JP2016183392A - Hard particle for sintered alloy blending, abrasion resistant iron-based sintered alloy and manufacturing method of abrasion resistant iron-based sintered alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard particle capable of improving abrasion resistance by a sintered alloy with being blended to an abrasion resistant iron-based sintered alloy and enhancing surface toughness with enhancing adhesiveness between the hard particle and a substrate and improving falling during mechanical processing, the abrasion resistant iron-based sintered alloy and a manufacturing method therefor.SOLUTION: There is provided a hard particle for sintered alloy blending which is blended to the sintered alloy as a raw material and contains, by mass%, Ni:41 to 60%, Mo:30 to 50%, Cr:15% or less, Mn:2 to 10%, Si:0.4 to 2%, C:0.5 to 1.5% and the balance Fe with inevitable impurities.SELECTED DRAWING: None

Description

  The present invention relates to hard particles for blending sintered alloys, wear-resistant iron-based sintered alloys, and methods for producing the same.

  Conventionally, as a sintered alloy used for manufacturing valve seats and the like in various engines, for example, as described in Japanese Patent No. 3596951, attention is paid to the characteristics of Mo and Mn contained in hard particles. , Mo: 20 to 70% by mass, C: 0.5 to 3%, Ni: 5 to 40%, Mn: 1 to 20%, the balance is hard using powder of hard particles composed of inevitable impurities and Fe An abrasion-resistant iron-based sintered alloy in which particles are dispersed in an area of 10 to 60% in an iron matrix is disclosed.

  In the sintered alloy described above, the amount of Ni contained in the hard particles is in the range of 5 to 40%.

Japanese Patent No. 359671

  In order to ensure further durability of the sintered alloy described above, it is preferable that the adhesion between the hard particles and the base is high, and the sintered alloy suppresses the hard particles from falling off the base during machining. It is preferable to improve the surface roughness. However, in the above-described sintered alloy, the adhesion between the hard particles and the base is not necessarily sufficient, and it is not sufficient to improve the surface roughness of the sintered alloy during machining, and there is room for improvement. there were.

  The inventors of the present application conducted a study on improving the adhesion between the hard particles and the base and improving the surface roughness of the sintered alloy at the time of machining. Is an essential element that stabilizes heat, and improves heat resistance and wear resistance, improves adhesion between hard powder and base, improves dropout during machining, and improves surface roughness As a result of intensive studies and examinations, the present invention has been found.

  In order to solve the above-mentioned problem, hard particles for blending sintered alloy according to claim 1 are hard particles blended as a raw material in a sintered alloy, and Ni: 41-60%, Mo: 30-50 by mass%. %, Cr: 15% or less, Mn: 2 to 10%, Si: 0.4 to 2%, C: 0.5 to 1.5%, and the balance being inevitable impurities and Fe.

  The hard particle for compounding a sintered alloy according to claim 2 is the hard particle for compounding a sintered alloy according to claim 1, characterized by containing Ni: 41% to 45%.

  The hard particles for blending a sintered alloy according to claim 3 are hard particles blended as a raw material in a sintered alloy, and Ni: 41 to 45%, Mo: 30 to 40%, Cr: 10% in mass%. Hereinafter, Mn: 2 to 6%, Si: 0.4 to 2%, C: 0.5 to 1.0%, and the balance is made of inevitable impurities and Fe.

  The wear-resistant iron-based sintered alloy according to claim 4 has hard particle components of Ni: 41 to 60%, Mo: 30 to 50%, Cr: 15% or less, and Mn: 2 when the hard particles are defined as 100%. 10%, Si: 0.4-2%, C: 0.5-1.5%, the balance of hard particles consisting of inevitable impurities and Fe, 1-50% by mass, carbon powder 0. A mixed material obtained by mixing 5 to 2.5% and the remaining Fe powder is sintered.

  The wear-resistant iron-based sintered alloy according to claim 5 has hard particle components of Ni: 41 to 45%, Mo: 30 to 40%, Cr: 10% or less, and Mn: 2 when the hard particles are taken as 100%. ~ 6%, Si: 0.4-2%, C: 0.5-1.0%, the balance of hard particles consisting of inevitable impurities and Fe, 1-50% by mass, carbon powder 0. A mixed material obtained by mixing 5 to 2.5% and the remaining Fe powder is sintered.

  The method for producing a wear-resistant iron-based sintered alloy according to claim 6 is characterized in that the hard particle powder according to any one of claims 1 to 3 is 1 to 50% by mass and carbon powder 0.5 A mixed material prepared by mixing ~ 2.5% and the remaining Fe powder is prepared, the mixed material is molded to form a green compact, and the green compact is sintered. A sintered alloy having the composition according to claim 5 is characterized.

  A valve seat according to a seventh aspect is formed of the wear-resistant iron-based sintered alloy according to the fourth or fifth aspect.

