JP2008189954A - Fe-BASED SINTERED ALLOY AND MANUFACTURING METHOD THEREFOR - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an Fe-based sintered alloy which has a base part and an extending part that is wider than the base part, and makes the density uniform, and to provide a manufacturing method therefor. <P>SOLUTION: The Fe-based sintered alloy 1 is manufactured by the steps of: filling a part to be filled of a molding die with a ferrous raw powder containing 4 to 8 wt.% Cu; pressurizing the raw powder in an axial direction to form a green compact; and sintering the green compact. The Fe-based sintered alloy has the base part 2 at one side in the axial direction and the extending part 3 that is arranged on the other side in the axial direction and is wider than the base part 2. A ratio of the length L3 of the extending part 3 to a total length L is 2 to 5. A Cu content in the base part 2 is higher than that in the extending part 3. Even when the base part 2 has lower density than the extending part 3 in a state of the green compact having been molded, Cu in the extending part migrates to the base part in the sintering step, which makes the Cu content in the base part 2 higher than that of the extending part 3, thereby increases the density of the base part 2 rightly by the increment, and makes the density of the Fe-based sintered alloy uniform. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a Fe-based sintered alloy having a base portion and a wider enlarged portion and a method for manufacturing the same.

  In this type of sintered alloy manufacturing method, for example, a raw material powder containing metal as a main component is supplied to a cavity of a molding die (powder supply step), and the raw material powder supplied to the cavity is compressed and compressed. After forming a molded body that is a powder (powder molding process), the molded body is heated and sintered in a sintering furnace (sintering process).

  Various types of green compacts can be formed corresponding to the shape of the cavity, and a green compact having a base and an enlarged portion wider than the base can be formed using a plurality of punches. .

Then, as shown in FIG. 8, as the base portion 101 and the enlarged portion 102, a boss portion and a gear portion (for example, Patent Literature 1), a helical gear portion and a flange portion (for example, Patent Literature 2), a first helical gear, There are various helical gears (for example, Patent Document 3) and various types such as a small diameter cylindrical portion and a large diameter cylindrical portion.
JP-A-5-302102 JP-A-7-70612 Japanese Patent Laid-Open No. 10-156590

  As described above, in the molding of the green compact provided with the base 101 and the enlarged portion 102, since a method of pressing the raw material powder from both sides in the axial direction is used, even if a plurality of punches are used, compared to the short enlarged portion 102 Thus, it is difficult to apply a pressing force to the base 101 side continuous with the enlarged portion 102, and the density of the central side 101A on the base 101 side in the state of the green compact becomes low. There is a problem that the density of the gold base 101 is lowered and the overall density is likely to be uneven.

  Accordingly, an object of the present invention is to provide an Fe-based sintered alloy capable of achieving uniform density in a sintered alloy having a base portion and an enlarged portion wider than the base portion, and a manufacturing method thereof.

  In the invention of claim 1, an iron-based raw material powder containing 3 to 8% by weight of Cu is filled in a filling part of a molding die, the raw material powder is pressed from the axial direction to form a green compact, The Fe-based sintered alloy obtained by sintering the green compact includes a base on one side in the axial direction and an enlarged part provided on the other side in the axial direction, and has an overall length that is larger than that of the enlarged part. The length is 2 to 5 times, and the Cu content of the base is higher than that of the enlarged portion.

  The invention according to claim 2 includes the through hole in the axial direction, and the entire length is 1.5 to 8 times the diameter of the through hole.

  Further, the invention of claim 3 includes 0.08 to 1.6% by weight of Mn.

  The invention of claim 4 includes a base portion on one axial side and an enlarged portion provided on the other axial side and wider than the base portion, and the overall length is 2 to 5 times the length of the enlarged portion. In a certain Fe-based sintered alloy manufacturing method, an iron-based raw material powder containing 3 to 8% by weight of Cu is filled in a filling portion of a molding die, and this raw material powder is pressed from the axial direction to be a green compact. Is formed and the green compact is sintered.

  Further, the invention of claim 5 is a method in which the Fe-based sintered alloy includes the axial through hole, and the entire length is 1.5 to 8 times the diameter of the through hole.

  The invention of claim 6 is a method containing 0.08 to 1.6% by weight of Mn.

  According to the structure of claim 1, even if the density of the base portion is lower than that of the enlarged portion in the state where the green compact is molded, the density of the base portion is increased by the amount that the Cu content of the base portion is higher than that of the enlarged portion. An Fe-based sintered alloy having a density is obtained.

