KR20100027320A - Manufacturing method of fe-based sintered body for filter and fe-based sintered body for filter - Google Patents

Abstract

PURPOSE: A manufacturing method of a Fe-based sintered body for a filter which has a thermal resistance function, and a Fe-based sintered body for a filter manufactured thereby are provided to easily sinter using cylindrical high-temperature sintering equipment. CONSTITUTION: A manufacturing method of a Fe-based sintered body for a filter which has a thermal resistance function is as follows. A molding body is manufactured by mixing and molding powder of Fe based alloy and powder for sintering. A Fe-based sintered body for a filter is manufactured to sinter the molding body. The average particle size of the powder of Fe based alloy is 100mesh or more, and 100mesh or less. The average particle size of the powder for sintering is 250mesh or more, and 100mesh or less. The powder for sintering is composed of Mn powder 95~45 weight% and Sn powder 5~55 weight%.

Description

Manufacturing method of iron-based porous sintered body for filter which prevents deterioration of heat resistance, and iron-based porous sintered body for filter produced by the same {Manufacturing method of Fe-based sintered body for filter and Fe-based sintered body for filter}

The present invention relates to a method for producing an iron-based porous sintered body for a filter using an iron base powder and a powder for sintering aids, and to an iron-based porous sintered body for a filter produced thereby.

BACKGROUND ART A method for manufacturing an iron-based porous sintered body for a filter and an iron-based porous sintered body for a filter produced thereby are known.

The iron-based porous sintered body for the filter is manufactured by sintering the iron base powder, but if the particle size of the iron base powder used is too small, it becomes a problem because it can not implement the proper air permeability, in order to solve this problem, the particle size of the iron base powder When the thickness is thick sintering is poor.

Therefore, in manufacturing the iron-based porous sintered body for filter, the powder for sintering aids to increase the size of the iron base powder to realize the proper air permeability, to compensate for the decrease in sinterability due to the coarse particle size of the iron base powder to promote sintering It is added together to the fat powder to allow sintering.

Powder for sintering aid added in the production of iron-based porous sintered body for filters, which has a lower melting point than iron (Cu), tin (Sn), zinc (Zn), phosphorus (P), boron (B), or cobalt Elements such as (Co) and copper alloys are used.

However, when the sintering aid powder having a low melting point is added to the iron base powder, the liquid phase is formed by melting during sintering, thereby greatly improving the sinterability, but the finished sintered body has a low heat resistance due to the low melting point of the sintering aid powder. Not only is there a disadvantage in that the pores are blocked due to over-melting during sintering, which also causes a problem of poor breathability.

That is, in the case of using a low melting point metal or a metal alloy alloyed to a low melting point as a powder for sintering aid, the sintering property is improved due to the opposite characteristics of sintering and heat resistance, but the heat resistance and breathability of the product itself are lowered.

This problem is particularly problematic for filters that are exposed to very hot environments. For example, in the case of a filter used in a gas generator of an automobile air bag, a gas of high temperature and high pressure is generated by the explosive powder, and the filter must have heat resistance and adequate breathability to withstand such high temperature and pressurized gas. The porous sintered body can realize proper air permeability, but has the disadvantage of being weak in heat resistance.

When the iron-based porous sintered compact for the filter is melted in a high temperature environment, it not only lowers the strength of the porous sintered compact, but also causes the pores of the porous sintered compact to be severely deteriorated, thereby acting as a factor that lowers the function of the porous sintered compact.

The present invention has been made to solve the problems of the prior art as described above.

On the other hand, the applicant of the present invention has filed a patent application of the Republic of Korea Patent Application No. 10-2008-0076955, the patent application in the powder for iron base powder having a relatively large particle size of the manganese powder constituting the sintered solid and iron powder for sintering aid powder When the mixture is added as a sinter and then sintered, it is possible to expect good sinterability during the manufacturing process and to propose a technique capable of preventing the heat resistance of the finished sintered body from being lowered.

The present invention further goes to the above patent application by mixing tin powder based on manganese powder as the sintering aid powder and sintering the mixed powder for sintering aid consisting of a mixed powder of manganese powder and tin powder to the iron base powder and sintering. As well as the effect of increasing the sintering property and the heat resistance, as well as to improve the crushing strength of the manufactured sintered body.

