first provided, wherein the material of the steel is manganese boron steel. Next, forming a composite protective layer on at least one surface of the steel substrate, wherein the step of forming the composite protective layer further comprises forming a nickel plating layer on at least one surface of the steel substrate, wherein the nickel plating layer has an average thickness of at least 4 μm.

Then, a sol-gel coating is formed on the above nickel plating layer. In one example, the sol-gel coating comprises a high temperature oxidation resistant coating, the high temperature resistant oxidation coating comprises a sol-gel composition, and the sol-gel composition may be composed of a metal alkoxide and a decane compound, wherein the metal alkane The metal of the oxide includes titanium or aluminum, and the sol-gel coating has an average thickness of 0.5 μm to 5 μm.

Thereafter, the above sol-gel coating is subjected to a baking step to form a high temperature resistant oxidation coating. In this embodiment, the composite protective layer is composed of a nickel plating layer and a high temperature resistant oxidation coating layer.

According to an embodiment of the invention, the average molecular weight of the above decane compound may be, for example, greater than 200.

According to an embodiment of the present invention, the sol-gel coating layer may be formed on the nickel plating layer by, for example, a spray coating method, a cast coating method, a roll coating method, or a dip coating method.

According to an embodiment of the invention, the above-described melt-baking step can be carried out, for example, at a temperature of 120 ° C to 300 ° C for 36 to 90 seconds.

According to another aspect of the present invention, a high temperature oxidation resistant coated steel sheet is obtained which is obtained by the above method.

According to still another aspect of the present invention, a hot stamping forming method for a high temperature oxidation resistant coated steel sheet is provided, comprising providing the above-mentioned high temperature oxidation resistant coated steel sheet, and heating the high temperature resistant coated steel sheet to prevent high temperature oxidation The coated steel sheet is converted into Worthfield iron, and the high temperature resistant oxidized coated steel sheet is placed in a mold to perform a hot stamping step, thereby forming a hot stamped steel sheet.

According to still another aspect of the present invention, a hot stamped steel sheet is produced which is obtained by the above method.

The high temperature oxidation resistant coated steel plate of the invention and the manufacturing method and application thereof are provided on the surface of at least one surface of the steel substrate with a composite protective layer composed of a nickel plating layer and a high temperature resistant oxidation coating layer, and the obtained high temperature oxidation resistant After the coated steel sheet is applied to the subsequent hot stamping forming treatment, the obtained hot stamped steel sheet has better resistance to high temperature oxidation, spot weldability and paintability.

As described above, the present invention provides a high temperature oxidation resistant coated steel sheet and a method for producing the same, which are provided with a composite protective layer composed of a nickel plating layer and a high temperature resistant oxidation coating on at least one surface of the steel substrate. The high-temperature oxidation coated steel sheet can have high-temperature oxidation resistance, spot weldability, and paintability after subsequent hot stamping forming treatment.

The term "high temperature oxidation resistant coated steel sheet" as used herein means a composite protective layer on at least one surface of the steel material to provide high temperature oxidation resistance, spot weldability and coating of the steel during subsequent hot stamping. Installability. in In one embodiment, the composite protective layer is adapted to be disposed on at least one surface of the manganese boron steel. In general, the composite protective layer may include a nickel plating layer provided on at least one surface of the steel material, and a high temperature oxidation resistant coating layer provided on the nickel plating layer. In another embodiment, the composite protective layer may be composed of a nickel plating layer provided on at least one surface of the steel substrate, and a high temperature resistant oxidation coating layer provided on the nickel plating layer.

In this embodiment, the nickel plating layer may be any conventional means such as an electroplating method, an electroless plating method, a hot dip plating method, a sputtering method, an evaporation method, or the like. Formed on at least one surface of the steel. It should be noted that if the average thickness of the nickel plating layer is less than 4 μm, the nickel plating layer thus obtained may not impart predetermined high-temperature oxidation resistance characteristics to the steel sheet during the subsequent hot stamping forming treatment.

