KR101531346B1 - Method for manufacturing diffusion bonding iron-based powders - Google Patents

Abstract

The present invention relates to a method of producing an iron-based diffusion bonded powder, wherein molten steel to which at least one metal component is added is sprayed to prepare an iron-based powder whose surface is oxidized, and an additive powder comprising at least one of metal- The surface of the iron powder is uniformly mixed with the oxidized iron powder, the iron powder and the add powder are reduced in the heat treatment furnace in a reducing atmosphere, the reduced powder is partially diffused and bonded to the surface of the iron powder, Disclosed is a method for producing an iron-based diffusion bonded powder, which comprises crushing a diffusion bonded lump.

Description

[0001] METHOD FOR MANUFACTURING DIFFUSION BONDING IRON-BASED POWDERS [0002]

The present invention relates to a method for producing an iron-based diffusion bonded powder, more particularly, to a method for manufacturing an iron-based diffusion bonded powder more economically than conventional methods using a surface-unoxidized unfired iron powder, a metal oxide powder and a metal powder .

BACKGROUND ART [0002] In recent years, the use of iron-based powders as raw materials has been rapidly increasing due to the development of a sintering component industry having a complex shape required for automobiles and machines.

Conventionally, sintered parts produced by pure iron powder have high corrosion resistance and have poor mechanical properties such as tensile strength and hardness. Particularly, in order to manufacture sintered parts for automobiles, there is a steadily increasing demand for higher strength of sintered bodies.

(Mo), copper (Cu), nickel (Ni), and nickel (Ni) as a method of improving the strength by alloying, in order to produce high strength sintered parts. There is known an alloying method or a mixing method which is produced by adding metal powders or oxide powders such as chromium (Cr), manganese (Mn), tungsten (W), vanadium (V) and graphite (C) It is very important to solve this problem because it involves many problems.

In order to improve the properties of the sintered product, the complete alloy powder in which the alloy powder is produced by melting one or more additive metals and spraying the molten alloy powder is uniform in the powder particle composition of each alloy, , There is a problem that the hardness of the powder particles is strong and the compressibility is lowered and the molding property and the sintering property are deteriorated.

There is also a case where the iron-based powder and one or more additional metals are physically mixed and used. However, since the added powder is fine and has different shape and specific gravity, separation and component segregation occur. Accordingly, various manufacturing methods have been devised to manufacture the diffusion bonded powder in the form that the additive metal powder is partially diffused on the iron-based surface to solve the above problems.

In order to obtain a uniform alloyed alloy without segregation, an alloy is prepared by plating the surface of iron with an electroless plating method. However, the electroless plating method has a problem in that the manufacturing cost is high and the process is complicated. Cu) and nickel (Ni) were the most commonly used powders for bonding to iron based diffusion bonding powders.

In addition, the alloy component commonly used is carbon, which serves as a reducing agent for reducing the amount of the oxide of the sintered body, and at the same time, has an effect of effectively increasing strength and hardness. The carbon is mixed with the iron-based powder before compression and mainly uses the form of graphite powder. When the carbon is alloyed with the iron-based powder in advance, the iron-based powder is solid-solved to have high strength properties, so that the compressibility will be lowered.

A conventional method for producing a diffusion bonded powder is to prepare a reduced powder prepared through a reduction process after water injection by mixing with an additive metal and a partial diffusion process by heat treatment. In such a case, there is a problem in that the manufacturing cost of the reducing powder is about twice as high as that of the pure iron powder, since the heat treatment is performed once in the production of the reducing powder and the heat treatment in the partial diffusion step is performed twice.

In order to solve the above problems, the present invention provides a method for manufacturing an economical iron-based partially diffusion bonded powder by shortening a bonding time by using at least one of metal oxide powder and metal powder as bonding powder.

In one or more embodiments of the present invention, there is provided a method of manufacturing a steel sheet, comprising the steps of: preparing an iron-based powder having a surface oxidized by spraying molten steel to which at least one metal component is added; Mixing an additive powder composed of at least one of a metal oxide powder or a metal powder with the oxidized iron powder uniformly; A step of partially diffusion-bonding the reduced powder to the surface of the iron-based powder while reducing the iron-based powder and the additive powder in a heat treatment furnace in a reducing atmosphere; And a step of crushing the partially diffusion bonded mass of powder.

