JPH0361302A - Molybdenum sintered body for plate rolling - Google Patents

Abstract

PURPOSE:To manufacture Mo plate material with a high yield of raw material by packing Mo powder in a vessel arranging projecting part in inner part, sintering after press-forming and rolling after making the sintered body having recessed part on flat surface part. CONSTITUTION:The Mo powder 30 is packed into a rubber-made case 41 having the similar shape as inner shape of a jig 40 for isostatic press, and after tightly closing this with rubber-made packing 44, this is charged into the thick steel plate-made case 42 having projection 43 in inner face. This is pressurized with the isostatic press and the Mo powder 30 is compressed to manufacture the pressed body 10 having recessed part 12 on the surface, and this is heated, e.g. at 1600-2300 deg.C and sintered in a hydrogen atmosphere to manufacture the Mo powder sintered body having recessed part 12 on the surface. By executing the hot rolling to this Mo powder sintered body, the Mo thick plate material having flat upper and lower faces and side faces, is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molybdenum sintered body for plate rolling, and more particularly to a molybdenum sintered body for plate rolling which has an improved yield of plate material after rolling.

[Prior Art] Generally, as a method for manufacturing molybdenum plates, which are high-melting point metals, molybdenum powder is filled into a rubber case that approximates the desired shape, and then subjected to hydrostatic pressure (1 to 3 t/cd).
to compress and harden the molybdenum powder. The shrinkage rate at this time is about 20%. Next, the pressed body is formed into a desired shape by cutting, cutting, polishing, etc., and heated at 1,600 to 2,300 degrees in a hydrogen atmosphere. The shrinkage rate in this case is about 15%. This is heated again to 800 to 1500 degrees, then hot rolled to form a thick plate (approximately 1 mm or more), or further cold rolled and stretched into a thin plate or foil, a so-called powder metallurgy process. law was used.

However, as shown in FIG. 5, in the above method,
When a rectangular parallelepiped sintered body is hot-rolled, the outer circumference of the plate material after rolling generally swells and becomes an oval shape that deviates from a rectangle. A processing step is required, and the cut remaining material is discarded, which has disadvantages in terms of yield and material costs due to the discarded remaining material.

As a means to solve this problem, FIG. 6(a) shows.

As shown in (b), an attempt was made to form a curved recess 11 on the side surface of the sintered body 10 or on the side surface of a pressed body in a previous step, and then roll the sintered body 10 to produce a plate material. being done.

[Problems to be Solved by the Invention] However, the above-mentioned manufacturing method requires steps such as cutting and polishing the side surface of the sintered body or the side surface of the pressed body in the preceding process, which increases the processing cost. Not only that, the removed portion of the material is wasted and the yield on the material decreases.
On the contrary, it has the disadvantage of increasing material costs.

Furthermore, a sintered body or a pressed body having curved concave portions formed on its side faces has acute angles at its four corners, and there is a problem in that the corners may be damaged or cracked during each process.

In view of the above-mentioned drawbacks, the technical problem of the present invention is to form a molybdenum sintered compact for plate rolling, which allows a rectangular plate material to be obtained relatively easily after rolling by forming a recess on at least one surface of the sintered compact. An object of the present invention is to provide a manufacturing method.

[Means for Solving the Problems] According to the present invention, a molybdenum sintered body for plate rolling, which has a flat surface and a side surface and is rolled into a plate material, is characterized in that the flat surface has a recessed portion. A molybdenum sintered body for plate rolling is obtained.

The manufacturing process involves press-molding molybdenum powder in a filled container with a convex portion inside and heating it, thereby producing a sintered body with concave portions on the plane, which is then rolled. , manufactures board materials.

[Example] The present invention will be explained in detail below.

Figure 1 is a perspective view showing the sintered body of this example, Figure 2 is a hydrostatic press jig used in this example, and (a) shows the inside. The front view and (b) are a longitudinal cross-sectional view.

In this example, as shown in FIG. 2, as the first step,
First, molybdenum powder 30 is placed in a hydrostatic press jig 40.
A rubber case 41 having an inner shape similar to the inside shape is filled and sealed with a rubber gasket 44.

