JPH07106426B2 - Continuous casting method for hollow ingot - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a continuous casting method for hollow ingots, and more specifically, at the start of casting a hollow ingot, the core is wrapped and cast. The present invention relates to a casting start method for smoothly solving casting troubles such as molten metal flowing out from the inside of a lump.

(Prior Art) A hollow ingot which is a processing material for rolling a light metal such as aluminum is generally manufactured by a continuous casting method. That is,
The molten metal is continuously supplied to one end of a cylindrical mold that is held horizontally or vertically, and the metal formed into a hollow shape by the mold and the core is continuously withdrawn from the other end. Typical examples of the apparatus for carrying out such a continuous casting process are those having a forced cooling core shown in Japanese Patent Publication No. 45-19584 in the horizontal system, and those disclosed in Japanese Patent Application Laid-Open No. 54-72725 in the vertical system. A non-forced cooling core is known. There is also a combination of horizontal type and non-forced cooling core or vertical type and forced cooling core.

At the start of the continuous casting method for both horizontal and vertical methods, the drawing side of the tubular water-cooled mold is closed by a pedestal that is movable in the casting direction, and it is continuously connected to the annular mold space formed by the cylindrical mold and the core. While supplying the molten metal to the molten metal, the supplied molten metal is sequentially solidified at an appropriate position in the mold space, and the molten metal is solidified on the moving pedestal arranged so as to seal the drawing end of the casting space at the joining portion. From the stage of reaching the state where the hollow billet is formed, the pedestal is moved to draw out the hollow billet, and the ingot is cooled with or without jetting cooling water to the inner and outer peripheral surfaces of the drawn hollow billet. The supply of molten metal to the mold space is usually HotTop.
It is carried out through a refractory insulation container called as, or directly supplying hot water into the mold space by providing one or more supply devices capable of controlling the melt level consisting of a float and a dip tube. There are many.

In the start of casting as outlined above, the molten metal outlet temperature, the amount of cooling water in the mold, etc. are monitored, and the movement of the pedestal is started and moved again in consideration of the timing at which the molten metal on the moving pedestal has cooled and solidified. Although the moving speed of the pedestal inside is delicately controlled, the reality is that the skill of the operator must be used to carry out this series of operations.

(Problems to be Solved by the Invention) As described above, since the casting of the hollow billet is started empirically, when the casting factor such as the tapping temperature is out of the standard range, The metal melt solidified by cooling solidifies and shrinks to cast over the core, or conversely the solidified shell is so small that the melt flows out to the core side, making it difficult to continue casting. To do.

By the way, in the casting of the core ingot, in order to achieve the two purposes of stabilizing the start of casting and smoothing the casting surface, the core has a large diameter at the upper part of the molten metal immersion portion, It is essential that the lower diameter has a reduced draft. The larger the draft, the greater the effect, but specific casting defects are more likely to occur. That is,
When casting is performed in a state where the core has a large draft, a large wrapping pattern on the inner surface of the hollow ingot or a casting surface defect such as dripping on the inner surface of the unsolidified bath water is likely to occur. Therefore, it is not preferable to increase the draft in terms of ingot quality.

Further, in the continuous casting state in which the ingot is continuously drawn, the solidification shrinkage of the metal is generated between the molten metal or the solidified shell, which is to form the hollow inner surface, and the outer peripheral surface of the core. Along with this, frictional resistance is generated, and solidification shrinkage increases toward the casting method, so that frictional resistance below the core increases, so the core is drafted to avoid the resistance. Therefore, if the draft is too small, the frictional resistance will increase and a crack will form on the circumference of the hollow inner surface of the ingot, and the molten metal will flow out from the cracked part, or the core will be cast up and cannot be cast. Difficulty such as falling into. Therefore, in general, the core draft has an optimum range that is set for each alloy type and each dimension of the hollow ingot in order to make the casting surface of the hollow inner surface to be higher than the standard quality.