In order to solve the above problems, the present invention, in the manufacturing method of the iron-based porous sintered body for a filter for sintering the molded body after producing a molded body by mixing and molding the powder for iron base and powder for sintering aids of pure iron or iron alloy: The iron base powder is a coarse spherical powder having an average particle size of 100 mesh or more and 10 mesh or less; The powder for sintering aid is a mixed powder of manganese powder and tin powder having an average particle size of 250 mesh or more and 100 mesh or less and a weight ratio of 95: 5 to 45:55, wherein the powder for sintering aid is 1wt% with respect to the iron base powder. It is mixed at ~ 5wt%, characterized in that the sintering of the molded body is made between 1100 ℃ ~ 1350 ℃.

In the above, the iron base powder is preferably an average particle size of more than 40 mesh 10 mesh.

The iron-based porous sintered compact for filters produced by this is mostly composed of Fe-Mn solid solution in the surface and neck of the sintered particles constituting the sintered compact.

In the present invention, in the manufacture of a filter, when a coarse spherical powder having a mean particle size of 100 mesh or more and 10 mesh or less of pure iron or iron alloy powder is sintered, a mixed powder of manganese powder and tin powder is mixed as a sintering aid powder. By adding and mixing, the sintering can be promoted, and the sintering can be easily performed using a normal high temperature sintering equipment, and at the same time, the heat resistance and the air permeability of the completed filter sintered body can be prevented and the improvement of the crushing strength can be achieved.

Hereinafter, specific contents for the practice of the present invention will be described.

In general, a method for manufacturing an iron-based porous sintered body for a filter includes: i) mixing powders to form a mixture, ii) press forming the mixture to an appropriate pressure to produce a green body, and iii) Sintering the molded body.

Hereinafter, a description of a general method for manufacturing an iron-based porous sintered body for a filter will be omitted as much as possible, and the following will mainly describe specific or significant points in an embodiment of the present invention.

(1) formation of mixture

In order to form a mixture, the iron base powder, the mixed powder for sintering aids (mixed powder of manganese powder and tin powder), and a lubricant are mixed suitably.

It is understood that the lubricant may be suitably applied as long as it is a lubricant generally used in powder metallurgy.

The method of forming the mixture may be used a conventional mixing method for sintering, the specific matters are the particle size of the powder for the iron base, the particle size of the powder for the sintering aid, the mixing ratio of the powder for the sintering aid to the powder for the iron base, The mixing ratio of manganese powder and tin powder in the sintering aid powder.

1wt% ~ 5wt% of mixed powder for sintering aid is mixed with powder for iron base, iron base powder is coarse spherical powder with average particle size of 100 mesh or more and 10 mesh or less, and mixed powder for sintering aid has an average particle size of 250 It is preferable that they are mesh or more and 100 mesh or less.

Pure iron powder or iron-based alloy powder may be used as the iron base powder.

In addition to the pure iron powder, the inventors found that Fe-5.0wt% Sn-0.5wt% P-0.3 ~ 0.7wt% C, Fe-4wt% Ni-0.5wt% Mo-1.5wt% Cu-0.3 ~ 0.7wt as iron alloy powder. Experiments were conducted on% C, Fe-0.1wt% Mo-2.0wt% Cu-0.1wt% S-0.3 ~ 0.7wt% C, etc., but the effects of the present invention were verified, but in addition to the iron-based alloy powder, It is understood that the alloy powder can be used as the iron base powder of the present invention.

When iron is added as an iron base powder, or when iron is added to impurities or iron-based alloy powders have a lower melting point than iron, thereby lowering the sintering temperature.

For example, the effect of the carbon content in the iron, the melting point of iron is 1538 ℃, iron and carbon in the iron-carbon state diagram forms a process at 1123 ℃, iron composition containing 4.3% of carbon is 1123 ℃ Will melt in. However, iron base powders commonly used as sintering materials generally have a carbon content of less than 1.2%. In the section having a carbon content of less than 1.2%, they are slightly lower than the melting point of iron. The lower the sintering temperature can be lowered.

The average particle size of the iron base powder used as the known powder of the iron-based porous sintered body is preferably 100 mesh or more and 10 mesh or less.

In the case of a general iron-based sintered body, the particle size of the iron base powder is usually 100 mesh or less. However, in the case of the porous sintered body for the filter, in order to ensure good air permeability, the average particle size is preferably 100 mesh or more. As the average particle size of the iron base powder increases, the air permeability increases, but the sinterability decreases due to the reduction of the surface area of the powder. Since the surface area of the powder is proportional to the third power of the radius, the larger the particle size of the powder, the faster the surface area decreases, and thus the sinterability deteriorates rapidly.

