JP7207069B2 - Casting material manufacturing method - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to methods for manufacturing cast materials.

In Patent Document 1, a casting material is produced by injecting a molten metal (molten metal) into a mold space formed by a pair of block trains in which a plurality of dam blocks are connected by straps, and an upper belt and a lower belt sandwiching the aligned block trains. A method for continuous casting of is disclosed. Injection of molten metal into the mold space takes place from the tundish.

JP 2009-269053 A

A tundish generally comprises a main body for storing molten metal and a pouring part extending from the main body to the mold space. The pouring part has a region (hereinafter referred to as an exposed region) in which molten metal flowing therein is exposed to the atmosphere. Fluctuations in the surface of the molten metal flowing inside the pouring section can cause constituent metals of the molten metal to adhere to the inner surface of the pouring section. When this attachment point is the exposed region, the attached constituent metal is oxidized. If oxides adhere to the molten metal surface in the pouring part, the flow of the molten metal becomes unstable, which may adversely affect the resulting cast material, such as uneven solidification. In addition, if the oxide falls into the molten metal, it may become mixed with the resulting cast material as a foreign matter and cause wire breakage during processing of the cast material.

Accordingly, one of the objects of the present disclosure is to provide a method for producing a cast material that enables stable casting and obtains a high-quality cast material.

The method for manufacturing the cast material of the present disclosure includes:
A cast material is continuously cast by injecting molten metal from a tundish into a space composed of a pair of block groups in which a plurality of dam blocks are connected by straps and a pair of belts sandwiching the block groups. A manufacturing method comprising:
The injection of the molten metal from the tundish into the space is performed while heating a region between the tundish and the space where the molten metal is exposed to the atmosphere with a reducing flame.

The casting material manufacturing method of the present disclosure can perform stable casting and obtain a high-quality casting material

FIG. 1 is a schematic configuration diagram showing a twin-belt continuous casting apparatus that is used in a method for producing a cast material according to an embodiment.

[Description of Embodiments of the Present Disclosure]
First, the contents of the embodiments of the present disclosure will be listed and described.

(1) A method for manufacturing a cast material according to the present disclosure includes:
A cast material is continuously cast by injecting molten metal from a tundish into a space composed of a pair of block groups in which a plurality of dam blocks are connected by straps and a pair of belts sandwiching the block groups. A manufacturing method comprising:
The injection of the molten metal from the tundish into the space is performed while heating a region between the tundish and the space where the molten metal is exposed to the atmosphere with a reducing flame.

Of the areas where the molten metal flows (hereinafter referred to as the pouring section) between the tundish and the space (hereinafter sometimes referred to as the mold space), the area where the molten metal is exposed to the atmosphere (hereinafter referred to as the exposed area) ) can be heated with a reducing flame to shield the exposed area from the atmosphere. Further, by heating with a reducing flame, the exposed region can be substantially brought into a reducing atmosphere. Therefore, even if the surface of the molten metal flowing inside the pouring portion fluctuates and the constituent metals of the molten metal adhere to the inner surface of the pouring portion, the adhering constituent metals can be prevented from being oxidized. By suppressing the formation of oxides in the vicinity of the molten metal surface position in the pouring part, it is possible to ensure a stable flow of the molten metal and to suppress adverse effects on the obtained cast material. In addition, by suppressing the formation of oxides in the vicinity of the molten metal surface position in the pouring part, it is possible to suppress the inclusion of oxides as foreign matter in the obtained cast material. As described above, according to the method for manufacturing a cast material of the present disclosure, stable casting can be performed and a high-quality cast material can be obtained.

(2) As an example of the method for manufacturing the cast material of the present disclosure,
The heating may be performed by covering the entire region with the reducing flame.

By heating the entire exposed area with a reducing flame, the exposed area can be more effectively shielded from the atmosphere. Therefore, it is possible to more effectively suppress the adhesion of oxides to the inner surface of the pouring portion.

(3) As an example of the method for manufacturing the cast material of the present disclosure,
The injection of the molten metal from the tundish into the space may be performed while electromagnetically measuring the surface height of the molten metal injected into the space.

