JP4466957B2 - Wear-resistant sintered member and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wear-resistant sintered member that has improved machinability without causing a decrease in strength of the sintered member and a method for manufacturing the same. This is a technique suitable for a member requiring high performance.

  Abrasion-resistant sintered members manufactured by powder metallurgy are applicable to various sliding members because they can disperse various desired hard phases that cannot be manufactured by ordinary melting methods in the desired base. Has been. For example, the hard phase used in Patent Document 1 has a composition of Mo: 26 to 30%, Cr: 7 to 9%, Si: 1.5 to 2.5%, and Co balance by mass ratio. Therefore, it is described that 5 to 25% by mass of this hard phase is dispersed. Many combinations of this type of hard phase with various base structures have been proposed.

  On the other hand, the wear-resistant sintered alloy described in Patent Document 1 contains expensive Co in the base and the hard phase, and as a wear-resistant sintered alloy that does not contain expensive Co in response to the demand for lower prices. The wear-resistant sintered alloy of Patent Document 2 has been proposed and implemented. In the hard phase disclosed in Patent Document 2 and the like, the component composition is essentially a mass ratio of Cr: 4.0 to 25%, C: 0.25 to 2.4%, with the balance being Fe, and A hard phase forming powder composed of inevitable impurities is used, and Mo: 0.3-3.0%, V: 0.2-2.2% and W: 1.0-5.0% as additional elements It is described that one or more of these can be selected as desired. In the hard phase using such a hard phase forming powder, a hard particle group mainly composed of Cr carbide precipitates in the original hard phase forming powder portion, and Cr in the hard phase forming powder diffuses to the base, As a result of improving the hardenability of the Fe base, the base structure becomes martensite, and a portion close to the original hard phase forming powder has a high Cr concentration and forms a hard phase exhibiting a structure forming ferrite. That is, Cr carbide particles that improve wear resistance are deposited on the original hard phase forming powder portion, and the Cr carbide particles are prevented from falling off by covering the periphery with ferrite having a high Cr concentration. The base organization exhibits martensite to improve the wear resistance of the base. A number of combinations with various bases have also been proposed for the hard phase forming technique of Patent Document 2, and several wear-resistant sintered alloys combined with the hard phase of Patent Document 1 have also been proposed.

  In this way, various hard phases have been proposed in order to improve the wear resistance, but in response to the demand for higher efficiency of internal combustion engines in recent years, the alloy powders for forming hard phases of Patent Documents 3 and 4 and A wear-resistant sintered member using the same has been proposed. Patent Document 3 is an improvement of the hard phase used in Patent Document 1 and the hard phase obtained by changing the base of the hard particles to an Fe-based alloy. By mass ratio, Si: 1.0 to 12%, Mo : 20-50%, Mn: 0.5-5.0%, and the balance proposes an alloy powder for forming a wear-resistant hard phase comprising at least one of Fe, Ni, Co and inevitable impurities. is there. Patent Document 3 describes that by adding Mn to the base in this way, the effect of strengthening the base and improving the adhesion is achieved and the wear resistance is improved.

  Moreover, in patent document 4, in the improvement of the hard phase used in said patent document 1, whole composition is Mo: 48-60%, Cr: 3-12%, Si: 1-5% by mass ratio. There is proposed a hard phase forming alloy powder characterized in that the balance is Co and inevitable impurities. In Patent Document 4, by increasing the Mo content and increasing the Mo silicide content to precipitate the integrated Mo silicide, the plastic flow and adhesion are minimized and the wear resistance is improved. It is described to do.

  Thus, according to the demand for higher output of the internal combustion engine, the hard phase for the wear-resistant sintered member has been repeatedly improved, and the wear resistance has been improved. By the way, although such a wear-resistant sintered member has an advantage that it can be shaped into a near net shape, in some sliding members, cutting is essential under the demand for high accuracy. . For example, a valve seat used in an internal combustion engine is used by being press-fitted into the head of the engine, but similarly, concentricity with the valve guide to be press-fitted is required, and a cutting tool for valve guide processing and a cutting for valve seat processing It is processed concentrically with the valve guide by processing with an integrated tool. Such a wear-resistant sintered member is characterized by poor machinability due to its wear resistance and difficult to process. For this reason, various proposals for improving the machinability of the wear-resistant sintered member have been made and implemented.

  As described in claims 4 and 9 of Patent Document 2 and Claim 5 of Patent Document 3, the most common technique is to improve machinability of MnS powder or the like as a raw material powder. This is a technique in which powder is added and mixed to disperse machinability improving substance particles such as MnS particles in pores and powder grain boundaries of the sintered alloy. Patent Document 5 proposes to use at least one of a magnesium metasilicate mineral and an orthosilicate magnesium mineral as a machinability improving material as one of these methods. Boron nitride and manganese sulfide are proposed. And at least one of them. Since these novel machinability improving substances have cleavage properties, they have an effect of improving machinability. Note that Patent Document 6 is obtained by applying the technique of Patent Document 5 to the alloy of Patent Document 1.

Further, a machinability improving method different from the above-described method by adding a machinability improving substance has been proposed. Patent Document 7 uses a sulfide powder composed of at least one of MoS ₂ powder, WS ₂ powder, FeS powder, and CuS powder in combination with the hard phase forming powder of Patent Document 2 above, so that it is sulfided during sintering. Disclosed is a technique for improving the wear resistance and machinability of the hard phase part by decomposing the product powder and precipitating Cr sulfide together with Cr carbide. Further, in Patent Document 8, a mixed powder obtained by mixing and mixing a metal powder having an amount of S of 0.04 to 5% by mass with steel powder containing Mn: 0.1 to 8% by mass, By compression molding in a mold and sintering the molded body in a temperature range of 900 to 1300 ° C., 0.15 to 10 mass% of MnS particles of 10 μm or less are uniformly deposited in the crystal grains over the entire surface of the base structure. A technique for making dispersed sintered members is disclosed. Patent Document 8 discloses that these methods improve machinability by precipitating sulfides that improve machinability, and that these methods can be used in combination with the machinability improving substance addition method described above. It is described that the machinability can be further improved by the combined use.

Japanese Patent Publication No. 05-055593 (Claim 1 etc.) JP 09-195012 A (Claims etc.) JP 2002-356704 A (Claims etc.) Japanese Patent Application No. 2003-319554 (claims, etc.) JP 04-157139 A (Claims etc.) Japanese Patent Laid-Open No. 04-157138 (claims, etc.) JP 2000-064002 A (Claims etc.) JP 2002-332552 A (Claim 8 etc.)

  As described above, according to the demands of the times, the wear-resistant sintered member has been further improved in wear resistance and various improvements in its machinability. However, in recent years, there has been an increasing demand for further machinability improvement, and the above machinability improvement technology alone cannot meet the demand. That is, in Patent Document 8 described above, as shown in FIG. 2, precipitation of MnS for improving machinability is only in the iron-based alloy base portion, and wear resistance is improved as in Patent Document 3 and Patent Document 4 described above. There has been a situation where the machinability is insufficient for the hard phase that has become harder than the viewpoint. Therefore, an object of the present invention is to provide a wear-resistant sintered member that exhibits high wear resistance and is excellent in machinability, and also provides a manufacturing method thereof.

  In order to solve the above problems, the present inventors have studied based on the above-mentioned Patent Document 8, and as shown in FIG. 1, manganese sulfide is dispersed not only in the iron-based alloy base part but also in the hard phase part. It has been found that the machinability of the wear-resistant sintered member can be improved by improving the machinability of the hard phase portion. In addition, the present inventors have found production conditions capable of stably producing this manganese sulfide. That is, the type of sulfide that is easily decomposed during sintering, which is an S supply source for bonding with matrix and hard phase Mn, was identified. Furthermore, it discovered that the magnitude | size of sulfide powder had an influence on decomposition | disassembly of sulfide, and it discovered that the production | generation of stable manganese sulfide could be performed by specifying the particle size. Further, in the wear-resistant sintered member obtained under such measures, manganese sulfide was precipitated not only in the base portion but also in the hard phase portion, and it was confirmed that machinability was improved.