  The hard particles for blending a sintered alloy according to claim 1 are hard particles blended as a raw material in a sintered alloy, and Ni: 41-60%, Mo: 30-50%, Cr: 15% by mass% Hereinafter, Mn: 2 to 10%, Si: 0.4 to 2%, C: 0.5 to 1.5%, the balance is composed of inevitable impurities and Fe, and for the sintered alloy blending according to claim 3 The hard particles are hard particles blended as a raw material in the sintered alloy, and in mass%, Ni: 41 to 45%, Mo: 30 to 40%, Cr: 10% or less, Mn: 2 to 6%, Si : 0.4 to 2%, C: 0.5 to 1.0%, and the balance consists of inevitable impurities and Fe.

  In the hard alloy compounding hard particles according to the present invention, Ni is an essential element for stabilizing the austenite phase of the hard powder matrix together with C, and also improves heat resistance and wear resistance, and hard Focusing on the fact that it is an element that improves the adhesion between the powder and the base, improves the dropout during machining, and improves the surface roughness, the Ni content is from 41 to 60%, preferably Ni: 41. The sintered alloy produced by containing such hard particles improves wear resistance, improves the adhesion between the hard powder and the base, and improves the dropout during machining. Surface roughness can be improved.

  In addition, the wear-resistant iron-based sintered alloy according to claim 4 and claim 5 includes 1 to 50% by mass of the hard particle powder described above, 0.5 to 2.5% carbon powder, and the balance. Since it is obtained by sintering a mixed material mixed with Fe powder, it improves the wear resistance of the wear-resistant iron-based sintered alloy based on the characteristics of the hard particles described above, and the adhesion between the hard powder and the base Can improve the dropout during machining and improve the surface roughness.

Furthermore, when forming and sintering the wear-resistant iron-based sintered alloy, 1-50% by mass of the hard particle powder is mixed in the mixed material before sintering to form and sinter. By including hard particles as much as possible within the range that does not hinder, the wear resistance of the sintered alloy is improved, the adhesion between the hard powder and the base is improved, the dropout during machining is improved, and the surface roughness is reduced. Can be improved.
The sintered alloy produced as described above is suitable for use in a valve seat.

It is explanatory drawing which shows typically the abrasion resistance tester of a valve seat.

(Hard particles)
The hard particles according to the first embodiment are, in mass%, Ni: 41-60%, Mo: 30-50%, Cr: 15% or less, Mn: 2-10%, Si: 0.4-2%, C : 0.5 to 1.5%, the balance being inevitable impurities and Fe.

  Here, the Ni content is more preferably in the range of Ni: 41% to 45%.

  The hard particles according to the second embodiment are, in mass%, Ni: 41-45%, Mo: 30-40%, Cr: 10% or less, Mn: 2-6%, Si: 0.4-2%, C : 0.5-1.0%, the balance consists of inevitable impurities and Fe.

  In the hard particles according to the first and second embodiments described above, Ni is an essential element for stabilizing the austenite phase of the matrix of the hard powder together with C in the base, and also improves heat resistance and wear resistance. Wear resistance and workability in sintered alloys based on the fact that it is an element that improves hardness, improves adhesion between hard powder and base, improves dropout during machining, and improves surface roughness (workability) In order to achieve a good balance, the Ni content in the hard particles of the first embodiment is set in the range of 41% to 60%, and the Ni content in the hard particles according to the second embodiment is It is set in the range of 41 to 45%.

  Here, if the Ni content is less than 41%, sufficient effects on wear resistance and workability cannot be obtained, and if the Ni content exceeds 60%, the ductility becomes high and the workability deteriorates. To do.

  Mo is an essential element for generating Mo-based carbides in the hard powder and improving wear resistance. However, if it is added excessively, the hard powder becomes brittle, it becomes easy to fall off during machining into a valve seat shape, and the surface roughness deteriorates. Specifically, if the addition amount is less than 30%, the wear resistance is not sufficient. On the other hand, if the addition amount exceeds 50%, the brittleness increases and the surface roughness deteriorates.

  Cr is an essential element for improving the wear resistance by producing Cr carbide in the hard powder together with C. However, if more than 15% is added, the hard powder tends to fall off during machining and the surface roughness is deteriorated.

  Mn is an element that has the effect of improving the adhesion between the hard powder and the base during sintering. If less than 2%, the adhesion with the base is poor and the hard powder falls off during machining, resulting in poor surface roughness. Abrasion resistance also deteriorates. On the other hand, if it exceeds 10%, the diffusion to the base becomes too large and the shape of the hard powder cannot be maintained, and on the contrary, the adhesion is lowered and the surface roughness is deteriorated.