Continuous casting is generally performed while checking the surface height of the molten metal poured into the mold space. When the exposed area of the pouring part is heated with a reducing flame as in the present disclosure, the molten metal injection port side in the mold space is blocked by the reducing flame, making it difficult to check the inside of the mold space from the injection port side. Therefore, by electromagnetically measuring the surface height of the molten metal in the mold space, it is possible to continuously check the surface height of the molten metal in the mold space without checking the inside of the mold space from the injection port side in the mold space. Can be cast. Therefore, even if the exposed region of the pouring portion is heated by the reducing flame, efficient continuous casting can be performed.

(4) As an example of the method for manufacturing the cast material of the present disclosure,
The molten metal may be a copper alloy containing 0.05% by mass or more and 1.0% by mass or less of tin, with the balance being copper and unavoidable impurities.

When tin is contained in the molten metal, if tin adheres to the inner surface of the pouring portion and comes into contact with the atmosphere, tin oxides are likely to be generated. By heating the exposed region of the pouring part with a reducing flame, even if easily oxidizable tin is contained in the molten metal, the oxidation of tin can be suppressed. As described above, even if the molten metal contains tin, which is easily oxidized, stable casting can be performed and a high-quality cast material can be obtained.

[Details of the embodiment of the present disclosure]
Details of embodiments of the present disclosure are described below with reference to the drawings. The present invention is not limited to these exemplifications, but is indicated by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims. The same reference numerals in the drawings indicate the same names.

<Overview>
The casting material manufacturing method of the embodiment uses the twin-belt continuous casting apparatus 1 shown in FIG. ) to continuously cast the casting material 200 by pouring the molten metal 100 into. Pouring of the melt 100 into the mold space 7 takes place from the tundish 2 . In the casting material manufacturing method of the embodiment, when pouring the molten metal 100 from the tundish 2 into the mold space 7, the exposed region 23 where the molten metal 100 is exposed to the atmosphere between the tundish 2 and the mold space 7 is exposed to a reducing flame. One of the features is that it is heated at 80°C. In this embodiment, the reducing flame 80 is obtained using the burner 8 . Hereinafter, with reference to FIG. 1, the twin-belt type continuous casting apparatus 1 used in the method for manufacturing cast materials will be described first, and then the method for manufacturing cast materials will be described.

In FIG. 1, for convenience of explanation, the exposed area 23 and the reducing flame 80 in the tundish 2 are exaggerated. For convenience of explanation, FIG. 1 schematically shows a surface 110 of the molten metal 100 poured into the mold space 7 and a process in which the molten metal 100 is solidified to produce the cast material 200. In FIG. 1, one block group 3 of the pair of block groups 3 is illustrated.

<Twin belt type continuous casting machine>
A twin-belt continuous casting apparatus 1 includes a tundish 2 , a pair of block groups 3 and a pair of belts 4 . A pair of block groups 3 are arranged to face each other on the left and right. A pair of belts 4 are arranged vertically facing each other with both block groups 3 interposed therebetween. The twin-belt type continuous casting apparatus 1 uses a mold space 7 as a rectangular space surrounded by a pair of block groups 3 and a pair of belts 4, and solidifies continuously poured molten metal 100 to form a cast material 200. Manufactured continuously. A known configuration can be referred to for the basic configuration of the twin-belt continuous casting apparatus 1 . The twin-belt continuous casting apparatus 1 of this example includes a burner 8 that heats an exposed area 23 between the tundish 2 and the mold space 7 where the molten metal 100 is exposed to the atmosphere with a reducing flame 80 .