The present invention has been made as a result, specifically, wear resistant sintered member of the present invention, the iron-base alloy base, and the hard phase consists of, the hard in the iron-base alloy base with phase is dispersed, the hard phase, the alloy matrix of the hard phase, and hard particles consists, in the wear resistant sintered member in which the hard particles are precipitated and dispersed in the alloy matrix of the hard phase, wherein the iron with the entire surface over the crystal grains to 10μm of manganese sulfide particles of the base alloy matrix structure are uniformly dispersed, with exhibits a metallic structure 10μm of manganese sulfide particles are dispersed in the alloy base of the hard phase,
(1) The overall composition is, by mass ratio, Ni: 0.23 to 4.39%, Mo: 0.62 to 22.98%, Cr: 0.05 to 2.93%, Mn: 0.18 to 3.79%, Si: 0.01 to 4.0%, S: 0.04 to 5.0%, C: 0.3 to 1.2%, and the balance being Fe and unavoidable impurities It is made of gold, and the iron-based alloy base has a mass ratio of Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0.2 to 3.0%, and the balance is formed of a base forming steel powder composed of Fe and inevitable impurities, and the hard phase has a mass ratio of Mo: 10 to 50%, Si: 0.00. 5 to 10%, Mn: 0.5 to 5%, and the balance is formed of an alloy powder composed of Fe and inevitable impurities (Claim 1).
(2) The overall composition is, by mass ratio, Co: 0.7 to 35.6%, Ni: 0.23 to 4.39%, Mo: 0.62 to 22.98%, Cr: 0.05 to 2.93%, Mn: 0.18-3.79%, Si: 0.01-4.0%, S: 0.04-5.0%, C: 0.3-1.2%, and The balance is made of a sintered alloy with Fe and unavoidable impurities, and the iron-based alloy matrix has a mass ratio of Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0.2 to 3.0%, and the balance is formed of a base forming steel powder composed of Fe and inevitable impurities, and the hard phase is in a mass ratio, Mo: 10 to 50%, Si: 0.5 to 10%, Mn: 0.5 to 5%, and the balance is formed of an alloy powder composed of Co and inevitable impurities. Claim 2),
(3) The overall composition is, by mass ratio, Ni: 0.22 to 4.39%, Mo: 0.22 to 4.88%, Cr: 0.16 to 11.79%, Mn: 0.18 to 3.79%, S: 0.04 to 5.0%, C: 0.3 to 2.0%, the balance being made of a sintered alloy with Fe and unavoidable impurities, the iron-based alloy base is mass Ratio: Ni: 0.5-4.5%, Mo: 0.5-5.0%, Cr: 0.1-3.0%, Mn: 0.2-3.0%, and the balance The hard phase is formed of a base forming steel powder composed of Fe and inevitable impurities, and the hard phase has a mass ratio of Cr: 4 to 25%, Mn: 0.5 to 5%, C: 0.25 to 2 .4%, the balance being formed from an alloy powder consisting of Fe and inevitable impurities, and
The entire composition further contains at least one of Mo: 0.06-0.12%, V: 0.004-0.88% and W: 0.02-2.0%, and is hard The phase forming alloy powder contains one or more of Mo: 0.3-3%, V: 0.2-2.2%, W: 1-5% (Claim 3). ,
(4) The overall composition is, by mass ratio, Ni: 0.22 to 4.39%, Mo: 0.22 to 4.88%, Cr: 0.14 to 3.79%, Mn: 0.18 to 3.79%, W: 0.02-8.0%, V: 0.01-2.4%, S: 0.04-5.0%, C: 0.3-2.0%, balance Is made of a wear-resistant sintered alloy in which Fe and unavoidable impurities, and the iron-based alloy matrix has a mass ratio of Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0.2 to 3.0%, and the balance is formed of a base forming steel powder composed of Fe and unavoidable impurities, and the hard phase has a mass ratio Cr: 3 to 5%, W: 1 to 20%, V: 0.5 to 6%, Mn: 0.5 to 5%, C: 0.6 to 1.7%, the balance being inevitable with Fe Powder consisting of mechanical impurities It is more formed and,
The entire composition further contains at least one Mo or Co at 8.0% or less, and the hard phase forming alloy powder contains at least one Mo or Co at 20% or less ( (4), (1) to (4).

The manufacturing method of the wear-resistant sintered member of the present invention comprises a hard phase forming alloy containing Mn: 0.5 to 5% by mass in a base forming steel powder containing Mn: 0.2 to 3% by mass. The powder is mixed with and mixed with at least one of molybdenum disulfide powder, tungsten disulfide powder, iron sulfide powder, and copper sulfide powder, and sulfide powder in an amount of S of 0.04 to 5% by mass. The mixed powder is compression-molded in a mold, and the molded body is sintered in a temperature range of 1000 to 1300 ° C. The composition of the base-forming steel powder is Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0.2 to 3.0%, and the balance is Fe and inevitable impurities Consists of and
(5) The composition of the alloy powder for forming a hard phase is, by mass ratio, Mo: 10 to 50%, Si: 0.5 to 10%, Mn: 0.5 to 5%, and the balance is Fe or Co. In addition to unavoidable impurities, the amount of the graphite powder added is 0.3 to 1.2% by mass (claim 11),
(6) The composition of the alloy powder for forming a hard phase is, by mass ratio, Cr: 4 to 25%, Mn: 0.5 to 5%, C: 0.25 to 2.4%, and the balance is Fe. In addition to unavoidable impurities, the amount of the graphite powder added is 0.3 to 2.0% by mass, and the composition of the hard phase forming alloy powder is Mo: 0.3 to 3%, V : 0.2-2.2%, W: 1 type or 2 types or more of 1-5% are further contained (Claim 12),
(7) The composition of the hard phase forming alloy powder is, by mass ratio, Cr: 3 to 5%, W: 1 to 20%, V: 0.5 to 6%, Mn: 0.5 to 5%, C: 0.6 to 1.7%, and the balance is Fe and inevitable impurities, and the addition amount of the graphite powder is 0.3 to 2.0% by mass, and the composition of the alloy powder for forming the hard phase However, it is at least 1 type of Mo or Co: 20% or less is further contained by mass ratio (Claim 13), It is set as either (5)-(7), It is characterized by the above-mentioned .

  According to the wear-resistant sintered member of the present invention, it is possible to deposit and disperse fine manganese sulfide not only in the base portion but also in the hard phase portion, so that the machinability of the wear-resistant sintered member is improved compared to the conventional case. Can be greatly improved. In addition, according to the method for producing a wear-resistant sintered member of the present invention, the above-described manganese sulfide is stably precipitated, so that the machinability improving effect of the wear-resistant sintered member can be stabilized. It becomes possible to give.

  In the present invention, Mn is dissolved in a matrix part and a hard phase part (alloy matrix part of a precipitate-dispersed hard phase), and S is generated by decomposition from a separately added sulfide powder during sintering. As shown in FIG. 1, Mn is reacted to deposit fine manganese sulfides in the base portion and the hard phase portion, respectively. At this time, if the size of the precipitated manganese sulfide is large, the manganese sulfide is unevenly distributed and it becomes impossible to impart machinability uniformly to the wear-resistant sintered member. The thickness is preferably 10 μm or less.

  By the way, although it was recognized that all metal sulfides are stable, in fact, it has been confirmed by the above-mentioned Patent Documents 7 and 8 that some metal sulfides are decomposed during sintering. Actually, according to Reference 1 (Chemical Dictionary 9 Reprinted Kyoritsu Publishing Co., Ltd., issued on March 15, 1964), the following matters are described. That is, among metal sulfides, manganese sulfide (MnS) has a high melting point of 1610 ° C., and it is described that it is not attacked by heating with hydrogen at 1200 ° C., and manganese sulfide (MnS) is difficult to decompose. I understand. Further, chromium sulfide (CrS) has a high melting point and is described as being not reduced with hydrogen even at 1200 ° C., and it can be seen that it is a metal sulfide that is difficult to decompose.

On the other hand, for molybdenum disulfide (MoS ₂ ), if heated in an electric furnace, it becomes Mo molybdenum via Mo2S3, and if heated in air, it reacts with oxygen at 550 ° C. and decomposes into molybdenum trioxide and sulfur dioxide, It is described that it reacts with water vapor and red heat and is easily decomposed. Further, it is described that tungsten disulfide (WS ₂ ) starts to decompose at 1100 ° C. when heated in a vacuum, and becomes tungsten at 800 ° C. with hydrogen, which is also easily decomposed. Furthermore, about iron sulfide (FeS), when heated in air, it becomes iron oxide at about 200 ° C, when heated in a hydrogen stream, it becomes iron, and when heated above 1200 ° C with carbon, iron and carbon disulfide. It is easy to disassemble. In addition, with regard to copper sulfide (CuS), it is described that decomposition starts at 220 ° C. and produces cuprous sulfide (Cu ₂ S) to generate S, which is also easily decomposed.

