JPH07103405B2 - Punching machine for rod-shaped sintered material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a punching apparatus for obtaining a rod-shaped sintered material having excellent tensile strength and elongation characteristics.

[0002]

2. Description of the Related Art Conventionally, a penetrating body for injecting into a protective article is manufactured by reducing the diameter of a rod-shaped sintered material. For reducing the diameter of the rod-shaped sintered material, which is a powder molding material, it is common to use swaging using two or four dies or stamping taps. Then, this processing method is applied to the tensile strength T. S. When applied to a high-strength material of about 100 Kgf / mm ² , the processing load is large, so a large-scale special machine is required, and even if a large-scale special machine is used, a high density increase cannot be obtained, which is a technical problem. is there. In addition, since it is a discontinuous and intermittent processing method,
No significant improvement in dimensional accuracy can be expected, and bending is likely to occur.

Further, in such a processing method, since the compressive force does not act on the entire cross section and the tensile force in the radial direction acts on the central portion, a large hydrostatic pressure is exerted in the case of a material having low ductility and difficult to process. In addition to the lack of action, a so-called fir tree extending in the radial direction is likely to occur in the central portion during processing. This is because the sintered body obtained by sintering the powder has high strength and is brittle, and thus cracks easily occur during processing.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical problems, and the structure thereof is a fixing member 3 and a sliding guide guided by the fixing member 3.
Of the support member 13 and the fixing member 3 fixed to the support member 13
Has a tapered hole portion 14a which is arranged on the side and gradually reduces in diameter.
Of the movable lower plate 11 on which the die 14 is fixed
The movable upper plate 12 arranged on the other side and fixed to the column 13,
The movable upper plate 1 is disposed between the fixed member 3 and the movable upper plate 12.
Cylinder device 5 for reciprocating the movable plate 2 and the movable lower plate 11.
Has the door, it is sintered powder so as to form a <br/> remote larger diameter by the small diameter end of the tapered hole portion 14a of the die 14, the die 14
Punching processing apparatus der connexion, tapered hole of the end portion of the rod-shaped sintered material 21 die 14 of the rod-shaped sintered material using a rod sintered material 21 coated with the liquid lubricant 22 on the outer circumferential surface in the long relative Department
Inserted into 14a, both <br/> and to abut against the other end to the fixed member 3 to move the by connexion movable lower plate 11 to the cylinder device 5, the rod-shaped sintered material of the tapered hole portion 14a of the die 14 An apparatus for punching a rod-shaped sintered material, characterized in that the rod-shaped sintered material 21 is gradually passed from one end to give strain hardening by the punching processing to the rod-shaped sintered material 21.

[0005]

The rod-shaped sintered material whose outer peripheral surface is coated with the liquid lubricant is set between the fixing member and the tapered hole of the die. Then, the die is moved together with the movable lower plate by the cylinder device, and the rod-shaped sintered material whose one end abuts the fixed member is relatively press-fitted into the tapered hole portion of the die to reduce the cross-sectional area. And gradually push out from the small diameter end of the tapered hole . That
At this time, the movable lower plate can be supported by the columns supported by the fixed members.
Move with the moving board. Since the rod-shaped sintered material that has passed through the die is swaged in this manner, the mechanical properties (for example, tensile strength, elongation, impact value, etc.) of the rod-shaped sintered material can be improved.

When passing through the die, the rod-shaped sintered material having an incompressible liquid lubricant around it is relatively moved without being significantly affected by frictional force and is reduced in diameter, whereby punching is performed. A strain-hardened product according to is obtained. Further, the liquid lubricant applied to the outer peripheral surface of the rod-shaped sintered material is interposed between the die and the tapered hole of the die to reduce the frictional force, and to prevent surface roughening and seizure that are likely to occur in high strength materials. It can be prevented.

As described above, the rod-shaped sintered material relatively extruded from the small-diameter hole portion is compressed by a large hydrostatic pressure action due to the axial compressive force from the die,
Since it passes through the tapered hole and undergoes strain hardening due to relative punching, high density and high strength can be obtained satisfactorily. That is, the density increase of the rod-shaped sintered material having the pores in the powder molded material can be obtained extremely well, and the fir cracks can be satisfactorily prevented from occurring in the central portion of the rod-shaped sintered material made of the difficult-to-process material.

