JP4704949B2 - Mixed powder for producing iron-based sintered body and iron-based sintered body - Google Patents

Description

  The present invention belongs to a technical field related to a mixed powder for producing an iron-based sintered body and an iron-based sintered body, and in particular, an iron-based sintered body suitable as a high-strength sintered part for automobiles and the iron It belongs to the technical field related to mixed powders for the production of basic sintered bodies.

  The powder metallurgy method is a method in which a metal powder is pressed and molded in a mold and then sintered to form a sintered body. The powder metallurgy method is widely applied to the manufacture of automobile parts such as gears that require high dimensional accuracy, because it can also accurately manufacture mechanical parts having complicated shapes.

In powder metallurgy, when iron powder is used as metal powder, alloy components such as Cu powder and graphite powder are usually mixed with iron powder, and about 0.8% of a lubricant is added to improve formability. The sintered body has a density of about 6.8 to 7.2 g / cm ³ . This sintered body contains Cu and the like in addition to Fe, but uses Fe as a base (basic) component. The raw material powder (mixed powder for producing a sintered body) for obtaining this sintered body contains Cu powder in addition to iron powder, but uses iron powder as a base (basic) powder. .

  Such a sintered body containing Fe as a base component is hereinafter referred to as an iron-based sintered body. The raw material powder for obtaining the iron-based sintered body is hereinafter referred to as a mixed powder for producing an iron-based sintered body. Hereinafter, the base powder is referred to as mother powder.

  As a means for increasing the strength of the iron-based sintered body, a method by adding an alloy element has been proposed. Examples of the method by addition of the alloy element include those described in JP-A-9-87794, JP-A-9-59740, and JP-A-2000-64001.

In the above-mentioned Japanese Patent Application Laid-Open No. 9-87794, iron-base alloy powder containing Ni and Mo is used as a mother powder (base powder) of a mixed powder for producing an iron-based sintered body. In the one described in JP-A-9-59740, iron-base alloy powder (pre-alloyed steel powder) containing Ni, Mo or the like is used as a base powder of a mixed powder for producing an iron-based sintered body, An alloyed powder containing Ni, Mo or the like and Cu or Si is also included in the mixed powder for manufacturing the body. In the thing of Unexamined-Japanese-Patent No. 2000-64001, while using the iron-base alloy powder (alloy steel powder) which partially alloyed Ni and Mo as a mother powder of the mixed powder for iron-based sintered compact manufacture, Ni powder and Mo powder are also included in the mixed powder for manufacturing the knot.
JP-A-9-87794 JP-A-9-59740 JP 2000-64001 A

  However, such a method based on the addition of alloy elements necessitates the use of expensive alloy elements such as Ni and Mo, leading to an increase in cost and poor economic efficiency.

  The present invention has been made in view of such circumstances, and its purpose is to increase the strength of the iron-based sintered body without using expensive alloy elements such as Ni and Mo. An object of the present invention is to provide a mixed powder for producing an iron-based sintered body capable of obtaining a strong iron-based sintered body and an iron-based sintered body capable of having high strength.

  As a result of intensive studies to achieve the above object, the present inventors have completed the present invention. According to the present invention, the above object can be achieved.

The present invention, which has been completed in this way and has achieved the above object, relates to a mixed powder for producing an iron-based sintered body and an iron-based sintered body, and the iron-based sintered body according to claims 1 to 3. A mixed powder for production (mixed powder for producing an iron-based sintered body according to the first to third inventions), an iron-based sintered body (iron-based sintered body according to the fourth invention) according to claim 4 , which is The configuration is as follows.

That is, the mixed powder for producing an iron-based sintered body according to claim 1 contains iron powder and / or iron alloy powder as a mother powder, and contains a Cu alloy powder and graphite powder. The melting point of the Cu alloy powder is 1000 ° C. or less, the Cu alloy of the Cu alloy powder contains Mn as an alloy element, and the amount of the alloy element Mn is used for producing the iron-based sintered body. An amount of the iron-based sintered body obtained from the mixed powder is 0.1 to 1.3 mass%, which is a mixed powder for producing an iron-based sintered body [first invention].