  Although it has been described that molybdenum disulfide, tungsten sulfide, iron sulfide, and copper sulfide are easily decomposed under specific conditions, in the actual sintering process, moisture, oxygen, hydrogen contained in the atmosphere In addition, it is considered that decomposition conditions may be satisfied by desorption of moisture and oxygen adsorbed on the surface of the iron powder and may be decomposed. The conditions described in the above-mentioned Reference 1 are only for the decomposition conditions in the case where the sulfide alone is present. In the sintering process of the mixture of the metal powder and the sulfide powder, the sulfide becomes active at a high temperature. It is conceivable that the metal surface that reacts with the metal surface or becomes active at high temperatures acts as a catalyst to promote the decomposition of sulfides. In the present invention, the above-mentioned molybdenum disulfide, tungsten sulfide, iron sulfide, and copper sulfide, which are easily decomposed, are added to the raw material powder in the form of powder, thereby causing the decomposition of the sulfide powder in the sintering process, S is reliably supplied to the base and the hard phase. In addition, metal components generated by the decomposition of these sulfide powders diffuse into the base and work to strengthen the base. Of these sulfide powders, it is particularly preferable to use molybdenum disulfide powder.

  In order to precipitate and disperse a sufficient amount of manganese sulfide particles in the base portion and the hard phase portion using the above sulfide powder, the amount of sulfide powder added is 0.04% by mass or more as S content. Necessary. On the other hand, the addition of excessive sulfide powder causes a decrease in the strength of the wear-resistant sintered member due to an increase in the amount of pores remaining after decomposition, resulting in a decrease in wear resistance. The upper limit should be limited to 5% by mass with respect to S.

  In order to completely decompose the sulfide powder applied to the raw material powder during the sintering process, the sintering temperature needs to be 1000 ° C. or higher. In this temperature range, the metal powder surface activated during the sintering process reacts with the sulfide powder to reliably decompose the sulfide powder. However, if the heating exceeds 1300 ° C., the wear of the furnace increases, which is not economical, so the upper limit of the sintering temperature was set to 1300 ° C.

  In addition, the particle size of the sulfide powder is important in order to completely decompose the sulfide powder applied to the raw material powder during the sintering process. That is, since the decomposition reaction becomes active at the part in contact with the metal powder, if it is given in the form of a large sulfide powder, the decomposition reaction becomes insufficient in part, the S supply amount varies, the base part and the hard part The amount of manganese sulfide deposited in the phase portion becomes unstable. Therefore, in order to avoid this situation, a sulfide powder having a small particle size is suitable. Specifically, if the maximum particle size is 100 μm or less and the average particle size is 50 μm or less, the added sulfide powder It is possible to reliably decompose the product powder and to produce a stable manganese sulfide. In addition, when sulfide powder with a large particle size is used, after the sulfide powder decomposes and disappears, the original powder part remains as coarse Kirkendall pores, causing a decrease in strength and wear resistance. Therefore, it is required to use a sulfide having the above particle size range.

Further, in the decomposition of the sulfide powder, the influence of the sintering atmosphere is large, and the surface of the metal powder is activated, so that the sintering atmosphere is decomposed in a vacuum atmosphere or decomposed ammonia gas having a dew point of −10 ° C. or lower, When the atmosphere is either hydrogen gas or argon gas, the surface of the metal powder is cleaned and activated, and the sulfide powder can be reliably decomposed. On the other hand, if the sintering atmosphere contains oxygen to a certain extent, the surface of the metal powder is not oxidized and activated, and even if the sulfide powder decomposes, it easily binds to oxygen and produces harmful SO _X. This should be avoided as it is more likely to occur.

  For the hard phase in the present invention, a precipitate-dispersed hard phase is suitable, such as the Mo silicide precipitate-type hard phase used in Patent Documents 1, 3, and 4 described above, Patent Document 2 and the like. A hard phase of a Cr carbide precipitation type as used, a hard phase of a high speed tool steel system conventionally used (a carbide precipitation type such as W, Mo, Cr), or the like can be applied. In the present invention, by providing Mn as a solid solution in the alloy base portion of the precipitate-dispersed hard phase, the S and the alloy base portion generated by decomposition from the sulfide powder added separately are sintered. Mn is bonded to produce fine manganese sulfide particles of 10 μm or less in the crystal grains. The alloy base portion of the precipitation-dispersed hard phase may be a Co-based alloy used in Patent Documents 1, 3, and 4, an Fe-based alloy used in Patent Documents 2 and 3, and the like.

The ability to form sulfides has a correlation with electronegativity, and S tends to form sulfides by binding to elements having low electronegativity. Here, the electronegativity of each element is
Mn (1.5) <Cr (1.6) <Fe, Ni, Co, Mo (1.8) <Cu (1.9)
Since Mn is most easily bonded, manganese sulfide can be selectively deposited. This order is consistent with the description in Reference 1 above.

  Such a precipitate-dispersed hard phase can be easily formed by adding alloy powder obtained by alloying the components forming the hard phase to the raw material powder. The addition amount of the hard phase forming alloy powder is smaller than that of the base forming steel powder, and since the original powder hardness is hard, even if the powder hardness increases by containing Mn, the base The effect on the compressibility of the raw material powder is less as with the formed steel powder. Moreover, since hard particles are precipitated in the hard phase, the machinability is poor, but in order to improve the machinability of such a hard phase, a larger amount of manganese sulfide is required than in the base portion. For this reason, in order to deposit manganese sulfide necessary for improving machinability in the hard phase portion (alloy base portion of the precipitate dispersion type hard phase), the amount of Mn dissolved in the hard phase portion is 0.5 mass. % Or more is necessary. On the other hand, excessive addition of Mn increases the hardness of the alloy powder for forming a hard phase and impairs the compressibility, so the amount of addition needs to be 5% by mass or less.

  Specifically, in the case of forming a Mo silicide precipitation type hard phase, the composition is, by mass ratio, Mo: 10 to 50%, Si: 0.5 to 10%, Mn: 0.5 to 5 %, And the balance is preferably an alloy powder composed of Fe or Co and inevitable impurities. Moreover, when forming the hard phase of Cr carbide precipitation type, composition is Cr: 4-25%, Mn: 0.5-5%, C: 0.25-2.4% by mass ratio. Contains, if desired, contains Mo: 0.3-3%, V: 0.2-2.2%, W: 1-5% or more, and the remainder is inevitable with Fe It is desirable to use an alloy powder made of impurities and simultaneously give a predetermined amount of graphite powder for Cr carbide formation to the raw material powder. Furthermore, when forming a hard phase of a high-speed tool steel system, the composition is, by mass ratio, Cr: 3 to 5%, W: 1 to 20%, V: 0.5 to 6%, Mn: 0.00. 5 to 5%, C: 0.6 to 1.7%, optionally containing at least one of Mo or Co: 20% or less, with the remainder using an alloy powder consisting of Fe and inevitable impurities It is desirable to simultaneously give a predetermined amount of graphite powder for forming carbides such as Cr, W, V, and Mo to the raw material powder.

  From the viewpoint of wear resistance of the wear-resistant sintered member, such a precipitate-dispersed hard phase has an addition amount of the alloy powder for forming the hard phase in the raw material powder of 2 to 40% by mass and wear resistance. The amount of dispersion in the porous sintered member is preferably 2 to 40% by mass. That is, if the hard phase dispersion amount is less than 2% by mass, the effect of improving the wear resistance is poor. On the other hand, if the hard phase dispersion amount exceeds 40% by mass, the compressibility of the raw material powder decreases, The strength of the wearable sintered member is lowered, so that the wear resistance is lowered.

