JPH08157908A - Powder rolling device and powder rolling - Google Patents

Abstract

PURPOSE: To provide a powder rolling device and method with which a rolled stock homogeneous in a transverse direction is obtd. by simultaneously executing rolling and sintering of a powder material, an energy cost is reduced by eliminating a power source for large current supply and the constitution of insulation of the powder rolling mill is simplified. CONSTITUTION: The powder rolling device for obtaining the rolled stock 29 by supplying the powder material 28 to a spacing between at least a pair of rolling rolls 21A, 21B is provided with side weirs 23A adjustable in pressurization on both end faces of roll barrels in order to form a powder reserving part 22 together with the roll barrel surface of a pair of the rolling rolls. This powder rolling method comprises executing heating by supplying electricity in the transverse direction of the powder material between the roll bites of a pair of the rolling rolls and/or supplying electricity in the longitudinal direction of the roll barrels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder rolling method and a powder rolling apparatus for rolling and heating a powder material such as metal powder to directly form a rolled material.

[0002]

2. Description of the Related Art As a method for producing a product having a predetermined size and shape from a powder material, there are various methods such as press molding, drawing, extrusion, isotropic pressure molding, injection molding and powder rolling. Implemented or under consideration.

Among the various methods described above, the powder rolling method is a processing method in which a powder material is rolled by at least a pair of rolling rolls to continuously form a rolled material, and a long product is continuously produced directly from the powder material. In addition to being efficiently manufactured, high pressure is easily generated in the roll bite, which makes it suitable for plastic working of difficult-to-work materials. Suitable as a manufacturing method.

According to the powder rolling method, a hopper containing a powder material is stored in a space formed by sandwiching the upper half portions of the roll barrels of at least a pair of rolling rolls facing each other, that is, a powder reservoir. The basic operation is to supply a powder material, rotate a pair of rolling rolls, and roll the powder material supplied to the powder reservoir in a roll bite of the pair of rolling rolls to form a rolled material. Is. However, in the powder rolling method, since the powder material such as the metal powder that is the material to be rolled has fluidity, the powder material supplied to the powder reservoir between the roll barrels of the pair of rolling rolls moves in the roll barrel length direction. May also flow and flow out from the end faces at both ends of the powder collecting part, so that the supply amount of the powder material is insufficient at the end of the roll barrel between the rolling rolls, and the widthwise end part of the formed rolled material is A decrease in density may occur, which may cause a great problem in terms of quality and yield of rolled material and also in subsequent processes.

Therefore, in the conventional powder rolling method, the powder material supplied between the pair of rolling rolls is prevented from flowing in the length direction of the roll barrel of the rolling roll and flowing out from the end faces at both ends of the powder collecting portion. However, measures have been taken in order to form a good quality rolled material that does not have a decrease in the density or plate thickness at the widthwise end of the rolled material. However, these methods are not sufficient.

[0006] Therefore, Japanese Patent Laid-Open No. 63-149305 discloses a method of arranging a pair of rolls for suppressing the flow of powder material in the length direction of the rolling barrel of the rolling roll at both ends of the rolling barrel. , JP-A-63-
Japanese Patent No. 221014 discloses a method of winding endless belts having an L-shaped cross section that suppresses the flow of the powder material in the length direction of the roll barrel of the rolling roll, at both ends of the roll barrel of the rolling roll. -13509
Japanese Patent Publication No. 6 discloses a method of winding a belt around a rolling roll so as to suppress both widthwise ends of a powder compact.

Further, JP-A-3-247704 and JP-A-4-168204 disclose a method of providing a pair of side weirs between the roll barrels of a rolling roll to suppress the flow of powder in the length direction of the roll barrel. That is, in this method, a pair of side dams are erected between the roll barrels of the pair of rolling rolls of the powder reservoir formed between the roll barrels of the pair of rolling rolls, and the powders separated by the pair of side dams. This is a method of supplying powder to the inner part of the reservoir.

On the other hand, the rolled material formed by the powder rolling method is generally finished into an end product through complicated steps such as sintering, reheating, hot working, heat treatment, cold working after rolling. is there. Since this rolled material is in a compression molded state,
Until the end of the sintering process, it is fragile, and careful handling and handling to the next process are necessary, leaving a technical problem. In particular, in the case of a rolled material composed of a strip-shaped long body,
A great deal of effort is required to complete the sintering process. Generally, in the field of hot rolling and warm rolling of a material to be rolled, heating the material to be rolled in a rolling line is also performed. As the heating method, electric heating methods such as direct current heating and induction heating are known, and they have been put to practical use for heating the material to be rolled immediately before rolling or for controlling the temperature immediately after rolling.