  The mixed powder for producing an iron-based sintered body according to claim 2, wherein the amount of Cu in the Cu alloy of the Cu alloy powder is 50 mol% or more. [Second invention].

In the mixed powder for producing an iron-based sintered body according to claim 3 , the Cu alloy of the Cu alloy powder further contains one or more of P and Si as alloy elements , and the amount of the alloy elements P and Si is It is the quantity with respect to the iron base sintered compact obtained from the mixed powder for iron base sintered compact manufacture, and is 0.1-0.5 mass% in total, It is the mixed powder for iron base sintered compact manufacture of Claim 1 or 2 [ Third invention].

The iron-based sintered body according to claim 4 is an iron-based sintered body obtained from the mixed powder for producing an iron-based sintered body according to any one of claims 1 to 3 [ fourth invention].

  According to the mixed powder for producing an iron-based sintered body according to the present invention, the strength of the iron-based sintered body can be increased without using an expensive alloy element such as Ni or Mo, and a high-strength iron-based sintered body can be obtained. A sintered body can be obtained. The iron-based sintered body according to the present invention can have high strength, and therefore can be suitably used as a high-strength iron-based sintered body.

The mixed powder for producing an iron-based sintered body according to the present invention, as described above, contains iron powder and / or iron alloy powder as a mother powder, and produces an iron-based sintered body containing Cu alloy powder and graphite powder. The Cu alloy powder has a melting point of 1000 ° C. or less, the Cu alloy of the Cu alloy powder contains Mn as an alloy element, and the amount of the alloy element Mn is the iron-based sintered body. An amount of the iron-based sintered body obtained from the mixed powder for production, which is 0.1 to 1.3 mass%, is a mixed powder for producing an iron-based sintered body [first invention]. The iron alloy powder is a powder made of an iron alloy (powdered iron alloy), and the iron alloy is an alloy containing Fe as a base (basic) component. The iron powder and / or iron alloy powder is hereinafter referred to as iron-based powder (both iron powder and iron alloy powder are hereinafter referred to as iron-based powder).

  Conventionally, Cu powder has been used as a sintering auxiliary material for iron powder sintering. The secondary material Cu powder melts during the sintering (melting point of Cu 1083 ° C.), wets the iron powder interface, and the sintering of the iron powder proceeds.

  In the mixed powder for producing an iron-based sintered body according to the present invention, Cu alloy powder is used instead of this Cu powder, and the melting point of this Cu alloy powder is 1000 ° C. or less as described above. Alloy powder is easy to melt. Therefore, the sintering easily proceeds, and as a result, the bonding strength at the interface of the iron-based powder (iron powder, iron alloy powder) is improved, thereby improving the strength of the iron-based sintered body.

  Such an effect of improving the strength of the iron-based sintered body can be obtained without using an expensive alloy element such as Ni or Mo. That is, in the above-mentioned JP-A-9-87794, JP-A-9-59740, and JP-A-2000-64001, as described above, the base of the mixed powder for producing an iron-based sintered body is used. An iron-base alloy powder containing Ni or Mo as a powder, an iron-base alloy powder partially alloyed with Ni or Mo, or an alloy containing Ni or Mo in a mixed powder for producing an iron-based sintered body Ni powder, Ni powder, and Mo powder are contained, but according to the mixed powder for producing an iron-based sintered body according to the present invention, such Ni or Mo or the like, or partially alloyed, Even if it does not contain Ni powder and Mo powder, the sintering is easy to proceed, so the bonding strength at the iron-based powder interface is improved, and the effect of solid solution strengthening by the alloy element also acts, The strength of the base sintered body is improved.