  And if the ratio of Cu in the raw material powder is less than 3% by weight, the effect of uniformizing the density cannot be exhibited. On the other hand, if it exceeds 8% by weight, the dimensional accuracy is lowered, so that the above range is effective. I found it.

  In addition, if the length obtained by subtracting the length of the enlarged portion from the total length is the length of the base, and if the length of the base is less than 1 time of the enlarged portion, the density difference between the base and the enlarged portion during compression molding of the green compact On the other hand, if the total length exceeds 5 times the enlarged portion, the center side of the base portion is separated from the enlarged portion, so that it is difficult to obtain a density uniforming effect due to the movement of Cu. Was found to be effective.

  Further, according to the structure of claim 2, if the total length is less than 1.5 times the diameter of the through hole, the problem of density difference does not occur. Since it was difficult to obtain, the above range was found to be effective.

  Moreover, according to the structure of Claim 3, by containing Mn, melting | fusing point of Cu falls and it becomes easy to move, and Cu alloy becomes easy to move to the base part with a low density. And when the ratio of Mn was less than 0.08%, the melting point could not be lowered. On the other hand, when it exceeded 1.6%, the toughness was lowered, so the above range was found to be effective.

  According to the structure of claim 4, even if the density of the base is lower than that of the enlarged portion in the state where the green compact is molded, Cu melts and moves to the base side during sintering, and the density of the base increases and is uniform. Fe-based sintered alloy having a high density. That is, Cu moves by being swept away from a high density portion to a low portion.

  And if the ratio of Cu in the raw material powder is less than 3% by weight, the effect of uniformizing the density cannot be exhibited. On the other hand, if it exceeds 8% by weight, the dimensional accuracy is lowered, so that the above range is effective. I found it.

  In addition, if the length obtained by subtracting the length of the enlarged portion from the total length is the length of the base, and if the length of the base is less than 1 time of the enlarged portion, the density difference between the base and the enlarged portion during compression molding of the green compact On the other hand, if the total length exceeds 5 times the enlarged portion, the center side of the base portion is separated from the enlarged portion, so that it is difficult to obtain a density uniforming effect due to the movement of Cu. Was found to be effective.

  Further, according to the structure of claim 5, if the total length is less than 1.5 times the diameter of the through hole, the problem of density difference does not occur. Since it was difficult to obtain, the above range was found to be effective.

  Moreover, according to the structure of Claim 6, by containing Mn, melting | fusing point of Cu falls and Cu alloy becomes easy to move to the base part with a low density at the time of sintering. And when the ratio of Mn was less than 0.08%, the melting point could not be lowered. On the other hand, when it exceeded 1.6%, the toughness was lowered, so the above range was found to be effective.

  Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all of the configurations described below are not necessarily essential requirements of the present invention. In each example, by adopting a new Fe-based sintered alloy different from the conventional one and its manufacturing method, an unprecedented Fe-based sintered alloy and its manufacturing method can be obtained. Each method is described.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 4 show Example 1 of the present invention. As shown in FIG. 1, an Fe-based sintered alloy 1 includes a base 2 as a first cylindrical part and a second cylindrical shape having a diameter larger than that of the base 2. In this example, a through hole 4 that continuously penetrates the base 2 and the enlarged portion 3 is formed. Further, the base 2 and the enlarged portion 3 are located concentrically with respect to the axis of the circular through hole 4. A step portion 5 is formed between the base portion 2 and the enlarged portion 3.

  The length L (total length) of the Fe-based sintered alloy 1 is not less than 2 times and not more than 5 times the length L3 of the enlarged portion 3, and the length L2 of the base portion 2 is equal to that of the enlarged portion 3. It is 1 time or more and 4 times or less of the length L. Further, the length L of the Fe-based sintered alloy 1 is not less than 1.5 times and not more than 8 times the diameter D of the through hole 4.

  Further, the diameter D3 of the enlarged portion 3 is preferably not less than a dimension obtained by adding twice the length L2 of the enlarged portion 3 to the diameter D2 of the base portion 2 (D3> = D2 + L2 × 2). When D3 is small, the volume of the enlarged portion 3 is also small, and the amount of Cu moving from the enlarged portion 3 to the base portion 2 is also reduced.

  For example, the Fe sintered alloy 1 includes, by weight, Cu: 3 to 8%, Mn: 0.08 to 1.6%, Ni: 0.1 to 6%, Mo: 0.1 to 6 %, C: 0.1 to 2%, and the remaining Fe-based sintered alloy 1 having a composition composed of Fe and inevitable impurities can be used. : 4-8%, Mn: 0.08-1.6% (2-20% of Cu) at least, Fe-based sintered alloy having a composition composed of Fe and inevitable impurities can be used. .