Further, Japanese Patent Application Laid-Open No. 63-180311 discloses a method of heating a roll material by energizing a pair of rolling rolls through electrodes to heat the roll itself, and heating the material to be rolled by heat transfer from the rolls. Japanese Patent Laid-Open No. 63-1837
No. 06 discloses a method in which an electric current is passed between a pair of rolling rolls via a material to be rolled to directly heat the material to be rolled in a roll bite.

Further, in the powder rolling method, Japanese Patent Laid-Open No.
No. 115302, an electrically conductive powder material is supplied between a pair of rolling rolls, an electric current in a roll bite is passed through the powder material as a material to be rolled to directly energize and heat the powder material itself, and A method of rolling to obtain a rolled material is disclosed.

Now, a method of rolling by heating the material to be rolled (raw material is not a powder material) in the roll bite through the above-described rolling roll will be described. FIG. 8 shows a conceptual diagram of a method of rolling a plate material. In FIG. 8, the plate-shaped material 3 to be rolled is passed between the rolling rolls 1A and 1B that rotate to perform rolling. The pair of rolling rolls 1A and 1B are independently connected to the power source 2 and a current I is passed between the pair of rolling rolls 1A and 1B to directly energize and heat the material 3 to be rolled in the roll bite. When the projected contact length between the rolling rolls 1A and 1B and the material 3 to be rolled is L and the plate width is W (not shown in FIG. 8), the contact area S between the rolling rolls 1A and 1B and the material 3 to be rolled is It is expressed by the following equation (1).

S = L · W (1) If the average thickness of the rolled material 3 in the roll bite of the rolling rolls 1A and 1B is hm, the resistance value R in the roll bite of the rolled material 3 is It is represented by the formula 2). In the formula (2), ρ is the specific resistance value of the material 3 to be rolled.

R = ρhm / S = ρhm / (LW) (2) In order to secure a necessary rolling temperature for the material to be rolled which is a plate material in hot rolling and warm rolling Requires a predetermined current density. In the actual rolling of the plate material, in order to obtain a predetermined current density with the contact area shown in the equation (1), the power source 2
It is necessary to supply a large amount of current I from. Further, the resistance R in the roll bite of the material 3 to be rolled is shown in the equation (2),
The ratio hm / S between the average thickness hm and the contact area S on the right side of the equation (2) is generally an extremely small value in the rolling of the plate material, and the amount of Joule heat generated is proportional to the resistance R. This is extremely disadvantageous in the case of rapidly heating the material 3 to be rolled in the roll bite.

From the above, in the method of electrically heating the material to be rolled 3 through the rolling rolls 1A and 1B to perform rolling, since the electrically heating using the rolling rolls 1A and 1B as an electrode is inefficient, it is necessary to carry out heating for electrical heating. The power source 2 requires a high-current power source device. In addition, the facility cost of the rolling mill and the electrical cost are very high in consideration of the functions of conductors and electrodes for energizing the rolling rolls 1A and 1B from the power source 2. Become. Further, the rolling mill used in this rolling method needs to electrically insulate the rolling rolls to be energized, the housing, and the drive system, but in a rolling mill to which a large load is applied and a large current is passed, reliability and reliability are improved. In order to make an insulating structure in consideration of ensuring the life, a large facility cost is required both in terms of structure and selection of an insulating material.

Further, in order to enable the rolling rolls 1A, 1B themselves to be energized under a high surface pressure during rolling, those having specifications suitable for the electrical and mechanical characteristics of the material 3 to be rolled It is necessary to use, and the structure becomes more complicated and the cost is higher than the conventionally used rolling rolls, and even if it is used, the setup such as changing the rolling rolls is complicated.

[0016]

Next, a description will be given of a case where an electric current is applied to a pair of rolling rolls in the powder rolling method to electrically heat the powder material in the roll bite. FIG. 9 shows a conceptual diagram of the powder rolling method. In the figure, the powder material 15 stored in the hopper 14 is a rolling roll 11A,
The powder material 15 is supplied to the powder reservoir 12 constituted by the roll barrel 11B, and the powder material 15 rotates.
Rolled material 16 rolled by A, 11B roll bite
Comes out from the roll bite of the rolling rolls 11A and 11B.