  Therefore, according to the mixed powder for producing an iron-based sintered body according to the present invention, the strength of the iron-based sintered body can be increased without using an expensive alloy element such as Ni or Mo. An iron-based sintered body can be obtained.

  In the mixed powder for producing an iron-based sintered body according to the present invention, as described above, since the Cu alloy powder has a low melting point, it is easy to melt and sinter easily. In addition to the improvement, there is an advantage that the sintering time can be shortened.

  Here, the reason why the melting point of the Cu alloy powder is 1000 ° C. or less is as follows. The melting point of Cu is 1083 ° C., and the sintering temperature of general iron powder is 1120 to 1200 ° C. If the melting point of the Cu alloy powder, which is an auxiliary material, is 1000 ° C. or less, it can be melted at an early stage during the temperature rise, and a substantial sintering time can be obtained. Therefore, an effect cannot be obtained unless the melting point of the auxiliary material is 1000 ° C. or less for improving the strength by promoting the sintering. Therefore, the melting point of the Cu alloy powder as the auxiliary material is 1000 ° C. or less. In order to promote the sintering and improve the strength, the Cu alloy powder preferably has a melting point of 800 ° C. or lower. The lower the melting point, the better, but the lower limit is determined by the physical properties.

  The Cu alloy powder having a melting point of 1000 ° C. or lower is a powder made of a Cu alloy having a melting point of 1000 ° C. or lower. There are various types of Cu alloys having a melting point of 1000 ° C. or less and Cu alloys having a melting point of 800 ° C. or less. For example, there are Cu alloys containing P, Si, and Mn as alloy elements.

  The alloy element content and the melting point of the Cu alloy will be exemplified below. In a Cu alloy containing P, when the P content is 5 mol%, the melting point of the Cu alloy is 1030 ° C., but when the P content is 10 mol%, the melting point of the Cu alloy is 900 ° C. When the content is 13 mol%, the melting point of the Cu alloy is 800 ° C., and when the P content is 16 mol%, the melting point of the Cu alloy is 730 ° C. P content: Cu alloy with about 6-23 mol%, melting point is 1000 ° C. or less, P content: Cu alloy with about 13-17 mol%, melting point is 800 ° C. or less.

  The melting point of a Cu alloy containing 31 mol% of Si is 810 ° C., and the Cu melting point is 1000 ° C. or less with a Cu content of about 7 to 42 mol%. The melting point of the Cu alloy containing 35 mol% of Mn is 880 ° C., and the melting point is 1000 ° C. or less with the Cu alloy of Mn content: 10 to 58 mol%.

  A Cu alloy having a melting point of 1000 ° C. or lower and a Cu alloy having a melting point of 800 ° C. or lower can also be obtained by adding an element other than P, Si, and Mn.

  In the mixed powder for producing an iron-based sintered body according to the present invention, it is desirable that the amount of Cu in the Cu alloy of the Cu alloy powder is 50 mol% or more [second invention]. The reason is as follows.

  One of the main reasons why Cu has been used as an auxiliary material is that the Fe—Cu system has a very good wettability with a contact angle of 0 °. Although Cu has a lower melting point when alloyed, if the amount of alloy elements in the Cu alloy is too large, the wettability with Fe is impaired. From this point, it is desirable that the amount of alloy elements in the Cu alloy of the Cu alloy powder is less than 50 mol% (mol%), that is, the amount of Cu is 50 mol% or more.

In the mixed powder for producing an iron-based sintered body according to the present invention, the Cu alloy of the Cu alloy powder contains one or more of P, Si, and Mn as alloy elements, and the amount of the alloy element is the iron-based sintered powder. The total amount of the iron-based sintered body obtained from the mixed powder for body production is preferably 0.1 mass% or more . The reason is as follows.

  P, Si, and Mn in the Cu alloy of the Cu alloy powder are solid-solution strengthened by solid solution in the iron-based powder iron during sintering. In order to exhibit this effect, it is desirable that the amount of at least one of P, Si, and Mn is 0.1 mass% (mass%) or more in total in the iron-based sintered body.