  Of the above-mentioned precipitate dispersed hard phases, Mo silicide dispersed hard phases have been known to have Mo silicide self-lubricating properties. Especially recommended from the viewpoint of

  The base part of the wear-resistant sintered member is formed by dissolving Mn in a solid solution as in Patent Document 8 described above, so that the S and alloy base part generated by decomposition from the sulfide powder added separately are sintered. Mn is bonded to produce fine manganese sulfide particles of 10 μm or less in the crystal grains. In order to deposit this manganese sulfide reliably, the amount of Mn dissolved in the base portion is set to 0.2. It is necessary to set it as the mass% or more. On the other hand, in the wear-resistant sintered member in which hard particles are dispersed in the matrix, a hard phase forming alloy powder harder than the matrix forming steel powder is added. Therefore, in order to ensure a certain degree of compressibility as the raw material powder, it is necessary to ensure a certain degree of compressibility of the base-forming steel powder that occupies most of the raw material powder as compared with a sintered member in which the hard phase is not dispersed. is important. For this reason, it is necessary to suppress the amount of Mn dissolved in the base-forming steel powder as compared with the case of a sintered member in which the hard phase is not dispersed. Specifically, when Mn is added to the base forming steel powder in an amount of more than 3% by mass, the hardness of the base forming steel powder is increased and the compressibility of the entire raw material powder is impaired. The amount of Mn added must be 3% by mass or less.

  Further, as described above, the amount of Mn given to the steel powder for forming the base is 0.2 to 3% by mass, and the amount of Mn given to the alloy powder for forming the hard phase is 0.5 to 5% by mass. From the viewpoint of machinability of sintered members, it is more effective to improve the machinability by applying a large amount of manganese sulfide to the hard phase part which is hard and has poor machinability. It is recommended to give a larger amount of Mn contained in the hard phase forming alloy powder than the amount of Mn contained.

Now, considering the iron-based alloy base of the wear-resistant sintered member, the structure of the iron-based alloy base is bainite from the standpoint of self-wear resistance and opponent attack of the wear-resistant sintered member, and from the viewpoint of self-strength This is preferable. Addition of alloy elements such as Mo, Ni, Cr and the like is effective for the bainite formation of such a base structure. In order to exert this effect uniformly on the entire surface of the base structure, Fe obtained by alloying these alloy components with Fe. to use the alloy powder. Specifically, as a composition of the base forming steel powder, by mass ratio, Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0% , Mn: 0.2~3.0%, and the balance Ru using an alloy powder consisting of Fe and unavoidable impurities. That is, when Ni is less than 0.5% by mass, Mo is less than 0.5% by mass, and Cr is less than 0.1% by mass, the bainite of the base becomes insufficient. On the other hand, if Ni exceeds 4.5% by mass, the hardenability of the base is improved. As a result, a part of the structure becomes hard martensite and the wear of the sliding counterpart member is promoted. On the other hand, if the Cr content exceeds 3.0% by mass, a passive film of Cr is formed on the surface of the alloy powder, so that the sinterability is deteriorated and the strength and wear resistance are reduced. Furthermore, if Ni: more than 4.5 mass%, Mo: more than 5.0 mass%, Cr: more than 3.0 mass%, the hardness of the alloy powder is increased and the compressibility is lowered. This will cause a decrease in performance.

  However, the wear-resistant sintered member has a structure in which the hard phase is dispersed in the iron base alloy matrix, and some components diffuse from the hard phase forming alloy powder to the steel powder for forming the base. A part around the hard phase of the alloy base may have a structure other than bainite, but this is allowed because it is inevitable due to the influence of the hard phase. That is, it is not necessary that the entire base structure be bainite, and most of the base should be bainite. Ni metal is added to actively form different metal structures (in this example, martensite and austenite). If not.

  The graphite powder given to the raw material powder serves to strengthen the base structure, and serves as a C supply source for carbide formation when a carbide precipitation type hard phase is used. The C content necessary for strengthening the base is 0.3% by mass or more, and 0.3% by mass of graphite powder needs to be added. If the C content is excessive, hard and brittle FeC compounds such as cementite will be precipitated in the base structure, resulting in a decrease in strength and wear resistance. The upper limit should be 1.2% by mass, and when using a carbide precipitation hard phase, the upper limit should be 2.0% by mass.

  From the recommended composition of the steel powder for base formation and the recommended composition of the alloy powder for hard phase formation, the specific alloy composition of the recommended wear-resistant sintered member is the Mo silicide precipitation dispersion type. When an Fe-based alloy is selected as the alloy base portion of the hard phase and iron sulfide powder is selected as the sulfide powder, the overall composition is Ni: 0.23 to 4.39%, Mo: 0.00. 62-22.98%, Cr: 0.05-2.93%, Mn: 0.18-3.79%, Si: 0.01-4.0%, S: 0.04-5.0% , C: 0.3 to 1.2%, and the balance is Fe and an inevitable impurity wear-resistant sintered alloy. In addition, when molybdenum disulfide powder is used instead of iron sulfide powder as sulfide powder in the above, since the component generated by decomposition of sulfide powder is added to the base component, Mo: 0.13 to the above composition 6.86 mass% is added, and Mo amount in the whole composition will be 0.75-29.84 mass%. Furthermore, when using tungsten disulfide powder or copper sulfide powder instead of iron sulfide powder as the sulfide powder in the above, similarly, the above composition has W: 0.12 to 14.33 mass% or Cu: 0.08. It becomes the composition which further contains -9.91 mass%.

  When a Co-based alloy is selected as the alloy base portion of the Mo silicide precipitation-dispersed hard phase and an iron sulfide powder is selected as the sulfide powder, the overall composition is Co: 0.7-35.6 in mass ratio. %, Ni: 0.23 to 4.39%, Mo: 0.62 to 22.98%, Cr: 0.05 to 2.93%, Mn: 0.18 to 3.79%, Si: 0.00. 01-4.0%, S: 0.04-5.0%, C: 0.3-1.2%, and the balance is Fe and an inevitable impurity wear-resistant sintered alloy. Moreover, when using molybdenum disulfide powder instead of iron sulfide powder as the sulfide powder in the above, Mo: 0.13 to 6.86 mass% is added to the above composition, and the Mo amount in the whole composition is 0.75. It will be -29.84 mass%. Furthermore, when using tungsten disulfide powder or copper sulfide powder instead of iron sulfide powder as the sulfide powder in the above, similarly, the above composition has W: 0.12 to 14.33 mass% or Cu: 0.08. It becomes the composition which further contains -9.91 mass%.

  When a Cr carbide precipitation type hard phase is selected and iron sulfide powder is selected as the sulfide powder, the overall composition is Ni: 0.22 to 4.39% by mass ratio, Mo: 0.22 to 4 .88%, Cr: 0.16 to 11.79%, Mn: 0.18 to 3.79%, S: 0.04 to 5.0%, C: 0.3 to 2.0%, desired And additionally containing at least one of Mo: 0.06 to 0.12%, V: 0.004 to 0.88% and W: 0.02 to 2.0% in the composition, The balance is Fe and a wear-resistant sintered alloy with inevitable impurities. When molybdenum disulfide powder, tungsten disulfide powder or copper sulfide powder is selected as the sulfide powder, the total composition is Mo: 0.13 to 6.86%, W: 0.0. The composition further includes at least one of 12 to 14.33% and Cu: 0.08 to 9.91%.

  When a hard phase of a high-speed tool steel system is selected and an iron sulfide powder is selected as a sulfide powder, the overall composition is Ni: 0.22 to 4.39%, Mo: 0.22 by mass ratio. 4.88%, Cr: 0.14 to 3.79%, Mn: 0.18 to 3.79%, W: 0.02 to 8.0%, V: 0.01 to 2.4%, S : 0.04 to 5.0%, C: 0.3 to 2.0%, optionally containing at least one Mo or Co in addition to 8.0% or less in the composition, with the balance being Fe And it becomes a wear-resistant sintered alloy which is an inevitable impurity. When molybdenum disulfide powder, tungsten disulfide powder or copper sulfide powder is selected as the sulfide powder, the total composition is Mo: 0.13 to 6.86%, W: 0.0. The composition further includes at least one of 12 to 14.33% and Cu: 0.08 to 9.91%.

  As described above, 0.2 to 3% by mass of Mn is given to the base forming steel powder, and 0.5 to 5% by mass of Mn is given to the hard phase forming alloy powder. At the same time, when 0.04 to 5% by mass of sulfide powder as S content is given together with graphite powder, the sulfide powder is decomposed during sintering, S is supplied, and manganese sulfide is precipitated and dispersed in both, A metal structure is obtained in which manganese sulfide particles of 10 μm or less are uniformly dispersed in the crystal grains over the entire surface, and manganese sulfide particles of 10 μm or less are dispersed in the alloy base of the precipitate dispersion type hard phase. Further, the amount of manganese sulfide particles dispersed at that time is 0.3 to 4.5% by mass in the wear-resistant sintered member including the base portion and the hard phase portion, which contributes to improvement of machinability. .

