Stainless steel composite material and manufacturing method thereof

Abstract

Disclosed are a stainless steel composite material and a manufacturing method thereof, wherein the composite material is based on stainless steel and comprises a coloring agent and a sintering agent, is harmless to the human body because nickel is not included as a sintering agent, has a unique color thus has excellent decorative properties, and has excellent mechanical properties etc. The disclosed stainless steel composite material may comprise: stainless steel; at least one coloring agent selected from the group consisting of TiC and TiN; and a sintering agent.

Description

Stainless steel composite material and method for manufacturing the same

[0001] The present invention relates to a stainless steel composite material and a method for producing the same, and more particularly, to a stainless steel composite material having excellent decorative properties due to its unique color and superior mechanical properties, and a method for producing the same, which is a composite material including a colorant and a sintering agent based on stainless steel.

[0002]

[0003] Stainless steel can be broadly classified into austenitic, ferritic, and martensitic types, with austenitic stainless steel accounting for 60% of total stainless steel usage.

[0004] Stainless steel has a beautiful surface and excellent mechanical properties, including strength and corrosion resistance. Because of these decorative and mechanical properties, stainless steel is used in a variety of applications, including construction materials, electronic components, tableware, and decorative materials.

[0005] However, stainless steel, as a silvery crystal, is difficult to use on its own for high-end decorative applications. Therefore, when manufacturing decorative composite materials, colorants and sintering agents play a crucial role in determining not only the product's appearance but also its mechanical properties. Metal oxides or nickel (Ni) are commonly used as sintering agents.

[0006] In particular, nickel (Ni) is phase stable and has advantages in strength and other aspects compared to metal oxides, but its price is unstable, making it difficult to supply stably. In addition, it is harmful to the human body, causing skin allergies and other problems.

[0007] Therefore, in manufacturing decorative composite materials based on stainless steel, there is a need to develop composite materials that are harmless to the human body because they do not use nickel as a sintering agent, and that have not only decorative properties but also phase stability and excellent mechanical properties.

[0008]

[0009] The present invention has been created in consideration of the above-mentioned points, and its purpose is to provide a stainless steel composite material including stainless steel; at least one colorant selected from TiC and TiN; and a sintering agent, which is economical based on stainless steel, does not contain nickel as a sintered body, is harmless to the human body, and can improve strength, wear resistance, corrosion resistance, etc., and a method for manufacturing the same.

[0010]

[0011] In order to achieve the above-mentioned purpose, a stainless steel composite material according to the present invention comprises: stainless steel; at least one colorant selected from TiC and TiN; and a sintering agent.

[0012] The above stainless steel composite material further comprises an additive, and the additive is characterized in that it comprises at least one selected from Si, Cr, and Mo.

[0013] The above stainless steel is characterized in that it contains at least one of Mn and N, and contains 2 to 5 wt% of Mn and 0.12 to 0.5 wt% of N based on the total weight% of the stainless steel.

[0014] The above stainless steel composite material is characterized by its color being gray, yellow or brown.

[0015] The above-mentioned sintering agent is characterized by containing at least one of Co, TiH2, and TiCN.

[0016] The above stainless steel composite material is characterized by a tensile strength of 890 MPa or more.

[0017] The method for manufacturing the above stainless steel composite material comprises a first step of preparing a composite powder including stainless steel, at least one colorant selected from TiC and TiN, and at least one sintering agent selected from TiH2, Co, and TiCN; a second step of preparing a mixture by mixing the composite powder with a liquid material including a solvent, a lubricant, and a viscosity agent; a third step of molding the mixture to obtain a molded body; and a fourth step of sintering the molded body.

[0018] The first step includes 30 to 80 wt% of stainless steel based on the total weight% of the composite powder, 1 to 50 wt% of at least one colorant selected from TiC and TiN, and 0.5 to 20 wt% of at least one sintering agent selected from TiH2, Co, and TiCN.

[0019] The first step is characterized by further including 0.1 to 15 wt% of at least one additive selected from Si, Cr, and Mo based on the total weight% of the composite powder.

[0020] The method further comprises a step of coating with a titanium compound after the fourth step, wherein the titanium compound comprises at least one selected from TiC, TiN, and TiBN.

[0021]

[0022] The stainless steel composite material according to the present invention is characterized by including stainless steel; at least one colorant selected from TiC and TiN; and a sintering agent, and is environmentally friendly and harmless to the human body because it does not contain nickel as a sintering agent based on stainless steel, contributes to phase stabilization and economic stabilization by dissolving nitrogen in stainless steel and adding manganese, and exhibits excellent gloss and a unique color by including a colorant and a sintering agent, and has the effect of improving mechanical properties such as toughness, tensile strength, wear resistance, and corrosion resistance.