The term "high temperature oxidation resistance" as used herein refers to a high temperature oxidation resistant coated steel sheet having the above composite protective layer. After the subsequent hot stamping forming treatment, the composite protective layer does not fall off, and there is no high current spot welding. There is no welding head bonding phenomenon in the explosion, and the hot stamped steel sheet has a tensile strength of at least 1500 MPa or more, and can be directly subjected to electro-coating without being subjected to rust removal treatment.

In one embodiment, the high temperature resistant oxidation coating is formed by a coating and baking step of a high temperature resistant oxidation coating, wherein the high temperature resistant coating comprises a sol-gel composition. The above sol-gel composition may, for example, be composed of a metal alkoxide and a decane compound, wherein the metal of the metal alkoxide may include, for example, titanium or aluminum. The alkyl group of the metal alkoxide and the alkyl group of the decane compound may be the same or different saturated or unsaturated linear hydrocarbon group or branched hydrocarbon group, and the hydrocarbon group may optionally have a substituent. In one example, the sol-gel composition may be a pre-condensed or partially pre-condensed gel or in the form of a sol. The state is subjected to a reaction such as hydrolysis or pre-condensation in the presence of a conventional catalyst (for example, dibutyltin dilaurate or the like) to form a gel.

In the above embodiment, the decane compound is preferably less than 2 hectopascals (hPa) at a vapor pressure of 20 ° C, more preferably less than 1 hPa and more preferably less than 0.5 hPa. The above decyl halide may be organically crosslinked with a homologous or non-homogenous decanoate or with an organic monomer, oligomer or polymer, and crosslinked by an organic functional group to synthesize a higher molecular weight decanoate. In one example, the average molecular weight of the decane compound can be, for example, greater than 200.

The decyl halide may be an isocyanodecane previously crosslinked with a diol or a polyol, and is specifically, for example, 3-aminopropyltriethoxydecane, aminoethylaminopropyltrimethoxydecane, aminoethylamino Propyltrimethoxydecane, aminoethylaminopropyl decane, 3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2- Aminoethyl)-3-aminopropylmethyldimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, N-cyclohexyl-3-aminopropane -trimethoxydecane, benzylaminoethylaminopropyltrimethoxydecane, vinylbenzylaminoethylaminopropyltrimethoxydecane, vinyltrimethoxydecane, vinyltriethoxydecane, Vinyl dimethoxymethyl decane, vinyl tris(methoxyethoxy)decane, vinyl methoxymethyl decane, vinyl tris(O-methoxyethoxy) decane, vinyl three Ethoxy decane, methyl trimethoxy decane, n-hexyl trimethoxy decane, n-octyl triethoxy decane, propyl trimethoxy decane, propyl triethoxy fluorene Alkane, tert-butyltrimethoxydecane, isobutyltriethoxydecane, chloropropyltrimethoxydecane, glycidoxypropyltrimethoxydecane, glycidoxypropyltriethoxydecane (GPTES, Glyeo), glycidoxypropylmethyldiethoxydecane, phenyltrimethoxydecane, phenyltriethoxydecane, mercaptopropyl-trimethoxydecane, bis-triethoxy Mercaptopropyl propyl disulfide, bis-triethoxymethyl decyl-propyl disulfide, bis-triethoxymethyl decyl propyl tetrasulfide, tetraethoxy decane, N-cyclohexyl Aminomethylmethyldiethoxydecane, N-cyclohexylaminomethyltriethoxydecane, N-phenylaminomethyltrimethoxydecane, (methacryloxymethyl)methyl dimethyl Oxydecane, methacryloxymethyltrimethoxydecane, (methacryloxymethyl)methyldiethoxydecane, methacryloxymethyltriethoxydecane, A Acryloxyethyltrimethoxydecane, methacryloxypropyltrimethoxydecane (MPTS), 3-methylpropenyloxypropyltriethoxypropane, (isocyanate) Methyl)methyldimethoxydecane, 3-isocyanatopropyltrimethoxydecane, 3-trimethoxyformamidomethyl-0-methylcarbamate, N-dimethoxy- (A Carboxyalkylmethyl-0-methylcarbamate, 3-(triethoxycarbamidino)propyl succinic anhydride, methyltrimethoxydecane, methyltriethoxydecane (MTEOS), Dimethyldimethoxydecane, dimethylphenylvinylsilane (DMPhVS), dimethyldiethoxydecane, trimethylethoxydecane, isooctyltrimethoxydecane, isooctyl Triethoxy decane, hexadecyl trimethoxy decane, (octadecyl) methyl dimethoxy decane, phenyl triethoxy decane, (cyclohexyl) methyl dimethoxy decane, Dicyclopentyldimethoxydecane, tetraethyl phthalate, and the like.