In the mixed powder for producing an iron-based sintered body according to the present invention, the Cu alloy of the Cu alloy powder contains one or more of P and Si as alloy elements, and the amount of this alloy element is the iron-based sintered body produced. The total amount is preferably 0.1 to 0.5 mass% with respect to the iron-based sintered body obtained from the mixed powder for use [ third invention]. Moreover, the Cu alloy of the Cu alloy powder contains Mn as an alloy element, and the amount of the alloy element is 0.1 to 1.3 mass with respect to the iron-based sintered body obtained from the mixed powder for producing the iron-based sintered body. % Is desirable [ first invention]. The reason is as follows.

  If the amount of one or more of P, Si, and Mn is too large, the machinability of the iron-based sintered body is deteriorated (the cutting tool is easily worn). In order to suppress the deterioration of the machinability and obtain an iron-based sintered body having a good level of machinability, when the alloy element contains at least one of P and Si, The total amount of iron-based sintered body is preferably 0.5 mass% or less. When Mn is contained as an alloy element, the amount of this alloy element is 1.3 mass% in iron-based sintered body. The following is desirable. Therefore, in order to improve the strength of the iron-based sintered body by solid solution strengthening and to suppress the deterioration of the machinability of the iron-based sintered body, when containing one or more of P and Si as alloy elements, The total amount of the alloy elements is preferably 0.1 to 0.5 mass% in the iron-based sintered body. When Mn is contained as the alloy element, the amount of the alloy elements is iron-based sintered. In the body, it is desirable to be 0.1 to 1.3 mass%. In the case of Mn, the upper limit value of the desired amount (allowable value in terms of machinability) is larger than that in the case of P or Si because the low melting point composition region has a high Mn composition. (The lowest melting point range is about 31 mol% Mn).

According to the mixed powder for producing an iron-based sintered body according to the present invention, since the Cu alloy powder is easily melted, the sintering proceeds easily, and the bonding strength at the iron-based powder interface is improved, whereby the iron-based sintered body is improved. In addition to improving the strength of the iron-based sintered body, at least one of P, Si, and Mn in the Cu alloy powder of the Cu alloy powder is dissolved in iron and strengthened by solid solution. According to the mixed powder for producing an iron-based sintered body according to the third aspect of the invention, the strength of the iron-based sintered body is improved by improving the bonding strength at the interface of the iron-based powder, and further, one or more irons of P and Si are added. The solid solution strengthening by solid solution not only improves the strength of the iron-based sintered body, but also can suppress deterioration of the machinability of the iron-based sintered body and have a good level of machinability. According to the mixed powder for producing an iron-based sintered body according to the first invention, only the strength of the iron-based sintered body is improved by improving the bonding strength at the iron-based powder interface and strengthening the solid solution by solid solution of Mn in iron. In addition, it is possible to suppress deterioration of the machinability of the iron-based sintered body and to have a good level of machinability.

In the mixed powder for producing an iron-based sintered body according to the first to third inventions of the present invention, the addition amount of the Cu alloy powder is not particularly limited, but usually from the mixed powder for producing an iron-based sintered body. It is 1-5 mass% (weight%) with the quantity with respect to the obtained iron-based sintered compact. This amount is a general amount of sintering aid.

  The amount of graphite (graphite) powder added is not particularly limited, but is usually 0.3 to 1.5% by mass relative to the iron-based sintered body obtained from the mixed powder for producing the iron-based sintered body. This amount is a general amount of sintering aid. For the same alloy composition, strength and machinability are substantially correlated with the amount of graphite.