The core casting problem is most likely to occur when the forced cooling core is applied. That is, at the start of casting, when the molten metal flows into the annular hollow space formed by the core, the mold and the pedestal, the molten metal is rapidly cooled on the outer peripheral wall surface of the forced cooling core to form a solidified shell. To form,
The solidified shell develops quickly because the core is forcibly cooled. Further, since the molten metal is cooled in the process of the inflow movement between the portion directly below the pouring portion into the hollow space and the opposite side, an imbalance of cooling occurs, and the thickness of the solidified shell formed on the pedestal , The height varies depending on the place. Therefore, the timing of descending the pedestal and setting range of other casting conditions are narrow, especially when casting a thin hollow ingot with a thickness of about 8 mm to 50 mm with a mold with a forced cooling core, it is very difficult to start. Becomes

On the other hand, in the case of a heat insulating core, it depends on the material and size of the core to be used.For example, in the case of a commonly known graphite core, the thermal conductivity is higher than that of a fire resistant heat insulating material. Therefore, when used at room temperature, the same problems as those seen in the forced cooling core are likely to occur. Therefore, the graphite core may be preheated before use.
Not only does this preheating take a lot of time during mass production,
It is, in fact, extremely difficult to keep the core temperature at the start at a constant temperature range.

An object of the present invention is, in an apparatus for continuously casting a hollow ingot, solves the above-mentioned drawbacks that occur at the start of casting, and continuously casts a good-quality hollow ingot with no defects on the hollow inner surface casting surface. To provide a method.

(Means for Solving Problems) According to the present invention, a cylindrical forced cooling mold and a core having a taper on the drawing side are provided inside the mold, and one end between the cooling mold and the core is moved and received. In a continuous casting method of a hollow ingot, which is closed by a table, is supplied with a molten metal from the other end, and a hollow ingot formed by solidification of the molten solution is pulled out by a moving pedestal, at least the core The peripheral surface and, if necessary, the inner wall surface of the cylindrical mold and / or the surface of the pedestal that is in contact with the molten metal is coated with a fire-resistant heat insulating material, and the refractory heat-insulating material is cast-in as the molten metal melts. It is characterized in that the hollow ingot is started so as to be pulled out by a moving pedestal. In order to carry out this method, the present invention relates to a first embodiment in which the outer peripheral surface of the core is coated with only the fire insulating ring, and the outer peripheral surface of the core and the wall surface of the forced cooling mold are coated with the fire insulating ring. In addition to the second embodiment, the outer peripheral surface of the core, the inner wall surface of the forced cooling mold, and the upper surface of the moving pedestal are covered with a fire insulating ring, which can be embodied as the third embodiment.

That is, in the first embodiment of the present invention, the outer peripheral surface of the core is covered with a fireproof heat insulating ring to improve the thermal effect of the portion where the molten metal comes into contact with the core at the start of casting, It delays the growth of solidified shells on the outer peripheral surface.

The second embodiment improves not only the thermal effect of the core but also the thermal effect of the portion where the molten metal comes into contact with the mold at the start of casting by coating the inner wall of the mold with a fireproof heat insulating ring. The solidification is directed so that the solidification proceeds only by cooling from the pedestal, and the solidification of the molten metal in the hollow casting passage formed by the three surfaces of the core, the mold and the pedestal is delayed.

The third embodiment also improves the thermal effect from the moving pedestal and keeps the hollow casting channels adiabatic,
It is also possible to stably start the casting of a thin hollow ingot.

In a fourth embodiment, in the first to third embodiments, a projection made of a material that is not melted by the molten metal is fixedly provided on the surface of the moving pedestal, the projection is cast-in, and then the pedestal is fixed. By pulling out, a more stable start can be achieved.

