KR102599837B1 - High temperature and oxidation resistant coating material for hot stamping and high temperature and oxidation resistant coated steel manufactured using the same - Google Patents

Abstract

The present invention provides a high-temperature oxidation-resistant coating agent for hot stamping steel that can replace the existing aluminum-silicon hot-dip plating technology and provides enhanced corrosion resistance, and a high-temperature oxidation-resistant coated steel material formed using the same. According to one embodiment of the present invention, the high-temperature oxidation-resistant coating agent for hot stamping steel includes first metal particles having a first size; second metal particles having a second size smaller than the first size; third metal particles having a third size smaller than the second size; and a binder.

Description

High temperature and oxidation resistant coating material for hot stamping and high temperature and oxidation resistant coated steel manufactured using the same}

The technical idea of the present invention relates to steel materials, and more specifically, to a high-temperature oxidation-resistant coating agent for hot stamping steel materials and a high-temperature oxidation-resistant coated steel material formed using the same.

The need to apply high-strength steel sheets to reduce vehicle weight is increasing. However, due to the increased strength of steel materials, the formability for forming parts is decreasing. To overcome this, a hot stamping method was introduced in which steel was heated to a high temperature of over 800°C, forming and cooling were performed simultaneously while increasing the elongation. As a result, it became possible to manufacture parts that were difficult to form, which were previously impossible to manufacture with high-strength steel sheets. In addition, aluminum-silicon (Al-Si) hot-dip plating, which has excellent heat resistance, was applied to prevent surface oxidation of the base layer due to high-temperature heating before molding.

However, in the hot stamping process, when the steel material is heated, iron diffuses from the inside of the steel material to the aluminum plating layer, and as a result, the plating layer is alloyed and becomes brittle. Accordingly, there is a risk that defects such as cracks may occur in the plating layer during forming, exposing the steel sheet under the plating layer to the outside, and reducing corrosion resistance. In addition, when plating steel materials, surface security problems such as dross and ash may occur due to hot dip plating, and workability is greatly reduced.

Korean Patent Application No. 10-2015-0101474

The technical problem to be achieved by the technical idea of the present invention is to provide a high-temperature oxidation-resistant coating agent for hot stamping steel that can replace the existing aluminum-silicon hot-dip plating technology and provides enhanced corrosion resistance, and a high-temperature oxidation-resistant coated steel material formed using the same. is to provide.

However, these tasks are illustrative, and the technical idea of the present invention is not limited thereto.

According to one aspect of the present invention, a high-temperature oxidation-resistant coating agent for hot stamping steel that provides enhanced corrosion resistance and a high-temperature oxidation-resistant coated steel material formed using the same are provided.

According to one embodiment of the present invention, the high-temperature oxidation-resistant coating agent for hot stamping steel includes first metal particles having a first size; second metal particles having a second size larger than the first size; third metal particles having a third size larger than the second size; and a binder.

According to one embodiment of the present invention, the first size is in the range of 0.1 μm or more to 3 μm or less, the second size is in the range of more than 3 μm to 8 μm or less, and the third size is greater than 8 μm to 50 μm. It may be in the following range.

According to one embodiment of the present invention, based on the total weight of the first to third metal particles, the first metal particles are more than 10% by weight and less than 80% by weight, and the second metal particles are 10% by weight. Exceeding ~ 70% by weight or less, and the balance may be the third metal particles.

According to an embodiment of the present invention, based on the total weight of the first to third metal particles, the third metal particles may be more than 5% by weight and less than 60% by weight.

According to one embodiment of the present invention, the weight ratio of the first to third metal particles, the first metal particle: the second metal particle: the third metal particle, is 6:3:1 to 1. It can be in the :3:6 range.

According to an embodiment of the present invention, the weight ratio of the first to third metal particles, the first metal particle: the second metal particle: the third metal particle, may be 1:3:1. there is.

According to an embodiment of the present invention, at least one of the first metal particles, the second metal particles, and the third metal particles is zinc (Zn), aluminum (Al), or magnesium (Mg). , nickel (Ni), titanium (Ti), zirconium (Zr), or alloys thereof.

According to one embodiment of the present invention, the ratio of the total of the first to third metal particles and the binder may be in the range of 1:10 to 10:1 in weight ratio.

According to one embodiment of the present invention, the high-temperature oxidation-resistant coated steel includes a steel base layer; and a high-temperature oxidation-resistant coating layer located on the steel base layer, wherein the high-temperature oxidation-resistant coating layer includes first metal particles having a first size; second metal particles having a second size larger than the first size; and third metal particles having a third size larger than the second size.

According to an embodiment of the present invention, at least one of the first metal particles and the second metal particles may be located in the space between the third metal particles.