  In the wear-resistant sintered member of the present invention, a conventional machinability-improving substance addition method can be used together, and in the pores or powder grain boundaries of the wear-resistant sintered member, silicic acid is added. At least one of magnesium-based mineral, boron nitride, manganese sulfide, Ca fluoride, bismuth, chromium sulfide, and lead can be dispersed. These machinability improving materials are stable even at high temperatures, and even when added to the raw powder in the form of powder, they do not decompose during the sintering process, and are dispersed in the above locations as machinability improving materials to improve machinability. Can improve. By using this machinability improving substance addition method in combination, the machinability of the wear-resistant sintered member can be further improved. In addition, the amount of the machinability improving substance powder added when the machinability improving substance addition method is used in combination with the upper limit because excessive addition will impair the strength of the wear resistant sintered member and cause a decrease in wear resistance. Should be kept at 2.0% by weight.

  Furthermore, in the wear-resistant sintered member of the present invention, the pores of the wear-resistant sintered member, such as those used in Patent Document 2 above, are replaced with lead or lead alloy, copper or copper alloy, acrylic resin. It is possible to use a machinability improving technique that satisfies any of the above. In other words, acrylic resin, lead or lead alloy, copper or copper alloy are present in the pores, and the cutting mode is changed from interrupted cutting to continuous cutting during cutting, reducing the impact on the tool and preventing damage to the tool edge. There is an effect of improving machinability. Also, since lead or lead alloy, copper or copper alloy is soft, it adheres to the tool blade surface and protects the cutting edge of the tool, improving machinability and tool life, and at the time of use, the valve seat and valve It acts as a solid lubricant with the face surface and functions to reduce wear on both sides. Further, copper or copper alloy has a high thermal conductivity, and has the effect of escaping heat generated at the cutting edge during cutting to the outside, preventing heat accumulation at the cutting edge and reducing damage to the cutting edge.

<Example 1>
A base forming steel powder having a powder composition shown in Table 1 was prepared. Further, the powder composition is, by mass ratio, Mo: 35%, Si: 3%, Mn: 2%, and the hard phase forming alloy powder consisting of Fe and inevitable impurities, and the maximum particle size is 100 μm, A molybdenum disulfide powder having an average particle diameter of 50 μm and a graphite powder were prepared. These powders were blended together with a molding lubricant (zinc stearate 0.8 mass%) in the ratio shown in Table 1, and the mixed powder was molded into a ring of φ30 × φ20 × h10 at a molding pressure of 650 MPa. Next, these molded bodies were sintered in an ammonia decomposition gas atmosphere at 1160 ° C. for 60 minutes to prepare samples 01 to 06 having the compositions shown in Table 2. With respect to the above samples, the cross-sectional area ratio was measured for the amount of manganese sulfide deposited by observing the metal structure, and the value converted into the mass ratio is shown in the “MnS amount” column of Table 3. In addition, the wear resistance of the above samples was evaluated by a simple wear test, shown in “Valve wear” and “Valve seat wear” in Table 3, and the sum of these values in the “Total wear” column. Show. Further, the results of the machinability evaluation by the simple machinability test are shown in the “number of drilled holes” column of Table 3.

  The simple wear test was performed in a state in which tapping and sliding input were applied at a high temperature. Specifically, the ring-shaped test piece was processed into a valve seat shape having a 45 ° tapered surface on the inner diameter surface, and the sintered alloy was press-fitted into an aluminum alloy housing. Then, a disk-shaped counterpart material (valve) partially having a 45 ° tapered surface on the outer surface made of the SUH-36 material is moved up and down by a motor-driven eccentric cam to move the sintered alloy and The taper surfaces with the mating material were repeatedly collided. That is, the operation of the valve repeats the opening operation of separating from the valve seat by the eccentric cam rotated by the motor drive and the seating operation on the valve seat by the valve spring, thereby realizing the vertical piston motion. In this test, the counterpart material was heated with a burner, and the temperature was set so that the sintered alloy became 300 ° C., the number of hits of the simple wear test was 2800 times / minute, and the repetition time was 15 hours. Thus, the wear amount of the valve seat and the wear amount of the valve after the test were measured and evaluated.

  The simple machinability test is a test that drills holes with a 3mm carbide tip drill on a sample processed into a 5mm thick plate. A hole that could be drilled under a constant load of 1 tip drill and 5kN. The number of was measured. It is an evaluation that the more the number of holes processed, the better the machinability.

  For the sample of sample number 03 in Table 1, a metal structure photograph observed with a microscope is shown in FIG. 3, and a metal structure photograph observed with an electron microscope is shown in FIG. In FIG. 3 and FIG. 4, a portion showing a phase in which whitish fine particle groups are aggregated is a hard phase, and whitish fine particles are molybdenum silicide precipitate particles. The gap between the molybdenum silicide precipitate particles is an alloy base portion of the hard phase. Further, although gray particles are observed in the iron-based alloy matrix and in the hard phase of FIGS. 3 and 4, as a result of separate surface analysis, these particles are detected as Mn and S are concentrated in this portion. It was confirmed that manganese sulfide was formed. In addition, it was confirmed that the dispersed part of S and the dispersed part of Mo did not match, and that molybdenum disulfide was decomposed during sintering, and that S produced by the decomposition was selectively bonded to Mn given to the base. did. Furthermore, when the particle size of the gray manganese sulfide is referred to the gauge in FIG. 4 (the distance between the two white lines beside 10 μm is 10 μm), it can be confirmed that all are fine particles of 10 μm or less. . From FIG. 3, it can be confirmed that the structure of the iron-based alloy base is bainite, and the periphery of the hard phase has a partially different metal structure due to the diffusion of components from the hard phase.

  From Tables 1-3, as the amount of Mn in the steel powder for base formation increases, the precipitation amount of manganese sulfide increases, but when the amount of Mn in the steel powder for base formation is 2.0 mass% or more, The amount of precipitation is constant. This is because the amount of manganese sulfide produced by combining with S is constant because the amount of S combined with Mn is constant at 0.4% by mass in the entire composition, and there is an excess of Mn. This is probably because a certain amount or more of manganese sulfide cannot be deposited. Therefore, in the samples of sample numbers 05 and 06, it is considered that excess Mn is dissolved in the matrix.

  For this reason, as the amount of Mn in the base forming steel powder increases, the amount of wear on the valve seat decreases, but if the amount of Mn increases and the amount of solid solution in the base increases, the base becomes harder and the valve seat The amount of wear increases. Furthermore, in the sample No. 06 in which the amount of Mn in the base-forming steel powder exceeds 5% by mass, a large amount of Mn is dissolved in the base-forming steel powder and the compressibility of the powder is impaired. As a result, the density of the compact and the resulting decrease in the density of the sintered body cause a decrease in the strength of the base and an increase in the amount of wear on the valve seat. It can be seen that the aggressiveness becomes higher, the valve wear amount increases, and the total wear amount rapidly increases.

  The machinability (number of drilled holes) has the same tendency as the wear resistance. In the sample No. 01 sample that does not contain Mn in the steel powder for forming the base, manganese sulfide does not precipitate in the base. The number is low and the machinability is low. However, when 0.2% by mass of Mn is contained in the base forming steel powder, manganese sulfide is precipitated in the base and the machinability is improved. It is growing dramatically. Further, as the amount of Mn in the base forming steel powder increases, the amount of manganese sulfide deposited on the base increases, and the number of processed holes further increases. However, in the sample of sample number 06 in which the amount of Mn in the base forming steel powder exceeds 3.0% by mass, Mn dissolved in the base is excessive, and the machinability is greatly reduced.

  From the above, it was confirmed that when 0.2% by mass or more of Mn is contained in the base forming steel powder, manganese sulfide is precipitated in the base to improve machinability and improve wear resistance. . In addition, when Mn contained in the steel powder for forming the base exceeds 3.0% by mass, Mn dissolved in the base becomes excessive, and it is confirmed that the machinability improving effect and the wear resistance improving effect are impaired. It was.

  Moreover, when it confirmed in the metal structure observation, in the sample of the sample numbers 01-06, all the magnitude | sizes of the manganese sulfide to precipitate were 10 micrometers or less, and it confirmed that it was disperse | distributing uniformly in a base. .