As the fireproof heat insulating material used for coating in these embodiments, various materials having fireproof heat insulating properties at the temperature of the molten metal are selected. For example, for molten metal of aluminum or its alloys, a fireproof heat insulating material of a sheet made of various ceramic fibers or a ring-shaped sheet formed by sludge casting thereof is used. Alumina fiber, asbestos fiber, glass fiber , Carbon fiber, hardened marinite, etc. are suitable. Typical examples of commercially available products include ceramics paper (trade name, manufactured by Toshiba Monoflux Co., Ltd.) and Ibi wool paper (trade name, manufactured by Ibiden Co., Ltd.). The thermal conductivity of these materials is low, for example, Ibiwool paper (thickness 1mm), 700 ℃ ~ 600
The temperature is about 0.11 to 0.08 Kcal / mh ° C. These materials and their thickness are selected in consideration of the type of molten metal, temperature, heat capacity of the entire mold block, cooling conditions, and the like. The thickness will generally be in the range 0.5-3 mm.

Further, as a preferred specific example of these fire-resistant heat-insulating rings, those provided with protrusions that are unlikely to be damaged by the molten metal on the surface of the ring that comes into contact with the molten metal, the core, the wall of either or both of the molds There are holes that reach the middle or upper part of the ring, holes that reach the upper surface of the pedestal are drilled in the middle part of the ring, or a combination thereof. In these specific examples, projections, perforations and the like are fixed to the solidified metal mass at the start of casting, and the ring can be more stably released from the outer peripheral surface of the core and the inner peripheral surface of the mold. Further, it is effective that the protrusions on the movable pedestal surface in the fourth embodiment are fixedly provided with a single bolt or a plurality of thin rods or the like, but normally, two or three rods are arranged at equal intervals. Is enough.

(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows a state in which casting is started in an apparatus for continuously producing a cylindrical hollow billet. FIG. 2 is a partially enlarged view thereof. A core 8 is provided in the hollow part of the mold 1 opened up and down, and a metal melt 17 flows into an annular passage formed between the mold 1 and the core 8, and the metal melt 17 is fitted into the annular passage. It is held by the combined moving pedestal 16. Mold 1
A cooling chamber 3 is provided in the interior thereof, cooling water is introduced through a water conduit 2 to cool the casting mold 1, and at the same time, the cooling water radiated from the end of the casting mold 1 through the discharge hole 3a moves the pedestal 16 or the casting. Continuous cooling of the outer surface of the ingot enables continuous casting of the hollow ingot. Further, a refractory heat insulating container called a header 7 is provided on the upper part of the mold to store the molten metal 17, and the molten metal is continuously supplied to the annular passage.

On the inner surface of the mold 1, there are pores or slits 6 formed along the circumference with an open end in the annular groove 5 at the upper part of the inner surface of the mold.
Thus, the lubricating oil is continuously supplied to lubricate the molten metal 17 and the inner surface of the mold 1. Lubricating oil is mold 1
It is supplied by a supply pipe 4 connected to and is fed to an annular groove 5 formed in an annular shape inside the mold.

In addition, the lower surface of the header protruding from the mold through the slit 53 provided on the upper surface of the mold, which is the joint surface between the header 7 placed on the upper part of the mold 1 and the upper surface of the mold, the inner surface of the mold, and the outer peripheral surface of the molten metal column. Introduce gas to the formed corner,
By applying pressure to the outer peripheral surface of the columnar molten metal, the chance of contact between the molten metal and the inner surface of the mold is reduced, and the casting surface of the ingot is improved. The gas is introduced into the annular groove 52 formed on the upper surface of the mold through the conduit 51, and is supplied to the slit 53 whose end is open to the annular groove 52.

