JPS5897463A - Continuous casting method for metallic pipe - Google Patents

Abstract

PURPOSE:To cast a pipe with less surface defects continuously without generation of cracks by maintaining the temp. on the wall surfaces of the hollow master mold and core of a mold for continuous casting of pipes in contact with molten metal at temp. higher than the solidifying temp. of casting metal. CONSTITUTION:Molten metal 8 is supplied into a mold and the height of the molten metal in the mold is maintained constant by means of a control valve 9 for melt surface. A heating element 2 is provided in the master mold 1 of said mold, and a heating element 4 is provided in a core 3 to maintain the temp. on the inside wall surfaces at the outside of the mold at temp. higher than the solidifying temp. of the casting metal. Further, the temp. of casting, the descending speed of a dummy pipe 5, etc. are controlled, and the pipe 5 is moved downward so that a pipe 11 is cast continuously under the outlet of the mold. By this method the pipe made of alloys which are heretofore difficult to produce pipes by plastic working is produced easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuous casting of metal tubes and an apparatus suitable for carrying out the method. In more detail, the temperature of the inner wall surface of the mold for metal casting, the solidification of cast metal I2! By heating and holding at a temperature higher than
The solidified shell is formed upstream, and the formation of the solidified shell is started as soon as it leaves the mold outlet, and the shape of the metal tube is determined by the cross-sectional shape of the receiving part in the mold. Regarding equipment.

Conventionally, continuous casting of metal tubes was considered extremely difficult, and mainly 1- Pipes have been manufactured by plastic working from fish lumps.

This method involves a complex process in which g and i are first cast from bath water, heated, then hot worked to form a rough tube, and then heat treatment and plastic working are repeated to create a tube of the desired diameter. Requires.

The method of making pipes by first rolling a clear ingot into a plate and then welding or joining the plates is prone to defects in the bonded parts. It is desirable to be able to immediately manufacture a pipe of a desired diameter from a molten metal in terms of saving energy consumption. However, with conventional molds for casting tubes that consist of a simple outer mold and core, the solidified shell generated within the mold rubs against the inner wall of the mold, causing breakout of the internal molten metal when the tube is pulled out. Such continuous casting has been considered extremely difficult, especially for alloys that have a wide solidification temperature range. For this reason, pipe casting is not continuous casting in the true sense of the word, but is instead solidified in a mold and then drawn out.
Intermittent casting methods have been used. However, such intermittent tube casting tends to produce striped surface defects on the tube, and such defects pose a risk of corrosion and mechanical failure of the tube.

The present invention applies to all meltable metals and alloys.
It is, of course, an object to provide a continuous method for producing tubes having smooth surfaces and inner surfaces free of surface defects.

That is, in the present invention, the temperature of the inner wall surface between the nuclear power plants is: IAj
Inside a hollow air-conditioned mold that is kept above the solidification temperature of the metal,
By attaching a core to form a pipe casting mold and keeping the temperature of the surface of the core below the solidification temperature of the cast metal, the formation of a solidified shell on the inner wall of the mold is prevented. Continuous casting of a metal tube, which is characterized by casting in such a way that 1 ml of surface layer condensation starts by cooling at the same time as the molten gold comes out of the mold exit km, and it (
It is a device that requires RC.

FIG. 1 is a longitudinal cross-sectional view showing one aspect of a continuous preparation apparatus for carrying out the present invention.

■ is the outer mold of the mold and has a heating element (■). ■ is the core of the mold and has a heating element (■). ■ is a tube dummy, which is cooled by water, air, or gas injected from the spray nozzle (■). At the start of casting, the dummy pipe (2) is placed at the lower end of the mold (2), and then bath water (2) is supplied into the mold through the hot water supply pipe (2). The height of the m molten metal in the mold is maintained constant by the molten metal level control valve (2). The dummy f■ is lowered by the rotation of the pinch roll ■. By controlling the pouring temperature, the height of the molten metal level in the mold, the temperature of the outer mold and core walls of the mold, and the descending speed of the dummy pipe, the pipe can be placed under the mold outlet.
is continuously cast.

The most important thing in the present invention is that the molten metal that has been completely poured into the mold does not completely form a solidified shell on the side walls of the mold, but rather forms a solidified shell at the bottom of the mold outlet and immediately forms a solidified shell. This means that various factors must be controlled to prevent molten metal from gushing out through the gap between the copper wall and the copper wall. Koe et al.'s various factors include solidification temperature of cast metal, pouring temperature 1
temperature, the height of the molten metal in the mold, the speed at which the tube is made, the temperature of the outer mold and core of the mold, the size and wall thickness of the tube, the temperature and amount of coolant, etc., but especially the cooling and casting of the tube. The drawing speed is the most important factor. If the tube drawing speed is too high relative to the cooling series, it can cause breakouts at the mold outlet.

FIG. 2 is a longitudinal sectional view of a main part showing another aspect of the present invention.

0 is the appearance of the mold, ■ is the heating element, and ■ is the core of the mold, which contains the [phase] heating element. 0 is a dummy tube, which is cooled by water, air, or gas injected from the spray ①.

- At the start of manufacturing, the dummy pipe 0 is brought into close contact with the mold (2), and then the hot water of the [phase] passes through the hot water supply vibrator (0) and is supplied into the mold @ through the tamp (2). and,[
The water level control valve of [phase] controls the temperature of the tank [
The height of the hot water level is kept constant.

The dummy tube [phase] is moved by rotation of the pinch roll @. Pouring temperature, height of the hot water level in tump 7-@, temperature of the outer mold of the mold and the wall ml of the core (2), dummy-g.

By fully controlling the speed of movement of the mold, a tube of cast metal is formed outside the mold outlet.

The mold referred to in the present invention is different from the concept of a conventional mold, in which the molten metal is solidified in the mold to produce an ingot or casting, but the molten metal does not form a solidified shell in the mold, and at the outlet of the mold,
This mold is used to shape the molten metal to eventually solidify into a tube.

The method of the present invention is particularly superior to conventional tube creation methods in that tubes with fewer surface defects can be continuously cast without the occurrence of cracks. This is an innovative method for casting tubes, as it has the advantage of being able to easily manufacture tubes made of alloys, which are difficult to manufacture by plastic working.

4. Between additional related nuclear power plants, the temperature of the inner wall surface of the outlet of the mold for supplying molten metal from one end and continuously obtaining ingots from the other end is maintained at or above the solidification temperature of the metal-forming metal. The present invention relates to a continuous casting method and mold for metal ingots having the following feature 5-.
The pipe is continuously cast using a casting mold.
The present invention would not exist without the use of a nuclear reactor in an application that requires the temperature of the inner wall surface of the mold outlet to be above the solidification temperature of the cast metal.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional front view showing one embodiment of the present invention, and FIG. 2 is a vertical cross-sectional IE plane view of essential parts showing another embodiment of the present invention. 112... Mold outer mold El 19... Molten metal 213 Heating element Q 21 - Molten metal level control valve 314 - Mold core 1o22... Pinch roll 415 - Heating element 1123 - Pipe 516 - Dummy pipe 122 o -・Tampjuro 1
7-・Cooling spray 718・Hot water pipe

Claims (1)

[Claims]L The temperature of the wall surface in contact with the molten metal of a mold consisting of a hollow outer mold and a core, for supplying bath water τ from one end and continuously supplying the tube from the other end, Should it be kept above the freezing temperature?
! -Featured continuous manufacturing method for metal tubes. 2. A continuous metal tube characterized by having a cross-shaped mold consisting of a core containing a heating element and a hollow outer mold containing a heating element.
construction equipment.