  Si is an essential element for increasing the hardness of the hard powder and improving the wear resistance by dissolving in the matrix. However, if added excessively, the hard powder becomes brittle. Specifically, if the addition is less than 0.4%, the wear resistance is not sufficient. On the other hand, if the addition exceeds 2%, the brittleness increases and the wear resistance deteriorates.

  C is an essential element for forming Mo-based carbides and Cr-based carbides in the hard powder to prevent adhesive wear, and for austenizing the matrix together with Ni. However, specifically, when added over 1.5%, the ductility is improved and the surface roughness is deteriorated. On the other hand, when the added amount is less than 0.5%, the adhesiveness with the base is deteriorated and easily falls off. The rough surface becomes worse. Thereby, the wear resistance is also deteriorated.

  The hard particles according to the first embodiment and the second embodiment may be manufactured by an atomizing process for atomizing a molten metal, or may be a powder obtained by mechanically pulverizing a solidified body obtained by solidifying a molten metal. As the atomization treatment, an atomization treatment in a non-oxidizing atmosphere (inert gas atmosphere such as nitrogen gas or argon gas or in vacuum) can be employed.

  The average particle size of the hard particles can be appropriately selected according to the use and type of the iron-based sintered alloy, but is generally about 20 to 250 μm, about 30 to 200 μm, and about 40 to 180 μm. be able to. However, it is not limited to this. The hardness of the hard particles is generally about Hv 350 to 750 and about Hv 450 to 700, although it depends on the amount of Mo carbide and the like. However, the present invention is not limited to this. In short, it is only necessary that the hard particles are hard to be used, such as a sintered alloy base.

(Abrasion-resistant iron-based sintered alloy)
The wear-resistant iron-based sintered alloy produced using the hard particles according to the first embodiment has a hard particle component of Ni: 41-60%, Mo: 30-50% when the hard particles are taken as 100%, Cr: 15% or less, Mn: 2 to 10%, Si: 0.4 to 2%, C: 0.5 to 1.5%, balance of hard particles composed of unavoidable impurities and Fe in 1% by mass It is produced by sintering a mixed material obtained by mixing ˜50%, carbon powder 0.5˜5%, and the remaining Fe powder.

  Further, the wear-resistant iron-based sintered alloy produced by using the hard particles according to the second embodiment has Ni: 41 to 45% of the hard particle component and Mo: 30 to 30% when the hard particles are taken as 100%. 40%, Cr: 10% or less, Mn: 2 to 6%, Si: 0.4 to 2%, C: 0.5 to 1.0%, the balance being hard particles powder consisting of inevitable impurities and Fe It is produced by sintering a mixed material obtained by mixing 1 to 50%, carbon powder 0.5 to 2.5%, and the remaining Fe powder.

  Regarding the composition of the sintered alloy base, in order to ensure the wear resistance of the iron-based sintered alloy, to secure the hardness of the iron-based sintered alloy base, Including organizations can be employed. The pearlite-containing structure may be a pearlite structure, a pearlite-austenite mixed structure, a pearlite-ferrite mixed structure, or a pearlite-cementite mixed structure. In order to ensure wear resistance, it is preferable that the amount of ferrite having low hardness is small. Although the hardness of the base depends on the composition, it can generally be about Hv 120 to 300 and about Hv 150 to 250, but is not limited thereto. The hardness of the hard particles is harder than that of the base, and can generally be about Hv 350 to 750 and about Hv 450 to 700, but is not limited thereto.

  In addition, according to each of the above-mentioned wear-resistant iron-based sintered alloys, the composition of the hard particles and the preferable composition range of the hard particles are basically the same as those of the hard particles according to the first and second embodiments. It is. The average particle size of the hard particles can be selected as appropriate according to the use and type of the iron-based sintered alloy, but is generally about 20 to 250 μm, about 30 to 200 μm, and about 40 to 180 μm. it can. The hardness of the hard particles is generally about Hv 350 to 750 and about Hv 450 to 700, although it depends on the amount of Mo carbide and the like. However, it is not limited to this.

(Method for producing wear-resistant iron-based sintered alloy)
In the manufacturing method of each wear-resistant iron-based sintered alloy described above, the hard particle powder according to the first embodiment or the second embodiment is 1 to 50% by mass, and the carbon powder is 0.5 to 2.5. % And a mixed material in which the remaining Fe powder is mixed, the mixed material is molded to form a green compact, and the green compact is sintered.

  The hard particles described above are dispersed in the base of the sintered alloy and constitute a hard phase that enhances the wear resistance of the sintered alloy. If the ratio of hard particles is small, the wear resistance of the sintered alloy is not sufficient. When the ratio of the hard particles is excessive, it is difficult to ensure the retention of the hard particles with respect to the base. For this reason, the compounding quantity of the hard particle powder is 1 to 50% by mass. In general, graphite powder can be used as the carbon powder. The carbon (C) of the carbon powder diffuses into the base of the sintered alloy or hard particles, and forms a solid solution or generates a carbide (such as Mo carbide or Cr carbide). For this reason, the compounding quantity of carbon powder shall be 0.5 to 2.5%.