A current I is supplied from the power source 13 to the rolling rolls 11A and 11B to carry out rolling by the rolling rolls 11A and 11B, and at the same time, electric heating is carried out in the roll bite.
Although not specifically shown, the roll journal of the rolling roll, which protrudes outward from the roll chock, is energized via a slip ring.

Here, the roll barrel referred to in the present invention refers to the entire peripheral surface of the rolling part of the rolling roll, and the roll bite refers to the part where the material to be rolled is pressed and rolled.

In the powder rolling method, rolling rolls 11A, 1
As the powder material 15 supplied to 1B progresses from the roll bite inlet to the outlet, the relative density (in the present invention, the ratio to the true density) increases, and the conditions are determined so that a predetermined relative density is obtained at the outlet. .

However, since there are powder materials to rolled materials in the roll bite of the rolling roll, mechanical clarification including the contact length between the rolling roll and the powder is possible as compared with ordinary materials (not powder). This is unsolved, and there is an unknown part in the resistance distribution and the current density distribution inside the rolling rolls 11A and 11B even when the current is heated. Uniformity occurs.

Then, in the powder rolling in which the powder is rolled while the power is supplied to the powder through the rolling rolls, as shown in FIG.
The same kind of problem occurs in the method of rolling while energizing the material to be rolled of the plate material as described above. In other words, if the rolling roll is used as an electrode for electric heating, the efficiency is poor and a large-current and large-capacity power supply device is required, and the equipment cost is high because the rolling mill has an insulating structure.

The present invention has been made based on the above-mentioned circumstances, and at the time of powder rolling to directly obtain a rolled material from the powder material, the rolling and sintering of the powder material are simultaneously performed, and the width direction of the obtained rolled material is obtained. Another object of the present invention is to provide a powder rolling method and a powder rolling apparatus capable of obtaining a homogeneous rolled material.

Further, in addition to the above-mentioned object, the present invention makes it possible to reduce the energy cost by eliminating the need for a power supply device for supplying a large current, and the powder rolling apparatus has a simple insulating structure. It is an object to provide a method and a powder rolling apparatus.

Further, in addition to the objects of the above items, the present invention further provides a powder rolling method capable of more firmly preventing the powder material from flowing out from both ends of the powder reservoir between the roll barrels of the pair of rolling rolls. An object is to provide a powder rolling apparatus.

[0025]

In order to achieve the above object, in the powder rolling apparatus according to the invention of claim 1, a powder rolling apparatus for supplying a powder material between at least a pair of rolling rolls to obtain a rolled material, In order to form a powder reservoir together with the roll barrel surfaces of the pair of rolling rolls, side weirs capable of pressing and adjusting are provided on both end surfaces of the roll barrel.

Further, the powder rolling apparatus of the invention of claim 2 is
The side weir of claim 1 is an electrode and is characterized in that energization is performed by energizing the powder material between roll bites in the width direction and / or the roll barrel length direction.

Further, the powder rolling apparatus of the invention of claim 3 is
The side dam of claim 2 is made of a conductive material. Further, the powder rolling apparatus of the invention of claim 4 is characterized in that the side dam of claim 2 is a composite material having an insulating part and a conductive part.

Further, in the powder rolling method according to the invention of claim 5, in the powder method of supplying the powder material between at least a pair of rolling rolls to obtain a rolled material, the powder material between roll bites of the pair of rolling rolls. It is characterized in that energization is performed by energizing in the width direction and / or energizing in the roll barrel length direction.

The powder rolling method of the invention of claim 5 is
A means for energizing the powder material between the roll bites of the pair of rolling rolls according to claim 4 in the width direction and / or in the roll barrel length direction is provided on both end faces of the roll barrel, a side weir, a roll, a belt, and a roll. It is characterized in that it is one of the side weirs between the barrels.

[0030]

According to the powder rolling apparatus of the present invention, the powder material is supplied between at least a pair of rolling rolls to obtain a rolled material. By forming side weirs on both end faces of the roll barrel to adjust the pressure, the powder material peculiar to powder rolling flows in the length direction of the roll barrel, and further from the end of both ends of the powder reservoir to the outside. The leakage and disappearance of can be firmly prevented.

