JP5575629B2 - Iron-based sintered material and method for producing the same - Google Patents

Description

The present invention relates to an iron-based sintered material that can achieve both environmental load reduction, cost reduction, and securing of mechanical properties, and a method for manufacturing the same.

In order to reduce the manufacturing cost of each member, a material or a member obtained by sintering an iron-based powder compact (hereinafter simply referred to as “iron-based sintered material ”) is used. Since this iron-based sintered material is close to the final shape, the manufacturing cost can be reduced by reducing machining or improving yield.

Conventional iron-based sintered materials contain a large amount of various alloy elements in order to ensure mechanical properties such as strength. In particular, copper (Cu) and nickel (Ni) were considered to be almost essential elements for the iron-based sintered material . However, an increase in the amount of alloy elements increases the material cost of the iron-based sintered material . Also, it is not preferable to use Cu or Ni that is an allergic element that inhibits the recyclability of iron-based scrap.

Japanese Patent Publication No.58-10962 Japanese Patent No. 3446322

In the above patent document, an alloy powder for an iron-based sintered material in which the content of Cu, Ni and other alloy elements is suppressed is proposed. However, these alloy powders still contain a large amount of chromium (Cr) and molybdenum (Mo), and contain a variety of alloy elements in small amounts.

Under such circumstances, the present invention provides an iron-based sintered material capable of maintaining high strength while further reducing production costs including raw material costs by limiting the type and amount of alloy elements to be used. With the goal. Moreover, it aims at providing the manufacturing method suitable for manufacture of the iron-based sintered material collectively .

The present inventor has intensively studied to solve this problem, and as a result of repeated trial and error, high-strength iron can be obtained by adding a small amount of vanadium (V) on the assumption that an appropriate amount of carbon (C) is present. It was newly found that a base sintered material can be obtained. By developing this result, the present invention described below has been completed.

《 Iron-based sintered material 》
(1) ferrous sintered material of the present invention is a ferrous sintered member formed of a sintered body obtained by sintering a molded body by pressure molding a raw material powder mainly composed of Fe, the entire 100 It is characterized by comprising 0.05 to 0.6% by mass of V, 0.1 to 1.0% by mass of C, and the balance of Fe and unavoidable impurities.

(2) According to the present invention, even if the elements other than Fe, which is the main component, are only an appropriate amount of C and a small amount of V, at least the strength is equal to or higher than that of a conventional sintered steel material and the iron has a corresponding elongation. A base sintered material is obtained. According to this iron-based sintered material, it is possible to achieve both reduction in manufacturing costs including raw material costs and securing of mechanical characteristics. Of course, since the iron-based sintered material of the present invention does not substantially contain Cu, Ni or the like, it is possible to improve the recyclability of the scrap material and reduce the environmental load.

(3) However, the mechanism etc. in which the iron-based sintered material of the present invention exhibits excellent mechanical properties are not necessarily clear. The current situation is considered as follows. When the inventor observed the metal structure of the iron-based sintered steel under a microscope, a refined pearlite phase and a reduced ferrite phase were observed. This is presumably because V was finely and uniformly deposited as vanadium carbide (VC) in the base of the iron-based sintered steel. In addition, since V is a small amount, even if the sintering time is short, segregation does not occur, and the iron-based sintered material is uniformly increased in strength without being segregated.

(4) Such an effect of V can be exhibited even when one or more of molybdenum (Mo), manganese (Mn), and silicon (Si) coexist. Furthermore, when V coexists with one or more of Mo, Mn, or Si, the mechanical properties of the iron-based sintered material can be further improved.