  The Fe powder constitutes the base of the wear-resistant iron-based sintered alloy. According to the manufacturing method described above, the cost of the starting material can be reduced, and further, the compression molding property of the green compact can be achieved, which is advantageous for increasing the density of the green compact and thus the sintered alloy. It becomes.

  According to the manufacturing method described above, in the hard particles and the matrix, the alloy element contained in one diffuses to the other during the sintering, so that the adhesion between the hard particles and the matrix increases. In particular, when the hard particles according to the first and second embodiments are employed, a good balance between wear resistance and workability in the sintered alloy can be achieved based on the characteristics of Ni.

  As the sintering temperature, about 1050 to 1250 ° C., particularly about 1100 to 1150 ° C. can be adopted. As the sintering time at the sintering temperature, 10 minutes to 120 minutes, especially 15 to 40 minutes can be employed. The sintering atmosphere is preferably a non-oxidizing atmosphere such as an inert gas atmosphere. Examples of the non-oxidizing atmosphere include a nitrogen atmosphere, an argon gas atmosphere, and a vacuum atmosphere.

  The wear-resistant iron-based sintered alloy produced as described above is suitable as a sintered alloy used in valve seats of various engines such as gasoline, light oil, compressed natural gas and liquefied petroleum gas as vehicles. .

  Examples according to the present invention will be described below together with comparative examples.

  For producing the wear-resistant iron-based final bond according to each example, first, alloy powders of hard particles A to Y having the composition shown in Table 1 were manufactured by gas atomization using an inert gas (nitrogen gas). . These were classified into a range of 44 μm to 250 μm to obtain a powder of each hard particle.

Among the alloy powders A to Y described above, the alloy powders A to N are powders corresponding to hard particles within the scope of the present invention, and correspond to examples of the present invention. In the alloy powders A to N, Ni is in the range of 41% to 60%, Mo is in the range of 30% to 50%, Cr is in the range of 0% to 15%, and Mn is in the range of 2% to 10%. , Si is contained in the range of 0.4% to 2%, and C is contained in the range of 0.5% to 1.5%.
Further, any one of the components of the alloy powders O to Y is out of the scope of the present invention, and corresponds to a comparative example. Specifically, in the powder alloy O, the Ni content is 35%, which is low from the range of 41% to 60% of the present invention. In the powder alloy P, the Ni content is 65%, which is far from the range of 41% to 60% of the present invention, and the Mo content is 25%, and the range of the present invention is 30% to 50%. Is low. In the powder alloy Q, the Mo content is 25%, which is low from the range of 30% to 50% of the present invention. In the powder alloy R, the Mo content is 55%, which is far from the range of 30% to 50% of the present invention. In the powder alloy S, the Cr content is 20%, which is highly deviated from the range of 15% or less of the present invention. In the powder alloy T, the Mn content is 0%, which is low from the range of 2% to 10% of the present invention. In the powder alloy U, the content of Mn is 12%, which is far from the range of 2% to 10% of the present invention. In the powder alloy V, the Si content is 0%, which is low from the range of 0.4% to 2% of the present invention. In the powder alloy W, the content of Si is 2.5%, which is highly deviated from the range of 0.4% to 2% of the present invention. In the powder alloy X, the C content is 0.2%, which is low from the range of 0.5% to 1.5% of the present invention. In the powder alloy Y, the content of C is 1.7%, which is highly deviated from the range of 0.5% to 1.5% of the present invention.

  Furthermore, the above-described powder alloys (hard particle powders) A to Y, graphite powder, and pure Fe powder were mixed by a mixer at the ratio shown in Table 2 below. Examples 1 to 14 and Comparative Example The mixed powder used for 1-11 was formed, respectively. As shown in Table 2, in all of Examples 1 to 14 and Comparative Examples 1 to 11, the mixing amount of hard particles was 40%. Further, as shown in Table 2, the mixing amount of the graphite powder was mixed in the range of 1.2% to 1.5% in Examples 1 to 14, and Comparative Example 1 to Comparative Example 11 Then, it mixed in 1.1%-1.6% of range.

Further, a test piece having a ring shape was compression-molded by using a mold and the mixed powder blended as described above at a pressure of 78.4 × 10 7 Pa (8 tonf / cm ² ) to form a green compact. The test piece was molded into a valve seat shape.

  Then, each compacting body was sintered in an inert atmosphere (nitrogen gas atmosphere) at 1140 ° C. for 20 minutes, and the sintered bonding of Examples 1 to 14 and Comparative Examples 1 to 11 according to the test pieces was performed. Gold (valve seat) was formed.