Therefore, the average particle size of the iron base powder is preferably 40 mesh or more and 10 mesh or less.

A mixed powder of manganese powder and tin powder is added and mixed as a sintering aid powder in order to prevent sintering deterioration due to the increase in the particle size of the iron base powder.

A mixed powder of manganese powder and tin powder is added to the iron base powder as the sintering aid powder.

45 wt% to 95 wt% of the sintering aid powder is composed of manganese powder in order to prevent sintering and deterioration of heat resistance when manufacturing the iron-based sintered body for the filter.

Since manganese powder has a high affinity with oxygen, when the particle size of the powder is small, it is difficult to store and handle due to its high reactivity with oxygen. Because of this problem, it is generally recommended to use a particle size of more than 325 mesh.

However, in addition to the above handling and oxidation problems, the average particle size of the manganese powder is preferably 250 mesh or more in consideration of aggregation of fine particles.

On the other hand, the larger the particle size of the manganese powder, it is preferable to have an average particle size of a smaller size than the powder for iron base because the concern about segregation and partial excessive liquid phase may occur. Therefore, the average particle size of the manganese powder is preferably 100 mesh or less.

In consideration of this point, the average particle size of the manganese powder is most preferably 250 mesh or more and 200 mesh or less.

1 is a Fe-Mn state diagram.

As can be seen in Figure 1 pure manganese has a melting point of 1246 ℃, pure iron has a melting point of 1538 ℃

Iron and manganese also form a shiver solid solution that is employed at all rates. In addition to manganese, there are elements that make up the solid solution to iron (nickel (Ni), chromium (Cr), cobalt (Co), vanadium (V), platinum (Pt), palladium (Pd) and rhodium (Rh)). Most of the other elements are very expensive and the melting point is very high, which does not improve the sinterability.

That is, in general, elements that make up a solid solution to iron may be added to the iron base powder for the purpose of improving heat resistance, but these elements have a very high melting point and thus cannot be used for the purpose of promoting sinterability. The use of such elements requires a much higher sintering temperature than 1250 ° C., which is the sintering temperature in the normal high temperature range, and therefore cannot be sintered with a conventional sintering apparatus and requires a special sintering apparatus. In addition, if the particle size of the iron base powder is thicker, the surface area of the powder is reduced and the iron base powder is more stabilized.The principle of sintering is that the particle size of the powder is small. Because of the tendency to stabilize and reduce the surface area, the diffusion phenomenon occurs and sintering is promoted. Therefore, in the case of iron base powder having a large particle size, such sintering driving force is small or absent, so that it is more difficult to promote sintering using the above elements. .

However, when the iron base powder and the manganese powder are sintered in a mixed state, the overall melting temperature of the manganese powder can be lowered due to the low melting point of the manganese powder.In addition, in the sintered sintered body, manganese is dissolved in iron to form Fe-Mn solid solution. The -Mn solid solution is different depending on the component ratio, but has a relatively high melting point, thereby improving heat resistance.

In addition, as the amount of manganese powder is increased, the sintering property may be accelerated because the sintering property is promoted. The melting point of the powder is more affected. That is, when the manganese powder addition amount is added, the finished sintered compact has relatively high heat resistance (that is, a melting point close to the melting point of iron).

When the manganese powder is mixed with the iron base powder as the sintering aid powder as described above, not only the sintering property can be improved but also the heat resistance deterioration due to the sintering aid powder can be prevented.

In order to improve the crushing strength of the sintered compact when manufacturing the iron-based sintered compact for the filter, 5 wt% to 55 wt% of the sintering aid powder is composed of tin powder. In addition, when the tin powder is 55wt% or more, the sintering promoting effect is sharply improved to increase the sintering ability, but the surface diffusion between the coarse spherical powders is increased during sintering, which increases the pore blockage between the coarse spherical powders and thus lowers the breathability. Due to the residual tin, there is a problem that the heat resistance is lowered. When the tin powder is 5 wt% or less, the effect of adding tin is extremely small. Therefore, the manganese powder and the tin powder in the sintering aid powder are preferably mixed in a weight ratio of 95: 5 to 45:55.

As described above, the present embodiment not only uses manganese powder as the powder for sintering aid, but also adds tin powder to the extent that it does not affect the effect of preventing the lowering of heat resistance by the manganese component, thereby improving the crushing strength of the sintered compact.