Further, in the powder rolling apparatus of the second aspect of the present invention, the side weirs of the first aspect are used as electrodes, and the powder material between the roll cutting tools is energized in the width direction and / or the roll barrel length direction. By performing electric heating, it is possible to perform electric heating more efficiently than when a rolling roll is used as an electrode, a power supply device for supplying a large current is unnecessary, and a rolling roll is not used as an electrode. Therefore, the structure is simple as compared with the case where the rolling roll is electrically insulated from the housing and the drive system.

Further, in the powder rolling apparatus of the third aspect of the invention, the side weir of the second aspect is energized in the width direction of the powder material between the roll cutting tools and / or in the length direction of the roll barrel satisfactorily by the electrically conductive material. can do.

Further, in the powder rolling apparatus of the invention of claim 4, the side weir of claim 2 is made of a composite material having an insulating part and a conductive part, whereby the kind of powder material to be rolled and the rolling roll. The energization mode can be variously changed according to various conditions such as the diameter, the rolling roll peripheral speed, the plate thickness or width of the rolled material on the roll bite exit side.

Further, in the powder rolling method of the invention of claim 5, in the powder rolling method of supplying a powder material between at least a pair of rolling rolls to obtain a rolled material, the powder between roll bites of the pair of rolling rolls is used. By performing energization heating by energizing in the width direction of the material and / or energizing in the length direction of the roll barrel, it becomes possible to perform energization heating more efficiently than in the case where the rolling roll is used as an electrode, and large current can be achieved. Since a power supply device for supply is not required and the rolling roll is not used as an electrode, it is simpler than the case where the rolling roll is electrically insulated from the housing and the drive system.

Further, in the powder rolling method of the invention of claim 6, means for energizing the powder material between the roll bites of the pair of rolling rolls of claim 4 in the width direction and / or in the roll barrel length direction, By using one of the side weirs provided at both ends of the roll barrel, the roll, the belt, and the side weir between the roll barrels, the flow of the powder material peculiar to powder rolling in the length direction of the roll barrel, and further the powder. It is possible to firmly prevent leakage and disappearance from the end surfaces of both ends of the pool portion to the outside.

Further, even when the powder material is a non-metal and not a conductor, the roll barrel itself of the rolling roll is locally and efficiently heated by electrically conducting from the lengthwise direction of the roll barrel of the pair of rolling rolls. By the heat conduction of the heated rolling roll barrel, rolling and heating of powder which is not a conductor can be realized at the same time.

Further, even when an insulating roll such as a ceramic roll is used as the rolling roll, only the powder material between the roll bites of the pair of rolling rolls can be efficiently electrically heated.

In the present invention, the powder material which is the material to be rolled means all materials which generate Joule heat when energized or all materials which can be sintered or molded by heating. That is, pure metal powder, alloy powder,
A powder material in which different metals are mixed, a composite powder of a metal and an inorganic material or an organic material, a powder of an organic material, etc. is a raw material, which is put into a rolling roll in a powder state and is roll-formed into a rolling roll. The rolled material has a shape with a predetermined relative density when it comes out.

By energizing the powder material between the roll bites of the rolling rolls in the width direction and / or the roll barrel length direction, the temperature for energizing and heating is hot rolling temperature, warm rolling temperature, necessary for sintering. The temperature is, for example, the temperature at which the rolled material is heated accurately according to the purpose based on the stress state in the roll bite of the rolling roll.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 to 3 show a schematic configuration of a rolling apparatus used in the powder rolling method of the present invention. Rolling roll 2
1A and 21B are arranged horizontally and parallel to each other, and are supported by housing posts 25A and 25B as shown in FIG. 3, and are rotated by a rotation drive device (not shown).

A space portion sandwiched between the upper half portions of the roll barrels of the pair of rolling rolls 21A and 21B, which face each other, is formed as the powder reservoir 22. A pair of side weirs 23A, 23B are arranged on both end surfaces of the roll barrels of the pair of rolling rolls 21A, 21B, respectively.
The pair of side weirs 23A, 23B closes both end faces in the roll barrel length direction of the powder reservoir 22 formed by being sandwiched between the roll barrels of the pair of rolling rolls 21A, 21B,
The pair of side dams 23A and 23B are pressed against and contact the end faces of both ends of the powder reservoir 22 so as not to leak the powder. The pair of side dams 23A and 23B are made of a conductive material for conducting electricity.

Further, as shown in FIG. 3, the pair of side dams 23A, 23B are attached to the housing posts 25A, 25B via an insulating member 26 in an insulated state. The upper ends of the pair of side dams 23A and 23B are horizontally bent and connected to the power supply device 24.