For the sintered alloys (valve seats) of Examples 1 to 14 and Comparative Examples 1 to 11 formed as described above, an abrasion test was performed and surface roughness was measured under predetermined conditions.
Here, the wear test and the surface roughness measurement are based on the sintered alloy according to Example 2 considered as a preferred example, and in Table 2, the firing of Example 2 containing 40% hard particles B is used. The wear amount value and the surface roughness value obtained in the other examples and comparative examples are expressed as a ratio, with the wear amount value and the surface roughness value obtained with the bond gold being 1.000.

  First, the wear tester used in the wear test will be described with reference to FIG. In FIG. 1, in the wear tester M, the propane gas burner 1 is used as a heating source, and the ring-shaped valve seat 2 and the valve face 4 of the valve 3 are test pieces made of a sintered alloy prepared as described above. The sliding part was a propane gas combustion atmosphere. The valve face 4 is a SUH35 material. The temperature of the valve seat face 5 is controlled to 300 ° C., and a load of 25 kgf is applied by the spring 6 when the valve seat face 5 and the valve face 4 are brought into contact with each other at a rate of 3250 times / min. Went.

In Table 2, since the amount of wear of the sintered alloy according to Example 2 was used as a reference as described above, the amount of wear of the sintered alloys according to other Examples and Comparative Examples was the sinter bonding according to Example 2. The wear amount of gold is assumed to be 1.000. Here, when the value of the wear amount ratio is larger than 1.000, it indicates that the wear is greater than the sintered alloy of Example 2, and when the value of the wear amount ratio is smaller than 1.000. Shows that the amount of wear is smaller than that of the sintered alloy of Example 2.
The upper limit value of the wear amount ratio is 1.5. The upper limit of “1.5” is based on the sintered alloy of Example 2 because the sintered alloy of Example 2 obtained by containing 40% of hard particles B is considered suitable. A guess based on that. Therefore, if the value of the wear amount ratio is larger than 1.5, it is considered that the wear amount exceeds the allowable limit and is not suitable as a product. On the other hand, if the wear amount ratio value is smaller than 1.5, the wear amount is considered to be unacceptable. The amount is within acceptable limits.

  In the abrasion test performed on the sintered alloys according to Examples 1 to 14, as shown in Table 2, the values of the wear amount ratios of the sintered alloys according to Example 1 and Examples 3 to 14 are In both cases, a value of 1.5 or less was obtained, and the test result in the wear test was good.

  Moreover, in the abrasion test performed about Comparative Example 1-Comparative Example 11, as shown in Table 2, with the sintered alloy which concerns on Comparative Example 2, Comparative Example 4, Comparative Example 5, Comparative Example 7, and Comparative Example 11, it is worn out. The values of the quantity ratios are all 1.5 or less, which is good, but in the sintered alloys according to Comparative Example 1, Comparative Example 3, Comparative Example 6, Comparative Example 8, Comparative Example 9 and Comparative Example 10, the wear ratio Each of the values exceeds 1.5, and the wear resistance is low.

Next, the evaluation of the surface roughness of each sintered alloy will be described.
First, the sintered alloy test pieces (having a ring shape with an outer diameter of 30 mm, an inner diameter of 22 mm, and an overall length of 9 mm) according to Examples 1 to 14 and Comparative Examples 1 to 11 generated as described above were prepared. Each test piece was set on an NC lathe having a carbide cutting tool coated with titanium nitride aluminum. In the NC lathe, the traverse cutting was performed in a wet manner under the conditions of a rotation speed of the cemented carbide tool of 970 rpm, a cutting amount of 0.3 mm, a feed amount of 0.08 mm / rev, and a cutting distance of 320 m. Thereafter, the surface roughness Ra of each test piece was measured and evaluated using a surface roughness measuring machine.

In Table 2, since the surface roughness of the sintered alloy according to Example 2 was used as a reference as described above, the surface roughness of the sintered alloys according to other Examples and Comparative Examples is related to Example 2. The surface roughness of the sintered alloy is 1.000, and the surface roughness ratio is expressed with respect to this value. Here, when the value of the surface roughness ratio is larger than 1.000, it indicates that the measurement surface is rougher than the sintered alloy of Example 2, and the value of the surface roughness ratio is more than 1.000. When it is smaller, the measurement surface is smoother than the sintered alloy of Example 2.
The upper limit value of the surface roughness ratio is 1.5. Since the upper limit value of “1.5” is considered to be suitable for the sintered alloy of Example 2 obtained by containing 40% of hard particles B as in the case of the wear resistance ratio, This is an estimated value based on the sintered alloy of Example 2 as a reference. Therefore, if the value of the surface roughness ratio is larger than 1.5, the measurement surface exceeds the allowable limit and is considered to be unsuitable as a product, while the value of the surface roughness ratio is more than 1.5. If it is smaller, the roughness of the measurement surface is within the allowable limit.