<Example 2>
Using the base forming steel powder (Mn content: 0.5% by mass) used in Sample No. 03 of Example 1, 5% by mass of the hard phase forming alloy powder having the composition shown in Table 4 was used. And 1.0% by mass of graphite powder and 1.0% by mass of molybdenum disulfide powder having a maximum particle size of 100 μm and an average particle size of 50 μm, together with a molding lubricant (0.8% by mass of zinc stearate). Samples of sample numbers 07 to 11 having the entire composition shown in Table 5 were prepared from the mixed powder under the same sample preparation conditions as in Example 1. These were evaluated under the same evaluation conditions as in Example 1, and the results are shown in Table 6. Moreover, the data of the sample of sample number 03 of Example 1 are written together in Tables 4-6.

  From Tables 4-6, as the amount of Mn in the hard phase forming alloy powder increases, the amount of precipitation of manganese sulfide increases, but the amount of Mn in the hard phase forming alloy powder is 2.0% by mass. In the above, the amount of precipitation is constant. This is the same as in Example 1, because the amount of S is constant, and therefore Mn in the hard phase forming alloy powder is excessive when the amount exceeds a certain amount. In the sample, excess Mn is dissolved in the matrix.

  The tendency of the wear resistance is the same as in Example 1. As the amount of Mn in the hard phase forming alloy powder increases, the amount of wear on the valve seat decreases. If Mn dissolved in the alloy base becomes excessive and the amount of Mn exceeds 5% by mass, the aggressiveness of the valve of the mating material increases and the amount of valve wear increases and the total amount of wear also increases. I understand.

  The machinability also shows the same tendency as in Example 1, but in the sample No. 07 (conventional technology disclosed in Patent Document 8) that does not contain Mn in the alloy powder for forming the hard phase, Although manganese sulfide does not precipitate and the amount of manganese sulfide is not significantly different from the sample of sample number 08, it can be seen that the number of processed holes is small and machinability is low. On the other hand, when 0.5 mass% of Mn is contained, manganese sulfide is precipitated in the alloy base of the hard phase, the machinability is improved, and the number of processed holes is increased. Further, as the amount of Mn in the hard phase forming alloy powder increases, the amount of manganese sulfide deposited on the hard phase alloy base increases, and the number of processed holes further increases. However, in the sample of Sample No. 11 in which the amount of Mn in the hard phase forming alloy powder exceeds 5% by mass, Mn dissolved in the hard phase alloy base is excessive, and the machinability is greatly reduced. .

  From the above, it was confirmed that the machinability can be improved from that disclosed in Patent Document 8 by precipitating manganese sulfide on the alloy base portion of the hard phase, and the effect of the present invention was confirmed. In that case, machinability and wear resistance can be improved by adding 0.5 mass% or more of Mn to the hard phase forming alloy powder, but 5 mass of Mn is contained in the hard phase forming alloy powder. It was confirmed that Mn dissolved in the base excessively exceeded the% and the machinability improving effect and the wear resistance improving effect were impaired.

  In addition, also in the samples of sample numbers 07 to 11, when the size of the manganese sulfide was confirmed at the time of observing the metal structure, all of them were 10 μm or less, and it was confirmed that they were uniformly dispersed in the base.

<Example 3>
The base forming steel powder and the hard phase forming alloy powder used in Sample No. 03 of Example 1 were used. To these powders, 1.0% by mass of graphite powder, the maximum particle size was 100 μm, and the average particle size was 50 μm, and the additive amount of molybdenum disulfide powder shown in Table 7 was blended with a molding lubricant (0.8% by mass of zinc stearate), and the mixed powder was mixed with the same sample preparation conditions as in Example 1. Samples were prepared with sample numbers 12 to 16 having the entire composition shown in Table 8. These were evaluated under the same evaluation conditions as in Example 1, and the results are shown in Table 9. In Tables 7 to 9, data of the sample No. 03 of Example 1 are also shown.

  From Tables 7 to 9, the precipitation amount of manganese sulfide increases as the addition amount of molybdenum disulfide powder increases, but the precipitation amount is constant when the addition amount is 1% by mass or more. This is because the amount of Mn contained in the matrix and the hard phase is constant, so even if the sulfide powder is provided exceeding the amount of S that can be combined with this amount of Mn, the amount of precipitation exceeding the amount of Mn cannot be obtained.

  Under such circumstances, the number of processed holes continued to increase as the amount of molybdenum disulfide powder added increased, and the decrease in the number of processed holes as seen in Example 1 and Example 2 was observed. I can't. This is because Mn verified in Example 1 and Example 2 has the effect of increasing the hardness of the matrix by dissolving in the matrix, and as a result of acting in the direction of impairing the machinability, the excess Mn is Although the effect of improving machinability due to manganese sulfide precipitation is offset, application of Mn above a certain amount has an adverse effect, but S has little negative effect as described above, and excess S is sulfided next to Mn. This is considered to contribute to the improvement of machinability by forming sulfides with Cr, which is easy to form an object, and then with Fe, Co, Ni, Mo, etc., which is easy to form a sulfide.

  On the other hand, as for wear resistance, the valve seat wear amount improves and shows good wear resistance up to a certain amount of manganese sulfide precipitation, but beyond that, the valve seat wear amount gradually increases and disulfide disulfide increases. It can be seen that when the amount of molybdenum powder added exceeds 12.65% by mass (the amount of S in the entire composition is 5% by mass) and becomes excessive, the base strength decreases, resulting in rapid wear.

  From the above, the addition of 0.2% by mass or more of sulfide powder in the amount of S in the overall composition has the effect of improving machinability and the effect of improving wear resistance, but the amount of S in the overall composition is 5% by mass. It has been found that addition of more than 10 results in a decrease in wear resistance as a result of a decrease in matrix strength.

  In addition, also in the samples of sample numbers 07 to 11, when the size of the manganese sulfide was confirmed at the time of observing the metal structure, all of them were 10 μm or less, and it was confirmed that they were uniformly dispersed in the base.

<Example 4>
As the base forming steel powder, the base forming steel powder used in sample numbers 02 and 05 of Example 1 and the base forming steel powder having the same composition other than Mn and containing no Mn were prepared. Further, as the hard phase forming alloy powder, the hard phase forming alloy powder used in sample numbers 08 and 10 of Example 2 and the hard phase forming alloy powder having the same composition other than Mn and containing no Mn were prepared. To these powders, as shown in Table 10, graphite powder 1.0% by mass, molybdenum disulfide powder having a maximum particle size of 100 μm and an average particle size of 50 μm and having the composition shown in Table 10 were molded and lubricated. A mixed powder mixed with an agent (zinc stearate 0.8% by mass) was prepared under the same sample preparation conditions as in Example 2, and samples of sample numbers 17 to 19 having the overall composition shown in Table 11 were prepared. Obtained. These were evaluated under the same evaluation conditions as in Example 1, and the results are shown in Table 12.

  From Tables 10-12, the sample which added the minimum amount of sulfide powder using the steel powder for base formation of the minimum Mn amount determined in Examples 1 to 3 and the alloy powder for hard phase formation of the minimum amount of Mn. When the sample No. 18 is compared with the sample No. 17 containing no Mn in the base forming steel powder and the hard phase forming alloy powder and no addition of the sulfide powder, the sample No. 18 is manganese sulfide. The amount of precipitation is 0.3% by mass, and even with this amount, the wear resistance and machinability (the number of processed holes) are improved compared to the sample of sample number 17 where manganese sulfide is not dispersed. The effect of the present invention was confirmed. Sample No. 19 uses the maximum Mn content base forming steel powder obtained in Examples 1 to 3 and the maximum Mn content hard phase forming alloy powder, and the maximum amount of sulfide powder. In this case, the precipitation amount of manganese sulfide in this case is 4.5% by mass, as seen in the examples in which each condition is excessive in Examples 1 to 3, It was confirmed that no significant deterioration in properties was observed, and extremely excellent machinability was exhibited.

<Example 5>
The base forming steel powder used in Sample No. 03 of Example 1 was prepared as the base forming steel powder, and the hard phase forming alloy powder having the composition shown in Table 13 was prepared as the hard phase forming alloy powder. As shown in Table 13, 1.0% by mass of graphite powder and 1.0% by mass of molybdenum disulfide powder having a maximum particle size of 100 μm and an average particle size of 50 μm were added to these powders as a molding lubricant (stearic acid). The mixed powder mixed with and mixed with 0.8% by mass of zinc was subjected to sample preparation under the same sample preparation conditions as in Example 1, and samples of sample numbers 20 to 22 having the entire composition shown in Table 14 were obtained. These were evaluated under the same evaluation conditions as in Example 1, and the results are shown in Table 15. In Tables 13 to 15, for comparison, data of the sample No. 03 of Example 1 and the sample No. 17 of Example 4 (an example in which manganese sulfide is not dispersed) are also shown.