According to one embodiment of the present invention, the first metal particles may be located in the space between the second metal particles.

According to one embodiment of the present invention, the first size is in the range of 0.1 μm or more to 3 μm or less, the second size is in the range of more than 3 μm to 8 μm or less, and the third size is greater than 8 μm to 50 μm. It may be in the following range.

According to one embodiment of the present invention, the steel may be a steel for hot stamping.

According to the technical idea of the present invention, high-temperature oxidation-resistant coated steel is formed using metal particles having various sizes in the coating layer, thereby increasing the filling rate of the metal particles in the coating layer, preventing the penetration of oxidizing gas, and It can prevent diffusion of iron (Fe) and prevent defects such as cracks from forming in the coating layer during hot press molding.

The effects of the present invention described above have been described as examples, and the scope of the present invention is not limited by these effects.

Figure 1 is a schematic diagram showing a high-temperature oxidation-resistant coated steel material according to an embodiment of the present invention.
Figure 2 is a schematic diagram showing a coating device for manufacturing a high-temperature oxidation-resistant coated steel material according to an embodiment of the present invention.
Figure 3 is a scanning electron microscope photograph showing the coating layer of a high-temperature oxidation-resistant coated steel material according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The embodiments of the present invention are provided to more completely explain the technical idea of the present invention to those skilled in the art, and the following examples can be modified into various other forms, and the embodiments of the present invention The scope of the technical idea is not limited to the following examples. Rather, these embodiments are provided to make the present disclosure more faithful and complete and to fully convey the technical idea of the present invention to those skilled in the art. In this specification, like symbols refer to like elements throughout. Furthermore, various elements and areas in the drawings are schematically drawn. Accordingly, the technical idea of the present invention is not limited by the relative sizes or spacing drawn in the attached drawings.

High-temperature oxidation-resistant coating for hot stamping steel

A high-temperature oxidation-resistant coating agent for hot stamping steel according to an embodiment of the present invention includes first metal particles having a first size; second metal particles having a second size larger than the first size; third metal particles having a third size larger than the second size; and a binder.

For example, the first size may range from 0.1 μm to 3 μm. The second size may range from greater than 3 μm to less than or equal to 8 μm, for example. The third size may, for example, range from greater than 8 μm to less than or equal to 50 μm.

Here, the size may be the diameter if the metal particles are circular, the average of the major axis diameter and the minor axis diameter if the metal particles are oval, and the diagonal length if the metal particles are polygonal. . Additionally, if the metal particles have a flake shape, the size may be an average of the major axis length and minor axis length.

Based on the total weight of the first to third metal particles, the first metal particles may be, for example, more than 10% by weight and less than 80% by weight, and the second metal particles may be, for example, 10% by weight. It may be more than 70% by weight or less, and the third metal particles may be the balance, for example, more than 5% by weight and 60% by weight or less.

The weight ratio of the first to third metal particles, the first metal particle: the second metal particle: the third metal particle, may range from 6:3:1 to 1:3:6. For example, in the weight ratio, while the value corresponding to the second metal particle is fixed at 3, the value corresponding to the first metal particle is changed to a range of 1 to 6, and the value corresponding to the first metal particle is changed to 3. Independently of the change in the corresponding value, a range in which the value corresponding to the third metal particle is changed from 1 to 6 may be included. Additionally, the weight ratio of the first metal particles: the second metal particles: the third metal particles may be 1:3:1.

At least one of the first metal particles, the second metal particles, and the third metal particles is zinc (Zn), aluminum (Al), magnesium (Mg), nickel (Ni), and titanium (Ti). ), zirconium (Zr), or alloys thereof. The coating agent may include at least one of zinc (Zn), aluminum (Al), and magnesium (Mg).

The binder may be a conventional binder and may include an organic binder or an inorganic binder. In the case of the inorganic binder, for example, it may include a sol-gel solution in which silane and an acid catalyst are mixed in an aqueous solution, but the technical idea of the present invention is not limited thereto.

The ratio of the total of the first to third metal particles and the binder is a weight ratio (i.e., the total weight of the first to third metal particles: the weight of the binder), for example, 1:10 to 10:1. It may be a range, for example, 1:4 to 4:1.

High-temperature oxidation-resistant coated steel according to an embodiment of the present invention can be formed using the above-described high-temperature oxidation-resistant coating agent for hot stamping steel.

Figure 1 is a schematic diagram showing a high-temperature oxidation-resistant coated steel material 100 according to an embodiment of the present invention.

Referring to Figure 1(a), a comparative example is shown. The coated steel material 10 of the comparative example includes a coating layer 20 located on the steel base layer 10. The coating layer 20 includes metal particles 32 having approximately the same size, and includes metal particles 32 having approximately the same size within a normal distribution of metal particle sizes that can generally be manufactured.