[0023] In addition, the method for manufacturing stainless steel according to the present invention includes a first step of preparing a composite powder including stainless steel, at least one colorant selected from TiC and TiN, and at least one sintering agent selected from TiH2, Co, and TiCN; a second step of preparing a mixture by mixing the composite powder with a liquid material including a solvent, a lubricant, and a viscosity agent; a third step of molding the mixture to obtain a molded body; and a fourth step of sintering the molded body; thereby providing excellent effects such as high productivity and smoothness.

[0024]

[0025] Figures 1 and 2 illustrate watch parts using a stainless steel composite material according to the present invention.

[0026]

[0027] All terms described in this specification are currently widely used and have been selected in consideration of the functions of the present invention. However, these terms may vary depending on the intentions of those skilled in the art, customs, or the emergence of new technologies. Furthermore, if the inventor specifies any term in the present invention, its meaning will be described in the description of the invention. Therefore, the terms used in the present invention should not be interpreted simply as names of terms, but rather based on the actual meaning of the term and the overall content described in the description of the present invention.

[0028]

[0029] The present invention provides a stainless steel composite material and a method for manufacturing the same.

[0030] [Stainless steel composite material]

[0031] A stainless steel composite material according to an embodiment of the present invention comprises stainless steel; at least one colorant selected from TiC and TiN; and a sintering agent. In addition, the stainless steel composite material according to an embodiment of the present invention may further comprise an additive. The additive may comprise at least one selected from Si, Cr, and Mo.

[0032] The stainless steel composite material of the present invention contains the above-mentioned components as active ingredients, is based on stainless steel, and does not contain nickel (Ni) as a sintering agent, making it environmentally friendly and harmless to the human body. Therefore, when used as a decorative material, it does not cause side effects such as skin allergies. Furthermore, the stainless steel composite material according to an embodiment of the present invention not only has decorative properties with its luster and unique color, but also possesses excellent mechanical properties.

[0033] Therefore, the stainless steel composite material of the present invention can be usefully used as a decorative material. That is, it can be used as accessories for jewelry, ornaments, watches (such as wristwatches), electronic products, etc. In particular, the stainless steel composite material according to an embodiment of the present invention can be used as a wristwatch component, for example, and can be used as a case body, bezel, dial, front cover, or rear cover of the wristwatch. In addition, the stainless steel composite material according to an embodiment of the present invention can have various shapes depending on the use, and specifically, can be shaped into a ring, a disc, a polygonal plate, etc. Hereinafter, essential and optional components in the stainless steel composite material according to an embodiment of the present invention will be described in detail.

[0034]

[0035] (1) Stainless steel

[0036] The above stainless steel is used as the main component of the stainless steel composite material of the present invention. Commercially available stainless steels can be used without limitation. Stainless steels can be broadly classified into austenitic, martensitic, and ferritic types, and are characterized by a beautiful surface and excellent corrosion resistance due to the formation of chromium oxide on the surface. Due to these characteristics, stainless steel can be used in various applications, such as electronic product materials and decorative materials. In the present invention, 316 stainless steel, which has excellent corrosion resistance, can be primarily used, but is not limited thereto.

[0037] Accordingly, the stainless steel may be included in an amount of 30 to 80 wt% based on the total weight% (solid powder) of the stainless steel composite material of the present invention. As another example, the stainless steel may be included in an amount of 70 to 80 wt%. If the content of the stainless steel is less than 30 wt%, the strength, corrosion resistance, wear resistance, toughness, etc. of the stainless steel composite material may be reduced, and if it exceeds 80 wt%, the content of the coloring agent and sintering agent may be relatively reduced, which may result in a reduction in gloss or sinterability, etc.

[0038] In addition, since the stainless steel composite material of the present invention does not use nickel (Ni) as a sintering agent to improve mechanical properties, the stainless steel can contain nitrogen (N) and manganese (Mn) to improve phase stabilization and mechanical properties such as strength and corrosion resistance. In addition, the stainless steel can contribute to economic stabilization by dissolving nitrogen and adding manganese. That is, nitrogen is a stabilizing element of austenitic stainless steel and can increase strength and improve ductility to a high level, thereby improving corrosion resistance. In addition, manganese is a stabilizing element of austenitic stainless steel and can increase the solid solution of nitrogen, thereby improving the strength of the stainless steel.

[0039] Accordingly, the stainless steel may contain 0.12 to 0.5 wt% of nitrogen and 2 to 5 wt% of manganese. When the nitrogen content is less than 0.12 wt%, it may interfere with the stabilization of the stainless steel, and when it exceeds 0.5 wt%, precipitates may be formed due to excessive solidification, which may reduce mechanical properties such as corrosion resistance. In addition, when the manganese content is less than 2 wt%, it may inhibit the solubility of nitrogen in the stainless steel, thereby interfering with the stabilization of the stainless steel, and when it exceeds 5 wt%, it may combine with impurity elements such as oxygen (O) to form non-metallic inclusions such as manganese oxide (MnO). The non-metallic inclusions may cause a problem of reducing the pitting resistance of the stainless steel.