  Note that the hard phase forming alloy powder used in the sample No. 20 sample is a Mo silicide in a Co alloy phase in which the base material of the hard phase forming alloy powder used in the sample No. 03 sample is changed from Fe to Co. An example of a hard phase in which precipitation is dispersed, an alloy powder for forming a hard phase used in the sample of sample number 21 is an example of a hard phase of a Cr carbide precipitation type, and an alloy powder for forming a hard phase used in the sample of sample number 22 is high. It is an example of a hard phase (carbide precipitation type such as W, Mo, Cr) of a speed tool steel.

  According to Tables 13 to 15, even if the type of the hard phase is changed, high wear resistance and excellent machinability are realized as compared with the sample in which manganese sulfide is not dispersed (Sample No. 17). It can be seen that almost the same characteristics are exhibited. From this, the technology of the present invention, in which Mn is contained in the precipitate-dispersed hard phase and manganese sulfide is precipitated on the alloy base portion of the hard phase, the molybdenum silicidation in the Fe bases of the first to fourth embodiments described above. It was confirmed that not only the hard phase in which the product is precipitated and dispersed but also other precipitated and dispersed hard phases have similar machinability and wear resistance improving effects.

<Example 6>
As the base forming steel powder, the base forming steel powder and the hard phase forming alloy powder used in Sample No. 03 of Example 1 were prepared, and graphite powder was prepared. Moreover, tungsten disulfide powder, iron sulfide powder and copper sulfide powder were prepared as sulfide powders. These powders were blended together with a molding lubricant (zinc stearate 0.8% by mass) in the proportions shown in Table 16, and the mixed powder thus mixed was subjected to sample preparation under the same sample preparation conditions as in Example 1. Table 17 Samples of sample numbers 23 to 25 having the entire composition shown in FIG. These were evaluated under the same evaluation conditions as in Example 1, and the results are shown in Table 18. In Tables 16 to 18, data of the sample No. 03 of Example 1 using molybdenum disulfide powder as the sulfide powder are also shown. In addition, about the addition amount of sulfide powder, it adjusted and added so that the amount of S in a whole composition might be 0.4 mass%.

  As a result of observing the metal structure of samples Nos. 23 to 25, even if the type of the sulfide powder was changed from molybdenum disulfide powder to tungsten disulfide powder, iron sulfide powder, or copper sulfide powder, molybdenum disulfide powder As in the case of, it was confirmed that manganese sulfide was precipitated and dispersed in the matrix and the alloy matrix of the hard phase. It was also confirmed that the particle size of manganese sulfide precipitated in these samples was as fine as 10 μm or less.

  According to Tables 16 to 18, the amount of sulfide powder added was adjusted so that the amount of S in the overall composition was 0.4 mass%, and as a result, the amount of manganese sulfide deposited was almost equal. This sample also shows good machinability and wear resistance. From the above, the sulfide powder effective for precipitation of manganese sulfide is not limited to molybdenum disulfide powder, and even if it is changed to tungsten disulfide powder, iron sulfide powder, or copper sulfide powder, machinability and wear resistance are improved. It is confirmed that there is an improvement effect, and it is considered that the same effect can be obtained if the sulfide powder is easily decomposed.

<Example 7>
As shown in Table 19, except that the particle size of the molybdenum disulfide powder was changed, the same powder as the sample No. 03 of Example 1 was used, and the sample was prepared under the same sample preparation conditions as in Example 1. , By mass ratio, Ni: 1.49%, Mo: 3.28%, Cr: 0.19%, Mn: 0.57%, Si: 0.15%, C: 1%, S: 0.4 % And the balance were Fe and inevitable impurities. Samples Nos. 26 and 27 were obtained. These were evaluated under the same evaluation conditions as in Example 1, and the results are shown in Table 20. Tables 19 and 20 also show the data of the sample No. 03 of Example 1.

  From Tables 19 and 20, when the particle size of the sulfide powder is within the range of the maximum particle size of 100 μm or less and the average particle size of 50 μm or less, the added sulfide powder is sufficiently decomposed, and the machinability and wear resistance are In the sample of Sample No. 27, which shows a good value but uses a sulfide powder having a maximum particle size of 100 μm and an average particle size of 50 μm, the precipitation amount of manganese sulfide is reduced. Is considered insufficient. For this reason, in the sample of Sample No. 27, the effect of improving the wear resistance is insufficient and the amount of wear of the valve seat is increased, and the effect of improving the machinability is also insufficient and the number of processed holes is greatly reduced. As described above, by using a sulfide powder having a maximum particle size of 100 μm or less and an average particle size of 50 μm or less, the added sulfide powder can be sufficiently decomposed to sufficiently precipitate manganese sulfide. I knew it was possible.

  The present invention relates to a technique for improving the machinability of a wear-resistant sintered member in which hard particles are dispersed. For example, the invention is used for a member that requires machinability as well as wear resistance such as a valve seat of an internal combustion engine. Can do.

It is a schematic diagram which shows the metal structure of the abrasion-resistant sintered member of this invention. It is a schematic diagram which shows the metal structure of the conventional abrasion-resistant sintered member. It is a metal structure photograph by microscope observation of the wear-resistant sintered member of the present invention. It is a metallographic photograph by the electron microscope observation of the abrasion-resistant sintered member of this invention.

Claims (18)