≪Tundish≫
The tundish 2 has a body portion 21 and a pouring portion 22 . The body portion 21 is a container that temporarily stores the molten metal 100 supplied from a melting furnace (not shown). The body portion 21 is covered with a cover or the like so that the molten metal 100 inside is not exposed to the atmosphere. The pouring part 22 is a channel that extends outward from the body part 21 and pours the molten metal 100 into the mold space 7 . The pouring part 22 extends from the body part 21 to the mold space 7 . A pair of block groups 3 and a pair of belts 4 that constitute the mold space 7 are rotated by pulleys 5 as will be described later. Therefore, it is preferable not to provide a cover or the like at least in the vicinity of the mold space 7 in the pouring section 22 . This is because if a cover or the like is provided in the vicinity of the mold space 7, the cover or the like may be caught in the rotation of the pair of block groups 3 and the pair of belts 4. Therefore, the pouring part 22 is not covered with a cover or the like, and has an exposed area 23 where the molten metal 100 flowing inside is exposed to the atmosphere. In this example, the entire pouring portion 22 is provided with an exposed region 23 .

≪Block group≫
Each block group 3 is a member in which a plurality of dam blocks 31 are connected by endless straps 32 . The block group 3 constitutes both sides of the endless track mold. Dam block 31 is made of copper or a copper alloy. Strap 32 is made of stainless steel. A pair of block groups 3 are arranged facing left and right and sandwiched between a pair of belts 4 to be described later. Each block group 3 rotates in synchronization with rotation of the belt 4 . A portion of each block group 3 sandwiched by the belt 4 is restrained from moving up and down by the belt 4 . Guide portions (not shown) are arranged on the left and right outer sides of each block group 3 . This guide portion suppresses the lateral movement of the block group 3 .

The total length of the plurality of dam blocks 31 forming the block group 3 (in a non-thermally expanded state) is shorter than the circumferential length of the straps 32 of the block group 3 . The difference between the total length and the peripheral length prevents the molten metal 100 from leaking through the gaps between the adjacent dam blocks 31, and allows the block group 3 to move around.

The twin-belt continuous casting apparatus 1 includes a cooling bath 6 that cools a portion of each block group that is not sandwiched between the belts 4 . The cooling bath 6 is arranged in the vicinity of the discharge port of the casting material 200, and part of the block group 3 is continuously introduced. The cooling bath 6 can effectively cool the dam block 31 that has been heated in contact with the molten metal 100 and the cast material 200 .

≪Belt≫
Each belt 4 is an endless belt stretched over a plurality of pulleys 5 . Belt 4 is made of stainless steel. Each belt 4 runs (rotates) as the pulleys 5 rotate. A pair of belts 4 are arranged to face each other vertically, sandwiching a pair of block groups 3 . Both belts 4 constitute the upper and lower surfaces of the mold. A plurality of backup rolls 51 are arranged between the pulleys 5 on each belt 4 . The backup roll 51 suppresses vertical movement of the belt 4 . Both belts 4 are arranged so that their facing surfaces are parallel to each other, and are inclined with respect to the horizontal direction so that the side on which the molten metal 100 is poured from the tundish 2 is higher than the side on which the cast material 200 is discharged. ing. Each belt 4 is cooled by a cooling mechanism (not shown).

≪Burner≫
The burner 8 includes a tip portion 81 forming a tip portion and a joint tube 82 connected to the tip portion 81 . As the burner 8, a Bunsen burner, a propane gas burner, a butane gas burner, or the like can be used. The burner 8 is arranged at a location where the exposed area 23 of the pouring part 22 is covered with the reducing flame 80 and the inside of the exposed area 23 can be heated by the reducing flame 80 . In this example, the burner 8 is arranged near the body portion 21 of the tundish 2 and jets flame (reducing flame 80 ) from the body portion 21 side toward the pouring portion 22 .

The flame jetted from the burner 8 produces a reducing flame 80 (inner flame) inside an oxidizing flame (outer flame) having an oxidizing action. The flame of the burner 8 adjusts the amount of combustion gas and air mixed so that the exposed area 23 of the pouring part 22 is heated by the reducing flame 80 . The length and width of the reducing flame 80 can be adjusted by the crater of the tip portion 81 . The reducing flame 80 is preferably jetted so as to cover the entire exposed area 23 of the pouring section 22 . The length of the reducing flame 80 is, for example, 450 mm or more and 850 mm or less, 500 mm or more and 800 mm or less, further 550 mm or more and 750 mm or less, particularly 600 mm or more and 700 mm or less. For convenience of explanation, FIG. 1 shows only the reducing flame 80 among the flames injected from the burner 8 .