From the viewpoint of reducing raw material costs, the total amount of these alloy elements (V + Mo + Mn + Si) is 1.5% by mass or less, 1.2% by mass or less, 1% by mass when the total amount of the iron-based sintered material is 100% by mass. The iron-based sintered material exhibits sufficient mechanical properties even when the content is 0.8% by mass or less. Not only the total amount regulation but also replacing some of the expensive V and Mo with cheap Mn and Si makes it possible to further reduce the raw material cost, and further increase the iron-based sintered material equivalent to or better than the conventional one. It can be provided at low cost. In the present specification, unless otherwise specified, mass% is used for the composition, and hereinafter simply expressed as “%”.

《Method for producing iron-based sintered material 》
The present invention can be grasped not only as the iron-based sintered material described above but also as a manufacturing method thereof. That is, the present invention includes a molding step of obtaining a molded body by pressure molding the raw material powder, and a sintering step of heating the molded product in oxidation atmosphere to obtain a sintered body, the above-described ferrous sintered material It may be a method for producing an iron-based sintered material characterized in that

<Others>
(1) “Inevitable impurities” as used herein are elements other than Fe, C, V, Mo, Mn, and Si contained in the raw material powder or in the iron-based sintered material . There are various such elements, and the allowable content (upper limit) varies depending on the type of element.

  For example, phosphorus (P): 0.03% or less, sulfur (S): 0.03% or less, chromium (Cr): 0.1% or less, aluminum (Al): 0.1% or less, niobium (Nb) : 0.1% or less, cobalt (Co): 0.1% or less, copper (Cu): 0.2% or less, nickel (Ni): 0.1% or less, tungsten (W): 0.1% or less Oxygen (O): 0.25% or less, boron (B): 0.03% or less, and the like.

In addition to the Fe, C, V, Mo, Mn, and Si, the raw material powder or the iron- based sintered material according to the present invention includes an effective element (modifying element) that can improve the properties of the iron- based sintered material. obtain. There are no limitations on the properties to be improved, but examples include strength, toughness, ductility, and dimensional stability. The type, combination, composition, etc. of the modifying element are arbitrary. However, from the viewpoint of cost reduction, the amount of the modifying element is preferably a trace amount. The modifying element may be an element exemplified as an inevitable impurity (for example, Cr).

(2) The “ iron-based sintered material ” of the present invention includes both a material or a member made of iron-based sintered steel regardless of its form. Examples of the material made of iron-based sintered steel include a bulk shape, a rod shape, a tubular shape, and a plate shape. The member made of iron-based sintered steel may be a final product or a product close thereto.

(3) There are various “mechanical properties” of iron-based sintered materials , but tensile strength and elongation are typical. The tensile strength of the iron-based sintered material of the present invention is preferably, for example, 600 MPa or more, 700 MPa or more, 800 MPa or more, 850 MPa or more, further 900 MPa or more. The elongation of the iron-based sintered material of the present invention is preferably 2% or more, 3% or more, 4% or more, 5% or more, and further 6% or more.

(4) Unless otherwise specified, “x to y” in this specification includes a lower limit value x and an upper limit value y. The various lower limit values or upper limit values described in the present specification may be arbitrarily combined to constitute a range such as “ab”. Furthermore, a new numerical value range can be set by using an arbitrary numerical value within the numerical value range described in the present specification as an upper limit value or a lower limit value.