When the mixed powder for sintering aids in which manganese powder and tin powder are mixed in a weight ratio of 95: 5 to 45:55 is mixed with the iron base powder, the tin powder during sintering precedes the manganese powder due to the low melting point (232 ° C) of the tin powder. As the molten metal reacts with the iron base powder to form α-Fe, the diffusion speed increases, and most of the tin diffuses into the iron base powder before reacting with manganese. After the reaction with the powder, the finished sintered body is made of iron base powder as sintered particles, and most of the surface part and the neck part are made of Fe-Mn solid solution. However, when the tin powder is 55wt% or more in the powder for sintering aid, the sintering promoting effect is sharply improved and the sintering property is further increased. Increased air permeability is lowered and heat resistance due to residual tin is lowered.

As an element that can be contrasted with tin, copper (Cu, melting point 1083 ° C) and zinc (Zn, melting point 420 ° C), which are low melting point elements that can be used for sintering aids, promote sintering when added for sintering aids. Although the effect occurs, the sinterability is improved, but in the case of copper and zinc, copper or zinc is first melted during sintering to react with the iron base powder to form γ-Fe, and the diffusion rate is slow. Reacted with manganese powder, the finished sintered compact forms a large amount of Fe-Mn-Cu solid solution or Fe-Mn-Zn solid solution on the surface and the neck by using the iron base powder as sintered particles. It becomes a factor which rather inhibits the effect of the heat resistant fall prevention by Fe-Mn solid solution formation.

That is, when the iron base powder and the mixed powder of manganese powder and tin powder are sintered, the overall melting temperature of the sintered compact can be lowered due to the low melting point of the manganese powder and tin powder. First of all, the surface part and the neck part of the iron base powder, which are dissolved in iron and some of the tin is dissolved in manganese, and then dissolved in iron to form the sintered particles of the sintered body, are mostly composed of Fe-Mn solid solution. It will contain Sn.

Therefore, the sintered body composed mainly of Fe-Mn solid solution of the surface part and the neck part of the sintered particles has a relatively high melting point to prevent a decrease in heat resistance of the sintered body. Physical properties such as strength are improved.

For this reason, the sintering aid powder, which is a mixed powder of manganese powder and tin powder, preferably has an average particle size of 250 mesh or more and 100 mesh or less, more preferably 250 mesh or more and 200 mesh or less, and manganese powder of the sintering aid powder. The mixing ratio of and tin powder is preferably 95: 5 to 45:55 by weight.

The addition ratio of the mixed powder for sintering aid is preferably mixed at 1wt% to 5wt% with respect to the iron base powder.

The addition ratio of the mixed powder for the sintering aid is related to the particle size of the manganese powder and the tin powder and the particle size of the iron base powder, but in any case, when it is added at 0.5 wt% or less with respect to the iron base powder, The role is minimal. Therefore, the mixed powder for the sintering aid is preferably added 1wt% or more based on the iron base powder.

In addition, when the mixed powder of manganese powder and tin powder is added more than 10wt% with respect to the iron base powder, the excessive liquidity or sintering surface adversely affects air permeability, and also causes difficulty in dimensional management or shape maintenance. Therefore, the mixed powder of manganese powder and tin powder is preferably added at 5wt% or less relative to the iron base powder.

Lubricant is added to facilitate molding, and it is sufficient that a conventional powder metallurgical lubricant is used. Lubricant is removed during the process of heating the shaped body to reach the sintering temperature. A representative example of a lubricant is stearic acid. Stearic acid may usually be added in an amount of about 0.5 wt% to 1.0 wt% based on the total weight of the powder.

(2) molding body forming step

Producing a molded body from the mixture as described above may be used as is conventional conventional methods.

For example, a molded article may be manufactured by molding the mixture obtained by the above mixing at a pressure of 600 to 700 MPa. However, the molding pressure may be used in a variety of molding pressure depending on the performance of the product required, the molding method may also be used in a variety of ways, such as pressure molding as well as filling molding.

(3) sintering step

The sintering step can be divided into the main sintering and the pre-sintering for removing the lubricant, but the pre-sintering is naturally solved in the process of raising the temperature in the sintering furnace for the main sintering, and thus cannot be regarded as the core of the present invention.

The molded product prepared as described above is sintered between 1100 ° C. and 1350 ° C. in a sintering furnace or heating apparatus in which a protective atmosphere is maintained.

The sintering temperature may be selected from 1100 ° C to 1350 ° C according to the composition of the iron base powder, the particle size of the iron base powder, the particle size of the sintering aid powder, the addition ratio of manganese powder and tin powder.