Further, since the frictional force between the rod-shaped sintered material and the die is extremely small due to the liquid lubricant interposed on the outer periphery of the rod-shaped sintered material, the inside of the rod-shaped sintered material being processed is reduced. The variation of the strain distribution of the product is small, and the non-uniformity in the mechanical properties of the product is significantly reduced. The rod-shaped sintered material is
In addition to processing at room temperature, it is also possible to heat up to about 500 ° C. and perform processing while warm.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a punch processing apparatus according to an embodiment of the present invention. In the drawings, reference numeral 1 indicates a fixed frame body, which includes a fixed lower plate 2 and a fixed upper plate 3 which is a fixing member.
It is configured by connecting with a column 4 of a book. Nuts 4a are screwed into both ends of each pillar 4 having a small diameter.
A through hole 2a for taking out a product is provided in the central portion of the fixed lower plate 2.
Is formed, and a concave portion is formed in the central portion of the inner surface of the fixed upper plate 3 facing the fixed lower plate 2, and a contact surface 3b is formed by the support member 3a press-fitted into the concave portion. There is.

Further, the outer surface center portion of the fixed upper plate 3, a cylinder 5a of the cylinder device 5 in the double-acting is fixed, the piston 5b which fits freely private dynamic in cylinder <br/> da 5a Then, the upper chamber 5c and the lower chamber 5d are partitioned. Reference numeral 5e is a piston rod which is inserted into the rod cover in a liquid-tight manner, and an upper end portion of the protrusion is coupled to a lower surface of a movable upper plate 12 described later. The side surfaces of the fixed lower plate 2 and the fixed upper plate 3 and the upper end of the cylinder 5a are firmly fixed to the reinforcing member 7.

On the other hand, 10 indicates a movable frame body, and the movable lower plate 1
1 and the movable upper plate 12 are connected by two columns 13. The support column 13 has a function as a guide post by inserting the fixed upper plate 3 in a freely movable manner, and a function as a tie rod by connecting the movable lower plate 11 and the movable upper plate 12. Nuts 13a are screwed into both ends of each column 13 having a small diameter. A stepped through hole 11a consisting of a large diameter hole and a small diameter hole, which are connected via a stepped surface, is formed in the center of the movable lower plate 11, and a die 14 is press-fitted and fixed to the stepped through hole 11a. . The die 14 is located at an upper portion and has a taper hole portion 14a whose diameter is gradually reduced downward.
And a small diameter hole portion 14b connected to the lower end of the tapered hole portion 14a.
Have and. The upper end of one of the columns 13 in the lowered state is slidably inserted into the tubular portion 13b of the reinforcing member 7. Thus, the movable lower plate 11 is vertically movable with the support columns 13 guided by the fixed upper plate 3 and the tubular portion 13b.

A hydraulic pump 18 is connected to the cylinder 5a via a switching valve 15 having positions a, b and c, a flow rate variable control valve 16 and a relief valve 17. Each 19 is a reservoir for storing a working liquid,
20 is a pressure gauge.

Next, the operation of the above embodiment will be described. The rod-shaped sintered material 21 is a powder molded material obtained by sintering metal powder, and has a tensile strength T.I. S. It is made of a high-strength material (for example, W-Ni-Fe sintered alloy) of about 100 Kgf / mm ² . The rod-shaped sintered material 21 forms a rod-shaped body having a diameter slightly larger than the small-diameter end portion of the tapered hole portion 14a of the die 14 and the small-diameter hole portion 14b (specifically, 20 to 30% larger in cross-sectional area). , Sufficiently long for the die 14. On the outer peripheral surface of such a rod-shaped sintered material 21, as shown in FIG. 4, a liquid lubricant 22 is applied in advance so as to form a thin film. The liquid lubricant 22 is sol-like molybdenum disulfide having a high viscosity.

First, the switching valve 15 is set to the position a and the hydraulic liquid is pumped into the upper chamber 5c by the hydraulic pump 18 to drain the lower chamber 5d and drive the movable frame 10 downward. By this operation, the space between the movable lower plate 11 and the fixed upper plate 3 is sufficiently enlarged, and between the contact surface 3b of the fixed upper plate 3 and the tapered hole portion 14a of the die 14 of the movable lower plate 11. The rod-shaped sintered material 21 is set. When the setting is completed, the switching valve 15 is set to the b position, the chambers 5c and 5d are drained, and then the c position is set to drive the movable frame 10 up and drive the movable lower plate 11. As a result, the rod-shaped sintered material 21 whose upper end abuts on the abutting surface 3b is relatively press-fitted into the tapered hole portion 14a of the die 14, the cross-sectional area is reduced, and the rod-shaped sintered material 21 is gradually pushed out from the small diameter hole portion 14b. The rod-shaped sintered material 21 that has passed through the die 14 in this manner is swaged to improve its mechanical properties (for example, tensile strength, elongation, impact value, etc.).