  A method for producing a test product of the Fe-based sintered alloy 1 will be described with reference to FIGS. In the Fe-based sintered alloy 1 shown in FIG. 1, the test product has the length L of 30 mm, the length L3 of 10 mm, the diameter D of 15 mm, the outer diameter D2 of the base portion 2 of 25 mm, and the enlarged portion 3. The one having a diameter D3 of 45 mm was used. And as a raw material powder used for the test products (A) to (E), by weight percent, Fe powder, Fe-Mo powder, Fe-Ne-Mo powder, Cu powder, so as to have the ratio shown in Table 1 below, Cu-Mn powder and graphite powder are mixed as raw material powder (S1: Step 1), and the mixed raw material powder is formed into a green compact of a predetermined shape by pressing at a predetermined pressure within a range of, for example, 400 to 800 MPa (S2). Then, the green compact was sintered (S3) under a condition of holding for 20 minutes at a predetermined temperature in the range of 1990 to 1100 ° C. in an ammonia decomposition gas atmosphere to obtain an Fe-based sintered alloy 1.

In the present invention, as shown in FIG. 4, the sintering (S3) is performed with the base portion 2 facing down.
Experimental Examples The experimental products (A) to (E) were produced under the same conditions as the test examples (X) to (Z) in which the raw material powder used had the composition shown in Table 1 below.

本発明では、前記基部２を下にした状態で、前記焼結（Ｓ３）を行うことにより、焼結時に溶融したＣｕが基部２に移動することにより、基部２の密度が上がり、焼結合金１の密度均一化が図られ、これは上記の表１も明らかである。

In the present invention, by performing the sintering (S3) with the base portion 2 facing down, the molten Cu at the time of sintering moves to the base portion 2, thereby increasing the density of the base portion 2 and the sintered alloy. 1 is made uniform, which is clear from Table 1 above.

  Thus, in this embodiment, corresponding to claim 1, iron-based raw material powder containing 3 to 8% by weight of Cu is filled in the filling portion of the molding die, and this raw material powder is added from the axial direction. In the Fe-based sintered alloy 1 formed by pressing and forming the green compact, and sintering the green compact, a base portion 2 on one side in the axial direction and an enlarged portion 3 wider than the base portion 2 provided on the other side in the axial direction; The ratio of the length L3 of the enlarged portion 3 to the entire length L is 2 to 5, and the Cu content of the base portion 2 is higher than that of the enlarged portion 3, so that the green compact is expanded in a molded state. Even if the density of the base part 2 is lower than that of the part 3, the density of the base part 2 increases as the Cu content of the base part 2 is higher than that of the enlarged part 3, and the Fe-based sintered alloy having a uniform density is obtained.

  And if the ratio of Cu in the raw material powder is less than 3% by weight, the effect of uniformizing the density cannot be exhibited. On the other hand, if it exceeds 8% by weight, the dimensional accuracy is lowered, so that the above range is effective. I found it.

  Thus, in this embodiment, corresponding to claim 2, the axial through hole 4 is provided, and the ratio of the diameter D of the through hole 4 to the overall length L is 1.5 to 8. Therefore, if the overall length L is less than 1.5 times the through-hole diameter D, the problem of density difference does not occur. On the other hand, if it exceeds 8 times, it is difficult to obtain a density uniforming effect due to the movement of Cu. We found that the range of is valid.

  As described above, in this embodiment, corresponding to claim 3, since 0.08 to 1.6% by weight of Mn is contained, the melting point of Cu is lowered, it becomes easy to move, and the base 2 having a low density is formed. Cu alloy moves easily. And when the ratio of Mn was less than 0.08%, the melting point could not be lowered. On the other hand, when it exceeded 1.6%, the toughness was lowered, so the above range was found to be effective.

  Thus, in the present embodiment, corresponding to claim 4, the base portion 2 on one side in the axial direction and the enlarged portion 3 provided on the other side in the axial direction are wider than the base portion 2, and the length L3 of the enlarged portion 3 is provided. In the manufacturing method of the Fe-based sintered alloy 1 in which the ratio of the total length L is 2 to 5, an iron-based raw material powder containing 3 to 8% by weight of Cu is filled in the filling part of the molding die. The raw material powder is pressed from the axial direction to form a green compact, and the green compact is sintered with the base 2 facing downward. Even if it is low, Cu melts at the time of sintering and moves to the base 2 side, the density of the base 2 increases, and an Fe-based sintered alloy having a uniform density is obtained.