Sample No. It is a metallographic micrograph of 1-1. Sample No. It is a metallographic microscope photograph of 1-4. Sample No. It is a metallographic micrograph of 1-27. It is a graph which shows the relationship between the tensile strength of each sample (sintering temperature: 1150 degreeC) from which V amount differs, and Mo amount. It is a graph which shows the relationship between the elongation of each sample (sintering temperature: 1150 degreeC) from which V amount differs, and Mo amount. It is a graph which shows the relationship between the tensile strength of each sample (sintering temperature: 1250 degreeC) from which V amount differs, and Mo amount. It is a graph which shows the relationship between the elongation of each sample (sintering temperature: 1250 degreeC) from which V amount differs, and Mo amount. It is a graph which shows the relationship between the tensile strength and Mo amount of each sample (sintering temperature: 1150 degreeC) from which V amount and Gr amount differ. It is a graph which shows the relationship between the elongation of each sample (sintering temperature: 1150 degreeC) from which V amount and Gr amount differ, and Mo amount. It is a graph which shows the relationship between the tensile strength and Mo amount of each sample (sintering temperature: 1250 degreeC) from which V amount and Gr amount differ. It is a graph which shows the relationship between the elongation of each sample (sintering temperature: 1250 degreeC) from which V amount and Gr amount differ, and Mo amount. It is the bar graph which contrasted the tensile strength of each sample from which Mo / V amount differs. It is the bar graph which contrasted the elongation of each sample from which Mo / V amount differs. It is the bar graph which contrasted the tensile strength of each sample from which the amount of (Mn + Si) / V differs. It is the bar graph which contrasted the elongation of each sample from which (Mn + Si) / V amount differs. It is the bar graph which contrasted the tensile strength of each sample (V: 0.1%) from which the amount of (Mn + Si) / Mo differs. It is the bar graph which contrasted the elongation of each sample (V: 0.1%) from which the amount of (Mn + Si) / Mo differs. It is the bar graph which contrasted the tensile strength of each sample (V: 0.2%) from which (Mn + Si) / Mo amount differs. It is the bar graph which contrasted the elongation of each sample (V: 0.2%) from which (Mn + Si) / Mo amount differs. It is a graph which shows the relationship between the tensile strength and Mo / V amount of each sample (sintering temperature: 1150 degreeC) from which a shaping | molding pressure and a cooling rate differ. It is a graph which shows the relationship between the elongation of each sample (sintering temperature: 1150 degreeC) from which a shaping | molding pressure and a cooling rate differ, and Mo / V amount. It is a graph which shows the relationship between the tensile strength and Mo / V amount of each sample (sintering temperature: 1250 degreeC) from which a shaping | molding pressure and a cooling rate differ. It is a graph which shows the relationship between the elongation of each sample (sintering temperature: 1250 degreeC) from which a shaping | molding pressure and a cooling rate differ, and Mo / V amount.

F Ferrite phase P Pearlite phase

The present invention will be described in more detail with reference to embodiments of the invention. In addition, the content demonstrated by this specification including the following embodiment can be suitably applied not only to the iron-based sintered material according to the present invention but also to the manufacturing method thereof. A configuration related to a manufacturing method can be a configuration related to an object if understood as a product-by-process. One or more configurations arbitrarily extracted from the present specification can be added to the configuration of the present invention described above. Which embodiment is the best depends on the target, required performance, and the like.

<Raw material powder>
(1) The iron-based sintered material of the present invention is obtained by sintering a compact of a raw material powder. This raw material powder may be a single type of powder or a mixed powder composed of a plurality of types of powder. When the raw material powder is a mixed powder, pure iron powder, low alloy steel powder, vanadium carbide powder, molybdenum carbide powder, graphite (Gr) powder, Fe-Mn-Si alloy powder (FeMS powder), Fe-Mn-Si- C alloy powder (FeMSC powder) or the like is used to blend the desired composition of the iron- based sintered material .

The particle size of each powder is not limited, but due to the formability (high density) and handling properties of the iron-based sintered material , the base pure iron powder and low alloy steel powder are 80-100 μm, each carbide powder, Gr Powder, FeMS powder, and FeMSC powder are preferably 1 to 10 μm. Incidentally, the particle size referred to here is specified by D50 which is 50% of the cumulative weight ratio in the particle frequency curve in which the particles are expressed in mass ratio at every fixed particle size interval.

(2) The raw material powder is preferably prepared from the viewpoint of securing the mechanical properties (particularly tensile strength) of the iron-based sintered material and reducing the raw material cost. V in the raw material powder is 0.05 to 0.6%, 0.1 to 0.5%, 0.15 to 0.4%, or 0.2 if the entire raw material powder is 100% by mass. It is more preferable in it being -0.35%.