The temperature of the heat treatment furnace is in the range of 600 to 900 ° C., and the reduction time in the heat treatment furnace is 20 to 120 minutes.

Metal component is added to the molten steel is a molybdenum (Mo), W (tungsten), chromium (Cr), manganese (Mn) or vanadium (V) can be one or more of the metal-oxide powder is one of Cu ₂ O or NiO And the metal powder is at least one of Cu and Ni.

The reducing atmosphere may be a hydrogen atmosphere or a mixed atmosphere of hydrogen and nitrogen, and the fraction of hydrogen in the mixed atmosphere of hydrogen and nitrogen is 30 wt% or more.

The content of molybdenum (Mo) added to the surface of the iron-based powder oxidized by spraying is 0.3 to 1.5% by weight, and the average particle size of the water-sprayed iron-based powder is 250 탆 or less .

In addition, when the metal powder excluding the oxygen (O) content is converted into the metal powder, the additive powder has an average particle size of 0.3 to 7.0 wt% And the total amount of copper and nickel is 2.0 to 7.0% by weight when converted into a metal component excluding the content of oxygen (O). .

According to the embodiment of the present invention, it is possible to provide a powder of excellent quality and reduce the manufacturing cost by directly preparing the iron-based diffusion bonded powder by oxidizing the surface-oxidized unreduced iron-based powder prepared by prealloying the additive powder.

In addition, since at least one powder of metal oxide powder or metal powder is used as the bonding powder, it is possible to manufacture economical iron-based diffusion bonded powder by shortening the processing time. As a result, it can greatly contribute to the improvement of the technology and price competitiveness of the automobile and machine-related parts industry utilizing the iron-based diffusion bonding powder.

FIG. 1 is a view illustrating a manufacturing process of an iron-based diffusion bonded powder according to an embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described in detail below. However, it is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It is intended that the disclosure of the present invention be limited only by the terms of the appended claims.

In the embodiment of the present invention, the oxidized unreduced iron-based powder and the additive powder are mixed, and the reduction and partial diffusion process are simultaneously performed through one heat treatment, thereby improving the productivity and manufacturing the partial diffusion bonded powder more economically.

1 is a view illustrating a manufacturing process of a partial diffusion bonded powder according to an embodiment of the present invention. Hereinafter, a procedure of manufacturing a partial diffusion bonded powder will be briefly described with reference to FIG.

The method of manufacturing an iron-based diffusion bonded powder according to an embodiment of the present invention is different from the conventional method of partially bonding an iron powder and a different kind of metal powder through heat treatment, (S10), mixing the oxidized iron-based powder with an additive powder containing at least one of metal-based oxide powder and metal powder (S20), and heat-treating the mixed powder in a reducing atmosphere (S30) the surfaces of the reduced iron-based powder and the additive powder are partially bonded (S30), and then the compacted powder is partially fractured at a high temperature (S40) They are separated from each other.

In the embodiment according to the present invention, components such as Mo, W, Cr, Mn, V and the like are added to the pure steel molten steel, which can be dissolved in the Fe powder to improve strength and hardness.

If 0.3 wt% or less of the molybdenum (Mo) is added to the pure steel molten steel, addition of less than 0.3 wt% does not exhibit sufficient strength. If the molybdenum is added in an amount of more than 1.5 wt% The content of molybdenum is limited to the above range in the examples according to the present invention. More preferably 0.5 to 1.0% by weight.

Oxygen existing on the surface or inside of the metal oxide powder not subjected to reduction treatment reacts with hydrogen upon heat treatment to form water vapor, and this water vapor has decarburization effect in the iron-based powder. At this time, the same effect can be obtained when a metal-based oxide powder other than metal powder is added to perform partial diffusion bonding. In addition, it is inexpensive as compared with the reduced metal powder, and a process cost saving effect can also be obtained.