[0040]

[0041]

[0042] (2) Colorant

[0043] The coloring agent may be at least one selected from titanium carbide (TiC) and titanium nitride (TiN). Any commercially available product may be used as the coloring agent without limitation. The coloring agent can provide decorative properties to the stainless steel composite material of the present invention with gloss and a unique color. Furthermore, the coloring agent can also improve the strength, wear resistance, etc. of the stainless steel composite material of the present invention.

[0044] The above TiC is a black powder having a face-centered cubic structure and can be included in the colorant. When the TiC is used alone, a silver-based gray color, i.e., a metallic color, can be realized. When the TiC is mixed with the TiN below and used, various colors such as dark gray, dark yellow, and brown can be realized depending on the mixing ratio. In addition, the TiC can be added to improve the strength, heat resistance, durability, etc. of the stainless steel composite material of the present invention. In particular, TiC nanoparticles have a large surface area and can be more effective in improving mechanical properties or using them for various purposes. In addition, when chromium or the like is added to TiC, the corrosion resistance, etc. of the stainless steel composite material of the present invention can be improved.

[0045] The above TiN is a titanium compound with high micro-strength and high chemical and thermal stability, and can be included in the above coloring agent. When the TiN is used alone, a gold-like yellow color can be realized. When the TiN is used in combination with the TiC, various colors such as dark gray, dark yellow, and brown can be realized depending on the mixing ratio. In addition, the TiN can increase the viscosity of the stainless steel composite material of the present invention, thereby enhancing the bonding strength, and thus improving the strength, etc.

[0046] Accordingly, the colorant may be included in the stainless steel composite material in an amount of 1 to 50 wt% based on the total weight% (solid powder) of the stainless steel composite material. As another example, the colorant may be included in an amount of 5 to 25 wt% based on the total weight% (solid powder) of the stainless steel composite material. When the content of the colorant is less than 1 wt%, effects such as gloss and coloring may be minimal, and mechanical properties may also be deteriorated. In addition, when the content of the colorant exceeds 50 wt%, a decrease in the content of stainless steel may occur, thereby deteriorating mechanical properties such as strength of the stainless steel composite material of the present invention. When the TiC is used alone, the content may be included in an amount of 10 to 50 wt% based on the total weight% of the stainless steel composite material, and when the TiN is used alone, the content may be included in an amount of 10 to 45 wt%. In addition, when using the above TiC and TiN in a mixed manner, it is preferable to use 1 to 45 wt% of TiC and 2 to 40 wt% of TiN based on the total weight% of the stainless steel composite material, and the total amount of these mixed should be 50 wt% or less.

[0047] In addition, the coloring agent may further include at least one of SiC (silicon carbide) and Si3N4 (silicon nitride). The SiC or Si3N4 may be a commercially available product without limitation. The SiC may be selected from black and / or green. When SiC and / or Si3N4 are added to the stainless steel composite material of the present invention, it may be colored in a unique color such as green, blue-green, or blue.

[0048] Therefore, the SiC and / or Si3N4 may be included in an amount of 1 to 30 wt% based on the total weight% of the stainless steel composite material. If the content of the SiC and / or Si3N4 is less than 1 wt%, effects such as coloring may be minimal. In addition, if the content of the SiC and / or Si3N4 exceeds 30 wt%, it may cause a decrease in the content of other components, thereby deteriorating mechanical properties.

[0049]

[0050] (3) Soap dispensing agent

[0051] The sintering agent may include at least one of Co, TiH2, and TiCN. Any commercially available product may be used as the sintering agent. The sintering agent not only enhances the sinterability of stainless steel and a coloring agent (TiC, TiN), thereby improving the appearance and mechanical properties of the stainless steel composite, but is also harmless to the human body as it does not contain nickel. Co, TiH2, and TiCN may be used alone or in combination.

[0052] The above Co (cobalt) is a silvery-white metallic element with ferromagnetic properties. Co can be used in the manufacture of stainless steel to enhance its strength. Furthermore, when Co is oxidized, it forms a tricobalt tetroxide compound, forming a thin film on the metal surface to prevent corrosion. Therefore, it can be added as a sintering agent to improve the mechanical properties of the stainless steel composite material of the present invention. The following chemical formula 1 illustrates the bonding of Co and oxygen.

[0053] <Chemical Formula 1>

[0054] 3Co + 2O2 -> Co3O4

[0055] The above TiH2 (titanium hydride) is a silvery-white transition metal with a metallic luster, and commercialized products can be used without limitation. The above TiH2 not only has excellent strength and corrosion resistance, but can also enhance the corrosion resistance of the stainless steel composite material of the present invention through chemical reactions.