When Mo, Mn or Si coexists in the iron-based sintered material together with V in such a range, the metal structure (ferrite phase and pearlite phase) is further refined and mechanical properties are further improved. obtain. Specifically, Mo is 0.05 to 0.5%, 0.1 to 0.45%, 0.15 to 0.4%, and further 0.25 to 0, based on 100% by mass of the entire raw material powder. .35% is preferable. Mn is preferably 0.03 to 0.6%, 0.1 to 0.5%, and more preferably 0.2 to 0.4%. Si is preferably 0.01 to 0.2%, 0.03 to 0.15%, and more preferably 0.05 to 0.1%. In any case, if the amount of each element is too small, the effect cannot be obtained sufficiently, and if it is excessive, the raw material cost increases.

However, compared with V and Mo, Mn and Si are general alloy elements of steel, and are inexpensive and easily available. Therefore, it is preferable to reduce the blending amount of V and Mo while increasing the blending amount of Mn and Si on the premise of securing desired characteristics of the iron-based sintered material . Incidentally, a single powder may be used as a supply source of Mn and Si, but the use of FeMS powder or the like can reduce the raw material cost. Thus, when adding Mn and Si simultaneously, when the whole raw material powder is 100 mass%, those total (Mn + Si) are 0.1-0.8%, 0.2-0.7% Is preferably 0.25 to 0.6%.

"Manufacturing process"
The iron-based sintered material of the present invention is obtained mainly through a molding process and a sintering process. Hereinafter, these steps will be described.

(1) Molding process A molding process is a process of obtaining the molded object which pressure-molded the above-mentioned raw material powder. By adjusting the molding pressure, the density of the compact (and consequently the density of the iron-based sintered material ) can be adjusted. For example, as the molding pressure increases to 400 MPa or more, 500 MPa or more, 600 MPa, or 700 MPa or more, it is possible to increase the density of the molded body and thus the iron-based sintered material . The forming process may be cold forming (room temperature forming) or warm forming. An internal lubricant may be added to the raw material powder. In this specification, the internal lubricant is considered to be included in the raw material powder.

  By the way, when high pressure molding is performed while ensuring the mold life, a mold lubrication warm pressure molding method (for details, refer to Japanese Patent No. 3309970) may be used. According to this molding method, not only when the molding pressure is about 700 MPa, ultrahigh pressure molding such as 800 MPa or more, 900 MPa or more, further 1000 MPa or more can be easily performed. In addition, the mold lubrication warm pressure molding method does not require the use of an internal lubricant, and therefore, the interior of the furnace is not contaminated when the obtained molded body is sintered, and is excellent in environmental performance.

(2) Sintering process A sintering process is a process of heating a molded object and obtaining a sintered compact. The sintering temperature and sintering time are appropriately selected in consideration of the desired properties and productivity of the iron-based sintered material. However, if they are too large, the energy cost increases, and if they are too small, the mechanical properties are secured. It becomes difficult. For example, the sintering temperature is preferably 1050 ° C. to 1350 ° C. or higher, and more preferably 1100 to 1300 ° C. For example, the sintering time is preferably 0.1 to 3 hours, and more preferably 0.3 to 1 hour.

The sintering process is preferably performed in an oxidation-preventing atmosphere. This is because if an oxide is present in the iron-based sintered material, its mechanical properties may deteriorate. Examples of the oxidation prevention atmosphere include a vacuum atmosphere, an inert gas atmosphere, and a nitrogen gas atmosphere.

When the raw material powder contains V, Mn, or Si that is particularly easily oxidized, the sintering atmosphere is preferably a high-level antioxidant atmosphere. As such an antioxidant atmosphere, for example, there is a reducing atmosphere in which hydrogen gas is mixed with nitrogen gas in an amount of about 2 to 5% by volume. If hydrogen gas is not used, the sintering atmosphere is preferably an inert gas atmosphere having an extremely low oxygen partial pressure corresponding to an oxygen partial pressure of 10 ⁻¹⁹ Pa or less (CO concentration of 100 ppm or less). In addition, this inert gas (N2 gas) atmosphere of the extremely low oxygen partial pressure is obtained, for example, using an oxynon furnace manufactured by Kanto Yakin Kogyo Co., Ltd.

