JP2635590B2 - Method of molding powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to agglomeration of powder or granules, or bonding of powder or granules to a surface of a certain base material or the inner surface of a base material hollow as a block, The present invention relates to a method for molding these powders into a shape after agglomeration.

<Conventional technology> Various metal and ceramic powders are molded into desired shapes,
Thereafter, the method of agglomerating by sintering or powder forging is widely known as powder metallurgy. This powder metallurgy method not only agglomerates the granular material itself, but also covers the outer periphery of a roll or the like with a heat-resistant case, fills the granular material between the roll and the case, and then heats the material. Utilizing a diffusion bonding method typified by a normal pressure pressing method, the method is also applied to a method of sintering the granular material and mounting it as a strong bonding layer around the roll.

However, when filling the granules into a certain space and pressing it under pressure, the weight of the granules acts or the pressing force varies depending on the direction, so uniform molding over the whole In the case where the body is difficult to obtain, especially when the roll core material is inserted into the above-mentioned case and the gap between the two is filled with the granular material, it is generally difficult to fill the gap because the gap is elongated. In addition, the unevenness of the packing density and the packing thickness of the obtained molded body must be remarkable. For this reason, although the surface layer that should be attached to the outer peripheral surface of the roll etc. may be thin, the gap between the case and the roll core material must be made larger and sintering in that state Although it is adopted, the material used as the surface layer of the roll or the like is originally a material having characteristics such as abrasion resistance and heat resistance that the roll base material itself does not have, and this material is difficult to cut into an expensive form. Since it is often a material, it is difficult to cut and remove an unnecessary portion thereafter, resulting in a large waste of both material cost and operation cost.

Further, for example, in the case of a roll, it may be advantageous if the material to be mounted as the surface layer has a directionality of strength. That is, a fibrous structure running in the roll axis direction is formed on the surface layer, and the strength in a direction perpendicular to the direction is improved. However, in the current method of covering the outer circumference of the roll with a case, and filling the gap between the case and the roll with the surface layer raw material, even if a fibrous material is used as the raw material, the case is not filled. The fibrous body can only be random at best,
Generally, in such a case, the raw material is filled in such a way that the raw material falls downward from the upper opening in a state where the case is set up. It is impossible to achieve the above objectives.

Therefore, the present inventor, when molding the granular material, put it into a plastically deformable case, or put the granular material between the case and the base material, and then apply local pressure deformation such as rolling Then, we developed a method of deforming and molding the case together,
Filed earlier. However, although this method is suitable for manufacturing solid or thick hollow bodies, thin hollow bodies cannot be manufactured, or the target base material and the granular material are bonded to each other during subsequent joining such as sintering. It has been found that there are some problems such as incompatibility when the material is made of difficult materials.

<Problems to be Solved by the Invention> The present invention relates to the agglomeration of the granular material itself, or the bonding of the granular material as a lump to the surface of another base material or to the inner surface of the base material hollow portion. In order to solve the above problems, to make the packing density of the granular material not unevenly distributed in each part, and to make the granular material exist only in the area where the granular material is required, a hollow mass can be obtained. It is an object of the present invention to provide a method capable of greatly reducing the restrictions on the components of the granules and the base material.

<Means for Solving the Problems> A space between the inner and outer walls of a double-walled metal cylindrical case having a space between the inner and outer walls is filled with a sinterable powder material, After sealing the opening, at least one of the inner and outer walls is locally pressurized from the outer surface side while rotating the cylindrical case about its longitudinal axis, and the entire case is deformed while moving the local pressurized portion It is characterized by being molded.

The sinterable powder applicable to the present invention is metal, ceramic, or a mixture thereof.

The "metal" in the metal powder or the metal case includes not only a pure metal but also an alloy, and the "ceramic" also includes so-called glass. Also includes any case where two or more types of ceramics are mixed.
Further, the metal, ceramic or carbon may be used as a composite in advance, or may be used in a form in which one is coated on the other.

In addition, the powdery or granular material includes a fibrous material, a small piece, or a short rod-like material such as a cut wire in addition to the powder and the granular material.

The local pressurization can employ various means such as pressing a small roller, pressing a spatula, or locally pressing with a hammer or the like, and the local pressurization may take a cold state. However, if necessary, a hot method by local or total heating may be employed.