[0056] That is, in the stainless steel composite material of the present invention, during the manufacturing and sintering of the composite powder, Cr reacts with oxygen, nitrogen, and carbon to form chromium oxide, chromium nitride, and chromium carbide, resulting in chromium deficiency. Chromium deficiency can ultimately act as a factor that reduces the corrosion resistance, etc. of the stainless steel composite material of the present invention. Therefore, in order to remove the chromium compound, which is the cause of the reduction in corrosion resistance, the TiH2 can be used as a sintering agent in an amount of 1 to 5 wt% based on the total weight% of the stainless steel composite material. TiH2 decomposes into Ti and H2 during the molding and sintering process at 300 to 500°C or higher, and reacts with the chromium compound to form a titanium compound. Through this reaction, chromium deficiency can be prevented, and the corrosion resistance, etc. of the stainless steel composite material of the present invention can be improved due to the titanium compound. Chemical formula 2 shows that the chromium compound reacts with TiH2 to form a chromium and titanium compound.

[0057] <Chemical Formula 2>

[0058] Cr2O3 + TiH2 -> 2Cr + TiO2 + H2O

[0059] Cr3N + TiH2 -> 2Cr + TiN + 2H

[0060] Cr3C2 + TiH2 -> 3Cr + 2TiC + 4H

[0061] Cr7C3 + TiH2 -> 7Cr + 3TiC + 6H

[0062] The above TiCN is harder than metal and has a highly chemically stable structure, allowing for unlimited use in commercialized products. Because TiCN possesses excellent wear resistance and hardness, it can be added as a sintering agent to enhance the mechanical properties of the stainless steel composite material of the present invention. When the sintering agent includes TiCN, strength and other properties can be effectively improved, at least compared to when nickel (Ni) is used.

[0063] Therefore, the sintering agent may be included in an amount of 0.5 to 20 wt% based on the total weight% (solid powder) of the stainless steel composite material. As another example, the sintering agent may be included in an amount of 0.5 to 15 wt% based on the total weight% (solid powder) of the stainless steel composite material. As another example, the sintering agent may be included in an amount of 0.5 to 10 wt% based on the total weight% (solid powder) of the stainless steel composite material. When the content of the sintering agent is less than 0.5 wt%, the effect of improving sinterability may be minimal. In addition, when the content of the sintering agent exceeds 20 wt%, the content of stainless steel and coloring agent may be reduced, resulting in a deterioration in mechanical properties.

[0064]

[0065] (4) Additives

[0066] The above additive may include a metal and / or a metal compound. That is, the above additive may include at least one of W (tungsten), Co (cobalt), Cr (chromium), Cu (copper), Al (aluminum), Ta (tantalum), Mn (manganese), Mo (molybdenum), Si (silicon), Ba (barium), Ge (germanium), Sn (tin), Sb (antimony), V (vanadium), and Bi (bismuth), but preferably may include at least one of Si, Cr, and Mo. The above additive not only improves the mechanical properties of the stainless steel composite material of the present invention, such as wear resistance and strength, but also removes specific harmful substances.

[0067] The above Si (silicon) is mainly used as a deoxidizer because it easily combines with oxygen during the composite powder manufacturing, molding, and sintering processes, thereby improving the corrosion resistance of the stainless steel composite material of the present invention. On the other hand, if the above Si (silicon) is added excessively, it may deteriorate mechanical properties such as toughness, and therefore, it may be limited to 0.1 to 0.5 wt% based on the total weight% of the composite powder.

[0068] The above Cr (chromium) can provide corrosion resistance to the stainless steel composite material of the present invention. That is, Cr increases the solid solubility of N (nitrogen), thereby increasing strength and improving ductility to a high level, thereby providing corrosion resistance to the stainless steel composite material of the present invention. If the above Cr is added excessively, it can cause uniformity in the structure, thereby reducing pitting resistance, and therefore, it can be limited to 8 to 10 wt% based on the total weight% of the composite powder.

[0069] The above Mo (molybdenum) can stabilize the stainless steel composite material of the present invention and improve corrosion resistance and local corrosion resistance. In particular, when the Mo is added together with nitrogen, it can have a synergistic effect that further enhances pitting resistance. If the Mo is added excessively, it can actually cause a deterioration in mechanical properties such as pitting resistance, and since it is an expensive alloying element, it can be limited to 1 to 4 wt% based on the total weight% of the composite powder.

[0070] Therefore, the additive may be included in an amount of 0.1 to 15 wt% based on the total weight% (solid powder) of the stainless steel composite material. If the content of the additive is less than 0.1 wt%, it may have minimal effect on improving the mechanical properties. In addition, if the content of the additive exceeds 15 wt%, it may cause a decrease in the contents of stainless steel, colorant, and sintering agent, which may also deteriorate the mechanical properties.