  As the iron-based powder (iron powder and / or iron alloy powder) of the mother powder, iron powder, iron alloy powder, or a mixed powder of iron powder and iron alloy powder is used. The composition of the iron alloy powder is not particularly limited, and iron alloy powder (pre-alloyed powder) containing Ni, Mo, or the like, or Ni, Mo, or the like is alloyed on or near the surface of the iron powder. Iron-based powders (partially alloyed powders) can be used, and other iron alloy powders containing various alloy elements, and iron-based powders obtained by alloying various alloy elements on the surface of iron powder and in the vicinity thereof are used. be able to. Among the iron-based powders, the iron alloy powder is a powder made of an alloy containing Fe as a base (base) component (that is, an iron-based alloy containing an alloy element), and the iron powder is other than the iron alloy powder. Yes, so-called pure iron powder. However, iron powder (pure iron powder) includes those containing inevitable impurities.

  When iron-base powder containing solid solution strengthening elements such as Ni or Mo, or iron-base powder alloyed with the solid solution strengthening element on or near the surface of the iron powder is used as the iron-base powder of the mother powder The strength of the iron-based sintered body is higher than when iron powder is used. For example, when iron powder is used as the iron-based powder of the mother powder, the tensile strength of the iron-based sintered body is about 500 MPa, and iron alloy powder (pre-alloyed powder) containing Ni as the iron-based powder of the mother powder Is used, the tensile strength of the iron-based sintered body is 600 to 800 MPa class, and the latter case has higher strength. In any of the above cases, the amount of graphite (graphite) powder added is 0.8% with respect to the mixed powder for producing an iron-based sintered body.

The iron-based sintered body according to the present invention is an iron-based sintered body obtained from the mixed powder for producing an iron-based sintered body according to the first to third inventions as described above ( fourth invention). That is, after pressing and molding the mixed powder for manufacturing an iron-based sintered body according to the first to third inventions, or a mixture of additives such as a lubricant added to the mixed powder as necessary. An iron-based sintered body obtained by sintering. This iron-based sintered body can have high strength even when an expensive alloy element such as Ni or Mo is not used. Therefore, it can be suitably used as a high-strength iron-based sintered body. The iron-based sintered body obtained from the mixed powder for producing an iron-based sintered body according to the first to third inventions can not only have high strength, but is also good in that deterioration of machinability is suppressed with it. Can have a certain level of machinability. Furthermore, the strength is further improved by heat treatment such as quenching and tempering.

  Examples of the present invention and comparative examples will be described below. The present invention is not limited to this embodiment, and can be implemented with appropriate modifications within a range that can be adapted to the gist of the present invention, all of which are within the technical scope of the present invention. include.

  Iron powder is used as the iron-based powder of the mother powder. To this iron powder, Cu alloy powder or Cu powder and graphite powder are added. Furthermore, zinc stearate is added as a lubricant, and a V-type mixer is used for 60 minutes. After mixing, the mixture was pressed and molded, and the resulting molded body (green compact) was sintered at 1120 ° C. for 30 minutes in a nitrogen atmosphere containing 10% hydrogen to obtain an iron-based sintered body. In addition, what added Cu alloy powder or Cu powder, and graphite powder to said iron powder is equivalent to the mixed powder for iron-based sintered compact manufacture.

At this time, as the iron powder, the chemical components shown in Table 1 were used. The addition amount of Cu alloy powder or Cu powder was an amount with respect to the iron-based sintered body, and was varied in the range of 1 to 5 mass% (mass%) as shown in Table 2. In any case, the amount of graphite powder added was 0.8 mass% with respect to the iron-based sintered body. In each case, the amount of zinc stearate added to the lubricant is 0.75 mass in terms of the amount of the mixed powder for iron-based sintered body production (iron powder plus Cu alloy powder or Cu powder and graphite powder). %. The pressure (molding pressure) at the time of pressure forming was adjusted so that the density of the iron-based sintered body was 6.9 to 6.95 g / cm ³ .

