JP2022042111A - Molybdenum mesh - Google Patents

Abstract

To provide a molybdenum mesh of a long life.SOLUTION: A molybdenum mesh 1 has a mesh structure 10 containing molybdenum. The mesh structure 10 has edges 13, 14, 15, 16. The edges 13, 14, 15, 16 have folded-back parts 21, 22.SELECTED DRAWING: Figure 1

Description

The present invention relates to a molybdenum mesh.

Conventionally, a method of sintering a rare earth magnet using a molybdenum mesh is described in, for example, Japanese Patent Application Laid-Open No. 2005-183810 (Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-183810

The conventional molybdenum mesh has a problem of short life.

The molybdenum mesh of the present disclosure comprises a mesh structure containing molybdenum. The mesh structure has an end and has a folded portion at the end.

FIG. 1 is a plan view of the mesh structure 10 constituting the molybdenum mesh 1 according to the embodiment. FIG. 2 is an enlarged plan view showing a portion surrounded by II in FIG. 1. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 is a photograph of the mesh structure 10 constituting the molybdenum mesh 1. FIG. 5 is an enlarged plan view showing a portion surrounded by V in FIG. 4. FIG. 6 is a diagram for explaining a method for manufacturing the molybdenum mesh 1. FIG. 7 is a diagram for explaining a method for manufacturing the molybdenum mesh 1. FIG. 8 is a diagram showing a molybdenum mesh 1 having an end portion 13 having no cut surface. FIG. 9 is a diagram showing a method for measuring the bending force of the molybdenum mesh 1.

[Explanation of Embodiments of the present disclosure]
First, embodiments of the present disclosure will be listed and described.

Conventionally, when firing using a molybdenum mesh-like molybdenum mesh, the life of the mesh is short and the production efficiency is poor, which is a technical problem.

Currently, there are members manufactured by firing or heat treatment in a reducing or inert gas atmosphere in the production process of ceramics or magnetic materials. In the process of firing or heat treatment, the object to be fired is often placed on a molybdenum mesh for the purpose of venting gas and used for manufacturing. At this time, it is known that the molybdenum mesh is exposed to the recrystallization of molybdenum or the embrittlement temperature during firing or heat treatment to cause an embrittlement phenomenon.

When a molybdenum mesh is used in this state, bending at the time of handling or impact generated by vibration in the process causes breakage of the end portion and fraying of the mesh. As a result, the number of times (life) that can be used repeatedly is shortened. In addition, if only the net is used, the strength is insufficient and deformation is likely to occur.

The molybdenum mesh according to the present disclosure comprises a mesh structure containing molybdenum. The mesh structure has an end and has a folded portion at the end.

Since the molybdenum mesh configured in this way has a folded structure at the end portion, it is possible to prevent the end portion from being unraveled as compared with the molybdenum mesh having no folded structure. As a result, the life of the molybdenum mesh is extended. Further, the strength of the end portion can be increased as compared with the molybdenum mesh having no folded structure. As a result, deformation of the molybdenum mesh can be suppressed.

Preferably, the end having the cut surface has the folded portion. The end having a cut surface is liable to be damaged when the sharp cut surface is easily caught during work and embrittled. Since only the end portion having the cut surface has the folded portion, the number of the folded portions can be reduced, and the manufacturing cost of the molybdenum mesh can be reduced.

Preferably, the thickness of the folded portion is 200% or less of the thickness of the mesh structure other than the folded portion. With this thickness, the step between the folded-back portion and the other portion becomes small, and the object to be fired can be placed on the folded-back portion.

The mesh structure is constructed by weaving or knitting molybdenum wire. The wire diameter of the molybdenum wire is preferably 0.1 mm or more and 0.5 mm or less. Within this range, workability in the press process can be ensured from the weaving and folding of the Mo wire. However, this range may be exceeded depending on the required size of the member and the like.

The width (folding allowance) of the folded portion is preferably 3 mm or more and 10 mm or less. However, in order to load the material to be loaded so that it does not come into contact with the material to be loaded, it is more preferably 3 mm or more and 5 mm or less. As the folding width increases, the load capacity decreases. The folded shape is U-shaped.

The number of folds at the end of the mesh structure is preferably one. However, if strength is required at the end, the effect of imparting strength can be improved by repeating it twice or three times.

The number of folded sides of the mesh structure needs to be at least two in the case of a rectangular net (square mesh structure), but it is more preferable that four sides are folded. However, the side where the cut surface does not exist may not be folded back.