  In the surface roughness measurement performed for the sintered alloys according to Examples 1 to 14, as shown in Table 2, the surface roughness ratios of the sintered alloys according to Example 1 and Examples 3 to 14 were used. As for the value of all, the value of 1.5 or less is obtained, and the measurement result in the surface roughness measurement is good.

  Moreover, in the surface roughness measurement performed about the comparative example 1-the comparative example 11, as shown in Table 2, in the sintered alloy which concerns on the comparative example 3 and the comparative example 8, all the values of surface roughness ratio are 1. In the sintered alloys according to Comparative Example 1, Comparative Example 2, Comparative Example 4, Comparative Example 5, Comparative Example 5, Comparative Example 6, Comparative Example 7, Comparative Example 9, Comparative Example 10 and Comparative Example 11, which are 5 or less Each of the surface roughness ratio values exceeds 1.5, and the measurement surface is in a considerably rough state.

  As described above, in the sintered alloys according to Example 1 to Example 14 using the hard particles A to N, both the value of the wear amount ratio and the value of the surface roughness ratio are not more than the upper limit value. The hard particles A to N are suitable as hard particles for blending a sintered alloy for generating a valve seat. In the sintered alloys according to Comparative Examples 1 to 11, there was no sintered alloy in which both the wear amount ratio value and the surface roughness ratio value were not more than the upper limit values.

Next, when producing the wear-resistant iron-based sintered alloy, the mixing amount of each of the hard particle powder and the carbon powder is adjusted by adjusting the mixed material by mixing the hard particle powder, the carbon powder, and the Fe powder. And the relationship between the wear amount ratio and the surface roughness ratio of the sintered alloy obtained by forming and sintering the mixed material. The results are shown in Table 3.
The wear ratio and the surface roughness ratio were measured by the same method as described above.

  In Table 3, five examples of Example 15 to Example 19 and seven comparative examples of Comparative Example 12 to Comparative Example 18 are shown. The hard particles (K, A, G, B, J) used in Examples 15 to 19 are the sintered alloys of Example 11, Example 1, Example 7, Example 2, and Example 10, respectively. It is a hard quantum used in generating. The hard particles (M, O, T, Q, W, X, S) used in Comparative Examples 12 to 18 were Example 13, Comparative Example 1, Comparative Example 6, Comparative Example 3, and Comparative Example, respectively. 9, hard particles used in producing the sintered alloys of Comparative Example 10 and Comparative Example 5.

  Here, the sintered alloy according to Example 15 was obtained by molding and sintering a mixed material in which 1% of the hard particles K, 1.6% of the graphite powder, and the remaining Fe powder were mixed. The sintered alloy according to Example 16 was obtained by forming and sintering a mixed material in which 5% hard particles A, 1.6% graphite powder, and the remaining Fe powder were mixed. The sintered alloy according to Example 17 was obtained by molding and sintering a mixed material in which 10% hard particles G, 1.7% graphite powder, and the remaining Fe powder were mixed. The sintered alloy according to Example 18 was obtained by molding and sintering a mixed material obtained by mixing 20% hard particles B, 1.7% graphite powder, and the remaining Fe powder. The sintered alloy according to Example 19 was obtained by molding and sintering a mixed material in which 50% hard particles J, 1.1% graphite powder, and the remaining Fe powder were mixed.

  In Comparative Example 12, an attempt was made to mold and sinter a mixed material in which 60% hard particles M, 1.4% graphite powder, and the remaining Fe powder were mixed, but the shape after pressure molding was unstable. There was no sintered alloy (see * on the cover). The sintered alloy according to Comparative Example 13 was obtained by molding and sintering a mixed material obtained by mixing 1% hard particles O, 1.5% graphite powder, and the remaining Fe powder. The sintered alloy according to Comparative Example 14 was obtained by molding and sintering a mixed material in which 5% hard particles T, 1.6% graphite powder, and the remaining Fe powder were mixed. The sintered alloy according to Comparative Example 15 was obtained by molding and sintering a mixed material obtained by mixing 10% hard particles Q, 1.3% graphite powder, and the remaining Fe powder. The sintered alloy according to Comparative Example 16 was obtained by molding and sintering a mixed material in which 20% hard particles W, 1.6% graphite powder, and the remaining Fe powder were mixed. The sintered alloy according to Comparative Example 17 was obtained by molding and sintering a mixed material in which 50% hard particles X, 1.5% graphite powder, and the remaining Fe powder were mixed. In Comparative Example 18, an attempt was made to mold and sinter a mixed material in which 60% hard particles S, 1.3% graphite powder, and the remaining Fe powder were mixed, but the shape after pressure molding was unstable, No sintered alloy was obtained (see * in Table 3).