That is, the sintering temperature of the present invention is 1100 ° C to 1350 ° C, which is a typical sintering temperature, because a mixed powder of manganese powder and tin powder is added as a sintering aid powder. That is, the sintering temperature of the present invention does not require a very high sintering temperature that cannot be sintered by a normal sintering of 1350 ° C. or more even though the powder for iron base having a very large particle size is sintered.

As described above, the appropriate temperature as the sintering temperature is lower as the particle size is smaller, and as the addition ratio of manganese powder and tin powder is higher, it is generally lowered according to the amount of elements other than iron contained in the iron base powder.

In addition, the sintering according to the present invention is formed so that the Fe-Mn solid solution forming the electrified solid so that the melting point of the sintered compact completed by sintering is not lowered, so that the heat resistance is not lowered compared to the iron alloy to prevent heat resistance lowering, conventional sintering The effect of improving heat resistance can be expected as compared with the preparation, and further improved sinterability can be expected by mixing tin powder with manganese powder, thereby increasing the crushing strength of the sintered body.

The iron-based porous sintered body for the filter manufactured by the series of manufacturing methods as described above has excellent breathability, relatively high heat resistance, and high rolling strength.

2 is a structure photograph of an iron-based porous sintered body for filters manufactured by various compositions.

Picture (A) on the left is a structure picture when the powder for sintering aid is not added. Picture (B) in the middle shows that the powder for sintering aid is added at 3wt% relative to the powder for iron base, but the powder for sintering aid is manganese powder. And the tin powder is a photograph of the structure when the weight ratio of 80:20, the photo on the right (C) shows that the sintering aid powder is added in 3wt% to the iron base powder, but the sintering aid powder is manganese powder and tin powder It is a structure | tissue photograph when it mixes in the weight ratio of 20:80.

When the sintering aid powder is added, it can be seen that the texture photographs of the surface and the neck of the sintered particles are different depending on the mixing ratio of the manganese powder and the tin powder.

In the picture, the sintered particles forming the structure of the sintered body are iron base powder, and in the case of the sintered body (B) manufactured with manganese powder and tin powder at 80:20, most of the surface and neck portions of the sintered particles are diffused with manganese. Therefore, it exists in the rich (rich) phase of the Fe-Mn solid solution dissolved in iron, and the pores formed between the sintered particles form open pores vented to the outside of the sintered body.

However, in the case of the sintered compact (C) prepared by using manganese powder and tin powder at 20:80, Fe-Mn solid solution in which manganese is dissolved in iron is partially present. That is, in the case of C, the surface portion and the neck portion of the sintered particles are mostly sintered by diffusion while the tin powder melts as the sintering proceeds. It is made of a relatively low melting point Fe-Sn intermetallic compound formed by the reaction, the iron-based porous sintered body thus produced causes a problem that the heat resistance at a high temperature is lowered.

Experimental Example 1

Iron coarse spherical powder having an average particle size of 20 mesh and a sintering aid powder having a mean particle size of 200 mesh (a mixed powder obtained by mixing a manganese powder with a tin powder in a weight ratio of 45:55) having a pure iron composition, based on the weight of the iron base powder. After mixing from 0.1wt% to 7wt% and mixing under pressure at 1500kgf / cm ² to produce molded bodies of the same type, the molded bodies were sintered at 1300 ° C. for 60 minutes in a sintering furnace with a protective atmosphere.

The characteristics (pressure strength, neck size) of the iron-based porous sintered compact for filters were confirmed.

Experiment number Powder addition rate for sintering aid (wt%) Characteristics Rolling strength (kgf / mm ² ) Neck size (μm) Remarks 1-01 0.1 51 150-200 NG 1-02 0.3 55 250-300 NG 1-03 0.5 62 350-400 NG 1-04 One 90 550-850 OK 1-05 3 115 650-950 OK 1-06 5 134 850 ~ 1150 OK 1-07 7 177 1300-1700 Over melting occurrence

As can be seen from the above test results, as the addition rate of the powder for sintering aid increases, the crushing strength of the sintered body is improved, and it can be seen that the size of the neck becomes large.

Experiment Nos. 1-01 to 1-03 were determined to be poor because they had too low strength, and Experiment Nos. 1-07 were determined to be poor because of poor air permeability due to overmelting of the sintering aid powder.