The material of the mesh structure is pure molybdenum or molybdenum alloy. The pure molybdenum material used for the mesh structure is preferably a molybdenum material having a general purity of 98.5% or more. The molybdenum alloy may contain a metal additive in an amount of more than 0 and 1.0% by mass or less. As the metal additive, one or more of La and Si are preferable. La and Si are measured by inductively coupled plasma (ICP) emission spectroscopy. In the ICP emission analysis method, ICPS-8100 type (Shimadzu Corporation) is used.

The mesh structure contains unavoidable impurities (eg, at least one of Al, Ca, Fe and Mg). Inevitable impurities are (JIS H 1404 2001) Section 7.4 (Inductively coupled plasma (ICP) emission spectroscopy: Measurement of Fe), Section 8.3 (Inductively coupled plasma (ICP) emission spectroscopy: Measurement of Ca). According to Section 10.4 (Mixed Acid Decomposition Inductively Coupled Plasma (ICP) Emission Spectroscopy: Measurement of Al) and Section 11.3 (Inductively Coupled Plasma (ICP) Emission Spectroscopy: Measurement of Mg). In the ICP method, ICPS-8100 type (Shimadzu Corporation) is used.

The shape of the mesh structure may be other than a quadrangle. The weaving method of Mo mesh may be any weaving method.

The thickness of the mesh structure is measured with an anvil of the measuring unit and a digital micrometer of D6 mm having a flat measuring surface of the spindle. When the mesh structure is a quadrangle, measure 4 points in the center of each side.

Specifically, the thickness is measured at the center of the four sides. When the number of sides with folded portions is 0, the average value of the thicknesses of the four sides is taken as the thickness of the sides without folded portions.

When the number of sides with folded portions is 1, the thickness of one side with folded portions is defined as the thickness of the sides with folded portions. The average value of the thicknesses of the three sides without folded portions is defined as the thickness of the sides without folded portions.

When the number of sides with folded portions is 2, the average value of the thicknesses of the two sides with folded portions is taken as the thickness of the sides with folded portions. The average value of the thicknesses of the two sides without folded portions is defined as the thickness of the sides without folded portions.

When the number of sides with folded portions is 3, the average value of the thicknesses of the three sides with folded portions is taken as the thickness of the sides with folded portions. The thickness of one side without a folded portion is defined as the thickness of the side without a folded portion.

When the number of sides with folded portions is 4, the average value of the thicknesses of the four sides with folded portions is taken as the thickness of the sides with folded portions. The thickness is measured at the center of the mesh structure, and the average value of the thicknesses of the two sides without folds is taken as the thickness of the sides without folds.

The thickness of the folded portion of the mesh structure is 100% to 200%, more preferably 100 to 120% of the thickness of the portion where the folded portion does not exist.

FIG. 1 is a plan view of the mesh structure 10 constituting the molybdenum mesh 1 according to the embodiment. As shown in FIG. 1, the molybdenum mesh 1 as a floor plate includes a mesh structure 10 containing molybdenum.

The mesh structure 10 is made of molybdenum or a wire rod made of molybdenum alloy. Folded portions 21 and 22 are provided at the ends 13, 14, 15, and 16 of the mesh structure 10.

The mesh structure 10 is formed by weaving or knitting the wire rods 11 and 12. The end faces of the wire rods 11 and 12 are the cut surfaces 11e and 12e. The cut surfaces 11e and 12e are formed by cutting the wire rods 11 and 12. The mesh structure 10 shown in FIG. 1 is formed by bending each side of a mesh of an octagonal molybdenum alloy wire having square corners removed. Therefore, the bent portions at the corners do not overlap. It is not always necessary to adopt this structure, and the mesh structure 10 may be formed by bending each side of the mesh of the quadrangular molybdenum alloy wire. In this case, the mesh has a structure in which three layers are stacked at the corners of the mesh structure 10.

FIG. 2 is an enlarged plan view showing a portion surrounded by II in FIG. 1. As shown in FIG. 2, the mesh structure 10 is formed by intersecting the wire rods 11 and 12. A plurality of stitches 19 are formed by intersecting the wire rod 11 extending in the vertical direction and the wire rod 12 extending in the horizontal direction.

In this embodiment, the wires 11 and 12 extend so as to be orthogonal to each other. However, the wires 11 and 12 may extend so as to form an acute angle with each other.

FIG. 3 is a cross-sectional view taken along the line III-III in FIG. As shown in FIG. 3, the cross section of the wire rod 11 is round. The cross section of the wire rod 11 may be square. Similarly, the wire rod 12 may have either a round cross section or a square cross section.