The reducing flame 80 may or may not enter the mold space 7 . Even if the reducing flame 80 does not enter the mold space 7, as long as it reaches the vicinity of the boundary between the pouring part 22 and the mold space 7, the effect of shielding the exposed region 23 of the pouring part 22 from the atmosphere is reduced. get enough. As long as the reduction flame 80 does not enter the mold space 7 and does not directly hit the surfaces of the block group 3 and the belt 4 , wear of the block group 3 and belt 4 by the burner 8 can be suppressed. The block group 3 and the belt 4 that constitute the mold space 7 are rotating. Therefore, the pouring part 22 side of the mold space 7 is exposed to the atmosphere, and even if the constituent metals of the molten metal 100 adhere to the block group 3 and the belt 4, the constituent metals are unlikely to be oxidized.

It is preferable that the position of the burner 8 with respect to the pouring part 22 is fixed. In this example, a cutout portion (not shown) is provided on the outer peripheral surface of the main body portion 21 of the tundish 2, and the coupling pipe 82 is fitted along the cutout portion for fixing.

<Molten metal>
The molten metal 100 consists of copper or a copper alloy. Copper is pure copper containing 99.9% by mass or more of copper (Cu). A specific example is tough pitch copper. The copper alloy is a copper-based alloy containing 50% by mass or more, preferably 90% by mass or more of Cu, and containing additional elements other than Cu. Examples of additive elements for copper alloys include tin (Sn) and silver (Ag). When Sn is contained as an additive element, the content of Sn is 0.05% by mass or more and 1.0% by mass or less, further 0.2% by mass or more and 0.8% by mass or less, particularly 0.3% by mass or more and 0 .7% by mass or less. When Ag is contained as an additive element, the content of Ag may be 0.05% by mass or more and 0.5% by mass or less, and more preferably 0.1% by mass or more and 0.4% by mass or less.

<Manufacturing method of casting material>
In the casting material manufacturing method, the twin belt type continuous casting apparatus 1 described above is used to continuously cast the casting material 200 by injecting the molten metal 100 from the tundish 2 into the mold space 7 . The pouring of the molten metal 100 from the tundish 2 into the mold space 7 is performed while heating the exposed region 23 of the pouring part 22 with the reducing flame 80 . Specifically, the exposed region 23 of the pouring portion 22 is covered with the reducing flame 80 jetted from the body portion 21 side of the tundish 2 and heated by the reducing flame 80 . At this time, it is preferable to cover the entire exposed region 23 of the pouring portion 22 with the reducing flame 80 . In particular, it is preferable to cover the entire exposed region 23 including the inner surface of the molten metal 100 near the surface of the molten metal 100 in the pouring part 22 with the reducing flame 80 . The exposed region 23 of the pouring part 22 is in a state of being blocked from the atmosphere by the reducing flame 80 . Also, the exposed region 23 of the pouring part 22 is substantially in a reducing atmosphere. Heating by the reducing flame 80 is continuously performed while the molten metal 100 is poured from the tundish 2 into the mold space 7 .

Continuous casting is performed while confirming the height of the molten metal surface 110 of the molten metal 100 poured into the mold space 7 . By doing so, the molten metal 100 can be stably injected into the mold space 7, the molten metal 100 can be solidified well in the mold space 7, and the casting material 200 of high quality can be easily obtained. The height of the surface 110 of the molten metal 100 in the mold space 7 is preferably measured electromagnetically. For example, it may be measured using a commercially available eddy current sensor 9 . Specifically, an eddy current is generated on the surfaces of the block group 3 and the belt 4 that constitute the mold space 7, and the eddy current sensor 9 detects the eddy current. If the surface 110 of the molten metal 100 in the mold space 7 is low, the exposed areas of the inner surfaces of the block group 3 and the belt 4 forming the mold space 7 are large, so that the generated eddy current is large. On the other hand, if the molten metal surface 110 of the molten metal 100 in the mold space 7 is high, the inner surfaces of the block group 3 and the belt 4 constituting the mold space 7 are shielded by the molten metal 100, so that the generated eddy current is small. . Therefore, the height of the surface 110 of the molten metal 100 in the mold space 7 can be grasped from the magnitude of the eddy current detected by the eddy current sensor 9 .