Next, a method of rolling will be described. The powder material 28 is supplied from the hopper 27 to the powder reservoir 22 formed along the length direction of the roll barrel by being sandwiched between the upper half portions of the roll barrels of the pair of rolling rolls 21A and 21B that face each other. . The pair of rolling rolls 21A and 21B are rotated in the direction of the arrow shown in the drawing by the rotation driving device, and the powder material 28 existing in the powder reservoir 22 is passed through a roll bite between the pair of rolling rolls 21A and 21B to perform pressure rolling. .

At the same time, the power supply device 24 energizes the pair of side dams 23A, 23B. In this case, if the rolling rolls 21A and 21B are made of an insulating material, the current flows only through the powder material 28 in the powder reservoir 22 and between the pair of side dams 23A and 23B. If the rolling rolls 21A and 21B are made of a conductive material, the current flows mainly between the powder material 28 in the powder reservoir 22 and the rolling roll 2
A pair of side weirs 2 through roll barrels 1A and 21B
It flows between 3A and 23B. Thereby, the rolling roll 21
The powder material to be pressure-molded in the roll bites A and 21B is electrically heated.

In this way, the powder material 28 has a continuous cross-sectional rectangle having a dense predetermined relative density as a result of the bonding between the powders being enhanced by the simultaneous generation of high pressure by rolling and simultaneous heating by energization and sintering. It becomes the strip-shaped rolled material 29.

Here, the pair of rolling rolls 21A, 21B
Side weirs 23A and 2A on both side surfaces of the roll barrel
3B are arranged, and the pair of side dams 23A and 23B are formed in contact with both end surfaces of the roll barrels of the rolling rolls 21A and 21B and sandwiched between the upper half portions of the pair of rolling rolls 21A and 21B. By closing both end faces of the powder reservoir 22, it is ensured that the powder material 28 flows out from the end faces of both ends of the powder reservoir 22 formed between the pair of rolling rolls 21A and 21B. Block.

Therefore, it is possible to prevent the supply amount of the powder material 28 from being insufficient at the end portion of the roll barrel 21A in the length direction between the rolling rolls 21A and 21B, and to prevent the density and the plate thickness from decreasing at the width direction end. A uniform rolled material 29 can be obtained.

Side dams 23A having conductivity on both end surfaces of the roll barrels of the pair of rolling rolls 21A, 21B, respectively.
23B is arranged and a pair of these side weirs 23A and 23B.
While closing both end surfaces in the roll barrel length direction of the powder reservoir 22 formed by being sandwiched between the upper half parts of the roll barrels of the pair of rolling rolls 21A and 21B, the pair of side dams 2
The powder material 28 is heated by passing an electric current between 3A and 23B to energize the powder material between the roll bits in the width direction and / or the pair of roll barrel length directions.

For this reason, the powder material 28 forms a pair of rolling rolls.
In addition to being able to reliably prevent the powder reservoir 22 formed between the roll barrels of the rolls 21A and 21B from flowing out from both ends, it is possible to heat the electricity more efficiently than when the rolling roll is used as the electrode. It does not require a power supply device for supplying a large current, and since the rolling roll is not used as an electrode, the rolling rolls 21A and 21B and the housing post 25A,
It is not necessary to electrically insulate 25B and the drive system, and the insulating structure is simpler and less expensive than when a rolling roll is used as an electrode.

Now, the powder rolling will be described.
In order to impart a predetermined density (including 100% relative density) to the rolled material 29, the diameter of the rolling rolls 21A and 21B, the set roll gap during rolling, the rolling speed, depending on the type of powder material, the grain size, etc. Parameters such as rolling temperature are used. The control of the rolling temperature is performed by controlling the current I supplied from the power supply device 24. When this current I is supplied from the width direction, if the effective contact length in the roll bite is Lp and the average thickness in this Lp is Hm, the side weir 2
The area Sp for energizing the pressurized powder material in the roll bite through 3A and 23B is as follows.

Sp = Lp · Hm (3) The electric resistance Rp of the powder material pressed at this time is expressed by the following equation. Rp = ρp · Wp / Sp = ρp · Wp / (Lp · Hm) (4) In the formula (4), ρp is the average resistivity of the powder material under pressure in the roll bite, and Wp is under pressure. This is the width of the powder material and corresponds to the roll barrel length direction of the rolling rolls 21A and 21B in FIG. On the other hand, when energizing through the rolling rolls 21A and 21B as shown in FIG. 9, the energized area Sp ′ and the resistance Rp ′ at this time are the same as those in the above-described formulas (1) and (2). It is the following formula.