FIG. 4 is a photograph of the mesh structure 10 constituting the molybdenum mesh 1. As shown in FIG. 4, in the mesh structure 10, the folded portions 21 are provided at the ends 13 and 14, but the folded portions 15 and 16 are not provided with the folded portions.

FIG. 5 is an enlarged plan view showing a portion surrounded by V in FIG. 4. As shown in FIG. 5, in the folded portion 21, the wire rods 11 and 12 are intricately intertwined. The folding allowance W of the folding portion 21 is the width from the end portion 13 to the portion (cutting surface 12e) where the folded portion 21 does not exist. Further, if strength is required, it is possible to repeat the folding multiple times.

FIG. 6 is a diagram for explaining a method for manufacturing the molybdenum mesh 1. As shown in FIG. 6, in order to manufacture the molybdenum mesh 1, first, the end portion 13 of the mesh structure 10 is bent as shown by an arrow 101. In this embodiment, the end portion 13 is bent upward, but the end portion 13 may be bent downward.

FIG. 7 is a diagram for explaining a method for manufacturing the molybdenum mesh 1. As shown in FIG. 7, the folded portion 21 is formed by pressing the vicinity of the end portion 13 in the direction indicated by the arrow 102. By pressing, the thickness of the folded portion 21 is reduced.

FIG. 8 is a diagram showing a molybdenum mesh 1 having an end portion 13 having no cut surface. As shown in FIG. 8, there is also a molybdenum mesh 1 having an end portion 13 having no cut surface. In this case, the wire rod 12 is woven at the end portion 13, and the molybdenum mesh 1 can be formed without cutting the wire rod 12. The end portion 13 having no cut surface does not need to be folded back.

(Example)
Hereinafter, the present invention will be described based on examples.

Example 1 (Sample No. 19)
First, an ingot (for wire) made of molybdenum material was manufactured.

(1) Mo sintered body manufacturing process As a raw material, Mo powder having an FSSS particle size of 3 μm by the Fisher method was used. The FSSS particle size is preferably 1.0 μm or more and 8.0 μm or less.

This powder was molded into a shape of φ45 × 800 mm at a molding pressure of 120 MPa using a press machine.

This molded product was fired in a hydrogen atmosphere at 2000 ° C. for 10 hours using a firing furnace to obtain a Mo porous body.

The firing atmosphere may be a vacuum or an inert gas atmosphere in addition to the hydrogen atmosphere. The firing temperature is preferably 1600 ° C. or higher, and the firing time is preferably 4 hours or longer.

Next, a long material of molybdenum wire was prepared.

(2) Rolling process The molybdenum ingot, which is a porous molybdenum body, is hot-swaged using a swage machine until it reaches φ13 mm, and then hot-swaged to φ0.36 mm at a temperature of 300 to 700 ° C. using a hot wire drawing machine. The wire was drawn.

The temperature of the hot swage processing is preferably 1000 ° C. or higher and 1500 ° C. or lower. If it exceeds this, the dimensional variation may become large. If it is less than this, disconnection or cracking may occur.

The reduction rate of the warm wire drawing is preferably 15% or more and 40% or less. If it exceeds this, disconnection or cracking may occur. If it is less than this, the variation in wire diameter may become large. In addition, "there is a risk" indicates that there is a slight possibility that such a situation will occur, and does not mean that such a situation will occur with a high probability.

(3) Electropolishing step The molybdenum wire after this warm wire drawing was polished to φ0.35 mm by electrolytic polishing. Electropolishing was performed using phosphoric acid.

(4) Heat treatment step The Mo wire was annealed while feeding the Mo wire in a hydrogen atmosphere at 1000 ° C. using an electric furnace equipped with a sending mechanism and a winding mechanism before and after the heat treatment step. The temperature at the time of heat treatment (annealing) is preferably 800 ° C. or higher and 1100 ° C. or lower. If it exceeds this, the tensile strength becomes low and there is a risk of disconnection during weaving. If it is less than this, the elongation becomes low and the surface quality of the Mo net may deteriorate. When the finished line was measured, the tensile strength was 900 N / mm ² to 1200 N / mm ² , and the elongation was 5 to 20%. As a result, the molybdenum wire of material number 1 in Table 1 was produced.