On the other hand, in order to confirm the change in the crushing strength due to the influence of the tin powder in the powder for sintering aid, when the sintering aid powder is a manganese single powder and the sintering aid powder is manganese powder and tin powder In the case of the mixed powder of, the crushing strength of the sintered compact when the addition amount of the powder for sintering aid was changed with respect to both is shown in FIG.

As shown, when the powder for sintering aid is added in an amount of 1wt% or more with respect to the iron base powder, the powder for sintering aid is a mixed powder (mixing of manganese powder and tin powder) when the powder for sintering aid is a single manganese powder. Compared with the strength increase of about 20%.

(Experiment 2)

Sintering aid powder (mixed powder of manganese powder and tin powder) with an average particle size of 200 mesh was added to the coarse spherical powder having an average particle size of 20 mesh with a pure iron composition at a weight of 3 wt% based on the weight of the iron base powder, and then 1500 kgf. The molded articles of the same shape were prepared by pressure molding at / cm ^2, and the molded bodies were sintered at 1300 ° C. for 60 minutes in a sintering furnace maintained with a protective atmosphere.

At this time, the mixing ratio of the manganese powder and the tin powder of the sintering aid powder was changed from 80:20 to 20:80 by weight ratio, and thus the characteristics (pressure strength, neck size, heat resistance) of the iron-based porous sintered compact for the filter were confirmed. .

The evaluation of heat resistance was carried out by placing the produced sintered compact in a furnace maintained at 1500 ° C. for 20 seconds in order to evaluate the heat resistance at a high temperature, and then confirming the appearance of abnormality.

Experiment number Mixing ratio of manganese powder and tin powder (wt%) Characteristics Mn Sn Rolling strength (kgf / mm ² ) Neck size (μm) Heat resistance 2-01 100 0 102 600-900 OK 2-02 95 5 104 600-900 OK 2-03 80 20 106 600-900 OK 2-04 70 30 108 650-950 OK 2-05 60 40 112 650-950 OK 2-06 50 50 113 650 ~ 1050 OK 2-07 45 55 115 700-1050 OK 2-08 40 60 122 800-1100 NG 2-09 30 70 131 850 ~ 1200 NG 2-10 20 80 134 900-1200 NG

As can be seen from the above test results, as the ratio of tin in the mixture ratio of manganese powder and tin powder increases, the strength of the sintered body is improved, and the size of the neck is increased, and the tin ratio is 60% or more. In case of experiment Nos. 2-08 to 2-10, it was confirmed that the heat resistance was weak due to the phenomenon of melting in the surface portion and the neck portion of the sintered particles during the heat resistance evaluation.

4 is a photograph of a filter sintered body in which no melt phenomenon is observed by the present experimental example, and FIG. 5 is a photograph of a filter sintered body in which a melt phenomenon is shown by this experimental example.

The above embodiments are merely preferred embodiments of the present invention, and the technical spirit of the present invention may be variously modified or adjusted by those skilled in the art. Such modifications and adjustments fall within the scope of the present invention if the technical idea of the present invention is used.

In the present invention, in manufacturing the iron-based porous sintered body for the filter, it is possible to promote the sintering of the iron-based porous sintered body for the filter and to prevent the decrease in heat resistance, and to increase the rolling strength.

1 is a Fe-Mn state diagram,

2 is a photograph of various structures of a porous sintered body for a filter,

3 is a graph showing the change in the crushing strength according to the addition ratio of the components of the powder for sintering aid and the powder for iron base,

4 is a photograph of a filter sintered compact in which no melting phenomenon is observed in Experimental Example 2;

5 is a photograph of a sintered filter for filters in which a melting phenomenon is observed in Experimental Example 2. FIG.

Claims (3)

In the manufacturing method of the iron-based porous sintered body for the filter for producing a molded body by mixing and molding the iron base powder and the sintering aid powder of pure iron or iron alloy: The iron base powder is a coarse spherical powder having an average particle size of 100 mesh or more and 10 mesh or less; The sintering aid powder is a mixed powder of manganese powder and tin powder having an average particle size of 250 mesh or more and 100 mesh or less and a weight ratio of 95: 5 to 45:55. Mixed at ~ 5wt%, The sintering of the molded body is made between 1100 ° C and 1350 ° C method for producing an iron-based porous sintered body for a filter. The method of claim 1, The iron base powder is a method for producing an iron-based porous sintered body for filters, characterized in that the average particle size is more than 40 mesh 10 mesh. Iron-based porous sintered body for a filter produced by the method of claim 1 or 2.

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