Sp ′ = Lp · Wp (5) Rp ′ = ρp · Hm / Sp ′ = ρp · Hm / (Lp · Wp) (6) Then, equations (3) to (6) are changed to Combined, the following equation is obtained.

Sp / Sp '= Hm / Wp (7) Rp / Rp' = (Wp / Hm) ² (8) From formula (7), the method of energizing through the side weir and rolling roll Compared with the method of energizing through, when energizing through the side weir in order to obtain a predetermined current density, it is sufficient to supply Hm / Wp times the current when energizing through the rolling rolls. Become. Further, (8) than, in the case of energizing through the roll if energized via a side weir when supplying the same current to the powder material pressurized by the roll bite (Wp / Hm) ² times Will generate Joule heat.

In the rolling of the plate material, the ratio of the width (Wp) to the average thickness (Hm) in the roll bite shows a large value, for example, Hm / W when the thickness is 3 mm and the width is 600 mm.
p = 5 × 10 ⁻³ , (Wp / Hm) ² = 4 × 10 ⁴ .

That is, as shown in FIGS. 1 to 3, when the powder material 28 is energized through the side weirs 23A and 23B, the current I supplied from the power supply device 24 is the rolling roll 2
When 1A and 21B are conductive materials, part of them is a rolling roll 2
Although the flow is divided via 1A and 21B, the predetermined rolling temperature can be secured at a value much smaller than that of the case where electricity is supplied through the rolling rolls 21A and 21B as shown in FIG.
That is, the power supply device 2 that energizes to generate Joule heat
The capacity of 4 can be much smaller. Further, when the energizing circuit is configured as shown in FIGS. 1 to 3, it is not necessary to provide the rolling mill with a complicated insulating structure.

Here, the side weirs 23A and 23B shown in FIGS. 1 to 3 are not limited to the shapes shown in the drawings, but may be formed along the roll barrel surface of the rolling rolls 21A and 21B, for example. 21A, 21
By increasing the contact area of B with the end surface of the roll barrel, the volume of the powder reservoir 22 can be increased as necessary, or the rolling rolls 21A and 21B can be preheated.

Further, in the present invention, a pair of side dams are provided on both end faces of the roll barrel of the rolling roll so as to be adjustable in pressure, and pressure is applied toward both end faces of the roll barrel, whereby the end faces of both end portions of the powder collecting part are It is possible to more strongly prevent the outflow of powder from the.

FIG. 4 shows an example of this method. The side dam base 31 is attached to the housing post 25 via an insulating member 26. The side dam base 31 has a side dam support portion 34, an inclined surface portion 35, and a shaft hole 39. The side weir 32 is provided on the side weir support portion 34 of the side weir base 31 so as to be displaceable along the axial direction (the direction of the arrow in the drawing) of the rolling roll. The pressing member 36 has a shaft portion 37 and a wedge-shaped portion 38, and is provided on the side dam base 31 by inserting the shaft portion 37 into the shaft hole 39 and bringing the wedge-shaped portion 38 into contact with the inclined surface portion 35. Then, when the shaft portion 37 of the pressing member 36 is pushed downward by an appropriate means, the wedge-shaped portion 38 moves along the inclined surface portion 35 of the side dam base 31, and the side dam 32 is brought to the roll barrel end surface of the rolling roll. Move it toward you. As a result, the side dam 32 is displaced along the side dam support portion 34 and comes into contact with the roll barrel end surface of the rolling roll (not shown). As a result, a pair of rolling rolls
It more firmly blocks outflow of powder from both ends of the powder reservoir between the roll barrels of the roll.

In FIG. 4, the current I shown in FIGS. 1 to 3 is concretely supplied by connecting a conductor to the side dam 32. A specific example using this method will be described.