[0071]

[0072] [Method for manufacturing stainless steel composite materials]

[0073] A method for manufacturing a stainless steel composite material according to an embodiment of the present invention may include a first step of preparing a composite powder including stainless steel, at least one colorant selected from TiC and TiN, and at least one sintering agent selected from TiH2, Co, and TiCN; a second step of preparing a mixture by mixing the composite powder with a liquid material including a solvent, a lubricant, and a viscosity agent; a third step of molding the mixture to obtain a molded body; and a fourth step of sintering the molded body. In addition, a step of coating with a titanium compound may be further included after the fourth step.

[0074]

[0075] [1] Stage 1 (composite powder)

[0076] The first step is to prepare a composite powder that constitutes a stainless steel composite material. Specifically, a composite powder is prepared by mixing stainless steel, at least one colorant selected from TiC and TiN, and at least one sintering agent selected from TiH2, Co, and TiCN. As another example, in the first step, an additive may be further added to the composite powder and mixed. The respective components of the composite powder are as described above.

[0077] Therefore, in the first step, a composite powder may be prepared by mixing 30 to 80 wt% of stainless steel, 1 to 50 wt% of at least one colorant selected from TiC and TiN, and 0.5 to 20 wt% of at least one sintering agent selected from TiH2, Co, and TiCN, based on the total weight% of the composite powder. As another example, the first step may further include 0.1 to 15 wt% of at least one additive selected from Si, Cr, and Mo, based on the total weight% of the composite powder. The additive may be 0.1 to 0.5 wt% of Si, 8 to 10 wt% of Cr, and / or 1 to 4 wt% of Mo, based on the total weight% of the composite powder.

[0078]

[0079] [2] Stage 2 (mixed)

[0080] The second step is a step of preparing a mixture by mixing the composite powder prepared in the first step into a liquid material. Specifically, the liquid material has a predetermined viscosity and includes a solvent, a lubricant, and a viscosity agent. The liquid material can be removed during a high-temperature sintering process. The solvent may be selected from at least one of water and an organic solvent, and specifically, at least one of water, ether, acetone, and alcohol (ethanol, etc.) may be selected. The lubricant may be selected from those commonly used in the art, and may be a metal stearate such as lithium stearate or zinc stearate, paraffin, wax, natural or synthetic fat derivatives, polyamide, or EBS (Ethylene Bis-Stearamide). The viscosity agent can improve the viscosity of the composite powder and thereby enhance the formability. The viscosity agent may be at least one of polyvinyl butyral, polyvinyl alcohol (PVA), etc., but is not limited thereto.

[0081] Accordingly, the liquid material may contain 0.5 to 30 parts by weight of a viscosity agent and 0.5 to 15 parts by weight of a lubricant per 100 parts by weight of a solvent. By mixing the composite powder with the liquid material, a mixture having a predetermined viscosity can be prepared. The mixture may be prepared by mixing the composite powder and the liquid material in a weight ratio of 1: 0.1 to 0.9. The mixture can be prepared by putting it into a stirrer and stirring it. As another example, the mixture can be obtained by putting it into a stirrer and stirring it, and then spraying it in the form of droplets using a sprayer, and then drying it to prepare a mixture in the form of granules having a uniform size.

[0082]

[0083] [3] Stage 3 (shaping)

[0084] The third step is a step of molding the mixture manufactured in the second step to obtain a molded body. Specifically, the molding agent may have any shape. That is, the molded body may have various shapes such as a ring, a disk, a polygonal plate, etc. As another example, the molded body may have a shape such as a finished product (a watch, a watch part, etc.) or a semi-finished product (a base). The molding method for manufacturing the molded body is not particularly limited. That is, the molding method may be selected from sheet molding, extrusion molding, injection molding, press molding, etc. The press molding is a method of manufacturing a molded body by filling a mold with powder and applying pressure. Depending on the method of applying pressure, there are uniaxial pressing molding for one direction, and isostatic pressing molding for multiple multi-axes. The molding method according to an embodiment of the present invention is mainly uniaxial pressing molding, in which powder is charged into a mold. Then, the mold filled with powder can be molded by pressing it at a predetermined pressure. Therefore, in the present invention, the temperature is preferably 0.5 to 5 tons / at room temperature through press forming. cm 2. A molded body having an arbitrary shape can be manufactured by applying pressure.