Among the bonding powders to be mixed with the additive powder, the metal powders other than the metal oxides can quickly react to the reduced steel surface preferentially during the heat treatment process, thereby reducing the diffusion time and shortening the overall process time.

The carbon present in the iron-based powder during the water-sprayed powder production reacts with the oxygen in the iron-based powder or the oxygen of the additive powder in the reducing step of the reducing atmosphere to increase the reducing effect. Therefore, it is important to maintain an appropriate ratio of the carbon and oxygen content in the iron-based powder to the oxygen content of the oxide powder added.

The metal oxide powder to be added to the iron-based powder may include at least one of Cu ₂ O and NiO, and the metal powder may include at least one of Cu and Ni.

In this case, the content of copper (Cu) is 0.3 to 7.0% by weight, and the content of copper (Cu) is an amount of metal converted into metal excluding the content of O in the state where the metal oxide powder and the metal powder are mixed. If it is added in an amount of less than 0.3% by weight, the effect of improving the strength by the addition of copper (Cu) can not be exhibited. If it is added in an amount of more than 7.0% by weight, The content of copper is limited to the above range. More preferably 0.5 to 5.0% by weight.

The content of nickel (Ni) is 0.3 to 3.0 wt%, and the content of nickel (Ni) is an amount of metal converted to metal, excluding the content of O in the state where the metal oxide powder and the metal powder are mixed. If it is added in an amount less than 0.3% by weight, there is no increase in strength and ductility, and when it is added in an amount exceeding 3.0% by weight, the strength is rather high and compressibility may be deteriorated. The content is limited to the above range. More preferably 0.5 to 2.0% by weight. The total content of the copper and nickel is preferably 2.0 to 7.0% by weight.

The average particle size of the iron-based powder produced through the water spraying may be 250 탆 or less, more preferably 50 to 150 탆.

Conveyor belt furnace can be used for the reduction and partial bonding process after uniformly mixing the iron-based powder and the metal-based oxide powder produced by the above-mentioned water-spraying.

Further, the temperature in the heat treatment furnace of the embodiment according to the present invention is limited to 600 to 1000 占 폚 and the reduction time to 20 to 120 minutes.

If the temperature of the heat treatment furnace is lower than 600 ° C, the productivity is lowered because a process time of 120 minutes or more is required to reduce all powders. When the temperature is higher than 1000 ° C, diffusion between the powders occurs actively, The surface of the layer is hardened and hydrogen can not permeate in the depth direction, so that the powder close to the conveyor belt may not be reduced. In order to reduce all the powders, a small amount of powder must be input, The temperature of the heat treatment furnace in the embodiment according to the present invention is limited to the above range.

Further, when the heat treatment in the embodiment according to the present invention is performed for less than 20 minutes, the reduction and partial diffusion bonding may not be sufficiently performed, and if it exceeds 120 minutes, there is no additional advantage. The heat treatment time in the example is limited to the above range.

In the reducing atmosphere in the embodiment according to the present invention, a hydrogen atmosphere or a mixed gas of hydrogen and nitrogen may be used, and the ratio of hydrogen in the mixed gas may be 30% or more. If the hydrogen ratio is lower than 30%, heat treatment is performed in an excessive amount of nitrogen atmosphere to cause trapping of nitrogen, thereby lowering the physical properties of the powder. Therefore, in the embodiment of the present invention, hydrogen The ratio is limited to 30% or more.

More specifically, the iron-based diffusion bonded powder is produced by preparing a molten steel for producing iron powder by using a converter or an electric furnace. At this time, the component contents such as molybdenum (Mo), chromium (Cr), manganese (Mn), vanadium (V) and the like are controlled through the component control of the molten steel. The iron-based powder thus produced is collected, dehydrated and dried using a predetermined dewatering equipment to remove water mixed with the iron-based powder in the case of moisture.

At this time, a process of separating the impurities of the dried iron-based powder may be further included. According to the conventional method of manufacturing a diffusion bonded powder, a reducing process for removing the oxide layer formed on the surface of the iron-based powder is performed in the next water-spraying step, whereby a reduced iron-based powder from which the oxide layer is removed on the surface can be obtained.