The molybdenum powder was rolled in the powder rolling apparatus shown in FIGS. 1 to 4. The main specifications and rolling conditions of the equipment are as follows. Rolling roll diameter: 300 mm Rolling roll length (roll barrel length): ~ 100 mm Rolling roll rotation speed: ~ 1 rpm Power supply: DC 10 V, 20,000 A Rolling atmosphere: Vacuum or inert gas Powder material: Molybdenum powder Outlet thickness: 0 .6 to 1/5 mm Powder temperature before heating: As a result of rolling under the condition of 20 ° C. or more, current is applied from the rolling roll shown in FIG. 9 (specifically, although not shown in the figure, the roll chock of the rolling roll is outside. It was confirmed that it is possible to make the rolled material on the roll bite exit side have a prescribed plate thickness and density with a much smaller current compared to the case of energizing the roll journal part protruding to the side through the slip ring). . This becomes more remarkable as the width of the rolled material increases. That is, the method of the present invention as an energization method can increase the effective resistance required for Joule heat generation as compared with the method of FIG.

Further, the density distribution and hardness distribution in the width direction of the rolled material including the width end portion of the rolled material are much more uniform in the method of the present invention than in the method of FIG. Even if it is a workable material, micro edge cracks do not occur at the width end of the rolled material when it is carried out by the method of the present invention. It was also confirmed that excellent results were obtained. That is, the side dam and the roll barrel of the rolling roll are completely closed to form a powder reservoir, and the effect of restraining the widthwise flow of the powder compact and the effect of the heating temperature due to the contact resistance at the time of energization are simultaneously exhibited. Is.

FIG. 5 shows another example of the method for applying a pressing force to the side dam. 5, the same parts as those in FIG. 2 are designated by the same reference numerals. A pair of pressing devices 41A and 41B, which are hydraulic cylinders and the like, connect the pair of side dams 23A and 23B through the insulating member 42 to the pair of rolling rolls 21.
It is displaced toward the end faces of the roll barrels of A and 21B and brought into contact with the end faces of the roll barrels of the pair of rolling rolls 21A and 21B. A pressure generator 43 such as a hydraulic pump applies pressure to the pair of pressing devices 41A and 41B. The pair of side dams 23A and 23B are connected to the power supply device 24.

Here, the load for the pressing devices 41A and 41B to press the pair of side dams 23A and 23B through the insulating member 42 will be examined. The rolling of the plate material is substantially plane strain, and an intermediate principal stress acts in the width direction. Moreover, the stress in the rolling direction is very small. When the rolling load is P, the widthwise load Ps acting on the side dam is expressed by the following formula: Ps = (P / 2) × (Hm / Wp) + α (9) In this formula, α is the rolling roll It is a contact load with the side surface of the roll barrel, and Hm / Wp is extremely small as described above. That is, the load capacity of the pressing devices 41A and 41B may be small, and therefore can be easily inserted and installed in the rolling mill. The side dams 23A and 23B can be made of a conductive material alone, but various other forms can be adopted.

FIG. 6 shows an example of the form of the side weirs 23A and 23B. FIG. 6A is an example in which all of the surfaces forming the powder reservoirs of the side dams 23A and 23B and the surfaces contacting the roll barrel end surface of the rolling roll are current-carrying surfaces. FIG. 6B shows that the side dams 23A and 23B are coated with an insulating material by thermal spraying or the like on the surface of the side dams 23A and 23B that is in contact with the roll barrel end surface (hatching portion).
This is an example in which electricity is not directly applied to the roll barrel end surface of the rolling roll from 3A and 23B, and electricity is uniquely applied only from the width direction of the powder material between the roll barrels. FIG. 6C is an example in which the energization contact area of the side dams 23A and 23B is limited to a narrow range to enhance the efficiency of energization heating. 6 (d) is the reverse of FIG. 6 (b) and is a side weir 23.
This is an example in which at least the portions of A and 23B that come into contact with the powder material between the roll barrels are coated with an insulating material by thermal spraying or the like, and electricity is supplied only from the end face of the roll barrel of the rolling roll.

The side weirs 23A and 23B exemplified above
Is the type of powder to be rolled, roll diameter, roll peripheral speed,
It is properly used depending on the rolling conditions such as the strip thickness and width of the rolled material.

The sectional shape of the rolled material 29 is not limited to the one having the simple rectangular section of each of the above-mentioned embodiments, and for example, as shown in FIG.
As shown in (a), (b), (c), and (d), a plate material having a cross-sectional shape with a different plate thickness in the width direction, that is, a so-called irregular-shaped rolled material is powdered by changing the shape of a rolling roll. Can be obtained by rolling. When roll-forming a rolled material having a complicated cross-sectional shape in this way, it is also possible to produce a good-quality long-shaped strip material having a predetermined straightness by combining different peripheral speed rolling and the energization method according to the present invention. You can

The present invention is not limited to the above-described embodiments, but can be implemented with various modifications. For example, the energization method in the powder rolling method of the present invention is not limited to the side weirs shown in the above-described embodiments, and energization in the width direction of the powder material between roll barrels and / or energization in the roll barrel length direction may be performed. If possible, various modifications are implemented.