(3) Cooling process or quenching process (sinter hardening)
A cooling step for rapidly cooling the high-temperature sintered body may be performed. As a result, the sintered body is quenched (sinter hardened) and can be further strengthened. This step is efficient if performed after the sintering step. Specifically, it is as follows.

  The sintered body after the sintering step is usually in a high temperature state at or above the A1 transformation point (about 730 ° C.). The sintered body is rapidly cooled from the high temperature range to the room temperature range (to the Ms point or less) (cooling step). Thereby, the sintered body is quenched (sinter hardened). The cooling rate at that time is 25 to 200 ° C./min (0.4 to 3.3 ° C./sec), 40 to 150 ° C./min (0.67 to 2.5 ° C./sec), and further 80 to 120 ° C. / Min (1.3-2 ° C./second). If the cooling rate is too low, quenching becomes insufficient and sufficient strength cannot be achieved. The realization of an excessive cooling rate increases the manufacturing cost.

《 Iron-based sintered material 》
(1) The iron-based sintered material of the present invention is appropriately subjected to a heat treatment such as annealing, normalizing, aging, tempering (quenching, tempering), carburizing, nitriding, etc. according to the required specifications. Adjustments may be made.

(2) The iron-based sintered material of the present invention may be used for any purpose, for example, various pulleys, transmission synchro hub, engine connecting rod, hub sleeve, sprocket, ring gear, parking gear, pinion gear, sun gear, drive It can be used for materials and products such as gears, driven gears and reduction gears.

The present invention will be described more specifically with reference to examples.
<Manufacture of test pieces>
(1) Preparation of raw material powder In order to prepare raw material powder, the following various powders were prepared. First, pure iron powder (ASC 100.29 manufactured by Höganäs AB, particle size 20 to 180 μm) is prepared as the main Fe source, and graphite (Gr) powder (JCPB manufactured by Nippon Graphite Co., average particle size is 5 μm or less) is prepared as the main C source. did. Next, vanadium carbide (VC) powder (manufactured by Nippon Shin Metal Co., Ltd .: particle size 1 to 3 μm) is prepared as a V source, and molybdenum carbide (Mo ₂ C) powder (manufactured by Nippon Shin Metal Co., Ltd .: particle size 1 to 2 μm) is prepared as a Mo source. did. Further, Fe-65% Mn-16% Si-2% C powder (manufactured by Toyo Denka Co., Ltd .: 5 μm or less) was prepared as a Mn source and a Si source. Unless otherwise specified, “%” in terms of composition means mass% (the same applies hereinafter).

  These various powders were blended so as to have the composition shown in each table, and ball mill type rotary mixing was performed for 30 minutes to prepare a uniform mixed powder (raw material powder) for each sample.

(2) Molding process The molding process was performed by the above-described mold lubrication warm pressure molding method. Specifically, it is as follows. A cemented carbide mold having a cavity corresponding to the shape of the test piece was prepared. The inner peripheral surface of the mold was previously subjected to TiN coating treatment, and the surface roughness was set to 0.4Z. The mold was previously heated to 150 ° C. with a band heater. An aqueous solution in which lithium stearate (LiSt), which is a higher fatty acid lubricant, is dispersed is uniformly applied to the inner peripheral surface of the heated mold with a spray gun at a rate of about 1 cm ³ / second (application process). . Thereby, a LiSt film of about 1 μm was formed on the inner peripheral surface of the mold.