When passing through the die 14, a rod-shaped sintered material 21 in which a non-compressible liquid lubricant 22 is provided in the form of a thin film around the periphery thereof.
Is relatively moved without being subjected to a large frictional force and is subjected to a diameter reduction process, whereby a product in which the strain hardening by the punching process is favorably obtained can be obtained. Furthermore, since the liquid lubricant 22 applied to the outer peripheral surface of the rod-shaped sintered material 21 is interposed between the tapered hole portion 14a and the small diameter hole portion 14b of the die 14,
In particular, a compressive force in the axial direction from the movable lower plate 11 acts on the rod-shaped sintered material 21 located in the tapered hole portion 14a of the die 14, and a compressive force via the liquid lubricant 22 is received from the outer periphery, It is compressed under hydrostatic pressure action to promote high density and high strength. Small-diameter hole portion 14 of the die 14
b functions to suppress the bending of the rod-shaped sintered material 21 whose diameter has been reduced by the tapered hole portion 14a and to shape it.

As described above, the rod-shaped sintered material 21 relatively extruded from the small diameter hole portion 14b receives not only the axial compressive force from the movable lower plate 11 but also the compressive force via the liquid lubricant 22. Received a large hydrostatic pressure and is compressed,
Since it passes through the tapered hole portion 14a and undergoes strain hardening due to relative punching, high density and high strength can be satisfactorily obtained. That is, the density increase of the rod-shaped sintered material 21 having pores in the powder molded material can be extremely excellently obtained, and it is also possible to satisfactorily prevent fir cracks from occurring in the central portion of the rod-shaped sintered material 21 made of a difficult-to-process material. . Specifically, the large pores in the rod-shaped sintered material 21, which is a sintered body, are largely compressed and crushed, the sizes of the mixed pores are made uniform, and the porosity can be reduced to 0.5% or less. , Mechanical properties can be improved.

Further, the liquid lubricant 22 which is interposed in a thin film form on the outer periphery of the rod-shaped sintered material 21 makes the frictional force between the rod-shaped sintered material 21 and the die 14 extremely small, so that it is high. Roughness and seizure of the surface, which are likely to occur in the strength material, can be prevented, fluctuations in strain distribution inside the rod-shaped sintered material 21 during processing become small, and nonuniformity in mechanical properties of the product is significantly reduced. The product that has passed through the die 14 and has been punched out is taken out from the through hole 2a while suppressing the bending by clamping the front end portion by the clamp tool 23 inserted from the through hole 2a of the fixed lower plate 2.

By the way, when the space between the movable lower plate 11 and the fixed upper plate 3 is reduced due to the progress of the punching process, the movable lower plate 11 is once driven down, and the abutting surface 3b of the fixed upper plate 3 and the rod-like shape. A rod-shaped member having a diameter smaller than that of the rod-shaped sintered material 21 is interposed between the upper end surface of the sintered material 21 and the movable lower plate 11 is again driven to rise. As a result, all of the rod-shaped sintered material 21 is passed through the die 14. Further, the rod-shaped sintered material 21 can be processed at room temperature, or can be heated to about 500 ° C. and processed while warm. The fixed upper plate 3 is driven downward while the die 14 shown in FIG.
It is conceivable to press into 4 and directly punch out, but in that case, the surface pressure of the contact surface 3b of the fixed upper plate 3 is greatly increased, and an excessive compression force acts on the rod-shaped sintered material 21. It is not desirable because it tends to

In practice, a rod-shaped sintered material 21 made of a W-Ni-Fe sintered alloy, which is a material for a penetrating body to be injected into a protective article, was punched. The rod-shaped sintered material 21 is manufactured by sintering powder after containing powder of 96% of tungsten in a rubber bag, using iron and nickel as binders, and hydrostatically molding and sintering the powder. . As shown in FIG. 5A, the unsintered rod-shaped sintered material 21 has an elongation El. Is 20% or more, and the tensile strength T. S. Of 100 Kgf / mm ² or less, variations in elongation quality were recognized. The rod-shaped sintered material 21 was punched using the die 14 having a small diameter hole portion 14b having a diameter of 30 mm by the above-mentioned apparatus so as to give a cross-sectional reduction rate of 20%. As a result, the elongation El. Is 8 to 13%, and the tensile strength T. S. Is 125 kg
A product having good properties of f / mm ² or more and relatively small quality variation was obtained. The penetrating body that is injected into the protective material has a tensile strength T. S. And the elongation of about 10% or more El. The characteristics are actually desired. The product indicated by c in FIG. 5 has a cross-section reduction rate of about 10% and has an elongation El. And tensile strength T. S. An intermediate property for was obtained. In FIG. 5, the result of the punching process is shown by the solid line A.