<Effect>
In the casting material manufacturing method described above, by heating the exposed region 23 of the pouring part 22 with the reducing flame 80, the exposed region 23 can be shielded from the atmosphere and the exposed region 23 can be substantially brought into a reducing atmosphere. In particular, by heating the entire exposed region 23 with the reducing flame 80, the exposed region 23 can be more effectively shielded from the atmosphere. By shielding the exposed region 23 from the atmosphere, the surface of the molten metal 100 flowing inside the pouring part 22 fluctuates. can suppress the oxidation of For example, even if the molten metal 100 contains tin, which is easily oxidized, and the tin adheres to the inner surface of the pouring part 22, the oxidation of tin can be suppressed. By suppressing the formation of oxides in the vicinity of the molten metal surface position in the pouring part 22, it is possible to ensure a stable flow of the molten metal 100 and to suppress adverse effects on the casting material 200 to be obtained. In addition, by suppressing the formation of oxides in the vicinity of the molten metal surface position in the pouring part 22, it is possible to suppress the inclusion of oxides as foreign matter in the cast material 200 to be obtained. As described above, according to the method for manufacturing the cast material, it is possible to perform stable casting and obtain the cast material 200 of high quality.

Further, in the method for manufacturing the cast material, the temperature of the molten metal 100 flowing inside the pouring portion 22 and the temperature of the inner surface of the pouring portion 22 are increased by heating the exposed region 23 of the pouring portion 22 with the reducing flame 80. You can suppress the decline. Therefore, it is possible to suppress deterioration in the ability of the molten metal 100 to separate from the pouring portion 22 . For this reason as well, in the casting material manufacturing method described above, it is possible to suppress the oxides of the constituent metals of the molten metal 100 from adhering to the inner surface of the pouring portion 22 .

In the casting material manufacturing method described above, since the exposed area 23 is shielded from the atmosphere by the reducing flame 80, the rotation of the pair of block groups 3 and the pair of belts 4 is not adversely affected. Furthermore, in the method for manufacturing the cast material, by adjusting the flame of the burner 8, the surface height of the molten metal 100 flowing inside the pouring section 22, the presence or absence of oxides, etc. can be visually confirmed.

Reference Signs List 1 twin-belt continuous casting apparatus 2 tundish 21 main body 22 pouring part 23 exposed area 3 block group 31 dam block 32 strap 4 belt 5 pulley 51 backup roll 6 cooling tank 7 mold space 8 burner 80 reducing flame 81 tip 82 Coupling tube 9 Eddy current sensor 100 Molten metal 110 Metal surface 200 Cast material

Claims (4)

Casting material for continuous casting by injecting molten metal from a tundish into a mold space composed of a pair of block groups in which a plurality of dam blocks are connected by straps, and a pair of belts sandwiching the block groups. A manufacturing method of
The tundish is
a main body that is a container for temporarily storing the molten metal;
a pouring part extending outward from the body part and serving as a flow path for pouring the molten metal into the mold space;
The pouring part has an exposed area where the molten metal flowing inside the pouring part is exposed to the atmosphere,
pouring the molten metal from the tundish into the mold space while heating the exposed area with a reducing flame ;
The reducing flame is jetted from the main body side toward the pouring part, reaches a boundary portion between the pouring part and the mold space, and does not enter the mold space .
A method for manufacturing cast materials. 2. The method of manufacturing a cast material according to claim 1, wherein the heating is performed so as to cover the entire exposed region with the reducing flame. 3. The production of casting materials according to claim 1, wherein the pouring of the molten metal from the tundish into the mold space is performed while electromagnetically measuring the surface height of the molten metal poured into the mold space. Method. The casting material according to any one of claims 1 to 3, wherein the molten metal is a copper alloy containing 0.05% by mass or more and 1.0% by mass or less of tin, and the balance being copper and inevitable impurities. manufacturing method.

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