Also, after the powder is filled between the double walls of the case and the opening is sealed, the inside of the case is evacuated so that the powder inside is kept during the subsequent operation or during the standing for a waiting period. This is preferable because the granules do not receive contamination such as oxidation.

As will be described in detail later, if the amount of the granular material to be filled is set to an amount occupying a smaller volume than the space in which the granular material is to be stored, the filling of the granular material is easy, and This is more effective because the powder and granules formed by the above method are more homogeneous in terms of their density and thickness. However, when filling the granular material into a certain space, particularly a narrow space, even if a special method such as pushing in a small amount or applying a small amount while applying impact vibration is adopted, Depending on the shape of the granules, the volume occupied by the granules is inevitably larger than that of the above space due to the voids generated between the granules or “shelf hanging parts” and the unavoidable voids generated at the upper end at the time of filling. Considering these facts, there is a difference in the degree in any of the above cases. ゝ The amount of powder and granules has a smaller occupied volume than the space in which it is stored. Become.

In the present invention, when the powder is to be rotated after the case is filled with the granular material, the case is placed in a horizontal, vertical or oblique shape in consideration of the shape of the case. In other words, from the viewpoint of equal distribution of powder and granules, in general, when the case is a long object in the vertical direction, the case is preferably in a horizontal shape from the viewpoint of reducing the effect of gravity, and the case is in a short flat shape. In the case of, even if it is placed vertically, it is not so much affected by gravity and considering the ease of rotation, it is preferable to place it vertically, but pack the powder sufficiently into every corner of the case, especially if there is a branch pipe in the case. In the case where the granular material is sufficiently packed in the branch pipe, it may be desirable to rotate the case vertically and utilize gravity in addition to centrifugal force. In addition, by rotating the case vertically and adjusting the centrifugal force and gravity at that time,
It is also possible to increase the amount (thickness) of the granular material sequentially from the upper part to the lower part of the case.

Therefore, whether the rotation is in the horizontal direction or in the vertical direction is appropriately selected in consideration of the above-described matters, and in some cases, there may be a diagonal direction intermediate between the two.

<Operation> The method of the present invention will be described in detail below.

First, a method of plastically deforming only the case in which the granular material is filled between the inner and outer walls by local pressing will be described.

That is, as shown in FIG. 1, the bottomed side wall is the inner wall (1a),
The granular material (2) is filled between the double walls of the cylindrical case (1) having the double wall structure of the outer wall (1b), and the tubular end plate (3) is applied to the upper opening and between the outer walls. Seal tightly. Then, as shown in FIG. 2, for example, the pressing jig (4) such as a roller is locally rotated while rotating around the longitudinal axis of the case using an appropriate rotating device (not shown), for example, in a horizontal position. , And a predetermined plastic deformation is applied to the case (1) while moving the pressing portion. In this operation, the side to which the pressing jig (4) is applied
Either from the outer wall (1b) side, from the inner wall (1a) side, or from both sides, it is naturally the opposite side to the inner surface of the double wall where the granular material (2) is in contact. Is called the outer surface side. In this case, when the amount of the granular material (2) in the case (1) is small compared to the space between the double walls of the case (1), the granular material (2) is merely clogged by a normal method. Even if it is packed, as a result of the rotation of the case (1), the "shelf hanging portion" existing in the above-mentioned granules is eliminated, or the voids are packed, so that any The body (2) is suspended in the space, and keeps a substantially uniform amount in any part, and gives plastic deformation by local pressing in that state, so that the molding density of the obtained molded body is Can be substantially constant regardless of its local area. In the case of plastic deformation due to the local pressurization, if the amount of deformation varies depending on the location, the hollow drum-shaped body shown in FIG. 3 and the large-diameter portion and the small-diameter portion are alternately repeated as shown in FIG. It is possible to obtain molded articles of various shapes such as hollow bodies as described above.

In the method of the present invention, part or all of
When the local pressurization is repeated while rotating the case (1) in the same manner as described above using a granular material (2) having a long shape in one direction such as a fibrous shape or a cut wire shape, the gap gradually narrows. The particles (2), which are long in one direction, are aligned with the direction parallel to the longitudinal direction of the case (1) with the rotation of the case (1). The powder (2) thus obtained can be formed into a green compact having directionality in its direction.

After the powder (2) is molded into the space in the case with a substantially uniform filling degree in this manner, it is sintered by hot isostatic pressing and other sintering methods for each case. Then, the case or the core material is left as it is or cut and removed to obtain a sintered body of the granular material, or a material in which such a granular material is bonded and attached to the case.