  The aqueous solution used was obtained by dispersing LiSt in water to which a surfactant and an antifoaming agent were added. As the surfactant, polyoxyethylene nonylphenyl ether (EO) 6, (EO) 10 and borate ester Emulbon T-80 were used. They were added by 1% by volume with respect to the whole aqueous solution (100% by volume). FS antifoam 80 was used as the antifoaming agent. 0.2 volume% of this was added with respect to the whole aqueous solution (100 volume%).

LiSt having a melting point of about 225 ° C. and an average particle size of 20 μm was used. The amount of dispersion was 25 g with respect to 100 cm ³ of the aqueous solution. The aqueous solution in which LiSt was dispersed was further refined with a ball mill pulverizer (Teflon-coated steel balls: 100 hours). An aqueous solution having a final concentration of 1% obtained by diluting the stock solution thus obtained 20 times was subjected to the coating step.

  Each raw material powder (without preheating) was naturally filled into a mold cavity in which a uniform LiSt film was formed on the inner surface (filling step). This raw material powder was molded at a molding pressure (490 to 784 MPa) shown in each table. Each of the obtained molded bodies could be easily removed from the mold with low output without causing galling or the like on the inner surface of the mold.

(3) Sintering step Each compact was sintered in a nitrogen gas atmosphere at 1150 ° C or 1250 ° C using a continuous sintering furnace (Oxynon furnace manufactured by Kanto Metallurgical Industry) (sintering process). The soaking time was 30 minutes, and the cooling rate after sintering was 100 ° C./min (1.67 ° C./sec) or 50 ° C./min (0.83 ° C./sec). The inside of the sintering furnace was an N ₂ gas atmosphere having a dew point of about −50 to −65 ° C. Thus, each test piece made of an iron-based sintered material was obtained.

<Measurement>
(1) Density and Dimensional Change Using the cylindrical test piece (φ23 × 7 mm) of each sample, the weight of the sintered body and the dimensions (outer diameter) before and after sintering were measured. From these measured values, the density and dimensional change (outer diameter change) of the sintered body were obtained, and those values were listed in each table. In addition, the dimensional change shown in each table | surface was calculated | required by 100x {(outer diameter after sintering)-(outer diameter before sintering)} / (outer diameter before sintering).

(2) Tensile strength and elongation Tensile tests were performed using flat tensile test pieces (55 × 10 × 3 mm) of each sample. Thereby, the strength (tensile strength) and elongation until each test piece broke was determined, and the values were listed in each table.

(3) Young's modulus Young's modulus was measured by an ultrasonic method using a columnar test piece (φ23 × 7 mm) of each sample, and the values were listed in each table. The ultrasonic method is a method of calculating the Young's modulus from the acoustic velocity of the ultrasonic wave obtained from the propagation time of longitudinal and transverse pulse echoes and the thickness of the cylindrical specimen and the density of the specimen.

<Evaluation>
<Metallic structure>
Metal micrographs of samples extracted from Table 1A and Table 1B (both tables are simply referred to as “Table 1”) are shown in FIGS. 1A to 1C. In the photograph, the white portion (F) indicates the ferrite phase, and the gray portion (P) indicates the pearlite phase.

  The structure of Fe-0.6% Gr (FIG. 1A) has a coarse ferrite phase and pearlite phase. In the structure further containing 0.5% V (FIG. 1B), the pearlite phase is refined and the ferrite phase is also reduced in diameter. In the structure further containing 0.3% Mo, that is, the composite addition structure of V-Mo (FIG. 1C), the ferrite phase or the pearlite phase tended to be further refined. It can be seen from Table 1 that the tensile strength increases as the metal structure becomes finer in this way.

<Mechanical properties>
(1) The mechanical properties (tensile strength and elongation) of each sample (Gr: 0.6%) shown in Table 1 are shown in graphs in FIGS. 2A to 3B. From this, we found the following. First, when V was added even at about 0.1%, the tensile strength improved rapidly, and the tensile strength increased as V approached 0.5%. However, the improvement in tensile strength tended to be almost saturated when V was about 0.5%.