The outer surface of this case 41 is held by a holding case 42 made of iron. This rubber case 41 has a thickness of 2.5 m1B so that it can follow the compression of the molybdenum powder 30, and the iron case 42 has a thickness of 2.3 m + m so that the shape of the rubber case 41 does not deform. have

Furthermore, an iron protrusion 43 is provided on the inner surface of the iron case 42.
is installed protrudingly. The position of this protrusion 43 corresponds to the position of a recess 12 on the surface of the sintered body 10, which will be described later, and
The shape is set according to the length, width, depth, and position of the protrusion 43, taking into account the shrinkage rate of the sintered body 10 in the third step and the shrinkage rate during hydrostatic pressing.

Next, in the second step, the molybdenum powder 30 filled in this case 41 is pressed at 1 to 3 tons/c-
Pressure is applied to compress the molybdenum powder 30 to produce a pressed body. At the time of this press body molding, a recess 12 is simultaneously formed on the surface of the press body. This recess 12 is the first
As shown in the figure, the recess 12 has a rectangular shape, and an inclined surface 13 that becomes thicker toward the outer periphery of the recess 12 is formed on the inner periphery.

In the third step, the pressed body was heated at 1600°C in a hydrogen atmosphere.
The sintered body 10 is formed by heating at ~2300°C.

Then, as a final step, the sintered body 10 is hot rolled to produce the plate material 20.

FIG. 4 shows the yield rates of various recess shapes based on experimental data under the following experimental conditions.

Experimental conditions: Amount of molybdenum powder to be filled...
...10kg Pressure of hydrostatic press...1.2t/cj External dimensions of sintered body...30X110X320 Depth of recess...・・5 +am External dimensions of the plate material after rolling---1, 5X 320 10% As a result, it was found that the shape of the recess 12 is preferably an ellipse with a long axis as shown in A in FIG. 4. That is,
The best results were obtained with a length of 200 mm, a width of 30 mm, and a depth of 5 mm.

However, regardless of whether the shape is diamond-shaped as shown in B or completely rectangular as shown in C, the yield is improved by about 10% compared to the conventional one without recesses. Furthermore, through these experiments, although the rolling ratio of the portion of the sintered body 10 corresponding to the concave portion 12 is smaller than other parts, the rolling ratio is 80% or more (in the sintered body in this example, the plate thickness is 6 m).
m or less), no difference in mechanical properties occurred.

[Effects of the Invention] As described above, the present invention includes forming a recess in the plane of the sintered body in a pre-process of rolling the sintered body, and then rolling the sintered body to produce a plate material. This not only makes the outer shape of the plate rectangular and improves the yield of plate cutting, but also eliminates the need for processes such as cutting and polishing, and allows the recesses to be formed at the same time during isostatic pressing, simplifying the manufacturing process and reducing manufacturing costs. It is possible to lower the

[Brief explanation of drawings]

Fig. 1 is a perspective view of a sintered body according to an embodiment of the present invention, and Fig. 2 is a hydrostatic press jig used in an embodiment of the present invention. Front view shown, (
2) is a longitudinal cross-sectional view, Figure 3 shows a sintered body with a concave shape with the best yield, (1) is a top view, and (2)
is a cross-sectional view, Fig. 4 is experimental data showing the yield rate for various concave shapes, Fig. 5 is an explanatory diagram showing changes in the external shape of the plate before and after rolling the sintered body, and Fig. 6 is , are perspective views showing the shapes of conventional sintered bodies, (1) is one in which curved recesses are formed on the side surfaces, and (2) is one in which curved recesses are formed in all the sides. DESCRIPTION OF SYMBOLS 10... Sintered compact, 12... Recessed part, GO3... Inclined surface, 20... Plate material, 30... Molybdenum powder, 40...
・・Jig for hydrostatic press, 41 ・・Rubber case, 4
2...Iron case, 43...Protrusion. Figure 1 Figure 2 Figure 3 Figure 5 Figure 6

Claims (1)

[Claims] (1) A molybdenum sintered body for plate rolling, which has a flat surface and a side surface and is rolled into a plate material, and is characterized in that the flat surface has a recess.