The additive powder including the reduced iron-based powder and the metal powder or the metal-based oxide powder may be uniformly mixed and then the additive powder may be partially diffused into the surface of the iron-based powder through the partial diffusion bonding heat treatment. The iron-based powder mass obtained through the heat treatment at a high temperature is prepared by separating the diffusion bonded powder clogged through a general crusher such as a ball mill, a hammer crusher and the like from each other to form an iron-based diffusion bonded powder.

In the embodiment of the present invention, the iron-based powder produced through the conventional water jetting process is subjected to a reduction process before mixing with the additive powder, but this process is omitted in the embodiment of the present invention, and then the reduction process is performed in the partial bonding heat treatment process And presented a method of treating them together.

In the process of manufacturing the iron-based diffusion bonded powder, it is necessary to perform a heat treatment process for reducing the oxidized iron-based powder produced by the water treatment and a partial bonding heat treatment process for joining the powder through the diffusion reaction between the powders mixed with the iron-based powder. This high-temperature process is more expensive than the previous water injection process, and hydrogen is used to create a reducing atmosphere, so the process cost is significantly higher. Accordingly, the iron-based diffusion bonded powder currently sold on the market is sold at about twice the price of pure iron powder.

As the demand for excellent mechanical properties in the component manufacturing technology using the iron-based powder increases, the demand for the iron-based diffusion bonded powder excellent in the dispersibility of the added powder in addition to the pure iron and iron mixed powder is also increasing. It is possible to manufacture the iron-based diffusion bonded powder by a more economical method.

In addition, when the metal-based oxide powder and the metal powder are mixed at the same time as the diffusion bonding powder, the oxygen in the surface of the iron-based powder and the additive powder reacts with hydrogen to generate steam, which increases the decarburization rate in the iron-based powder see.

In addition, when the metal oxide powder and the metal powder are added together in the embodiment according to the present invention, diffusion reaction occurs with the metal powder partially mixed and mixed on the surface of the steel during the heat treatment, and only the metal oxide powder is used The heat treatment time can be reduced as compared with the method of producing the diffusion bonded powder.

Hereinafter, embodiments of the present invention will be described in more detail.

≪ Example 1 >

A 0.5 wt% molybdenum (Mo) was added to the pure steel molten steel in the preparation of the iron-based powder using a high-pressure water jetting apparatus to prepare a surface-oxidized iron-based powder. Cu ₂ O and NiO, which are metal oxide powders, were added to the iron-based powder and uniformly mixed. At this time, the content of the metal oxide powder was added in a ratio of 1.5% by weight of metal Cu and 1.75% by weight of metal Ni, respectively. The uniformly mixed powder was subjected to a heat treatment for 90 minutes in a heat treatment furnace at a temperature of 1030 캜. At this time, the ratio of hydrogen to nitrogen in the heat treatment furnace was 1: 1 and the partial pressure of oxygen was kept below 100 ppm. Powder masses subjected to reduction and partial diffusion bonding by heat treatment were generally pulverized and crushed using a hammer crusher as a commercial equipment, and the diffusion bonded powder clumped at high temperature was peeled off to prepare iron type diffusion bonded powder.

Since the iron-based diffusion bonded powder according to the present invention was manufactured to specifically calculate the effect that can be generated by applying the present invention, and based on FD4600A of GKN Hoeganaes Co., which is currently sold as a comparative group, The same amount of composition was added. Table 1 shows the iron-based diffusion bonded powder (A), the iron-based diffusion bonded powder (B) prepared by the conventional method, the FD4600A (C) as the additive powder, Can be known.

division carbon
(weight%) Oxygen
(weight%) nitrogen
(weight%) Copper
(weight%) nickel
(weight%) molybdenum
(weight%) surface
density
(g / cm ³⁾ Flow rate
(s / g) A 0.0082 0.1258 0.0097 1.492 1.749 0.498 3.02 27.4 B 0.0079 0.1311 0.008 1.512 1.759 0.492 2.98 27.0 C 0.0078 0.1279 0.0067 1.505 1.751 0.503 3.01 27.3