  The composition of the Cu alloy powder is as shown in the composition column of Table 2. For example, the No. 1 Cu alloy powder is a Cu-16 mol% P alloy powder, which indicates a Cu alloy powder containing 16 mol% of P. The No. 9 Cu alloy powder is a Cu-31 mol% Si alloy powder, which indicates a Cu alloy powder containing 31 mol% of Si. These amounts of P, Si, and Mn (mol%) are all concentrations in the Cu alloy, that is, amounts (mol%) relative to the Cu alloy.

  The melting point of the Cu alloy powder is as shown in the melting point column of Table 2. For example, No. 1 Cu alloy powder has a melting point of 730 ° C.

  The amounts of P, Si, and Mn in the iron-based sintered body, that is, the amounts with respect to the iron-based sintered body are as shown in the column of alloys in Table 2. For example, the No. 1 iron-based sintered body contains P, and the amount (concentration) of P in the iron-based sintered body is 0.17 mass%. The iron-based sintered body of No. 9 contains Si, and the amount (concentration) of this Si in the iron-based sintered body is 0.33 mass%.

  The iron-based sintered body thus obtained was machined into an MPIF standard shape tensile test piece and subjected to a tensile test.

  Further, a cutting test was performed using an iron-based sintered body as a work material, and machinability was evaluated. This cutting test was performed as follows. Three iron-based sintered bodies are passed through bolts, spare rings are arranged on both sides, and sandwiched by nuts. Thereafter, the bolt was fixed to the center of the lathe, and the work material (iron-based sintered body) was cut.

  At this time, the cutting tool used was G10E (K-type carbide) manufactured by Sumitomo Electric Hardmetal Corporation. Turning conditions are cutting speed: 150 m / min, feeding speed: 0.1 mm / rev, cutting depth: 0.5 mm, cutting length: 100 m, cutting style: dry continuous cutting. The flank wear amount (tool wear amount) of the cutting tool was measured.

  The results of the tensile test are shown in the column of tensile strength in Table 2. The result of the cutting test is shown in the column of tool wear in Table 2.

  In the case of No. 10, Cu powder is used as Cu-based powder (Cu alloy powder or Cu powder) mixed with the iron powder of the mother powder. The melting point of this Cu powder is 1083 ° C. The No. 10 iron-based sintered body contains neither P, Si nor Mn. In the case of this No. 10 iron-based sintered body, the tensile strength is 506 MPa, and the amount of tool wear in the cutting test (the flank wear amount of the cutting tool) is 156 μm.

  On the other hand, in the case of No.1-9 and No.11-14, Cu alloy powder is used as Cu-type powder mixed with the iron powder of mother powder. This Cu alloy powder contains one kind of P, Si, and Mn as an alloy element, and has a melting point of 1030 to 730 ° C. The iron-based sintered bodies of No. 1 to 9 and No. 11 to 14 contain one type of P, Si, and Mn. In the case of the iron-based sintered bodies of No. 1 to 9 and No. 11 to 14, the tensile strength is higher than that of the iron-based sintered body of No. 10.

  Among these, when Cu alloy powder having a melting point of 1000 ° C. or less is used and the content of P, Si, or Mn in the iron-based sintered body is 0.1 mass% or more, the tensile strength of the iron-based sintered body High strength (No.1-9, No.13-14). This is because the Cu alloy powder is easily melted, so that the sinterability is improved and the bonding strength at the interface of the iron powder is improved, and the P, Si, and Mn in the Cu alloy of the Cu alloy powder are sintered. This is due to the combined effect of solid solution strengthening by solid solution in iron powder.