On the other hand, a characteristic in which a similar cross-section reduction rate is given by drawing using a die 14 having a diameter of the small diameter hole portion 14b of 18 mm is shown by a chain line B in FIG. The drawing is a processing method in which the tip of the rod-shaped sintered material 21 is pulled to pass through the die 14. In the figure, d is the as-sintered characteristic, e is the characteristic after drawing, and f is 10%.
The characteristics are given with the cross-sectional reduction rate of the degree. Then, it can be seen that the drawing process causes an excessive decrease in elongation and is inferior in the improvement of the tensile strength, as compared with the solid line A showing the characteristics by the punching process. This is because the punching process can favorably exert the hydrostatic pressure during the process.

[0021]

As can be understood from the above description,
According to the punching apparatus for a rod-shaped sintered material according to the present invention, it is easy to
Punching into rod-shaped sintered material using a punching machine with a simple structure
Processing, and as a result,
The effect of is obtained. (1) Continuous processing can be applied to a rod-shaped sintered material that is long with respect to a die, and good dimensional accuracy can be improved. (2) Not only the pressing force but also a large hydrostatic pressure acts on the inside of the rod-shaped sintered material, so that the density increase of the powder molded material can be satisfactorily obtained, and the compressive force also acts in the axial direction, so that the axial line is formed in the central portion. Since tensile stress in the direction is not generated, it is effective for preventing fir cracks in the center portion of the low ductility and difficult-to-process material that extends in the radial direction during processing. Moreover, this rod-shaped sintering
The axial compressive force acting on the material is applied to the fixing member at one end.
It is applied by moving the die to the rod-shaped sintered material that is in contact.
Therefore, it is possible to prevent the rod-shaped sintered material from acting excessively.
It Furthermore, since it passes through the tapered hole and undergoes strain hardening due to relative punching, high densification and high strength can be satisfactorily obtained. As a result, it is possible to obtain a rod-shaped sintered material in which tensile strength and elongation characteristics are well compatible with each other.

(3) Since the liquid lubricant intervenes in a thin film form between the rod-shaped sintered material and the die wall and remarkably reduces the friction between them, the strain distribution generated inside the rod-shaped sintered material during processing is reduced. The variation is small and the non-uniformity in the mechanical properties of the product is reduced. (4) Large pores in the rod-shaped sintered material, which is a sintered body, are largely compressed and crushed by hydrostatic pressure, the sizes of mixed pores are made uniform, and the porosity can be favorably reduced.
As a result, mechanical properties are improved.

[Brief description of drawings]

A front view showing a partially cut the punching processing apparatus according to an embodiment of the present invention; FIG.

FIG. 2 is a side view of the same.

FIG. 3 is a plan view similarly showing a partial incision.

FIG. 4 is a sectional view showing a rod-shaped sintered material.

FIG. 5 is a diagram showing elongation-tensile strength characteristics.

[Explanation of symbols]

1: fixed frame body, 2: fixed lower plate, 2a: through hole, 3: fixed upper plate (fixed member), 3a: support member, 3b: contact surface, 4:
Prop, 5: Cylinder device, 5a: Cylinder, 10: Movable frame, 11: Movable lower plate, 11a: Stepped through hole, 12: Movable upper plate, 13: Post, 14: Die, 14a: Taper hole part , 14b: small-diameter hole, 15: switching valve, 18: hydraulic pump, 21: rod-shaped sintered material, 22: liquid lubricant.

Front Page Continuation (72) Inventor Kiyotaka Nakao 4 Chatsu-cho, Muroran-shi, Hokkaido Inside Japan Steel Works (56) References JP-A-52-53756 (JP, A) JP-A-49-129063 (JP, A) JP-A-4-26709 (JP, A)

Claims (1)

[Claims] 1. A fixing member (3) and a fixing member (3).
A pillar (13) that is guided to move, and a pillar (13)
Is fixed to one side of the fixing member (3) and gradually
Die (14) having taper hole (14a) with reduced diameter
The lower side of the movable lower plate (11) fixed to the fixed member (3)
Movable upper plate (12) fixed to the column (13)
And between the fixed member (3) and the movable upper plate (12).
And reciprocates to the movable upper plate (12) and the movable lower plate (11).
And a cylinder device (5) for giving a die (14)
It by sintering the powder to form a larger diameter than the small diameter end portion of the tapered hole portion (14a) of the elongated relative to the die (14)
Rod-shaped sintered material whose outer peripheral surface is coated with liquid lubricant (22)
An apparatus for punching a rod-shaped sintered material using (21) , wherein one end of the rod-shaped sintered material (21) is inserted into a tapered hole portion (14a) of a die (14) and the other end is fixed. Element
When brought into contact with (3) both cylinder device (5) Niyotsu
The movable lower plate (11) is moved to gradually pass the tapered hole portion (14a) of the die (14) from one end of the rod-shaped sintered material (21) , and the strain hardening by punching is performed on the rod-shaped sintered material ( 21) An apparatus for punching a rod-shaped sintered material, characterized in that