  Next, this strength improvement effect by V shows the same tendency even if the amount of Mo changes, but Mo is 0.1 to 0.6%, further 0.15 to 0.5%, and the maximum tendency is shown. Indicated. Furthermore, the tensile strength increased when the sintering temperature was high, and the elongation increased stably when the sintering temperature was low.

(2) The mechanical properties (tensile strength and elongation) of each sample (Gr: 0.6% and Gr: 0.8%) extracted from Table 1 and Table 2 are shown as graphs in FIGS. 4A to 5B. It was. First, when the sintering temperature was 1150 ° C. or 1250 ° C., the tensile strength was large and the elongation was small when the amount of Gr was large.

(3) The mechanical properties (tensile strength and elongation) of each sample (V + Mo = 0.5%) extracted from Table 1 and Table 2 are shown in a graph in FIGS. 6A and 6B. From this, we found the following. V had a greater effect of improving tensile strength than Mo, and when Mo / V was 4 to 0 (0.4 / 0.1 to 0 / 0.5), the strength was greatly improved. In particular, when Mo / V was around 1.5 (0.3 / 0.2) (for example, Mo / V = 2 to 1), the tensile strength increased and the elongation was sufficient.

(4) The mechanical properties (tensile strength and elongation) of each sample (V + Mn + Si = 0.5%) extracted from Table 3 are shown in a graph in FIGS. 7A and 7B. From this, we found the following. Even when Mo was replaced with (Mn + Si), the same tendency as in FIGS. 6A and 6B was shown. However, when viewed in the range of 0.1 to 0.5% of V, Mo had a slightly greater effect of improving tensile strength and elongation than (Mn + Si).

(5) The mechanical properties (tensile strength and elongation) of each sample (V + Mo + Mn + Si = 0.5%) extracted from Table 3 are shown as graphs in FIGS. 8A to 9B. From this, we found the following. Even when V, Mo, Mn and Si were included, that is, even when a part of (V + Mo) was replaced with (Mn + Si), the tensile strength and elongation were sufficient.

(6) The mechanical properties (tensile strength and elongation) of each sample extracted from Table 4A and Table 4B (both tables are simply referred to as “Table 4”) are shown as graphs in FIGS. 10A to 11B. . From this, we found the following. Even when the molding pressure and the cooling rate after sintering changed, the tensile strength and elongation of each sample showed almost the same tendency as the case shown in FIG. 6A or 6B. However, the tensile strength improved as the molding pressure and cooling rate increased. Elongation also improved as the molding pressure increased, but did not significantly affect the cooling rate.

Claims (7)

An iron- based sintered material composed of a sintered body obtained by sintering a molded body obtained by press-molding a raw material powder containing iron (Fe) as a main component,
When the total is 100% by mass,
0.05 to 0.6 mass% vanadium (V);
0.1-1.0% by mass of carbon (C);
The balance Fe and inevitable impurities,
An iron-based sintered material comprising: The iron-based sintered material according to claim 1, further comprising 0.05 to 0.5 mass% of molybdenum (Mo). The iron-based sintered material according to claim 2 , further comprising 0.03 to 0.6 mass% of manganese (Mn). Further, ferrous sintered material according to claim 1 or 2 silicon the (Si) containing 0.01 to 0.2 wt%. The iron-based sintered material according to claim 1, further comprising 0.03 to 0.6 mass% of Mn and 0.01 to 0.2 mass% of Si. The iron-based sintered material according to any one of claims 2 to 5, wherein the total amount of alloy elements composed of one or more of V, Mo, Mn, or Si is 1.5 mass% or less. A molding step of obtaining a molded body obtained by pressure-molding the raw material powder;
A heating step of heating the molded body to obtain a sintered body,
A method for producing an iron-based sintered material , wherein the iron-based sintered material according to any one of claims 1 to 6 is obtained.