JPH03291101A - Method for producing deep-drawable Mo thin plate - Google Patents

Abstract

PURPOSE:To manufacture a deep drawable sheet metal of molybdenum by cross rolling a band shaped material which a specified base stock of molybdenum is rolled using a cross rolling mill. CONSTITUTION:A base stock of molybdenum with high purity of five-nines and more, preferably six-nines which is manufactured by electron beam melting is made into a band shape by rolling with roll. This band shape is cross rolled using the cross rolling mill. In that way, the sheet metal of molybdenum which is improved in deep-drawability can be manufactured in the shape of long size coil at high productivity. It is very expedient for working process of machinary that the sheet metal of molybdenum is obtained as coil and is useful to reduced the cost of the product of the sheet metal of molybdenum.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for efficiently manufacturing a Mol plate that can be deep drawn. [Prior Art] Mo tubes used as cathode parts of CRTs are manufactured by deep drawing of thin plates. As is well known, -Mo is a metal with poor workability, so it is not easy to obtain a Mo thin plate that can be deep drawn. The conventional manufacturing method is to prepare a plate made by sintering Mo powder and roll this plate alternately in the vertical and horizontal directions to form a thin plate. The reason why rolling is carried out alternately in longitudinal and transverse directions is because rolling in one direction causes anisotropy in the thin plate, which is inconvenient for deep drawing. Since the rolling process involves sheets, the efficiency of rolling is low, and since it cannot be handled in the form of a coil, it is disadvantageous for subsequent processing steps, and the cost of the thin sheet and its processed products inevitably increases. In recent years, a technology called ``cross rolling'' has been perfected, and when rolling a strip material, unlike simple roll rolling, it has become possible to simultaneously roll the material not only in the rolling direction but also in a direction perpendicular to it. Using this technique, it is possible to obtain a coil with little anisotropy. However, even if this cross rolling is applied to the production of Mo thin sheets, it is not possible to obtain thin sheets with sufficient deep drawability. There wasn't.

[Problem to be solved by the invention]

The purpose of the present invention is to advance the current state of such technology one step further, and to
o To provide a method for manufacturing a Mo thin sheet with high deep drawability by increasing efficiency by using cross-rolling technology in the manufacture of the thin sheet and making it possible to handle it in the form of a coil.

[Means to solve the problem]

The method for producing a deep-drawable Mo thin plate of the present invention involves rolling a Mo material manufactured by electron beam melting and having a high purity of five nines or more, preferably six nines, into a strip material, and cross-rolling this strip material. It consists of cross rolling using a machine. Particularly thin plates, e.g. thickness 0. In the case of manufacturing a thin plate of about 1 m, cross rolling may be followed by unidirectional finish rolling using rolls, and the influence of this unidirectional rolling on the physical properties of the thin plate is not very large. Work hardening caused by finish rolling can be alleviated by annealing under appropriate conditions.

[For use]

The principle of cross rolling is described, for example, in the magazine "Tetsu to Hagane" 1986.
No. 10, pp. 157-160, particularly as shown in Figure 5, a pair of oscillating rolls with axes approximately parallel to the material but narrowing in the direction of travel transport the material fed in the longitudinal direction. This operation consists of rolling in the width direction and rolling in the longitudinal direction by reciprocating rotational motion. Conventional repeated roll rolling in the longitudinal and lateral directions (the plate of the Mo powder sintered body used had a purity of about three nines).
This is because even if the purity of the raw metal is increased, contamination cannot be avoided during the powdering stage. In contrast, M produced by electron beam melting
o can easily have a high purity of about five nines to six nines. The reason why a Mo thin plate with high deep drawability can be obtained by combining such a high-purity Mo material and cross-rolling is thought to be because workability is improved by lowering the recrystallization temperature brought about by the high purity. [Example] A Mo ingot (purity 99.9995%) produced by electron beam melting was forged to a thickness of 50 mg, and hot rolled into a 20 m thick strip. This strip material was passed through a cross rolling mill to form a plate with a thickness of 1.2 mm. Subsequently, by hot roll rolling, the temperature was changed from 1.2 to 0.
The thickness was reduced from 5 to 0.15 m. At the 0.5 am stage, the plates were annealed at various temperatures for 1 hour.
A deep drawing test was conducted to measure the Erichsen value. The results are shown in FIG. 1 in comparison with the case where only one direction of roll rolling was repeated for the same material. From the graph in the figure, it was found that cross rolling improves the Erichsen value by about 1.5M and that annealing is preferably carried out at a relatively high temperature of about 700°C. Roughly 700'CX1 on the above 0.15m thick thin plate
After time annealing and cold roll rolling, the thickness is 0.10a.
Thinned to am. This Mo thin plate was annealed for 1 hour at various temperatures, and the same deep drawing test as above was performed to determine the Erichsen value. The results are as shown in Figure 2,
From the graph in the figure, it can be seen that although the deep drawability decreases due to rolling into a thin plate, it is possible to maintain the Erichsen value of 4M, which is a practical guideline, and that there are appropriate conditions for annealing in this case (650"C x 1 hour). It can be seen that the results are not good at too high a temperature. [Effects of the Invention] According to the manufacturing method of the present invention, Mo with improved deep drawability can be produced.
Thin sheets can be manufactured in the form of long coils with high productivity. The fact that the Mo thin plate can be obtained as Koi Jshi is convenient for subsequent processing steps and helps reduce the cost of Mo thin plate processed products.

[Brief explanation of drawings]

Both drawings show data of examples of the present invention, and Figure 1 shows the relationship between the annealing temperature and Erichsen value of a 0.5#2 thick Mo thin plate that is in the middle of the hot rolling process after cross rolling. It is a rough graph, and the second figure shows 0.1 due to cold rolling! It is a graph showing the relationship between the annealing temperature and the Erichsen value of a Moa plate having a fIIi thickness.

Claims (2)

[Claims] (1) Mo material that can be deep drawn by rolling a Mo material manufactured by electron beam melting and having a purity of five nines or higher into a strip material, and then cross-rolling this strip material using a cross rolling mill. Method of manufacturing thin plates. (2) The manufacturing method according to claim 1, further comprising performing cross rolling using a cross rolling mill, followed by finish rolling using rolls, and further annealing to improve deep drawability.