JPS5844957A - Production of pipe of high melting point metal - Google Patents

Abstract

PURPOSE:To facilitate the formation of a long-sized pipe of a high m.p. metal by forming a metallic pipe in a mold made of a water-cooled copper core in a vacuum or inert gaseous atmosphere. CONSTITUTION:Cooling water (a) is flowed sufficiently in the water-cooled copper mold 8 and water-cooled copper core 2 of a mold 1 made of a water- cooled core toward a discharge port (b). A high m.p. metal is melted by an electron beam laser or arc in a vacuum or inert gaseous atmosphere and is conducted into the mold 1, whereby a high m.p. metallic pipe is formed.

Description

[Detailed Description of the Invention] This invention relates to a high-purity long pipe made of high-melting point metal or alloy, and its purpose is to manufacture a long pipe with high purity compared to the conventional powder sintering method. , a pipe manufactured by melting by a combination of an outer water-cooled copper mold and a water-cooled copper core.

Conventionally, pipes made of high-melting point metals and alloys (tungsten, molybdenum, etc.), which are generally widely used, have been manufactured by a powder sintering method, but it is difficult to manufacture long ones. The disadvantages of pipe manufacturing using the powder sintering method will be described below.

1. Since powder is compression molded, it is difficult to mold long items. Also, the compressed density becomes constant.

For this reason, it may become deformed during high-temperature sintering, and it takes time to straighten it.

2. Thin-walled items, even those with #m dimensions, are likely to break or crack.

3. Since the material is powder, there are impurities (mainly oxygen content - number 1)
100pp) is common. This causes problems in weldability.

If a high-purity pipe is required, the molten ingot is forged and rolled into a thin plate. This is rolled into a cylindrical shape and the end face is manufactured by electron beam welding to produce a high-purity pipe, but it has the following drawbacks.

1. Because the plate material is forged and rolled from molten material and processed into a cylindrical shape, it is difficult to produce thick-walled materials.

2. Long items are difficult.

Disadvantage 1 of other manufacturing methods: Although it is possible to manufacture high-purity pipes by peripheral processing and boring from a molten ingot, there is a large amount of loss.

Also, long items have a large amount of loss and are relatively expensive.

The purpose of this invention is to manufacture high-melting point, high-purity pipes made of ^-point materials such as tungsten, molybdenum, and their alloys, which are used in energy equipment for nuclear fusion reactors, equipment related to the chemical industry, and others. Provides a manufacturing method.

This invention has conventionally produced ingots by electron beam or arc melting using a high-melting point metal melting method, but pipes can be easily produced by attaching a water-cooled copper core to the inside of this water-cooled copper mold. It turns out that it can be done.

This high-purity pipe uses an outer water-cooled copper mold and a water-cooled copper core in a high vacuum or ultra-high purity inert gas atmosphere, so there is almost no contamination by impurities.

The features are described below.

1. The thickness of the pipe can be changed depending on the size of the water-cooled copper core.

2. An electron beam is used as a heat source when manufacturing a single metal pipe or when the composition of an alloy does not change.

3. In the case of manufacturing alloy pipes, use a non-consumable arc as a heat source when compositional fluctuations are expected. In this way, if the composition does not reach the target value, there will be almost no fluctuation in the composition if the non-consumable arc melting method is used to manufacture the product.

4. It can also be manufactured from fine granular or spongy materials.

5. Since it is a pull-down method, a long pipe can be created by increasing the downward distance.

6. In the case of manufacturing long pipes, when the first melting material is finished melting and the second melting material is melted, no boundary surface with the end surface of the pipe can be seen. This is because the end face of the pipe is sufficiently formed into a melt zone before the melt droplets of the material to be melted are allowed to fall.

Next, the present invention will be explained in detail.

Example 1 MO powder was compression-molded and fired in a hydrogen furnace at 1800°C to obtain a sintered body of approximately 10φx6007mm.