  At this time, as the content of P, Si, and Mn in the iron-based sintered body increases, the tensile strength of the iron-based sintered body increases. Surface wear amount) increases, and the machinability of the iron-based sintered body decreases. When the iron-based sintered body contains P, if the P content in the iron-based sintered body is 0.5 mass% or less (No. 1-7), the machinability is good and sufficient ( However, if the P content exceeds 0.5 mass% (No. 13), the machinability is poor and insufficient. When the iron-based sintered body contains Si and the Si content in the iron-based sintered body is 0.5 mass% or less (No. 9), machinability is good and sufficient (allowable range) Is in). When the iron-based sintered body contains Mn and the Mn content in the iron-based sintered body is 1.3 mass% or less (No. 8), the machinability is good and sufficient (allowable range) However, if the Mn content exceeds 1.3 mass% (No. 14), the machinability is poor and insufficient.

  From the above, in order to obtain an iron-based sintered body having high strength, the Cu-based powder mixed with the iron-based powder of the mother powder has a melting point of 1000 ° C. or less and one of P, Si, and Mn as alloy elements. It can be seen that it is desirable to use Cu alloy powder that contains the above, and that the content of one or more of P, Si, and Mn in the iron-based sintered body is 0.1 mass% or more in total. In order to obtain an iron-based sintered body having high strength and good and sufficient machinability, it has a melting point of 1000 ° C. or lower and contains one or more of P, Si, and Mn as alloy elements, and iron The content of one or more of P, Si, and Mn in the base sintered body is 0.1 to 0.5 mass% for P, 0.1 to 0.5 mass% for Si, and 0.1 to 1.3 mass% for Mn. It can be seen that it is desirable to use such Cu alloy powder.

In addition, the mixed powder for iron group sintered compact manufacture in the case of No.1-7, 9, 12-12 is a reference example.

  In the iron-based sintered bodies of Nos. 1 to 14, when the P-, Si-, and Mn contents in the iron-based sintered bodies are the same or nearly the same, mixed powder for producing iron-based sintered bodies The tensile strength of the iron-based sintered body is higher when the melting point of the Cu alloy powder mixed therein is lower. This is because the lower the melting point of the Cu alloy powder, the easier it is to melt the Cu alloy powder, so that the degree of improvement in sinterability increases, and consequently the degree of improvement in the bonding strength at the iron powder interface increases. When the melting point of the Cu alloy powder is 1000 ° C. or less, the strength of the iron-based sintered body is sufficiently improved by improving the bonding strength at the iron powder interface.

  In the iron-based sintered bodies of Nos. 1 to 14, when the melting points of the Cu alloy powders mixed in the mixed powder for producing the iron-based sintered bodies are the same or nearly the same, the iron-based sintered bodies The tensile strength of the iron-based sintered body is higher when the content of P, Si, and Mn is higher. This is because the higher the content of P, Si, and Mn in the iron-based sintered body, the more the solid solution amount of iron, P, Si, and Mn in the Cu alloy powder, This is because the degree of strengthening increases. In order to improve the strength of the iron-based sintered body, it is desirable that the content of one or more of P, Si, and Mn in the iron-based sintered body is 0.1 mass% or more in total. In order not only to improve the strength of the iron-based sintered body, but also to ensure good and sufficient machinability, the content of P, Si, and Mn in the iron-based sintered body is 0.1 to It is desirable that the content be 0.5 mass%, 0.1 to 0.5 mass% in the case of Si, and 0.1 to 1.3 mass% in the case of Mn.

  FIG. 1 shows the relationship between the tensile strength of No. 1 to 14 iron-based sintered bodies and the amount of tool wear in the cutting test (the amount of flank wear of the cutting tool). It can be seen that as the tensile strength of the iron-based sintered body increases, the amount of tool wear in the cutting test increases, and the machinability of the iron-based sintered body decreases.