Preferably, the above decyl halides may include, but are not limited to, tetraethoxy decane (TEOS), methyl triethoxy decane (MTEOS), glycosaminoglycan Oxyl propyl triethoxy decane (GPTES, Glyeo), methacryloxypropyltrimethoxy decane (MPTS), dimethylphenyl vinyl decane (DMPhVS) and any combination of the above a group of people.

In general, the above-mentioned high temperature resistant oxidation coating can be applied to a nickel plating layer of a steel substrate by a spray coating method, a casting coating method, a roll coating method or a dip coating method to form a sol-gel coating. The average thickness of the sol-gel coating may be, for example, from 0.5 μm to 5 μm. If the thickness of the sol-gel coating is less than 0.5 μm, the resulting coated steel sheet is insufficient in high temperature oxidation resistance. If the sol-gel coating thickness is more than 5 μm, the resulting coated steel sheet has poor spot weldability and paintability.

In the application, the above-mentioned high-temperature resistant oxidized coated steel sheet can be continuously produced by a conventional steel coil or discontinuously produced by a sheet. When the steel coil is continuously produced, the steel coil can be obtained by unwinding, caustic washing, drying, roll coating or dip coating (double-sided), baking, coiling, etc., to obtain a coated steel coil. When using the discontinuous production of the sheet, the steel sheet can be obtained by punching, caustic washing, drying, spraying (single-sided), baking, spraying (the other side), baking, stacking and packaging, etc. .

After the hot stamping forming process of the coated steel sheet obtained above, the high temperature resistant oxidation coating does not fall off, and there is no flying explosion or no welding head bonding phenomenon during high current spot welding, and the hot stamped steel sheet has a tensile strength of at least 1500 MPa or more. The strength can be directly applied to the electro-coating without the need for rust removal. The above-mentioned hot stamping forming process, high current spot welding, and the like should be well known to those of ordinary skill in the art to which the present invention pertains, and will not be further described herein.

It should also be noted that since the composite protective layer comprises a nickel plating layer and a high temperature oxidation resistant coating formed by a sol-gel coating, when nickel plating is used in combination The thickness of the sol-gel coating can be greatly reduced. If nickel plating is not used, the average thickness of the sol-gel coating on the surface of the steel substrate cannot be effectively reduced to less than 5 μm, and the resulting coated steel sheet is subjected to subsequent hot stamping treatment, and the sol-gel coating is applied. The formed high temperature resistant oxidation coating is prone to the risk of falling off, and the high temperature current spot welding also causes flying explosion and weld head bonding, and the obtained hot stamped steel sheet cannot reach a tensile strength of at least 1500 MPa or more.

The following examples are used to illustrate the application of the present invention, and are not intended to limit the present invention. Those skilled in the art can make various changes without departing from the spirit and scope of the present invention. Retouching.

Example 1

In this embodiment, first, a high temperature oxidation resistant coating is prepared, which comprises a sol-gel composition, wherein the sol-gel composition is composed of a titanium alkoxide, an aluminoxane and a decane compound, and a solid component can be obtained. It is 50 to 60% by weight of a high temperature resistant oxidation coating.

