JPH01166868A - Continuous casting apparatus - Google Patents

Abstract

PURPOSE:To eliminate rough surface of a cast billet, variance of dimensional accuracy and segregation by inserting a molten metal introducing part composing of heat resistant material building-in heating element between a holding furnace and water-cooling mold. CONSTITUTION:The molten metal introducing part 3 is composed of the heat resistant material 10 arranging a molten metal introducing pipe part 9 at center part and this basic end part 3a is closely inserted into the opening hole part 11 of furnace wall 2 in the holding furnace. The basic end part of the graphite mold 6 of water cooled jacket 5 is closely inserted into the other end part 3b, and this water cooled jacket 5 and the graphite mold 6 are adjoined to the molten metal introducing part 3 and horizontally projected. The heating element of heating heater, etc., is built in the heat resistant material 10 so as to be possible to adjust the temp. By arranging the electromagnetic stirring device 12, the molten metal in the molten metal introducing part 3 becomes stirring rotary flow and supplied in the graphite mold 6 to obtain the cast slab 8 having high quality. The graphite mold 6 is closely inserted into the water cooled jacket 5 to constitute the water cooled mold part. By this method, the molten metal introducing part is uniformly heated, to form the uniform solidified shell and various defects of the rough surface, segregation, stroke mark, etc., can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a continuous casting apparatus that can prevent uneven solidification shells occurring in front of a mold.

[Prior art and its problems]

As shown in Fig. 2, in conventional continuous casting equipment, the holding furnace 20 and the water-cooled mold 21 were directly connected.
1 was transmitted to the inside of the holding furnace 20, and the molten metal 22 often formed a solidified shell on the side of the holding furnace 20 from the base end of the mold 21. However, the temperature of the molten metal in the holding furnace 20,
Due to variations in the cooling temperature from the mold 21, the shape and thickness of the solidified shell become non-uniform, resulting in the following problems. For example, ■ The surface of the slab is noticeably rough.

As the molten metal solidifies just before the base end of the mold in the holding furnace, a gap is created between the mold and the slab due to solidification shrinkage in the mold, and the solidified shell is melted away due to recuperation in that area, causing the gap to close. Molten metal is inserted into the slab, causing roughening of the surface of the slab.

■Differences in dimensional accuracy and segregation due to temperature differences in the molten metal are significant.

For example, in a holding furnace for horizontal continuous casting, there is a temperature difference between the upper and lower sides, so if a solidified shell is generated in the holding furnace as described above, the lower side will solidify faster than the upper side. As a result, the development of the solidified shell becomes unbalanced, causing round slabs to deform into elliptical shapes, and plate-shaped slabs to become thinner in the center and simultaneously bend. In terms of quality, being directly affected by the temperature difference between the top and bottom is a major cause of uneven crystal grains and segregation in the slab.

■With this conventional equipment, it is impossible to cast thin plate products with a thickness of 10m+ or less.The cooling from the mold is strong, and a solidified shell is completely generated in the pouring area, which is closer to the holding furnace than the mold. Thin plate products cannot be pulled out.

Cu-P, for which hot rolling is conventionally disadvantageous or impossible;
When manufacturing a thin plate of Cu-3n-P, Cu-5n, etc. with a thickness of 1 m or less, for example, a 12 to 20 nn+ material had to be cast and finished by cold rolling, which involves repeated annealing and rolling. This required a great deal of man-hours and equipment, making the product expensive.

Therefore, in order to reduce the cold rolling process as much as possible, the problem has been how to manufacture thinner and healthier materials by continuous casting.

In recent years, horizontal continuous casting has made it possible to produce thin plates up to a thickness of approximately 10 m using the steel alloys mentioned above, but with conventional equipment, it is difficult to manufacture thin plates with a thickness of 10 nn or less for the reasons mentioned above. there were.

■A solidified shell is formed at the pouring port due to cooling from a mold with deep stroke marks, but
This remains on the surface of the slab as deep stroke marks. This increases the number of processing steps in the post-process and significantly reduces the product yield.

On the other hand, as shown in FIG. 3, by setting a heating mold 30 on the casting furnace wall and heating the inside of the mold to a temperature higher than the melting point of the cast metal, nucleation and growth on the mold surface are prevented.
The OCC method (heated mold continuous casting method) in which the ingot 31 is cooled outside the mold 30 is known, but in this casting method, the ingot 31 is already formed at the tip of the heated mold 30 and the ingot 31 is cooled outside the mold 30. Since the heating is applied to the cooling device 32 at the stage of heating, the heating temperature and drawing speed are strictly controlled.

For this reason, production management has become very strict. Therefore, the molten metal temperature, heating temperature, and cooling temperature.

There was a drawback that even a slight change in the withdrawal speed had a large effect on the product and production control.

In addition, as shown in FIG. 4, the present inventors provided a melt guide section made of a heat-resistant material 42 between the holding furnace 40 and the water-cooled mold 41,
We have provided a technology in which an electromagnetic stirring device 44 is provided on the outer circumferential side of the molten metal guide part to turn the molten metal in the molten metal into a stirring rotational flow, and the molten metal in this stirring rotational flow is supplied into the water-cooled mold part 41 (specially (No. 59-212146).