  Next, the values of the wear amount ratio and the surface roughness ratio measured for the sintered alloys according to the examples and comparative examples will be examined. Here, when producing sintered alloys according to Example 15 to Example 19 and Comparative Example 12 to Comparative Example 18, the content of hard particles is in the range of 1% to 60%. When the content is increased, the wear resistance of the sintered alloy is improved, the value of the wear amount is lowered, and the value of the surface roughness is also lowered. On the other hand, when the hard particle content is reduced, the wear resistance of the sintered alloy is lowered, the wear value is increased, and the surface roughness value is also increased. Under such circumstances, the reference value of the wear amount ratio changes depending on whether the hard particle content is large or small, but the wear amount ratio of the sintered alloy corresponding to the hard particle content The upper limit of the surface roughness ratio is generally known. Specifically, when the hard particle content is 1% (Example 15 and Comparative Example 13), the upper limit value allowable as the wear amount ratio and the surface roughness ratio is about 2.7. Similarly, when the hard particle content is 5% (Example 16 and Comparative Example 14), the upper limit value acceptable as the wear amount ratio and the surface roughness ratio is about 2.2, and the hard particle content Is 10% (Example 17 and Comparative Example 15), the allowable upper limit of the wear amount ratio and the surface roughness ratio is about 1.9, and the hard particle content is 20% (Example). 18 and Comparative Example 16), the allowable upper limit for the wear amount ratio and the surface roughness ratio is about 1.8, and when the hard particle content is 50% (Example 19, Comparative Example 17). The upper limit allowable for the wear amount ratio and the surface roughness ratio is about 1.4.

  In Table 3, in the sintered alloy according to Example 15, the wear amount ratio is 2.512 and the surface roughness ratio is 2.101. In this case, the upper limit values of the wear amount ratio and the surface roughness ratio are 2. Therefore, both the wear amount ratio and the surface roughness ratio are below the upper limit value. Thus, the sintered alloy according to Example 15 is a good sintered alloy that satisfies both the wear amount ratio and the surface roughness ratio.

  In the sintered alloy according to Example 16, the wear amount ratio is 2.079 and the surface roughness ratio is 1.919, and the upper limit values of the wear amount ratio and the surface roughness ratio in this case are 2.2. Both the wear amount ratio and the surface roughness ratio are below the upper limit value. Thus, the sintered alloy according to Example 16 is a good sintered alloy that satisfies both the wear amount ratio and the surface roughness ratio.

  In the sintered alloy according to Example 17, the wear amount ratio is 1.268 and the surface roughness ratio is 1.752, and the upper limit values of the wear amount ratio and the surface roughness ratio in this case are 1.9. Both the wear amount ratio and the surface roughness ratio are below the upper limit value. Thus, the sintered alloy according to Example 17 is a good sintered alloy that satisfies both the wear amount ratio and the surface roughness ratio.

  In the sintered alloy according to Example 18, the wear amount ratio is 1.232 and the surface roughness ratio is 1.399, and the upper limit values of the wear amount ratio and the surface roughness ratio in this case are 1.8. Both the wear amount ratio and the surface roughness ratio are below the upper limit value. Thus, the sintered alloy according to Example 18 is a good sintered alloy that satisfies both the wear amount ratio and the surface roughness ratio.

  In the sintered alloy according to Example 19, the wear amount ratio is 0.904 and the surface roughness ratio is 1.328. In this case, the upper limit values of the wear amount ratio and the surface roughness ratio are 1.4. Both the wear amount ratio and the surface roughness ratio are below the upper limit value. Thus, the sintered alloy according to Example 19 is a good sintered alloy that satisfies both the wear amount ratio and the surface roughness ratio.

  In Comparative Example 12, an attempt was made to mold and sinter a mixed material in which 60% hard particles M, 1.4% graphite powder, and the remaining Fe powder were mixed, but the shape after pressure molding was unstable, No sintered alloy was obtained (see * in Table 3). This is presumably because the content of hard particles was too high at 60%, so that a stable shape could not be maintained even with the remaining base.

  In the sintered alloy according to Comparative Example 13, the wear amount ratio is 2.902 and the surface roughness ratio is 2.568, and the upper limit values of the wear amount ratio and the surface roughness ratio in this case are 2.7. The surface roughness ratio is not more than the upper limit value, but the wear amount ratio exceeds the upper limit value. Accordingly, the sintered alloy according to Comparative Example 13 has a problem in the wear amount ratio, and is unsuitable as a sintered alloy used for the valve seat.

  In the sintered alloy according to Comparative Example 14, the wear amount ratio is 2.551 and the surface roughness ratio is 2.545, and the upper limit values of the wear amount ratio and the surface roughness ratio in this case are 2.2. Both the wear amount ratio and the surface roughness ratio exceed the upper limit. Thus, the sintered alloy according to Comparative Example 14 has a problem in both the wear amount ratio and the surface roughness ratio, and is unsuitable as a sintered alloy used for the valve seat.