Next, the above-mentioned case (1) filled with the granular material (2) and the inside and the outer wall openings thereof are sealed is externally fitted to another base material or internally fitted into the hollow portion of the base material to form a local part. The method of pressure deformation will be described.

This method is also essentially the same as the method using only the case described above, except that the case is plastically deformed in a state where the case is fitted with another base material. That is, a case (1) filled with the granular material (2) as shown in FIG. 1 is used, and this is fitted on the outer periphery of another base material (5) as shown in FIG. As shown in FIG. 6, it is fitted into the hollow portion of another base material (5), and under this condition, a pressing jig is applied to plastically deform the case (1) to consolidate the granular material (2) under uniform density. And molding into a desired shape. In this case, the outer diameter of the substrate (5) or the inner diameter of the hollow portion of the substrate,
When the combination of the case (1) with the inner diameter or the outer diameter is such that the case (1) is loosely fitted, the case (1) can be easily fitted and the subsequent plastic deformation allowance is secured. Made and preferred. FIG. 6 shows a case where the hollow portion stays in the middle of the base material (5). However, both of the hollow portions may be open. There may be a part. Further, a substrate (5) to be used is provided with a concave portion or a groove on a surface side of the substrate (5) in contact with the case (1).
The case (1) after plastic deformation may be made to bite into these concave portions and grooves. The method using the base material (5) is different from the method using no base material (5) in that local pressurization is applied to only one of the inner wall (1a) and the outer wall (1b) of the case (1). There is no difference in that the amount of local press deformation is varied depending on the location and various shapes are obtained, or that the fibrous material is used in at least a part of the granular material to provide strength anisotropy. It is effective to use the case of the double wall structure when molding the granular material on the required surface of the other base material as follows. That is, it is preferable that the base material (5) and the granular material (2) to be used do not directly contact each other, or that the base material (5) and the granular material (2) are hardly bonded by the subsequent sintering. Considering the case, first, as shown in FIG. 7 (a), an intermediate material (6) made of a material that can be touched or easily bonded to the base material is fitted on the outer periphery of the base material (5), Plastic deformation is performed by repeating local pressurization similar to that used in the method of the present invention to obtain a product having a form as shown in FIG. 7 (b), and thereafter, as shown in FIG. If the method of fitting 7), filling the granular material (2), applying local pressure again, and plastically deforming the outer case (7) is adopted, the object can be achieved for the time being. If it is adopted, the number of steps increases accordingly. In the state of FIG. 7 (c), the outer case (7)
When the base material (5) is locally deformed, the fixing of the base material (5) and the intermediate material (6) and the outer case (7) is complicated, and the powder (2) may be contaminated by oxidation or the like. In the method of the present invention, since the case (1) having a double wall structure in which the intermediate member (6) and the outer case (7) are combined is used from the beginning, all of the above disadvantages are eliminated.

In this way, after the granular material is formed on the outer peripheral surface of the base material (5) or the inner peripheral surface of the hollow portion at a substantially uniform density and in a desired shape, each case is also sintered by various methods. And sintering the powder and granules, and joining the powder and granules integrally with the substrate via the inner or outer wall of the case, and leaving the case exposed on the outer surface as it is or removing it as necessary You do it.

<Examples> Hereinafter, examples of the present invention will be described in detail.

Example 1 In this example, a 2 mm thick outer diameter of 150 mmφ, and a 250 mm height open outer end of a mild steel inner cylinder body having the same thickness of 2 mm and an inner diameter of 16 mm.
A 0mmφ, 250mm-height open-ended mild steel outer cylinder is fitted, and the lower ends of the inner and outer cylinders are welded by applying a ring-shaped lower end plate to the lower ends of the inner and outer cylinders. About 80% of parts
Volume of austenitic stainless steel (SU
The powdery and granular material of S316) was put in, and a ring-shaped upper end plate was applied to the upper ends of both cylinders to perform welding, and the space between the cylinders was evacuated and sealed. This is placed horizontally on a rotating device, and while rotating, presses a small roller from both the inner cylinder and the outer cylinder side, performs local pressurization over the entire area, and then enters the hot isostatic pressurizer. After being charged and kept at 1150 ° C. and 1000 kg / cm ² for 2 hours, it was taken out, and both cylinders were cut off to obtain a sintered agglomerated stainless steel hollow body.