Specifically, a pair of rolls is provided at both ends of the roll barrel of the rolling roll, and a means for energizing through the rolls is provided, and endless belts are provided at both ends of the roll barrel of the rolling roll. Various means such as a means for energizing, a side weir provided between the roll barrels of the pair of rolling rolls, and a means for energizing via the side weir can be implemented. Further, a means for winding a belt-shaped belt around a rolling roll and energizing it through this belt, a means for energizing through a flange when a rolled material is manufactured with a flanged roll, and the like can be implemented.

[0069]

According to the powder rolling method and the powder rolling apparatus of the present invention, at the time of powder rolling to obtain a rolled material directly from the powder material, the rolling and sintering of the powder material are carried out at the same time, and the obtained rolled material is It is possible to obtain a rolled material that is uniform in the width direction.

Further, the present invention does not require a power source for supplying a large current as compared with the conventional powder rolling method and powder rolling apparatus,
The energy cost can be reduced, and the insulating structure in the powder rolling apparatus can be simplified.

Further, in addition to the above effects, the present invention can restrain the flow of the powder material in the width direction between the roll barrels of the pair of rolling rolls, and can firmly prevent the powder material from flowing out. Becomes

[Brief description of drawings]

FIG. 1 is a front view showing a powder rolling apparatus used in an embodiment of the present invention.

FIG. 2 is a plan view showing a powder rolling apparatus of the same example.

FIG. 3 is a diagram showing a configuration in which a side weir used in the powder rolling apparatus of the embodiment is provided.

FIG. 4 is a diagram showing another example of a configuration in which a side weir is provided.

FIG. 5 is a diagram showing another example in which a side weir is provided in a different configuration.

FIG. 6 is a view showing an example of the form of a side weir.

FIG. 7 is a diagram showing an example of the form of a rolled material.

FIG. 8 is a diagram showing a method of rolling a plate material.

FIG. 9 is a diagram showing an example of a conventional powder rolling method.

[Explanation of symbols]

1A, 1B ... Rolling roll, 2 ... Power source, 3 ... Rolled material, 11A, 11B ... Rolling roll, 12 ... Powder collecting section, 13 ... Power source, 14 ... Hopper, 15 ... Powder material, 16 ... Rolled material, 21A, 21
B ... rolling roll, 22 ... powder collecting section,
23A, 23B ... Side weir, 24 ... Power supply device,
25A, 25B ... Housing post, 26 ...
Insulating member, 27 ... Hopper, 28 ...
Powder material, 29 ... Rolled material, 31 ... Side weir base, 32 ... Side weir, 34 ... Side weir support portion, 36 ... Pressing member, 41A,
41B ... Pressing device, 42 ... Insulating member, 43 ... Pressure generating device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Day Kunio Toshiba Engineering Co., Ltd. 66-2 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa

Claims (6)

[Claims] 1. A powder rolling apparatus for supplying a powder material between at least a pair of rolling rolls to obtain a rolled material, wherein both end faces of a roll barrel are formed so as to form a powder reservoir with the roll barrel faces of the pair of rolling rolls. A powder rolling apparatus characterized in that a side weir whose pressure can be adjusted is provided on the side. 2. The side weir is an electrode, and is energized and heated by energizing the powder material between roll bites in the width direction and / or the roll barrel length direction. Powder rolling equipment. 3. The powder rolling apparatus according to claim 2, wherein the side dam is made of a conductive material. 4. The powder rolling apparatus according to claim 2, wherein the side dam is a composite material having an insulating portion and a conductive portion. 5. A powder rolling method for supplying a powder material between at least a pair of rolling rolls to obtain a rolled material, comprising energizing and / or roll barrel length in a width direction of the powder material between roll bites of the pair of rolling rolls. A powder rolling method, characterized in that energization heating is performed by energizing in a direction. 6. A means for energizing the powder material between roll bites of a pair of rolling rolls in the width direction and / or in the roll barrel length direction is a side weir provided on both end faces of the roll barrel, a roll, a belt, The powder rolling method according to claim 5, wherein any one of the side weirs between the roll barrels is used.