(5) Netting step A mother net having a width of 1.1 m and a length of 35 m was produced by a net weaving machine using molybdenum wire after heat treatment. The diameter D of the molybdenum wire constituting the master net was 0.35 mm, and the roughness of the mesh was # 24. # 24 means that there are 24 lines in a width of 1 inch (25.4 mm). The mesh is preferably # 16 to 50. Further, this mother net was cut using a slitter / shear or the like to prepare a net having a B × L of FIG. 1 of 360 mm × 360 mm.

(6) Folding process A folded part was prepared on each side of the net by using a press brake (SPH-60C manufactured by Amada) by 5 mm on each side.

(7) Pressing process The folded net was applied to a pressing device and pressed until the thickness became 0.91 mm.

Further, by setting the rolling distance of the rolling mill (100HP rolling mill manufactured by Yoshida Memorial Co., Ltd.) to 0.9 mm and rolling, a similar product could be produced.

(8) Sample Preparation According to the steps (1) to (4), the wire rods of material numbers 2 to 5 in Table 1 were manufactured. Using the wire rods of material numbers 1 to 5 in Table 1, the steps (5) to (7) above were repeated to prepare molybdenum mesh samples having different materials, different numbers of folded sides, and different thicknesses. Details of these samples are shown in Tables 2 and 3.

The "number of folded lines" in Tables 2 and 3 refers to the number of wires extending in the direction orthogonal to the folding direction included in the folding allowance W of the folding portion. For example, in FIG. 5, the number of wires 11 included in the folding allowance W. To say. In the sample provided with a plurality of folding portions, the same number of folding lines was used for all the folding allowances W. The "thickness without folding back (mm)" means the thickness at the portion without folding back, and the "folding thickness (mm)" means the thickness of the folded side.

(9) Bending strength evaluation method The bending strength of the completed molybdenum meshes of Sample Nos. 1 to 24 was measured using a digital force gauge (FGJN-5 manufactured by Nidec Symposium). FIG. 9 is a diagram showing a method for measuring the bending force of the molybdenum mesh 1. As shown in FIG. 9, the folded-back portion 22 is placed between the two tables 115 and 116. The distance between the tables 115 and 116 was set to 100 mm. The tip 112 of the digital force gauge 110 was brought into contact with a point on the folded-back portion 22 which was an intermediate point between the bases 115 and 116. The force when the folded-back portion 22 was pushed in by 5 mm by applying a force in the direction indicated by the arrow 111 was taken as the anti-folding force.

(10) Evaluation of the number of times of use Each molybdenum mesh is repeatedly inserted / removed 50 times in a hydrogen furnace at 1100 ° C., and the dimensional change of the molybdenum mesh due to the breakage or fraying of the Mo wire on each side and the amount of deformation of the entire net are measured. did.

The amount of deformation was measured by the following method. First, when the number of uses was 0, a molybdenum mesh was placed on the surface plate so that the convex direction was upward, and the height of the highest portion from the surface plate was measured with a digital caliper. Let the height be H1. After 50 times of use, a molybdenum mesh was placed on the surface plate so that the convex direction was upward, and the height of the highest part from the surface plate was measured with a digital caliper. Let the height be H2. H2-H1 was defined as the amount of deformation (mm). The results are shown in Tables 2 and 3.

The "consumable length (mm)" in Tables 2 and 3 is B × L before use (see FIG. 1) and B × L after use (see FIG. 1) (B- before use). It is calculated by the minimum value of B after use + L before use-minimum value of L after use) / 2. The evaluation is shown in Table 4.

In the "evaluation" column, "A" has a wear length of 30 mm or less, "B" has a wear length of more than 30 mm and 80 mm or less, "C" has a wear length of more than 80 mm and 110 mm or less, and "D" has wear. Indicates that the length exceeds 110 mm.

It can be seen that by providing the folds, a superior effect can be obtained as compared with the sample number 1 in which the folds are not provided.

The embodiments and examples disclosed this time should be considered to be exemplary and not restrictive in all respects. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Molybdenum mesh, 10 mesh structure, 11,12 wire rod, 11e, 12e cut surface, 13,14,15,16 end, 19th, 21,22 folded part, 101,102,111 arrow, 110 digital force gauge , 112 tip, 115,116 units.

Claims (3)

With a mesh structure containing molybdenum
The mesh structure is a molybdenum mesh having an end portion and a folded portion at the end portion. The molybdenum mesh according to claim 1, wherein the end portion having a cut surface has the folded portion. The molybdenum mesh according to claim 1 or 2, wherein the thickness of the folded portion is 100% or more and 200% or less of the thickness of the mesh structure other than the folded portion.

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