  In the sintered alloy according to Comparative Example 15, the wear amount ratio is 1.982, and the surface roughness ratio is 1.613. In this case, the upper limit values of the wear amount ratio and the surface roughness ratio are 1.9. The surface roughness ratio is not more than the upper limit value, but the wear amount ratio exceeds the upper limit value. Accordingly, the sintered alloy according to Comparative Example 15 has a problem in the wear amount ratio, and is unsuitable as a sintered alloy used for the valve seat.

  In the sintered alloy according to Comparative Example 16, the wear amount ratio is 1.863 and the surface roughness ratio is 1.919, and the upper limit values of the wear amount ratio and the surface roughness ratio in this case are 1.8. Both the wear amount ratio and the surface roughness ratio exceed the upper limit. Thus, the sintered alloy according to Comparative Example 16 has problems in both the wear amount ratio and the surface roughness ratio, and is unsuitable as a sintered alloy used for the valve seat.

  In the sintered alloy according to Comparative Example 17, the wear amount ratio is 1.612, and the surface roughness ratio is 1.673. In this case, the upper limit values of the wear amount ratio and the surface roughness ratio are 1.4. Both the wear amount ratio and the surface roughness ratio exceed the upper limit. Thus, the sintered alloy according to Comparative Example 16 has problems in both the wear amount ratio and the surface roughness ratio, and is unsuitable as a sintered alloy used for the valve seat.

  In Comparative Example 18, an attempt was made to mold and sinter a mixed material in which 60% hard particles S, 1.3% graphite powder, and the remaining Fe powder were mixed, but the shape after pressure molding was unstable, No sintered alloy was obtained (see * in Table 3). This is presumably because the content of hard particles was too high at 60%, so that a stable shape could not be maintained even with the remaining base.

  As described above, in the sintered alloys according to Examples 15 to 19, both the wear amount ratio and the surface roughness ratio are not more than the respective upper limit values. It is a sintered alloy suitable for manufacturing. From the content of hard particles in Examples 15 to 19, molding and sintering a mixed material obtained by mixing hard particle powder, carbon powder, and Fe powder in the range of 1 to 50% of hard particles. Thus, a more suitable sintered alloy can be obtained.

  As in Comparative Example 12 and Comparative Example 18, when the content of hard particles exceeds 60%, a stable shape cannot be maintained even with the remaining base, and a sintered alloy cannot be obtained.

  The present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the scope of the present invention.

1 Gas burner 2 Valve seat 3 Valve 4 Valve face 5 Valve seat face

Claims (7)

  Hard particles blended as a raw material in a sintered alloy, Ni: 41-60%, Mo: 30-50%, Cr: 15% or less, Mn: 2-10%, Si: 0.4 by mass% Hard particles for blending sintered alloy, characterized in that -2%, C: 0.5-1.5%, the balance being inevitable impurities and Fe.   The hard particle for compounding sintered alloy according to claim 1, comprising Ni: 41% to 45%.   Hard particles blended as a raw material in a sintered alloy, and Ni: 41 to 45%, Mo: 30 to 40%, Cr: 10% or less, Mn: 2 to 6%, Si: 0.4 by mass% Hard particles for blending sintered alloy, characterized in that -2%, C: 0.5-1.0%, the balance being inevitable impurities and Fe.   When hard particles are 100%, hard particle components are Ni: 41-60%, Mo: 30-50%, Cr: 15% or less, Mn: 2-10%, Si: 0.4-2%, C: 0.5 to 1.5%, the balance of hard particles consisting of inevitable impurities and Fe is 1 to 50% by mass, carbon powder 0.5 to 2.5%, and the remaining Fe powder. A wear-resistant iron-based sintered alloy obtained by sintering a mixed material.   When hard particles are 100%, hard particle components are Ni: 41-45%, Mo: 30-40%, Cr: 10% or less, Mn: 2-6%, Si: 0.4-2%, C: 0.5 to 1.0%, the balance of hard particles consisting of inevitable impurities and Fe is 1 to 50% by mass, carbon powder 0.5 to 2.5%, and the remaining Fe powder. A wear-resistant iron-based sintered alloy obtained by sintering a mixed material. The mixed material which mixed the powder of the hard particle | grains in any one of Claims 1-3 with 1-50% by mass%, carbon powder 0.5-2.5%, and the Fe powder used as the remainder. Prepare
The mixed material is molded to form a green compact, and the green compact is sintered to obtain a sintered alloy having the composition according to claim 4 or 5. A method for producing an iron-based sintered alloy. A valve seat formed of the wear-resistant iron-based sintered alloy according to claim 4 or 5.

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