The above high temperature resistant oxidizing coating was sprayed on a manganese boron steel sheet (average thickness of 1.6 mm) having a nickel plating layer (nickel content of 12% by weight and an average plating thickness of 4 μm) to form a high temperature resistant oxidation coating layer having a thickness of 3±1 μm. Bake at a temperature of 270 ° C for 48 seconds. Then, the coated steel sheet having the composite protective layer after baking was placed in an air furnace at 930 ° C for 5 minutes to the fermented state of Vostian, and then quickly transferred to a high-speed hot stamping in a mold. In the case of guaranteeing a certain pressure, the coated steel plate with composite protective layer is in the mold The body is quenched at a cooling rate of more than 27 ° C (° C / s) per second, and after pressure hardening, a coated steel sheet having a composite protective layer is obtained.

Examples 2 to 3 and Comparative Examples 1 to 4

Examples 2 to 3 and Comparative Examples 1 to 3 were obtained by the same method as in Example 1 to obtain a coated steel sheet having a uniform granulated iron structure and a composite protective layer, except that the composition, ratio, and treatment of the composite protective layer were carried out. The conditions are different, and the specific values are shown in Table 1. Further, Comparative Example 4 is bare steel (manganese boron steel sheet).

Evaluation method Coating adhesion

The evaluation was carried out by using a 100-gram test, applying a coated steel sheet having a composite protective layer after baking or after hot stamping with Examples 1 to 3 and Comparative Examples 1 to 3, and evaluating the coating film by peeling off or not. The film adhesion was measured as shown in Table 1, and the evaluation criteria were as follows: ◎: the coating film did not fall off at all; ╳: the coating film partially fell off (about 5%).

2. Surface resistance

This evaluation uses a planar light source resistance measurement module (Surface Resistance Meter, equipment manufacturer/model: Mitsubishi Chemical Analytech/Loresta-GP MCP-T610) to measure Examples 1 to 3 with four-point probe and constant current. The surface resistance of the coated steel sheets having the composite protective layers of Comparative Examples 1 to 3 was as shown in Table 1.

3. Spot welding test

This evaluation is based on the ASTM D8.9M:2012 specification, and the spot welding test is performed on the coated steel sheets having the composite protective layers of Examples 1 to 3 and Comparative Examples 1 to 3 at a high current of 7 kA to 87 kA. Whether there is flying explosion or welding head bonding phenomenon during welding, the welding characteristics are evaluated. The results are shown in Table 1. The evaluation criteria are as follows: ◎: no flying explosion and welding head bonding phenomenon during high current spot welding; ╳: high Slightly flying and sticking of the welding head during current spot welding.

4. Tensile strength

This evaluation was carried out in accordance with the standard test method ASTM E8 of the tensile test of metallic materials to evaluate the tensile strength of the coated steel sheets having the composite protective layers after hot stamping of Examples 1 to 3 and Comparative Examples 1 to 3. At the time of evaluation, the coated steel sheet test piece was subjected to a tensile test in the opposite direction to measure the tensile strength of the coated steel plate test piece.

The above results are shown in Table 1, in which the figure number "-" of Table 1 indicates that the specific treatment or test was not performed.

As can be seen from the test results of Table 1, the coated steel sheets having the composite protective layers of Examples 1 to 3 were subjected to hot stamping treatment, and the coating film adhesion and spot welding test results were good, and the tensile strength was 1500 MPa.

However, the spot welding test results of the coated steel sheets of Comparative Examples 1 to 3 were less than ideal.

The data of the above examples were obtained from three replicate experimental data for each sample.

In summary, the high temperature oxidation coated steel sheets having composite protective layers of Examples 1 to 3 of the present invention are exemplified by the above several embodiments, and the composite protective layer does not fall off after hot stamping, at a high current point. There is no flying explosion and no welding head bonding during welding, and it has better tensile strength.