[0085] In another embodiment, the molding method of the present invention may select at least one of extrusion molding or injection molding. Extrusion molding is a method of manufacturing a molded body having a desired shape by forcing a metal or ceramic material, etc., into a hole of an extrusion mold. It can be performed by preparing a billet of an appropriate size made of metal, etc., placing it into an extruder, forcing it into an extrusion die to produce an extruded product, heat treating it, and cutting it into an appropriate size. Therefore, extrusion molding allows for a variety of product shapes, and can produce products with improved strength, structural structure, etc. through cold or hot extrusion. Therefore, the mixture of the second step is prepared into billets of an appropriate size, sequentially placed into a hopper, and the molten and extruded mixture is pushed into an extrusion die to manufacture a molded body under normal extrusion conditions. The extrusion conditions are not particularly limited and can be selected according to each situation. Preferably, the temperature is about 50℃ higher than the melting point of the composite but higher than the decomposition temperature. Therefore, the extrusion conditions can be performed at room temperature, but can also be performed at high temperatures, and the extrusion pressure is 0.5 to 5 tons / cm. 2 A molded body can be manufactured by applying pressure.

[0086] Injection molding is performed by mixing and melting the above mixture in the second step, extruding the melt sequentially to make it into a pellet shape, and then putting it into an injection molding machine to obtain a molded body. The injection conditions are not particularly limited and can be selected and used according to each situation. It can be preferably performed at room temperature, but it can also be performed at high temperature, and the injection pressure is 0.5 to 5 tons / cm. 2 A molded body can be manufactured by applying pressure.

[0087]

[0088] [4] Stage 4 (sintering)

[0089] The fourth step is to sinter the molded body manufactured in the third step. The sintering step refers to the process of applying sufficient temperature and pressure to form a more dense mass of particles with a large specific surface area, such as powder. The sintering method can be classified into vacuum sintering, pressureless sintering, pressure sintering, spark plasma sintering, and reaction sintering depending on the process conditions. The present invention can be performed according to a conventional stainless steel sintering method. That is, the sintering can be performed using a high vacuum sintering furnace in a vacuum, argon (Ar), or nitrogen gas atmosphere at a maximum temperature of 1,300 to 1,450°C for 1.5 to 3.5 hours. Upon completion of the sintering, a sintered body of a decorative stainless steel composite material having excellent metallic luster and unique color as well as superior mechanical properties can be manufactured.

[0090]

[0091] [5] Step 5 (Coating)

[0092] Meanwhile, the method for manufacturing a stainless steel composite material according to an embodiment of the present invention may further include a fifth step of coating the sintered body obtained through the sintering process with a titanium compound. The titanium compound may be at least one selected from TiCN, TiC, TiN, and TiBN. In the present invention, the coating may be performed according to a conventional stainless steel coating method.

[0093] The above-mentioned TiCN is a compound with excellent properties, such as wear resistance and hardness, that is harder than metal and chemically very stable. Therefore, TiCN can be used for processing high-strength stainless steel plates, forming, and drawing punch molds. In other words, it can be primarily used for milling and forming operations that involve high mechanical stress.

[0094] Furthermore, TiN is a refractory compound with high microstrength and high chemical and thermal stability. Therefore, TiN can be used as a surface coating for titanium alloys, steel, carbides, carbide, and aluminum parts to improve surface properties. Furthermore, TiN can increase the viscosity of cemented carbides.

[0095] Furthermore, TiBN is a ceramic compound with excellent properties such as corrosion resistance and strength. Therefore, TiBN can be used as a surface coating for alloys and other materials, providing high strength to the base material and enhancing corrosion resistance, thereby extending the life of the sintered body. Therefore, upon completion of the coating, a stainless steel composite material with superior mechanical properties such as strength and corrosion resistance can be manufactured.

[0096] Therefore, the sintered body having completed the fourth step is prepared, and a Ti compound and a reaction gas are injected into the CVD chamber to be deposited by a CVD process at a predetermined temperature to coat the surface of the sintered body having completed the fourth step. The Ti compound and the reaction gas may include TiCl4, H2, N2, and CH4. The Ti compound and the reaction gas are not limited thereto. The predetermined temperature is characterized in that it is 1000 to 1200°C. Therefore, TiCl4, H2, N2, and CH4 are injected into the CVD chamber to raise the temperature to 700 to 1000°C, and then the surface of the sintered body can be coated by depositing by a CVD process at 1000 to 1200°C for 1.5 to 2.5 hours.

[0097] In addition, the method for manufacturing a stainless steel composite material according to the present invention may further include a step of processing a sintered body after the sintering in the fourth step or the coating in the fifth step is completed. That is, if the sintered body is a wristwatch component, it can be cut to have an actual shape. The cutting process can be performed through laser processing, etc., and can have the shape of parts such as a case body, bezel, and / or dial that constitute a wristwatch. Accordingly, FIGS. 1 to 3 are watch components using a stainless steel composite material according to the present invention, and with reference to FIGS. 1 to 3, the sintered body after processing can have an actual shape.

[0098] In this way, the method for manufacturing a stainless steel composite material according to an embodiment of the present invention provides a process that is based on stainless steel and includes a coloring agent and a sintering agent, thereby providing excellent decorative properties with excellent gloss and unique color, and excellent mechanical properties.