0.6% by weight of graphite and 0.6% by weight of lubricant (ZS1000F) were added to the A, B and C diffusion bonding powders, and the mixture was homogeneously mixed using a double cone mixer. Lt; / RTI > The uniformly mixed powders were evaluated for molding characteristics using a ring mold having an outer diameter of 40 mm, an inner diameter of 17 mm, and a thickness of 5 mm. Moldability evaluation was carried out more than ten times under the pressure of 700 MPa, and the density and the molding strength of the formed moldings were compared.

division Molding density (g / cm ³ ) Molding strength (average) A 7.12 ± 0.04 14.1 ± 0.5 B 7.12 ± 0.05 14.2 ± 0.5 C 7.11 + 0.02 14.0 ± 0.5

As shown in Table 2, the density of the molded article of the iron-based diffusion bonded powder produced by the example according to the present invention shows a molding density similar to that of the powder prepared by the conventional technique and the conventional powder, I could confirm.

In order to confirm the sintering characteristics of the iron-based diffusion bonded powder produced by the example according to the present invention, the ring-shaped formed body and the tensile strength specimen for measuring the tensile strength according to ASTM E8 And sintered at 1150 ℃ for 30 minutes. At this time, the atmosphere of the sintering furnace was 1: 3 ratio of hydrogen to nitrogen.

division Sintered density
(g / cm ³⁾ Maximum tensile strength
(MPa) Yield strength
(MPa) Elongation
(% in 25.4 mm) A 7.1 ± 0.3 650 ± 30 470 ± 30 2.8 ± 0.4 B 7.12 ± 0.4 670 ± 20 480 ± 30 3.1 ± 0.2 C 7.11 ± 0.3 660 ± 20 480 ± 20 3 ± 0.3

As shown in Table 3, the sintered density of the iron-based diffusion bonded powder produced by the example according to the present invention was similar to that of the diffusion bonded powder and the conventional powder prepared by the conventional method. In addition, the maximum tensile strength and yield strength showed a difference of about 10 to 30 MPa, but it was confirmed that the tensile strength and the yield strength have an approximate value. The elongation is in the range of 0.1 to 0.8, and the sintering property is equivalent to that of the commercial powder.

≪ Example 2 >

According to the embodiment of the present invention, when the iron-based diffusion bonded powder is produced, the content of the metal component in the metal oxide powder (Cu 2 O, NiO) bonded to the molybdenum (Mo) Thirteen specimens were fabricated and compared in order to calculate the effect specifically.

division Copper
(weight%) nickel
(weight%) molybdenum
(weight%) Forming density
(g / cm3, in 700 MPa) The tensile strength
(MPa) A 1.492 1.749 0.498 7.12 650 B 1.502 1.751 0.099 7.14 500 C 1.491 1.743 0.289 7.13 610 D 1.495 1.755 0.989 7.09 730 E 1.508 1.749 1.511 6.98 820 F 1.489 0.112 0.502 7.14 510 G 1.499 0.497 0.501 7.13 580 H 1.492 2.989 0.494 7.08 730 I 1.493 4.995 0.510 7.01 830 J 0.108 1.745 0.511 7.15 540 K 0.508 1.755 0.497 7.14 600 L 3.012 1.753 0.498 7.08 700 M 5.010 1.749 0.508 7.03 810

As shown in Table 4, there is a difference in molding density and tensile strength depending on the content of molybdenum (Mo) in the iron-based powder and the content of copper (Cu) and nickel (Ni) A to E show changes in the content of molybdenum (Mo) in each of the iron-based diffusion bonded powders produced by the examples according to the present invention. In the case of 0.1 wt%, the change in the molding density was insignificant but the mechanical properties were poor. The weight% showed good mechanical properties, but the molding density at the same pressure was low, indicating that the compressibility was not good.