In the case of the comparative example, the coating layer 20 can be formed using various processes. The size of the metal particles 32 may range from 0.1 μm to 50 μm. Metal particles 32 may include magnesium, zinc, aluminum, titanium, and alloys thereof. The metal particles 32 may be bonded to each other using a binder with a heat resistance temperature of 300° C. or lower.

The filling rate of the metal particles 32 may be relatively low, and voids between the metal particles 32 may be formed to be relatively large. Accordingly, it is easy for oxidizing gases such as oxygen to penetrate from the outside, and thus there is a risk that unwanted oxides such as surface scale may be generated by reacting with iron in the steel base layer.

Referring to Figure 1(b), an embodiment is shown. The high-temperature oxidation-resistant coated steel material 100 of the above embodiment includes a coating layer 120 located on the steel base layer 110. The coating layer 120 includes first metal particles 131 having a first size, second metal particles 132 having a second size larger than the first size; and third metal particles 133 having a third size larger than the second size.

At least one of the first metal particles 131 and the second metal particles 132 may be located in the space between the third metal particles 133. Additionally, the first metal particles 131 may be located in the space between the second metal particles 132.

In the case of the embodiment, the coating layer 120 may be formed using a roll-to-roll process. As described above, the metal particles include, for example, first metal particles 131 having a size ranging from 0.1 μm to 3 μm, and second metal particles 131 having a size ranging from more than 3 μm to 8 μm or less. It may include metal particles 132 and third metal particles 133 having a size ranging from, for example, more than 8 μm to less than 50 μm.

The first to third metal particles 131, 132, and 133 may include magnesium, zinc, aluminum, titanium, zirconium, nickel, and alloys thereof. The first to third metal particles 131, 132, and 133 may be bonded to each other with a high temperature binder of about 900°C, or the binder may be removed by heat treatment, and the first to third metal particles Fields 131, 132, and 133 may be alloyed with iron of the steel base layer 110.

As such, in the case of the embodiment, the first to third metal particles 131, 132, and 133 having various sizes are mixed in various proportions to increase the filling rate of the metal particles in the coating layer 120, that is, the metal filling rate. You can. Compared to the comparative example, which has almost the same size, if calculated by simple area, it can have a metal filling ratio that is, for example, about 1.64 times greater. Therefore, since penetration of external oxidizing gas can be prevented, oxidation resistance can be improved. The above metal filling ratio is exemplary, and the technical idea of the present invention is not limited thereto.

Figure 2 is a schematic diagram showing a coating device 200 for manufacturing a high-temperature oxidation-resistant coated steel material according to an embodiment of the present invention.

The steel material layer may include various steel materials, for example, hot rolled steel sheets or cold rolled steel sheets. However, this is an example and the technical idea of the present invention is not limited thereto.

Referring to FIG. 2, the coating device 200 may be a roll-to-roll method. The coating device 200 rotates in conjunction with a receiving portion 210 containing a high-temperature oxidation-resistant coating for hot stamping steel, a pickup roller (PUR) 220 that picks up the coating, and a pickup roller 220, and picks up the coating. Includes an applicator roller (APR) 230 for coating steel.

The rotation direction of the pickup roller 220 and the rotation direction of the applicator roller 230 may be opposite to each other, and through this movement, the coating agent may be transferred from the pickup roller 220 to the steel material through the applicator roller 230. The pickup roller 220 and the applicator roller 230 may be one or a pair. Therefore, the steel material may be coated on only one surface or both surfaces may be coated simultaneously.

However, the high-temperature oxidation-resistant coated steel material can be manufactured by various methods other than the roll-to-roll method described above. For example, spray-squeezing method, dipping method, etc. can be used.

Subsequently, after forming a coating layer on the steel material, the coating layer is dried to strengthen the adhesion between the steel material and the coating layer. The drying may be performed by one or more of a hot air method, an induction heating method, and a near-infrared heating method. The drying may be performed at PMT (Peak Metal Temperature), for example, at 80 to 140°C for 3 to 60 seconds.

Additionally, after forming a coating layer on the steel material and drying it, the steel material can be heat treated. The heat treatment may be performed, for example, in the range of 800°C to 950°C. By the heat treatment, the binder in the coating layer may be decomposed and discharged to the outside. Additionally, the metal particles in the coating layer may be alloyed with iron in the steel base layer.

In this way, by forming the high-temperature oxidation-resistant coating layer on the surface of the steel material, it is possible to prevent defects such as cracks from forming in the coating layer during hot press forming. Therefore, it can be applied as the steel for hot stamping.