The core 8 is suspended in the hollow portion of the mold 1 by an external holding mechanism. The core 8 is provided with a cooling chamber 10, and the cooling water in the cooling chamber 10 is supplied from the outside through a water conduit 9 and discharged to the outside of the core through a hole or slit 11 at the outer edge of the lower end of the core. The discharged water cools the moving pedestal 16 in the initial stage of casting and cools the inner surface of the hollow ingot after the start of casting drawing. By this cooling action, continuous casting of the hollow ingot is performed while maintaining the solidification interface at an appropriate position in the casting direction. Lubricating oil and gas are supplied to the core 8 for lubrication and gas pressurization, respectively. In FIGS. 1 and 2, 12 is a lubricating oil, 54 is a gas annular passage, 14 is a pore or slit having an open end at the annular passage 13, and 55 is an annular passage 52. As in the case of the mold 1, a lubricating oil and a gas are supplied to the inner surface of the core 8 respectively. In casting, the fireproof heat insulating ring 19 is fitted to the outer peripheral surface of the core. The molten metal forms a solidified shell 18 under the action of the primary cooling by the pedestal 16 and the mold 1 that receive the molten metal in the state where it is inserted in the casting apparatus, but the refractory heat insulating ring is formed on the core 8 side. The solidified shell 18 does not develop due to the presence of 19. On the other hand, FIG. 16 shows a case where the fireproof heat insulating ring 19 is not provided.
Grows on the outer peripheral surface of the core 8 to the same thickness as the other surfaces, and the core 8 is cast in the mold as the solidification shell shrinks. A draft 8a is formed on the outer peripheral surface of the core 8,
If the cast-in force is large, the role of the draft 8a cannot be fulfilled.

In FIG. 3 showing the state where the casting has proceeded further than FIG. 1, the solidified shell 18 has further developed, and finally the solidified shell 18 is also formed on the fire resistant heat insulating ring 19, and the fire resistant heat insulating ring is cast. It will be wrapped. In this state, the fireproof insulation ring 19
Is detachably coated on the core 8 so as to be pulled out at the start of casting. If the fire-resistant heat-insulating ring 19 is integrated with the core 8, if the movable pedestal 16 is pulled out when the ring 8 is in the cast-in state, the pull-heat insulating ring 19
The object of the present invention cannot be achieved because some of the debris are caught in the solidified shell 18 and cause casting defects. Therefore, in order to be able to pull out the fireproof heat insulating ring 19 together with the ingot, the pull heat insulating ring 19 is loosely fitted to the core 8.
One or more measures such as roughening the surface of the ring 19, forming irregularities, and netting the entire ring 19 are adopted.

In order to ensure that the fire-resistant and heat-insulating ring 19 can be pulled out together with the movable pedestal 16, the solidified shell 18 and the ring 19 must be connected more securely. A preferred method for this will be described with reference to FIGS.

In FIG. 4 in which details of the mold 1 and the core 8 are omitted, reference numeral 30 denotes a protrusion made of a material that is not damaged by the molten metal 17 (for example, steel in the case of the molten aluminum alloy 17) and has a fire insulation property. It penetrates through the ring 19 and projects into the casting path, and is cast and wrapped by the molten metal 17. The protrusion 30 shown in the figure has a "U" shape and has a portion facing the core 8,
Since this part is the reinforcement part of the part that protrudes to the inner surface,
Not required. Since it has developed as shown in Fig. 4,
The solidified shell 18 envelops the projection 30 to ensure the connection between the solidified shell 18 and the fireproof heat insulating ring 19. When the ingot thus combined is pulled out together with the moving pedestal 16, as shown in FIG. 5, the solidified shell 18 further develops during pulling and the whole (18, 19, 30) descends.

In the partially enlarged view of the fireproof heat insulating ring 19 shown in FIGS. 6A and 6B, a staple ball is used for the protrusion 30. Reference numeral 31 is a cooling groove formed by forming a U- or V-shaped notch on the upper edge of the fire-resistant heat-insulating ring 19, and acts as a solidification starting point where the molten metal enters this portion and starts solidification. . Therefore, by providing the cooling groove 31, the casting is further improved in cooperation with the action of the projection 30, and the fire-resistant heat-insulating ring 19 completely cast in the solidified metal surely descends together with the moving pedestal. .

FIG. 7 shows a cooling hole 32 which has the same function as the cooling groove. That is, in the initial stage of casting, the molten metal that has entered the cooling holes 32 solidifies faster than the main surface of the refractory heat insulating ring 19, so that the cooling holes 32 serve as solidification starting points. The preferred diameter of the cooling holes 32 is in the range of 1.5 to 15 mm. Below this lower limit, the effect is small, and above the upper limit, the fire-resistant heat-insulating ring 30.
It becomes difficult to reduce the chilling effect of the core due to the main surface of. The cooling hole 32 is not limited to the circular shape as described above, and may have a rectangular shape, a triangular shape, a polygonal shape, or a slit shape as long as the cross-sectional area is satisfied.