[0099] Below, manufacturing examples and examples are provided. The following manufacturing examples and examples are provided solely to aid in understanding the present invention.

[0100]

[0101] <Manufacturing of stainless steel composite materials>

[0102] [Examples 1 to 6] - Stainless steel composite material

[0103] In order to manufacture the stainless steel composite material of the present invention, stainless steel (316 stainless steel), a colorant (TiC, TiN), a sintering agent (Co, TiH2, TiCN), and additives (Si, Cr, Mo) were prepared as composite powders. At this time, the composite powders had different components and contents according to each example in Table 1 below. Next, a liquid material was prepared by mixing 5 parts by weight of a lubricant (lithium stearate) and 15 parts by weight of a viscosity agent (PVA) with respect to 100 parts by weight of a solvent. The composite powder and the liquid material were mixed in a weight ratio of 100:55, stirred using a ball mill to manufacture a mixture, and then spray-dried to manufacture a granule form having a uniform size. This was charged into a press mold to manufacture a plate-shaped molded body, and then hardened at 1350°C for 2 h in a vacuum atmosphere in a vacuum sintering furnace to manufacture a stainless steel composite material (specimen) according to each example. Table 1 below shows the components and contents of examples and comparative examples of the present invention.

[0104]

[0105] [Example 7] - Stainless steel composite material

[0106] A stainless steel composite material (specimen) manufactured according to Example 1 was prepared, and then TiCl4 (20 Lpm), H2 (200 Lpm), N2 (80 Lpm), and CH4 (10 Lpm) were injected into a CVD chamber, the temperature was raised to 1000°C, and then a coating layer was formed with a TiCN layer having a thickness of 7 μm on the surface by deposition through a CVD process at 1000°C for 2.5 hours.

[0107]

[0108] [Comparative Examples 1 to 3] - Stainless steel composite material

[0109] Comparative Examples 1 to 3 were manufactured by the same method as in Examples 1 to 6, except that the components and contents of the composite powder were different. Table 1 below shows the components and contents of the Examples and Comparative Examples of the present invention.

[0110]

[0111] Table 1 shows the components and contents of examples and comparative examples of the present invention.

[0112]

[0113] <Example of an exam>

[0114] [Example 1] - Personality Test

[0115] The fracture toughness of each stainless steel composite material specimen manufactured according to the examples and comparative examples of the present invention was measured using a Vickers hardness tester (Japan, Mitutoyo, AVK-C2) at a load of 10 kg.

[0116]

[0117] [Test Example 2] - Tensile Strength Test

[0118] The stainless steel composite material specimens manufactured according to the examples and comparative examples of the present invention were measured by a three-point bending strength test (span distance 30 mm, crosshead speed 0.5 mm / min) using a universal material testing machine (Instron, USA, Model No. 4206).

[0119]

[0120] [Example 3] - Gloss and color

[0121] The gloss and color of the stainless steel composite material specimens manufactured according to the examples and comparative examples of the present invention were evaluated visually.

[0122]

[0123] Table 2 shows the results of tests on toughness, hardness, and tensile strength according to examples and comparative examples of the present invention.

[0124] Examples and Comparative Examples Toughness (J) Tensile strength (MPa) Gloss Color Example 1 270.4 90 7.8 good light gray Example 2 265.7 109 0.3 good light gray Example 3 288.2 100 1.7 good yellow Example 4 303.1 99 5.1 excellent yellow Example 5 263.8 106 6.4 good light brown Example 6 220.1 89 3.5 excellent light brown Example 7 271.5 9 0.8 good light gray Comparative Example 1 264.5 8 04.3 good light gray Comparative Example 2 208.4 7 11.9 good metallic color Comparative Example 3 211.8 7 0.4 good light gray

[0125]

[0126] Referring to Table 2 above, it can be seen that the examples of the present invention exhibit higher toughness, superior tensile strength, and good gloss and color compared to the comparative examples. Specifically, it can be seen that the examples of the present invention exhibit a toughness of 220 J or higher and a tensile strength of 890 MPa or higher.

[0127] Specifically, looking at the toughness of the examples and comparative examples of the present invention, it was found that examples 1 to 5 had high toughness, while example 6, which did not include an additive, had lower toughness, and example 7, which was coated with example 1, had slightly higher toughness compared to example 1. On the other hand, although comparative example 1 had the same Mo (molybdenum) content as example 1, its toughness was lowered compared to example 1 depending on the presence or absence of other compositions, and comparative example 2 not only caused a decrease in toughness due to the excessive inclusion of Mo (molybdenum) and Si (silicon), but also did not contain a titanium compound, which is a colorant and improves mechanical properties, and thus showed the lowest toughness. In addition, it was found that comparative example 3, although it did not contain Mo (molybdenum), showed higher toughness than comparative example 2 because it contained TiC, which is a titanium compound, which is a colorant and improves mechanical properties. Therefore, it was found that the toughness of the examples and comparative examples of the present invention depended on the presence or absence of Mo (molybdenum), the relationship between Mo (molybdenum) and N (nitrogen), and the presence or absence of nitrogen solubility and manganese addition.