It should be noted that although the present invention exemplifies a composite protective layer of a specific composition ratio, a specific process, a specific analytical method, or a specific instrument, the high temperature oxidation resistant coated steel sheet of the present invention and a method for producing the same are provided, but the present invention belongs to It is to be understood by those skilled in the art that the present invention is not limited thereto, and the high temperature oxidation resistant coated steel sheet of the present invention and the method for producing the same may also use composite protection of other composition ratios without departing from the spirit and scope of the present invention. Layers, other processes, other analytical methods, or other instruments.

It can be seen from the above embodiments that the hot stamping forming method for the high temperature oxidation resistant coated steel sheet of the present invention has the advantages of the high temperature oxidation resistant coated steel sheet having the composite protective layer, and the composite protective layer is not formed after the hot stamping forming treatment. Shedding, no flying explosion at high current spot welding and no welding head bonding. Secondly, the hot-stamped coated steel sheet has a better tensile strength and can be directly subjected to electro-coating without rust removal.

While the invention has been described above in terms of several embodiments, it is not intended to limit the scope of the invention, and the invention may be practiced in various embodiments without departing from the spirit and scope of the invention. The scope of protection of the present invention is defined by the scope of the appended claims.

Claims (8)

A method for manufacturing a high temperature resistant oxidized coated steel sheet, comprising: providing a steel material, wherein one of the steel materials is a manganese-boron steel; forming a composite protective layer on at least one surface of the steel substrate, wherein the composite protective layer is formed The step of forming: forming a nickel plating layer on the at least one surface of the steel substrate, wherein one of the nickel plating layers has an average thickness of at least 4 μm; forming a sol-gel coating on the nickel plating layer, wherein the sol-condensation The glue coating comprises a high temperature resistant oxidation coating comprising a sol-gel composition consisting of a metal alkoxide and a decane compound, the metal alkoxide metal Including titanium or aluminum and the sol-gel coating has an average thickness of 0.5 μm to 5 μm; and performing a baking step on the sol-gel coating to form a high temperature resistant oxidation coating, wherein the composite protective layer It is composed of the nickel plating layer and the high temperature resistant oxidation coating layer. The method for producing a high temperature oxidation-resistant coated steel sheet according to the first aspect of the invention, wherein the one of the decane compounds has an average molecular weight of more than 200. The method for producing a high temperature oxidation-resistant coated steel sheet according to the first aspect of the invention, wherein the decane compound is selected from the group consisting of tetramethoxy decane, tetraethoxy decane, dimethyl dimethoxy decane, Dimethyldiethoxydecane, phenyltrimethoxydecane, dimethylphenylvinylguanidine A group consisting of dimethylphenylvinylsilane (DMPhVS) and any combination of the above. The method for producing a high temperature oxidation-resistant coated steel sheet according to the first aspect of the invention, wherein the sol-gel coating layer is formed on the nickel by a spray coating method, a cast coating method, a roll coating method or a dip coating method. On the plating. The method for producing a high temperature oxidation-resistant coated steel sheet according to the first aspect of the invention, wherein the baking step is carried out at a temperature of from 120 ° C to 300 ° C for from 36 to 90 seconds. A high temperature oxidation resistant coated steel sheet obtained by the method according to any one of claims 1 to 5. A hot stamping forming method for a high temperature oxidation resistant coated steel sheet, comprising: providing a high temperature oxidation resistant coated steel sheet as described in claim 6; and heating the high temperature resistant coated steel sheet to a heat resistance step The high temperature oxidized coated steel sheet is transformed into Worthfield iron; and the high temperature resistant oxidized coated steel sheet is placed in a mold for a hot stamping step to form a hot stamped steel sheet. A hot stamped steel sheet obtained by the method of claim 7, wherein the hot stamped steel sheet has a tensile strength of at least 1500 MPa.