A specific example of the second embodiment relating to the position of the fireproof heat insulating ring will be described with reference to the drawings (FIG. 8, FIG. 9, FIG. 10).

FIG. 8 is a drawing showing a casting apparatus of the same portion at the same casting time as FIG. The fireproof heat insulating rings 19 and 20 are arranged along the outer peripheral surface of the core 8 and the inner peripheral surface of the mold 1, respectively, and as a result, solidification along the peripheral surfaces of the mold 1 and the core 8 is suppressed, and the rings move. A directivity that promotes solidification due to heat removal from the pedestal 16 appears, and as a result, the growth interface of the solidified shell 18 becomes flat. As a result, core 8, mold 1, moving pedestal
Solidification is delayed in the hollow casting path composed of 16 members, and the drawing timing tolerance is greatly eased. The fireproof heat insulating ring 20 on the mold 1 side also needs to be pulled out together with the ingot in the same manner as described for the ring 19 on the core 8 side with reference to FIG. Also, FIGS. 9 and 10 are drawings corresponding to FIGS. 4 and 5, respectively, in which the solidified shell 18 is made of a fireproof heat insulating ring on both the mold side and the core side by the action of the projections 30 and 30 '. Tightly bond with 19.

Furthermore, a specific example of the third embodiment will be described with reference to the drawing (FIG. 11). FIG. 11 is a drawing showing the same casting device section at the same casting time as FIG. The fireproof heat insulating rings 19 and 20 are arranged along the outer peripheral surface of the core 8 and the inner peripheral surface of the mold 1, respectively.
Is placed on the movable pedestal 16, and as a result, solidification in the hollow casting passage is delayed and the drawing timing tolerance is further relaxed. In addition, fire-resistant heat-insulating rings 20, 21 and the same sheet
22 needs to be pulled out together with the ingot, as described with reference to FIG.

FIG. 12 shows that the fire-resistant heat-insulating rings 19 and 20 and the fire-resistant heat-insulating sheet 22 shown in FIG. 11 are integrally formed, and a large number of cooling holes 32 and 33 are formed on the U-shaped wall surface, respectively. ) Shows a specific example. In this example, solidification delaying action by each wall and refractory heat insulating ring (sheet) by cooling holes
The cast-in action of (1) simultaneously progresses, and favorable results are obtained. The number and area of the cooling holes are determined so that the solidification retarding action does not become inactive.

In the specific example of the third embodiment, FIG. 13 and FIG.
As shown in the figure, the moving pedestal is coated only on a part of its upper surface. In the case of FIG. 14, the solidified shell first starts to grow from the uncovered portion of the moving pedestal 16 and develops in the vertical and horizontal directions, and eventually the peripheral portion of the solidified shell reaches the end of the refractory heat insulating ring 21,
Furthermore, it grows so as to crawl on it. After a little more time, a solidified shell is thinly formed on the surfaces of the fireproof heat insulating ring 19 covering the core 8 and the mold 1 side. When this stage is reached, the solidified shell is firmly connected to the moving pedestal 16 and the refractory insulating ring 19 so that
When 16 is pulled out, they are pulled together with the ingot.

A specific example of the fourth embodiment will be described with reference to the drawings (FIGS. 17, 18, and 19).

FIG. 17 is a drawing showing a principal part of the same casting apparatus at the same casting time as FIG. A hole 41 is formed in the movable pedestal 16, and a steel bolt 42 is screwed into the hole 41. FIG. 18 is a drawing showing a principal part of the same casting apparatus at the same casting time as FIG. A steel wire 43 having a head bent in an inverted L shape is driven into a hole 41 formed in the movable pedestal 16.