[0128] In addition, when examining the tensile strength, it was found that the examples and comparative examples of the present invention depended on the components of the stainless steel, the presence or absence of a titanium compound, the presence or absence of a sintering agent, and the presence or absence of an additive. In particular, it was found that the nitrogen solid solution and manganese content in the stainless steel, the relationship between TiH2 and Cr (chromium), and the relationship between Cr (chromium) and nitrogen affected the strength of the stainless steel composite material of the present invention. Therefore, it was confirmed that examples 2 and 5 exhibited high tensile strength, while comparative examples 1 to 3 exhibited lower tensile strength than the examples.

[0129] In addition, it was found that the stainless steel composite material specimen according to the embodiment of the present invention had excellent gloss and had gray, yellow, and brown colors depending on the type of coloring agent.

[0130]

[0131] [Test Example 4] - Wear Resistance Test

[0132] The stainless steel composite material specimens manufactured according to the examples and comparative examples of the present invention were processed, and a Pin on Disc friction wear tester was used to perform a reciprocating motion at 0.1 m / s for 24 hours under a load of 10 kg, and then the amount of wear was checked, thereby comparing the coefficient of friction and the amount of wear. When checking the amount of wear, the width of the wear track was measured.

[0133]

[0134] Table 3 shows the results of a wear resistance test according to an embodiment of the present invention.

[0135] Wear resistance test resultsExamples and comparative examplesFriction coefficientWeight change (g)Length change (mm)Example 10.0210.0580.32Example 20.0250.0650.41Example 30.0300.0780.53Example 40.0140.0410.21Example 50.0270.0680.45Example 60.0160.0530.25Example 70.0080.0210.12Comparative example 10.0200.0550.28Comparative example 20.0340.0810.58Comparative example 30.0240.0610.39

[0136]

[0137] Referring to Table 3 above, it was found that the wear resistance of the examples and comparative examples of the present invention depended on the presence or absence of a titanium compound and the presence or absence of a coating. Accordingly, it was found that Example 7, although having the same components and contents as Example 1, was a coated stainless steel composite material and had the best wear resistance. In addition, it was found that the examples of the present invention had an equivalent or superior wear resistance effect compared to the comparative examples.

Claims

1. In stainless steel composite materials, stainless steel; At least one colorant selected from TiC and TiN; and A stainless steel composite material comprising a sintering agent.

2. In paragraph 1, The above stainless steel composite material further contains an additive, A stainless steel composite material, characterized in that the additive comprises at least one selected from Si, Cr, and Mo.

3. In paragraph 1, The above stainless steel contains at least one of Mn and N, A stainless steel composite material characterized in that it contains 2 to 5 wt% of Mn and 0.12 to 0.5 wt% of N based on the total weight% of the stainless steel.

4. In paragraph 1, The above stainless steel composite material is characterized by a color of gray, yellow or brown.

5. In paragraph 1, A stainless steel composite material, characterized in that the above sintering agent contains at least one of Co, TiH2, and TiCN.

6. In any one of paragraphs 1 to 5, The above stainless steel composite material is a stainless steel composite material characterized by a tensile strength of 890 MPa or more.

7. In the method for manufacturing stainless steel composite materials, A first step of preparing a composite powder comprising stainless steel, at least one colorant selected from TiC and TiN, and at least one sintering agent selected from TiH2, Co and TiCN; A second step of preparing a mixture by mixing the composite powder into a liquid material including a solvent, a lubricant, and a viscosity agent; A third step of molding the mixture to obtain a molded body; and A method for manufacturing a stainless steel composite material, comprising: a fourth step of sintering the above-mentioned molded body.

8. In paragraph 7, A method for manufacturing a stainless steel composite material, characterized in that in the first step, a composite powder is prepared by including 30 to 80 wt% of stainless steel, 1 to 50 wt% of at least one coloring agent selected from TiC and TiN, and 0.5 to 20 wt% of at least one sintering agent selected from TiH2, Co, and TiCN, based on the total weight% of the composite powder.

9. In paragraph 8, A method for manufacturing a stainless steel composite material, characterized in that the first step further comprises 0.1 to 15 wt% of at least one additive selected from Si, Cr, and Mo based on the total weight% of the composite powder.

10. In paragraph 7, After the fourth step, a step of coating with a titanium compound is further included. A method for manufacturing a stainless steel composite material, characterized in that the titanium compound comprises at least one selected from TiC, TiN and TiBN.

Images