However, even this prior art basically does not solve the various drawbacks that occur in the conventional device shown in FIG.

[Purpose of the invention]

The present invention was invented in view of the actual situation of conventional devices, and eliminates all quality defects that occur in conventional devices.
It is an object of the present invention to provide a continuous casting apparatus that is capable of manufacturing extremely thin cast products and that can stably mass-produce homogeneous cast products.

[Structure of the invention]

The gist of the configuration of the present invention for achieving the above object is that a metal guide section made of a heat-resistant material and having a built-in heating element is interposed between the holding furnace and the water-cooled mold.

〔Example〕

FIG. 1 is a schematic vertical sectional view of a sprue system of a horizontal continuous casting apparatus according to an embodiment of the present invention, and in this case, casting of a copper alloy billet material is illustrated.

In the figure, 1 is the molten metal, 2 is the holding furnace wall, 3 is the lead part,
4 is a heating element, 5 is a water-cooling jacket, 6 is a graphite mold, and 8 is a slab 6 The melt guide section 3 is made of a heat-resistant material 10 or a fire-resistant heat insulating material with a molten metal conduit section 9 in the form of a through hole in the center. and its proximal end 3a
is tightly fitted into the opening 11 of the holding furnace wall 2 and is held so as to protrude horizontally from the holding furnace wall 2, and the base end of the graphite mold 6 of the water cooling jacket 5 is tightly fitted into the other end 3b. is,
The water cooling jacket 5 and the graphite mold 6 are also horizontally protruded adjacent to the molten metal guide section 3.

A feature of the device of the present invention is that the hot water guide section 3 has a heating element 4 built into its heat-resistant material 10. The heating element 4 may be a heater, an induction coil, or the like, but is not particularly limited. Further, a plurality of heating elements 4 may be built in at regular intervals, or may be built in a coil shape, and
This heating element 4.

The temperature can be adjusted so that the temperature of the molten metal in the introducing section 3 immediately before being poured into the graphite mold 6 can be maintained uniform at all times.

In addition, an electromagnetic stirring device 12 (rotary coil type, linear coil type) is installed on the outer circumferential side of the hot water introduction part 3.

If a solenoid coil type, etc.) is installed, the hot water lead section 3
Since the molten metal therein is supplied into the graphite mold 6 in the form of a stirring rotational flow, it is more effective in eliminating temperature differences, and high quality slabs 8 can be obtained.

On the other hand, the graphite mold 6 has an inner diameter shaped like the outer diameter of the slab 8 and is tightly fitted into the water-cooled jacket 5, forming a so-called water-cooled mold section. This water-cooled mold part is fixed in a horizontal state as shown in FIG. 5, and a water supply pipe 13 and a drain pipe 14 are connected to the water-cooled jacket 5.

[Action of the invention]

In the sprue system of the above embodiment configured in this way, the molten metal 1 discharged from the holding furnace is first fed into the molten metal conduit section 9 of the molten metal introduction section 3 in a completely unsolidified state and while maintaining the molten metal temperature uniformly at all times. It is supplied to the water-cooled mold section, solidifies once it enters the water-cooled mold section, and forms a slab 8 of a predetermined shape.

〔Effect of the invention〕

As explained above, the continuous casting apparatus of the present invention uniformly heats the molten metal in the introducing section interposed between the holding furnace and the water-cooled mold, thereby eliminating the temperature difference between the upper and lower sides of the introducing section.
Since the structure is such that molten metal at a constant temperature can be supplied into the water-cooled mold, a solidified shell is formed only in the mold, and uniform solidification occurs. The i1 layer can be developed.

As a result, various drawbacks that occurred in conventional equipment, such as (1) rough surface of the slab, (2) variations in dimensional accuracy and segregation, and (2) deep stroke marks, were eliminated.

Furthermore, the most important effect of the present invention is that the apparatus of the present invention enables the casting of thin-walled castings (approximately 2 to 3 I thick), which was considered impossible with conventional apparatus.

The reason for this is that it is possible to prevent uneven solidified shells occurring at the mold tip, to form solidified shells for the first time within the mold, and to develop a uniform and healthy solidified layer.

Furthermore, since molten metal at a constant temperature is poured into the mold, operating conditions are stable, which has a significant effect on improving productivity.

In the above embodiments, a horizontal continuous casting apparatus has been described, but a vertical continuous casting apparatus can be used in the same manner, and the same effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal sectional view of a sprue system of an apparatus according to an embodiment of the present invention, and FIGS. 2 to 4 are schematic longitudinal sectional views of a sprue system of a conventional apparatus. 3... Molten metal introduction part 4... Heating element 5... Water cooling jacket 8... Slab 10... Heat resistant material 12... Electromagnetic stirring device, Ishio-Yukigorutou 4 Genqtoichi' entrance/Morning '→Ka+2 to Sakukirimon

Claims (1)

[Scope of Claims] 1) A continuous casting apparatus characterized in that a melt guide section made of a heat-resistant material and having a built-in heating element is interposed between a holding furnace and a water-cooled mold. 2) The continuous casting apparatus according to claim 1, wherein the heating element is a heat generating heater. 3) The continuous casting apparatus according to claim 1, wherein the heating element is an induction coil.