In these FIGS. 17 and 18, the solidified shell 18 that has grown encases the bolt 42 or the steel wire 43. This solidifies the shell 18
Is more firmly connected to the moving pedestal 16, so that when the moving pedestal 16 is pulled out, the moving pedestal 16, the solidified shell 18, and the fireproof heat insulating ring 19 are reliably pulled out as a unit. As a result, the start of casting is extremely stable.

FIG. 19 is a drawing showing a principal part of the same casting apparatus at the same casting time as FIG. 14. On the movable pedestal 16, a hole 41 is formed at a corresponding position in the non-covered portion of the fireproof heat insulating ring 21, and a steel nail 42 is driven into the hole 41. The solidified shell starts to grow from the uncovered portion of the moving pedestal 16 and thinly develops along the steel nail 42 and on the upper surface of the fireproof heat insulating ring. Over time, the solidified shell casts on the steel nail and bonds with the solidified shell developed from the adjacent uncoated portion.

In this way, the solidified shell 18 and the fire-resistant heat-insulating rings 19, 21 are firmly connected to the moving pedestal 16 by the steel nails 42, and are reliably pulled out together when the moving pedestal 16 is pulled out. , The start of casting will be quite stable.

In the above description of the embodiments and specific examples, the description has been given of the case where the refractory heat insulating ring that is the feature of the present invention is applied to the forced cooling core, but the present invention is also applied to the non-forced cooling core. be able to. That is, the non-forced cooling core is usually preheated to start casting in order to moderate the degree of cooling, but in the case of a core used without being preheated, especially a graphite core, there is a problem of core encapsulation. Therefore, when the non-preheated core is covered with the fireproof heat insulating ring, the same effect as the forced cooling core can be obtained. Even if a non-preheated core is used, the pulling timing of the moving pedestal can be determined with a margin if one casting is performed. However, since mass production scale continuous casting is multi-casting, the molten metal inflow speed into each mold is variable, and it is extremely difficult to determine the timing of pulling the moving cradle that supports all the ingots all at once. Become. Therefore, if the core is sufficiently preheated, this difficulty can be solved to some extent, but it is still effective to apply the fireproof heat insulating ring according to the present invention to the core.

Further, although the vertical continuous casting apparatus has been described in the above description of the embodiments and specific examples, the present invention can be similarly applied to the horizontal continuous casting apparatus as shown in FIG. In FIG. 15, 1 is a cylindrical mold forcibly cooled by cooling water 3, cores 8 and 80 made of graphite and held concentrically inside thereof are a molten metal receiving tank, and 81 is an intermediate portion between the molten metal receiving tank and the mold 1. And 82 are intermediate orifice plates for connecting these, 82 is a molten metal injection pipe, 83 is a moving pedestal, and 84 is a drawing rod of the moving pedestal. In such a horizontal continuous casting apparatus, the temperature of the molten metal is high in the vicinity where the molten metal flows from the injection pipe 82, but the temperature of the molten metal decreases on the side opposite to the inflow position (about 20 ° C. in the case of an aluminum alloy).
Therefore, especially in a thin hollow ingot, imbalance of solidification occurs due to the temperature difference, and it becomes very difficult to set the pulling timing of the moving pedestal 83. In order to overcome such difficulties, the solidification of the molten metal of the refractory heat insulating material 19 of the present invention is promoted. It is very effective to arrange them on the outer peripheral surface of the core and the upper surface of the movable pedestal 83.

It goes without saying that the present invention is not limited to the case where the core is held concentrically with respect to the mold, but is similarly applied to the continuous casting of non-concentric cores, that is, uneven thickness hollow ingots. In the case of a non-concentric core, the third embodiment is suitable for a site where the space between the mold and the core is narrow, and the first embodiment is suitable for a site where the space is wide, By such combination, it is possible to eliminate the cooling imbalance and achieve stable continuous casting.

(Operation) According to the present invention, at least the fire-resistant heat-insulating ring that covers the core does not cast the core, but acts as a joint with the molten metal, and is pulled together with the ingot, resulting in smoothing of the casting surface. It is possible to highly satisfy the contradictory requirements of forming a strong pull-out joint.