An iron base alloy base and a hard phase, and the hard phase is dispersed in the iron base alloy base ,
The hard phase is composed of a hard phase alloy base and hard particles, and in the wear-resistant sintered member in which the hard particles are precipitated and dispersed in the hard phase alloy base ,
The overall composition is, by mass ratio, Ni: 0.23 to 4.39%, Mo: 0.62 to 22.98%, Cr: 0.05 to 2.93%, Mn: 0.18 to 3.79. %, Si: 0.01 to 4.0%, S: 0.04 to 5.0%, C: 0.3 to 1.2%, and the balance is Fe and a sintered alloy containing inevitable impurities ,
The iron-based alloy base has a mass ratio of Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0.2 to 3.0%, and the balance is formed of a base forming steel powder consisting of Fe and inevitable impurities,
The hard phase is an alloy powder for forming a hard phase in which, by mass ratio, Mo: 10 to 50%, Si: 0.5 to 10%, Mn: 0.5 to 5%, and the balance is Fe and inevitable impurities Formed by
Together with the iron-base alloy base structure entirely over crystal grains to 10μm of manganese sulfide particles of are uniformly dispersed, exhibit a metallic structure 10μm of manganese sulfide particles are dispersed in the alloy base of the hard phase A wear-resistant sintered member.   An iron base alloy base and a hard phase, and the hard phase is dispersed in the iron base alloy base,
  The hard phase is composed of a hard phase alloy base and hard particles, and in the wear-resistant sintered member in which the hard particles are precipitated and dispersed in the hard phase alloy base,
  The overall composition is, by mass ratio, Co: 0.7 to 35.6%, Ni: 0.23 to 4.39%, Mo: 0.62 to 22.98%, Cr: 0.05 to 2.93. %, Mn: 0.18 to 3.79%, Si: 0.01 to 4.0%, S: 0.04 to 5.0%, C: 0.3 to 1.2%, and the balance is Fe And a sintered alloy that is an inevitable impurity,
  The iron-based alloy base has a mass ratio of Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0.2 to 3.0%, and the balance is formed of a base forming steel powder consisting of Fe and inevitable impurities,
  Hard phase forming alloy powder in which the hard phase is composed of Mo: 10 to 50%, Si: 0.5 to 10%, Mn: 0.5 to 5%, and the balance being Co and inevitable impurities. Formed by
  Presenting a metal structure in which manganese sulfide particles of 10 μm or less are uniformly dispersed in crystal grains over the entire surface of the iron-base alloy matrix, and 10 μm or less of manganese sulfide particles are dispersed in the hard-phase alloy matrix. A wear-resistant sintered member characterized by An iron base alloy base and a hard phase, and the hard phase is dispersed in the iron base alloy base,
The hard phase is composed of a hard phase alloy base and hard particles, and in the wear-resistant sintered member in which the hard particles are precipitated and dispersed in the hard phase alloy base,
The overall composition is, by mass ratio, Ni: 0.22 to 4.39%, Mo: 0.22 to 4.88%, Cr: 0.16 to 11.79%, Mn: 0.18 to 3.79. %, S: 0.04 to 5.0%, C: 0.3 to 2.0%, the balance is made of a sintered alloy containing Fe and inevitable impurities,
The iron-based alloy base has a mass ratio of Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0.2 to 3.0%, and the balance is formed of a base forming steel powder consisting of Fe and inevitable impurities,
An alloy for forming a hard phase in which the hard phase is, by mass ratio, Cr: 4 to 25%, Mn: 0.5 to 5%, C: 0.25 to 2.4%, and the balance being Fe and inevitable impurities Formed by powder,
10 μm or less of manganese sulfide particles are uniformly dispersed in the crystal grains over the entire surface of the iron-based alloy matrix, and a metal structure in which 10 μm or less of manganese sulfide particles are dispersed in the hard phase alloy matrix,
In addition to at least one of Mo: 0.06-0.12%, V: 0.004-0.88% and W: 0.02-2.0% in the overall composition, The hard phase forming alloy powder contains one or more of Mo: 0.3 to 3%, V: 0.2 to 2.2%, W: 1 to 5%. wear resistant sintered member. An iron base alloy base and a hard phase, and the hard phase is dispersed in the iron base alloy base,
The hard phase is composed of a hard phase alloy base and hard particles, and in the wear-resistant sintered member in which the hard particles are precipitated and dispersed in the hard phase alloy base,
The overall composition is, by mass ratio, Ni: 0.22 to 4.39%, Mo: 0.22 to 4.88%, Cr: 0.14 to 3.79%, Mn: 0.18 to 3.79. %, W: 0.02 to 8.0%, V: 0.01 to 2.4%, S: 0.04 to 5.0%, C: 0.3 to 2.0%, the balance being Fe and It consists of a wear-resistant sintered alloy that is an inevitable impurity,
The iron-based alloy base has a mass ratio of Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0.2 to 3.0%, and the balance is formed of a base forming steel powder consisting of Fe and inevitable impurities,
The hard phase has a mass ratio of Cr: 3 to 5%, W: 1 to 20%, V: 0.5 to 6%, Mn: 0.5 to 5%, C: 0.6 to 1.7. %, The balance is formed of a hard phase forming alloy powder consisting of Fe and inevitable impurities,
10 μm or less of manganese sulfide particles are uniformly dispersed in the crystal grains over the entire surface of the iron-based alloy matrix, and a metal structure in which 10 μm or less of manganese sulfide particles are dispersed in the hard phase alloy matrix,
The total composition further contains at least one Mo or Co at 8.0% or less, and the hard phase forming alloy powder contains at least one Mo or Co at 20% or less. A feature of a wear-resistant sintered member. The amount of manganese sulfide particles dispersed in the iron-based alloy base and the alloy base of the hard phase is 0.3 to 4.5 mass% in the wear-resistant sintered member. Item 5. The wear-resistant sintered member according to any one of Items 1 to 4 . The wear resistance according to any one of claims 1 to 5 , wherein the amount of the hard phase dispersed in the iron-based alloy matrix is 2 to 40 mass% in the wear-resistant sintered member. Sintered member.   The wear-resistant sintered member according to any one of claims 1 to 4, wherein the structure of the iron-based alloy base is bainite. In the overall composition of the sintered alloy, by mass ratio, Mo: 0.13 to 6.86%, W: 0.12 to 14.33%, and Cu: 0.08 to 9.91% The wear-resistant sintered member according to any one of claims 1 to 7 , further comprising at least one kind. At least one of magnesium silicate mineral, boron nitride, manganese sulfide, Ca fluoride, bismuth, chromium sulfide, and lead is dispersed in pores or powder grain boundaries of the wear-resistant sintered member. The wear-resistant sintered member according to any one of claims 1 to 8 . Pores lead or lead alloy of the wear resistant sintered member, copper or a copper alloy, wear resistance according to any one of claims 1 to 9, characterized in that is filled with any of acrylic resin Sintered material. The base forming steel powder includes at least one of a hard phase forming alloy powder containing Mn: 0.5 to 5% by mass, molybdenum disulfide powder, tungsten disulfide powder, iron sulfide powder, and copper sulfide powder. At the same time, a mixed powder obtained by mixing and mixing sulfide powder with an amount of S of 0.04 to 5% by mass and graphite powder is compression-molded in a mold, and the compact is formed at 1000 to 1300 ° C. Sintering in the temperature range ,
The composition of the base forming steel powder is, by mass ratio, Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0 .2 to 3.0%, and the balance consists of Fe and inevitable impurities,
The composition of the hard phase forming alloy powder is, by mass ratio, Mo: 10 to 50%, Si: 0.5 to 10%, Mn: 0.5 to 5%, and the balance is Fe or Co and inevitable impurities And a method for producing a wear-resistant sintered member , wherein the graphite powder is added in an amount of 0.3 to 1.2% by mass . The base forming steel powder includes at least one of a hard phase forming alloy powder containing Mn: 0.5 to 5% by mass, molybdenum disulfide powder, tungsten disulfide powder, iron sulfide powder, and copper sulfide powder. At the same time, a mixed powder obtained by mixing and mixing sulfide powder with an amount of S of 0.04 to 5% by mass and graphite powder is compression-molded in a mold, and the compact is formed at 1000 to 1300 ° C. Sintering in the temperature range,
The composition of the base forming steel powder is, by mass ratio, Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0 .2 to 3.0%, and the balance consists of Fe and inevitable impurities,
The composition of the hard phase forming alloy powder is, by mass ratio, Cr: 4-25%, Mn: 0.5-5%, C: 0.25-2.4%, and the balance is Fe and inevitable impurities together consist of, the addition amount of the graphite powder Ri 0.3 to 2.0% by mass,
The composition of the hard phase forming alloy powder is one or more of Mo: 0.3 to 3%, V: 0.2 to 2.2%, and W: 1 to 5% by mass ratio. A method for producing a wear-resistant sintered member, further comprising: The base forming steel powder includes at least one of a hard phase forming alloy powder containing Mn: 0.5 to 5% by mass, molybdenum disulfide powder, tungsten disulfide powder, iron sulfide powder, and copper sulfide powder. At the same time, a mixed powder obtained by mixing and mixing sulfide powder with an amount of S of 0.04 to 5% by mass and graphite powder is compression-molded in a mold, and the compact is formed at 1000 to 1300 ° C. Sintering in the temperature range,
The composition of the base forming steel powder is, by mass ratio, Ni: 0.5 to 4.5%, Mo: 0.5 to 5.0%, Cr: 0.1 to 3.0%, Mn: 0 .2 to 3.0%, and the balance consists of Fe and inevitable impurities,
The composition of the alloy powder for forming the hard phase is, by mass ratio, Cr: 3-5%, W: 1-20%, V: 0.5-6%, Mn: 0.5-5%, C: 0 .6～1.7%, and with the balance being Fe and unavoidable impurities, the amount of the graphite powder Ri 0.3 to 2.0% by mass,
The composition of the alloy powder for forming a hard phase further contains at least one of Mo or Co: 20% or less by mass ratio . The method for producing a wear-resistant sintered member according to any one of claims 11 to 13, wherein the sulfide powder is a powder having a maximum particle size of 100 µm or less and an average particle size of 50 µm or less. The method for producing a wear-resistant sintered member according to any one of claims 11 to 14, wherein an addition amount of the alloy powder for forming a hard phase is 2 to 40% by mass. The sintering, or the dew point in a vacuum atmosphere -10 ° C. or less of cracked ammonia gas, nitrogen gas, hydrogen gas, to any one of claims 11 to 15, characterized in that in one of an atmosphere of argon gas The manufacturing method of the abrasion-resistant sintered member of description. To the mixed powder, magnesium silicate mineral, boron nitride, manganese sulfide, Ca fluoride, bismuth, to any one of claims 11 to 16, wherein the adding at least one powder of chromium sulfide, lead The manufacturing method of the abrasion-resistant sintered member of description. The wear-resistant sintering according to any one of claims 11 to 17 , wherein after the sintering, any one of lead, a lead alloy, copper or a copper alloy, and an acrylic resin is infiltrated or impregnated. Manufacturing method of member.