Embodiment 2 In this embodiment, an inner and outer cylinder made of nickel and having the same dimensions and shape as those used in the first embodiment is used, and a copper alloy-based corrosion-resistant alloy powder is interposed between the two cylinders. About 90% of the volume, and the upper end is also sealed with a nickel upper plate (also evacuated).
0mmφ, 250mm in length, fitted on the outer circumference of a rod-shaped base material, and at both ends, a nickel-made annular end plate is also welded between the outer circumference of the base material and the inner cylindrical body, and further welded. The inner cylinder was evacuated and then sealed. Next, this was locally rotated while being rotated horizontally in the same manner as in Example 1, and thereafter at 850 ° C.
After holding for 1 hour under the condition of 900 kg / cm ² , taking out and cutting and removing only the outer cylinder, a copper alloy sintered layer was firmly attached to the outer periphery of the S45C substrate via a nickel inner cylinder. Got the product.

<Effects of the Invention> As described above, according to the method of the present invention, the agglomeration of the granular material itself, or the agglomerate of the granular material, when the other member is attached to a required part, the raw material is used. It is easy to load a certain granular material, and even if the space to be filled with the granular material is narrow, the case has not yet been deformed at the time of the granular material loading, so it can be widened accordingly. As a result of the rotation (rotation) and local deformation, the powder and granular material are filled at a uniform density in each part, so that there is no unevenness in the density and dimensions of the product due to agglomeration by sintering or powder forging, A homogeneous and accurate product can be made.

Further, in the method of the present invention, since the local pressure deformation is performed after the granular material is put in the case, the size and shape of the case to be used do not need to be so strict, and an inexpensive welded pipe is sufficient. Powders generally have different apparent densities depending on their shape,
Although it is difficult to manufacture it by controlling it to be as constant as possible, in the present invention, it is necessary to determine the amount by weight as the exact amount since it is pressurized from the outside after filling and it is compacted. It is easy to find the exact amount regardless of the amount.

Further, in the method of the present invention, since the compaction of the granular material is performed in a dry manner, even if a part of the case is broken, it can be easily repaired or replaced. When using a high-pressure liquid, if a part of the case breaks, there is a problem in that the liquid is pressed into the inside and becomes totally unusable. On the other hand, the method of the present invention can easily cope with such an accident.

Furthermore, a flange-shaped body is formed on the outer periphery as a product obtained by changing the amount of local pressure deformation from the outside depending on the location, or by using a difference in that a concave portion or a groove is formed in advance on the base material surface. It is also possible to produce a product having a form having a wear-resistant material or the like in a desired shape such as a spiral shape, and it is also possible to form a reinforcing rib of a case.

Also, in the present invention, since the double-walled structure is employed as the case, there is no fear that the powder and the granular material to be filled therein will be contaminated during work or storage, and that there is a certain base material. Even if it is better not to allow the powder to be used directly, or if it is difficult for the powder to be directly bonded to the base material, isolation by the case or selection of the material of the case can be integrated. It can also be joined.

[Brief description of the drawings]

FIGS. 1 and 2 are process diagrams of the method of the present invention, respectively. FIGS. 3 and 4 are explanatory diagrams showing examples of molded products obtained by the method of the present invention. FIGS. Explanatory drawing showing another example of the method of the present invention, FIGS. 7 (a), (b),
(C) is each process drawing of the comparative example for showing the characteristic of this invention, respectively. In the figure, (1): case (2): granular material (3): annular end plate (4): pressing jig (5): base material

Claims (4)

(57) [Claims] 1. A space between inner and outer walls of a metal cylindrical case having a double wall structure having a space between inner and outer walls is filled with a sinterable powdery material, and an opening of the case is sealed. Then, while rotating the cylindrical case around its longitudinal axis, at least one of the inner and outer walls is locally pressurized from the outer surface side, and the entire case is deformed and molded while moving the local pressurized portion. A method for molding a granular material characterized by the following. 2. The method according to claim 1, wherein the amount of the granular material is an amount having an occupied volume smaller than the volume of the space filled with the granular material. . 3. The method according to claim 1, wherein the amount of deformation of the local pressurization of the case is varied depending on the location. 4. The powder according to any one of claims 1 to 3, wherein at least a part of the powder has a shape elongated in one direction such as a fiber or a rod. Granulation method.