F ~ I and A show the results depending on the content of nickel (Ni). When the content is less than 0.5% by weight, a sharp decrease in the strength is observed. When the content is 5% by weight, J ~ M, A is the experimental result according to the content of copper (Cu) which is partially diffusion bonded. As in the case of nickel, no further improvement was found in the powder of 0.5 wt% or less or 5 wt% of copper (Cu) diffusion bonded. In addition, as a result of the tests of I and M, it was confirmed that when the content of copper (Cu) and nickel (Ni) is 5 wt% or more in total, the molding density is not good.

Molding pressure and sintering conditions can be minimized to obtain mechanical properties such as density, which is a target in manufacturing automobile and sintering parts by using powder having excellent moldability and sintering ability, so that the lifetime of expensive mold requiring precision is extended , It is possible to manufacture parts having high density and high strength and toughness, so that the effect of increasing the physical properties of the parts for sintering can be expected.

Through such examples, the powder, molding and sintering characteristics of the iron-based diffusion bonded powder produced by the examples according to the present invention exhibited the same level of properties as those of the conventional powder and the method used for producing the conventional diffusion bonded powder .

≪ Example 3 >

In the third embodiment, a case where an oxide powder and a metal powder are added as an additive powder will be described.

Molybdenum (Mo) of 0.5 wt% was added to the pure steel molten steel in the preparation of the iron - based powder using a high - pressure water jetting apparatus to prepare a surface - oxidized unreduced iron - based powder. A metal oxide powder (Cu ₂ O or NiO) and metal powder (Cu, Ni) were simultaneously mixed with the iron-based powder.

The content of metal copper (Cu) and nickel (Ni) in the metal oxide powder and the metal powder used as the bonding powder were 1.5% by weight and 1.75% by weight, respectively, except for O ₂ contained in the metal oxide to be. At this time, the ratio of the metal oxide powder to the metal powder used as the bonding powder was 1: 1. The uniformly mixed powder was subjected to a heat treatment for 90 minutes in a heat treatment furnace at a temperature of 1030 캜. At this time, the ratio of hydrogen to nitrogen in the heat treatment furnace was 1: 1, and the partial pressure of oxygen was maintained at 100 ppm or less. Powder masses subjected to reduction and partial diffusion bonding by heat treatment were generally pulverized and crushed using a hammer crusher as a commercial equipment, and the diffusion bonded powder clumped at high temperature was peeled off to prepare iron type diffusion bonded powder.

division Mo
(weight%) Cu
(weight%) Ni
(weight%) C
(weight%) O
(weight%) N
(weight%) surface
density
(g / cm3) Flow rate
(s / g) A 0.499 1.495 1.753 0.0077 0.1269 0.008 2.98 27.1 B 0.501 1.499 1.745 0.0092 0.1305 0.0082 2.99 27.1 C 0.498 1.512 1.749 0.0082 0.1258 0.0097 3.02 27.4 D 0.503 1.505 1.751 0.0078 0.1279 0.0067 3.01 27.3

To calculate the possible effects of the examples according to the present invention, the same amount of composition was added based on GKN Hoeganaes FD4600A currently sold as a comparative group. Also, in order to verify the effect of the metal oxide powder and the metal powder mixed powder as the bonding powder, they were manufactured under the same conditions using only the metal powder and the metal oxide powder, respectively.

The results are shown in Table 5. Table 5 shows the iron-based diffusion bonded powder (A) produced by the example according to the present invention, the iron-based diffusion bonded powder (B) produced by using the metal powder as the bonding powder and the metal- The component content, the apparent density and the fluidity of the prepared iron-base diffusion bonded powder (C) and the commercial powder FD4600A (B).

As a result of the component analysis and the powder characteristics evaluation, it was confirmed that the method of manufacturing the iron-based partial diffusion bonding through one heat treatment process using the powder for bonding which is the mixture of the unreduced iron-based powder, the metal oxide powder and the metal powder, It is possible to fabricate an iron-based partially diffusion bonded powder at a level equivalent to that of commercially available powders currently sold. It can be seen that B and C powders using only metal powders and metal oxide powders as bonding powders respectively have powder characteristics equivalent to those of A and D.