  And if the ratio of Cu in the raw material powder is less than 3% by weight, the effect of uniformizing the density cannot be exhibited. On the other hand, if it exceeds 8% by weight, the dimensional accuracy is lowered, so that the above range is effective. I found it.

  Thus, in this embodiment, in correspondence with claim 5, the Fe-based sintered alloy includes an axial through hole 4, and the diameter D of the through hole 4 and the overall length L Since the ratio is 1.5 to 8, if the overall length L is less than 1.5 times the through-hole diameter D, the problem of density difference does not occur. On the other hand, if it exceeds 8 times, the density is uniformized by the movement of Cu. Since it is difficult to obtain the effect, the inventors have found that the above range is effective.

  In this way, in this example, corresponding to claim 6, since 0.08 to 1.6 wt% of Mn is contained, the melting point of Cu is lowered, and the Cu alloy moves to a low density base during sintering. It becomes easy to do. And when the ratio of Mn was less than 0.08%, the melting point could not be lowered. On the other hand, when it exceeded 1.6%, the toughness was lowered, so the above range was found to be effective.

  5 and 6 show a second embodiment of the present invention, where the same reference numerals are given to the same portions as those in the first embodiment, and detailed description thereof is omitted. As shown in FIG. In the base sintered alloy 1A, the enlarged portion 3 is eccentric with respect to the through hole 4, and in this example as well, Cu in the enlarged portion 3 can move to achieve a uniform density. Corresponding to each claim, the same operations and effects as the first embodiment are obtained.

  FIG. 7 shows a third embodiment of the present invention, where the same reference numerals are given to the same parts as those of the above-mentioned embodiments, and detailed description thereof is omitted. As shown in FIG. The gold 1B is not provided with the through hole 4, and the base 2 and the through hole 4 are solidly formed. The diameter D2 ′ of the base 2 in this example is a dimension obtained by subtracting the diameter D from the diameter D2 (D2 '= D2-D), and the diameter D3' of the enlarged portion 3 is a dimension obtained by subtracting the diameter D from the diameter D2 (D3 '= D3-D).

  Also in this example, the Cu in the enlarged portion 3 can move to the base portion 2 and the density can be made uniform. Also in this embodiment, the embodiment described above corresponds to claims 1, 3, 4, and 6. The same operation and effect as 1 are produced.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible. For example, the enlarged portion and the base portion may be a gear as described in the background art or may have a square cross section. Further, in the case of a toothed gear, the diameter of the root circle may be the respective diameter.

It is a longitudinal cross-sectional view which shows Example 1 of this invention. It is a top view same as the above. It is a flowchart figure of a manufacturing method same as the above. It is sectional drawing at the time of sintering same as the above. It is a longitudinal cross-sectional view which shows Example 2 of this invention. It is a top view same as the above. It is a longitudinal cross-sectional view which shows Example 3 of this invention. It is a longitudinal cross-sectional view which shows a prior art example.

Explanation of symbols

1 Fe-based sintered alloy 2 Base 3 Enlarged portion 4 Through hole L Length (total length)
L3 length (length of the enlarged part)
D Diameter

Claims (6)

An iron-based raw material powder containing 3 to 8% by weight of Cu is filled in the filling part of the molding die, and this raw material powder is pressed from the axial direction to form a green compact, and this green compact is sintered. An Fe-based sintered alloy comprising a base portion on one axial side and an enlarged portion provided on the other axial side and wider than the base portion, the overall length being 2 to 5 times the length of the enlarged portion A Fe-based sintered alloy characterized in that the Cu content of the base is higher than that of the enlarged portion. 2. The Fe-based sintered alloy according to claim 1, wherein the Fe-based sintered alloy includes the through-holes in the axial direction and has an overall length of 1.5 to 8 times the diameter of the through-holes. The Fe-based sintered alloy according to claim 1 or 2, comprising 0.08 to 1.6% by weight of Mn. A method for producing an Fe-based sintered alloy comprising a base on one side in the axial direction and an enlarged portion provided on the other side in the axial direction and wider than the base, the total length being 2 to 5 times the length of the enlarged portion In this method, an iron-based raw material powder containing 3 to 8% by weight of Cu is filled in a filling part of a molding die, the raw material powder is pressed from the axial direction to form a green compact, A method for producing an Fe-based sintered alloy, comprising sintering. 5. The Fe-based sintered bond according to claim 4, wherein the Fe-based sintered alloy has through-holes in the axial direction, and the entire length is 1.5 to 8 times the diameter of the through-holes. Gold manufacturing method. The method for producing an Fe-based sintered alloy according to claim 4 or 5, comprising 0.08 to 1.6% by weight of Mn.

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