This was set in the furnace (1). The degree of vacuum inside the furnace is 1
It was set to 10-5T Orr or more. An electron beam (6) was used as a heat source. Sufficient cooling water (a) was poured into the water-cooled copper mold (8) and the water-cooled copper core (2) toward the drain port (b).The annular bottom plate (3) was made of the same material as the material to be melted (5). After making a sufficient amount of molten liquid, the tip of the material to be melted was irradiated and the molten droplets were allowed to fall onto the bottom plate.When the molten metal was uniformly collected around the circumference (diameter), the annular stop shaft (4) was used. move and
While the bottom plate (3) was moved downward little by little, the material to be melted was also fed downward at appropriate times. Thus the outer diameter is 70
φ x inner diameter 60φ x 1500g+- length pipe (7)
I got it. The oxygen-containing chains of this pipe ranged from 1 to 3 pp-. Moreover, the outer peripheral surface and inner surface of this pipe were clean and did not require any special machining.

Example 2 When manufacturing a high-purity pipe made of Mo-V-C alloy, a non-consumable arc was used as the heat source because the composition changes when melted in a high vacuum due to the presence of ■. The composition ratio of this alloy is 0.05%G and 1.0%V.

After sufficient mixing with the heavy chain ratio of the remaining MO as in Example 1, the mixture was fired to obtain a material to be melted. After setting this in the furnace, the inside of the furnace is 1
The pressure was reduced to below x 10"ST orr, and argon gas was filled in to clean the inside of the furnace. After returning to a high vacuum state, 300 TOrr of ultra-high purity argon gas was filled in. Four tungsten electrodes were used as electrodes.

One of these was used for melting the material to be melted, and the remaining three were used for melting the bottom plate and the circumference (diameter) of the pipe. The water-cooled copper mold and the water-cooled copper core were of the same quality and diameter as in Example 1, and a pipe of the same diameter was obtained. on this pipe.

Cut out the middle and bottom three parts and perform a constant analysis of each composition. Results: Vl; tO09~1.0%; C 100~3
Within the range of 00 pp-, the remainder was MO, and almost no segregation was observed. Also, the amount of oxygen contained is 2 to 4 pp
It was within the range of −.

Example 3 Granular niobium was charged into a hopper, and an electron beam was used as the heat source. Water-cooled copper mold diameter is 40φ, water-cooled copper core is 3
One with a diameter of 0φ was used. After the niobium bottom plate was melted to form a sufficient melt, the diaphragm in the hopper was gently vibrated, and the melt was allowed to fall little by little from above the mold through the hole. Three beam guns were used to thoroughly comb the surrounding area and move the bottom plate downward. In this way, a pipe with an outer diameter of 40φ, an inner diameter of 30φ, and a length of 1500 m was obtained. Both the outer peripheral surface and the inner surface were smooth. As a result of quantitative analysis, the oxygen content was in the range of 1 to 5,901.

This invention has made it possible to easily manufacture high-purity, long metals such as MO and their alloys in long lengths.

In addition, modifications and application examples are as follows.

■For example, it can be applied to manufacturing irregularly shaped pipes, such as making a water-cooled copper mold circular and making a water-cooled copper core square, or vice versa.

■Plasma arc can also be used as a heat source.

■It is applicable not only to high melting point metals but also to other metals and their alloys.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an apparatus for manufacturing a refractory metal jaw pipe according to the present invention. 1, outer water-cooled copper mold 2, water-cooled copper core 3, bottom plate 4 for receiving the material to be melted, stopper shaft of the bottom plate 5, material to be melted 6, heat source 7, pipe

Claims (1)

[Claims] Electron beam in vacuum or inert gas atmosphere. A method for manufacturing a high-melting point metal pipe, which is characterized by melting a high-melting point metal with an arc and passing the molten metal through a water-cooled copper core mold body to form a high-point metal pipe. .