(Effect of the invention) As a result, a considerable variation is allowed in the time from the pouring of the molten metal into the mold to the start of the drawing of the moving pedestal, which improves the surface quality and yield of the ingot, It brings quality and high productivity.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a vertical continuous casting apparatus showing an embodiment of the present invention in which a coating with a fireproof heat insulating ring is applied to a core, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. Drawings showing a state in which solidification has progressed from the state shown in Fig. 1 and the movable pedestal 16 can be pulled out. Figs. 4 and 5 are fire-resistant heat-insulating rings with projections shown in Fig. 6. FIG. 6 (a) is a cross-sectional view for explaining a casting start performed by using FIG. 6, FIG. 6 (a) is a drawing showing a specific example in which a projection is provided on a fireproof heat insulating ring, and FIG. )-(A) sectional view, FIG. 7 is a drawing showing a specific example in which cooling holes are formed in the fireproof heat insulating ring, and FIG. 8 is an embodiment in which the coating by the fire heat insulating ring is applied to the core and the mold. The same drawing as in FIG. 1 is shown, and FIGS. 9 and 10 are made by forming projections on the fireproof heat insulating ring of FIG. FIG. 11 is a cross-sectional view for explaining the pulling-out start, and FIG. 11 is a drawing similar to FIG. FIG. 12 is a perspective view showing a concrete example in which the fire resistant heat insulating ring (sheet) of FIG. 11 is integrated, FIG. 13 is a conceptual diagram showing a modification of the embodiment of FIG. 11, and FIG. A drawing similar to FIG. 13, FIG. 15 is a cross-sectional view showing an embodiment in which the present invention is applied to a horizontal continuous casting apparatus, FIG. 16 is an explanatory view of the start of casting by the conventional method, and FIG. FIG. 18 is a cross-sectional view showing an embodiment in which bolts are fixedly mounted on the receiving surface of the drawing, and FIG. 18 is a sectional view showing an embodiment in which protrusions of inverted L-shaped steel wires are fixedly mounted on the receiving surface of FIG. FIG. 19 is a sectional view showing an embodiment in which steel nails are fixedly mounted on the receiving surface of FIG. 1 ... Mold, 3 ... Cooling chamber, 5 ... Annular groove, 7 ... Header, 8 ... Core, 12 ... Lubricating oil annular passage, 16 ... Moving cradle, 19 ... Fire insulation ring

Claims (6)

[Claims] 1. A cylindrical forced cooling mold held vertically or horizontally and a core having a taper on the pulling side provided inside thereof, and one end between the cooling mold and the core is a moving pedestal. Close,
In a continuous casting method of a hollow ingot which is supplied with a molten metal from the other end, and a hollow ingot formed by solidification of the molten metal is pulled out by a moving pedestal, at least the molten metal on the peripheral surface of the core is Continuous casting of a hollow ingot, characterized in that the contact surface is coated with a refractory heat insulating material, and the solidified metal melt solidifies the hollow refractory insulating material to start the hollow ingot to be pulled out by a moving pedestal. Method. 2. A refractory heat insulating material is coated on an inner wall surface of the cylindrical mold and / or a surface of the movable pedestal, which is in contact with the molten metal, and is cast and wrapped by the molten metal.
Method described in section. 3. The method according to claim 1, wherein a refractory heat insulating material having a protrusion made of a material that is not melted by the molten metal is used to cast and encase the protrusion, and then the movable pedestal is pulled out. the method of. 4. A projection which is made of a material that is not melted by molten metal is fixedly provided on the surface of the movable pedestal, the projection is cast-in, and then the movable pedestal is pulled out. The method according to the range 1 or 2. 5. A refractory heat insulating material having a hole penetrating a wall surface of the refractory heat insulating material is used, and after the molten metal is solidified in the through hole,
Claim 1 characterized in that the movable cradle is pulled out.
The method according to Item 2 or Item 2. 6. A groove is formed in an upper end edge of a ring of a refractory heat insulating material coated on the peripheral surface of the core, and the moving pedestal is pulled out after the molten metal is solidified in the groove. The method according to any one of claims 1 to 3, wherein