<Example 4>

division Powder for bonding Heat treatment time (min)
Oxygen concentration (% by weight) / degree of dispersion (%) 30 minutes 40 minutes 50 minutes 60 minutes 90 minutes A Cu ₂ O, NiO
Cu, Ni 0.4213 / 85 0.1531 / 91 0.1308 / 96 0.1299 / 97 0.1269 / 98 B Cu, Ni 0.4158 / 86 0.1684 / 91 0.1384 / 93 0.1328 / 97 0.1305 / 97 C Cu ₂ O, NiO 0.5181 / 79 0.3128 / 83 0.2569 / 88 0.1351 / 92 0.1258 / 96

Table 6 shows changes in the properties of the powders with heat treatment time. In the case of preparing the A and B powders prepared in Example 3, it is possible to investigate the time reduction effect of the heat treatment process when the metal powders are mixed using the heat treatment process time. The characteristics of the powders were evaluated using the oxygen content according to the heat treatment time and the degree of dispersion indicating the degree of adhesion of the bonding powder to the surface of the steel.

The iron-based diffusion bonded powder produced by the example according to the present invention was divided into 10 equal parts, and a small amount of the specimens were sampled and filtered at 75 μm or more. Since the average particle size of the added metal powder was 40 μm or less, the degree of dispersion was measured by analyzing the components of the powder that was filtered at 75 μm or more by using the unfiltered powder and polish.

The oxygen content of A, B and C was high in 30 min, but the reduction of oxygen content in A and B is expected to occur actively from 40 min. As a result of the oxygen content, it was found that A and B added with the metal powder were compared with C prepared by using only the metal oxide powder, and the time reduction of the powders A and B was higher than that of the C powder The metal powders were rapidly diffused to shorten the partial diffusion process time. Although the shortened process time seems to be insignificant, in the present experiment, since 100 kg powder is manufactured per one experiment, it is expected that the process cost will be greatly reduced since it is increased to several thousand tons in actual commercialization stage. In the case of A and B, the oxygen content and the degree of dispersion were the same, but the metal oxide powder was inexpensive in terms of the raw material cost, and thus the business was excellent.

While the present invention has been described in connection with certain exemplary embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (12)

A step of preparing a non-reduced iron-based powder having a surface oxidized by spraying molten steel to which a metal component including molybdenum (Mo) is added;
Uniformly mixing an additive powder composed of a metal oxide powder and a metal powder into a non-reduced iron-based powder whose surface is oxidized;
A step of partially diffusion-bonding the reduced powder to the surface of the iron-based powder while reducing the iron-based powder and the additive powder in a heat treatment furnace in a reducing atmosphere; And
And crushing the partially diffusion bonded mass of powder,
The content of the molybdenum (Mo) is 0.3 to 1.0% by weight,
Wherein the metal oxide powder is Cu2O, NiO, or a combination thereof, and the metal powder is Cu, Ni,
Wherein the additive powder has a total content of copper and nickel of 2.0 to 5.0% by weight when converted into a metal component excluding the content of oxygen (O). The method according to claim 1,
Wherein the temperature of the heat treatment furnace is in the range of 600 to 900 占 폚. 3. The method of claim 2,
Wherein the reduction time in the heat treatment furnace is 20 to 120 minutes. The method according to claim 1,
Wherein the metal component added to the molten steel is at least one of W (tungsten), Cr (Cr), Mn (Mn), and vanadium (V). delete 3. The method of claim 2,
Wherein the reducing atmosphere is a hydrogen atmosphere or a mixed atmosphere of hydrogen and nitrogen. The method according to claim 6,
Wherein the hydrogen content in the mixed atmosphere of hydrogen and nitrogen is 30 wt% or more. delete The method according to claim 1,
Wherein the average particle size of the unirreated iron-based powder whose surface is oxidized by water spraying is 250 占 퐉 or less. The method according to claim 1,
Wherein the average particle size of the metal oxide powder and the metal powder is 10 to 40 占 퐉. delete delete

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