  In the above example, the Cu alloy powder mixed with the iron-based powder of the mother powder is one containing one of P, Si, and Mn as an alloy element. However, one of P, Si, and Mn is used as the alloy element. Even when a material containing seeds or more is used, a result having the same tendency as in the above example is obtained. That is, in order to obtain an iron-based sintered body having high strength, the Cu-based powder mixed with the iron-based powder of the mother powder has a melting point of 1000 ° C. or less and one or more of P, Si, and Mn as alloy elements. The result shows that it is desirable to use Cu alloy powder that contains at least one P, Si, and Mn content in the iron-based sintered body to be 0.1 mass% or more in total. . In addition, in order to obtain an iron-based sintered body having high strength and good and sufficient machinability, the melting point is 1000 ° C. or less and at least one of P, Si and Mn is contained as an alloy element. , Cu alloy powder in which the total content of one or more of P and Si in the iron-based sintered body is 0.1 to 0.5 mass%, and the Mn content in the iron-based sintered body is 0.1 The result which shows that it is desirable to use Cu alloy powder which will be -1.3 mass% is obtained.

  In the above example, iron powder is used as the iron-based powder of the mother powder. However, when the iron alloy powder is used, the same tendency results as in the above example are obtained. That is, in order to improve the strength of the iron-based sintered body, the content of one or more of P, Si, and Mn in the iron-based sintered body should be 0.1 mass% or more in total. In order to ensure good and sufficient machinability as well as to improve the strength of the iron-based sintered body, the content of P, Si, and Mn in the iron-based sintered body is P. In the case of 0.1 to 0.5 mass% in the case of Si, 0.1 to 0.5 mass% in the case of Si, and 0.1 to 1.3 mass% in the case of Mn are desirable. However, the melting point of the Cu alloy powder mixed in the iron-based sintered body production mixed powder, and the P, Si, and Mn contents in the iron-based sintered body are the same and compared, The strength of the iron-based sintered body is higher when the iron alloy powder is used than when the iron powder is used (in the case of the above example). This difference in strength differs depending on the type of iron alloy powder (type of alloy element and its content, structure).

  In the above example, the amount of graphite powder added to the iron-based powder of the mother powder was 0.8 mass% in terms of the amount based on the iron-based sintered body. The same trend results are obtained as in the example. However, when the melting point of the Cu alloy powder mixed in the mixed powder for manufacturing the iron-based sintered body and the contents of P, Si, and Mn in the iron-based sintered body are the same, graphite is compared. The more powder is added, the higher the strength and the better the machinability.

  According to the mixed powder for producing an iron-based sintered body according to the present invention, it is possible to increase the strength of the iron-based sintered body without using an expensive alloy element such as Ni or Mo, and to produce a high-strength iron-based sintered material. Since a sintered body can be obtained, the mixed powder for producing an iron-based sintered body according to the present invention can be suitably used as a raw material powder when producing a high-strength iron-based sintered body with good economic efficiency. . Since the iron-based sintered body according to the present invention can be produced with good economic efficiency and has high strength, it can be suitably used as a high-strength iron-based sintered body.

It is a figure which shows the relationship between the tensile strength and tool wear about the iron-based sintered compact which concerns on the Example and comparative example of this invention.

Claims (4)

Iron powder and / or iron alloy powder as a mother powder, mixed powder for iron-based sintered body production containing Cu alloy powder and graphite powder, the melting point of the Cu alloy powder is 1000 ℃ or less , Cu alloy of the Cu alloy powder contains Mn as an alloy element, and the amount of the alloy element Mn is 0.1 to 1.3 mass with respect to the iron-based sintered body obtained from the mixed powder for producing the iron-based sintered body. %, Which is a mixed powder for producing an iron-based sintered body.   The mixed powder for producing an iron-based sintered body according to claim 1, wherein the amount of Cu in the Cu alloy powder is 50 mol% or more. The Cu alloy powder Cu alloy further contains one or more of P and Si as alloy elements , and the amount of the alloy elements P and Si is obtained from the mixed powder for producing the iron-based sintered body. The mixed powder for producing an iron-based sintered body according to claim 1 or 2, wherein the total amount is 0.1 to 0.5 mass% with respect to the body. An iron-based sintered body obtained from the mixed powder for producing an iron-based sintered body according to any one of claims 1 to 3 .

Images