Experiment example

Below, preferred experimental examples are presented to aid understanding of the present invention. However, the following experimental examples are only intended to aid understanding of the present invention, and the present invention is not limited by the following experimental examples. Any information not described here can be technically inferred by anyone skilled in the art, so description thereof will be omitted.

After changing the mixing ratio of the first to third metal particles to form three mixed solutions, a coating layer was formed on the steel material. The ratio of the total weight of the first to third metal particles and the weight of the binder was controlled in the range of 1:4 to 4:1.

Subsequently, the total area of the coating layer and the metal area within the coating layer were derived from the microstructure photo of the coating layer through an image analyzer. Then, the metal filling ratio (i.e., metal area/total area) was calculated. Here, the mixing ratio was calculated based on weight.

Table 1 is a table showing the mixing ratio and metal filling ratio for the coating layer of the high-temperature oxidation-resistant coated steel material according to an embodiment of the present invention.

division mixing ratio
(First metal particle: Second metal particle: Third metal particle) entire
area
(pixel) metal
area
(pixels) metal
Filling rate
(%) Example 1 6:3:1 712216 155163 21.8 Example 2 1:3:6 714756 151007 21.1 Example 3 1:3:1 713470 335651 47.0

Figure 3 is a scanning electron microscope photograph showing the coating layer of a high-temperature oxidation-resistant coated steel material according to an embodiment of the present invention.

Referring to Figure 3, (a) corresponds to Example 1, (b) corresponds to Example 2, and (c) corresponds to Example 3. On the left is a photo of the microstructure of the coating layer, and on the right is a photo of the microstructure converted for image analysis, where the black portion represents the metal particle and the red portion represents the binder.

Referring to FIG. 3 and Table 1, Example 1, in which the ratio of the first metal particles, second metal particles, and third metal particles is 6:3:1, has a metal filling ratio of 21.8%, and the ratio is 1:3. Compared to Example 2, which had a ratio of 6:6, at 21.1%, Example 3, which had the largest proportion of medium-sized second metal particles, i.e., where the ratio was 1:3:1, had the highest metal filling ratio of 47.0%. Example 3 showed a metal filling ratio of about 2.2 times that of Examples 1 and 2.

Therefore, Example 3 can most effectively prevent penetration of external oxidizing gas and diffusion of iron on the surface of the base metal, thereby improving oxidation resistance.

The technical idea of the present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible without departing from the technical idea of the present invention. It will be clear to those skilled in the art.

Claims (13)

first metal particles having a first size;
second metal particles having a second size larger than the first size;
third metal particles having a third size larger than the second size; and
Including a binder;
At least one of the first metal particles, the second metal particles, and the third metal particles is zinc (Zn), aluminum (Al), magnesium (Mg), nickel (Ni), and titanium (Ti). ), zirconium (Zr), or alloys thereof,
At least one of the first metal particles and the second metal particles is located in the space between the third metal particles, and the first metal particles are located in the space between the second metal particles,
The weight ratio of the first to third metal particles, the first metal particle: the second metal particle: the third metal particle, is 1:3:1,
High-temperature oxidation-resistant coating for hot stamping steel. According to claim 1,
The first size ranges from 0.1 μm to 3 μm,
The second size ranges from more than 3 μm to less than 8 μm,
The third size ranges from greater than 8 μm to less than or equal to 50 μm,
High-temperature oxidation-resistant coating for hot stamping steel. delete delete delete delete delete According to claim 1,
The ratio of the total of the first to third metal particles and the binder is in the range of 1:10 to 10:1 in weight ratio,
High-temperature oxidation-resistant coating for hot stamping steel. Steel base layer for hot stamping; and
It includes a high-temperature oxidation-resistant coating layer located on the steel base layer,
The high-temperature oxidation-resistant coating layer includes first metal particles having a first size; second metal particles having a second size larger than the first size; And third metal particles having a third size larger than the second size,
At least one of the first metal particles, the second metal particles, and the third metal particles is zinc (Zn), aluminum (Al), magnesium (Mg), nickel (Ni), and titanium (Ti). ), zirconium (Zr), or alloys thereof,
At least one of the first metal particles and the second metal particles is located in the space between the third metal particles, and the first metal particles are located in the space between the second metal particles,
The weight ratio of the first to third metal particles, the first metal particle: the second metal particle: the third metal particle, is 1:3:1,
Steel for hot stamping with high temperature oxidation resistant coating. delete delete According to clause 9,
The first size ranges from 0.1 μm to 3 μm,
The second size ranges from more than 3 μm to less than 8 μm,
The third size ranges from greater than 8 μm to less than or equal to 50 μm,
Steel for hot stamping with high temperature oxidation resistant coating. delete

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