JPH0832355B2 - Clad casting method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a clad casting method for aluminum and aluminum alloys, in which a clad ingot having a uniform fine metal structure and easy to roll can be safely obtained by continuous casting. It is about law.

(Prior Art) A clad material obtained by compounding materials having different compositions can have the characteristics of each compounded material, and can exhibit characteristics that cannot be realized by a single material. Various studies have been conventionally conducted on its manufacture.

That is, a general method for obtaining such a clad material is
After casting each member into individual pieces, the ingots are chamfered, or subjected to preforming such as rolling or extrusion and then face-to-face, and then subjected to rolling to form a clad plate material or extrusion of a desired shape. And a rod-shaped clad material. In contrast to such a general method, as a method for producing a clad material without the face-to-face step, one member constituting the clad material is cast with a molten metal to be the other member, and an integrated clad ingot is formed. A method for forming a clad material by molding is proposed in Japanese Patent Publication No. 52-31814.

(Problems to be Solved by the Invention) It is clear that the above-mentioned general method requires a considerable number of man-hours for preforming such as chamfering, rolling or extrusion, and a partial micro-gap at the clad interface. It can be confirmed by visual observation that a part is generated. In addition,
Even if it is possible to avoid the disadvantage of the above-mentioned many man-hours according to No. 814, a mold for continuously casting the skin material, and a mold for continuously casting the core material above the mold are respectively arranged, and this mold device is used. It is a method to obtain a clad ingot by casting and forming a molten metal that serves as a skin material on a high-temperature core material immediately after casting using casting, and the core material mold is a method of directly pouring cooling water into the ingot. In contrast, cooling water goes around inside the jacket mold, and the cooled mold indirectly cools the molten metal and solidifies it to form an ingot, so the casting speed is slow and the productivity is poor, and the solidification speed is high. Since it is slow, columnar crystals are likely to occur, and rolling problems such as meandering of the clad material during rolling are likely to occur due to the influence of the columnar crystal structure. In addition, the jacket mold is expensive to manufacture, and the mold arrangement by the clad casting method is
Perspiration may occur on the surface of the jacket mold for the core material, and water droplets may drop on the surface of the molten metal that serves as the skin material. Therefore, it is necessary to make a difficult device such as completely sealing the skin material casting portion from the dripping water.

An object of the present invention is to solve the above-mentioned problems and provide a clad casting method capable of safely obtaining a clad ingot having a uniform fine metal structure and easy to roll by continuous casting.

(Means for Solving the Problem) In order to solve the above-mentioned drawbacks, the inventors have conducted extensive research and, when casting a core ingot by direct water-cooling continuous casting, solidify in the mold. , The ingot surface, which is the core material drawn downward, is coated with the cooling water flowing out from the lower part of the mold, immediately after removing the cooling water, the casting is finished, and the heat of the ingot is retained by the ingot. When the clad ingot is formed by directly casting the molten metal that serves as the skin material on the side surface of the ingot by the water-cooled continuous casting method while it is being reheated at Then, they have found that it is possible to safely obtain a clad ingot that is easily rolled, and have completed the present invention. That is, the clad casting method according to the present invention is a method for producing a clad ingot having a core material and a skin material of aluminum or aluminum alloy by a direct water-cooled continuous casting method, while directly applying cooling water to the ingot serving as the core material. Casting, the applied cooling water is immediately removed from the ingot, the casting is finished, the ingot is reheated, and while the temperature of the ingot is 400 ° C. or higher, the side surface of the ingot is covered. It is characterized in that a molten metal as a material is continuously cast to form an ingot as a skin material.

(Operation) In the clad casting method of the present invention, when continuously casting a core ingot, cooling water is immediately removed after being applied to the ingot,
When the ingot is reheated and its temperature is set to 400 ° C. or more, the surface of the ingot and the molten metal for the skin material cast on the side surface of the ingot are easily alloyed and become the core material. Since the ingot serving as the skin material is cast on the side surface of the ingot after the casting is completed, it is possible to safely perform casting without causing water drops to drop on the molten metal surface of the ingot serving as the skin material. Moreover, since the ingot to be the core material and the skin material is directly water-cooled, it is possible to obtain a clad ingot which has a fine structure and can be easily rolled without meandering during rolling.

Next, the clad casting method of the present invention will be specifically described with reference to the schematic explanatory diagrams of the longitudinal cross-sections illustrated in FIG. 1 and FIG. In FIG. 1, 1 is an upper mold for a water-cooled core material for continuous casting, which is open at the top and bottom, and 2 is an axis line of the mold as the bottom of the upper mold is initially closed to form a core material ingot in the upper mold. It is a lower mold for a core material that descends along the.

The molten metal 4 for the core material supplied through the float 3 into the upper mold 1 for the core material draws the ingot solidified in the mold downward by lowering the lower mold 2, and the molten metal for the ingot is formed on the surface of the ingot. By applying the cooling water 19 flowing out from the lower part of the upper mold 1, it is rapidly cooled and solidified to form an ingot having a uniform and fine structure. Immediately after coating, the cooling water 19 applied to the ingot is blown with air from the air nozzle 5 to be removed onto the cover 6, and the temperature of the ingot is reheated to 400 ° C. or higher by the heat retained by the ingot. The amount of air blown at this time varies depending on the casting speed of the ingot, the cooling water amount, etc., but when the casting speed is 50 to 150 mm / min and the cooling water amount is 3 to 30 / min per 10 cm ingot circumference length, The cooling water 19 can be removed by setting it to about 40 to 80 / min per 10 cm of ingot circumference. The method of removing the cooling water immediately after casting is, in addition to the above-mentioned effect of reheating the temperature of the ingot, casting cracks are likely to occur, for example, A7000 alloy, casting when ingot of a structure is cast. It has the effect of preventing cracking.

In this way, the ingot is obtained, and while the ingot is reheated and has a temperature of 400 ° C. or higher, the skin material mold 20 is assembled on the side surface of the ingot, and the skin material molten metal 18 is cast to form the clad. Get an ingot. As for the assembling of the skin material mold 20, as shown in FIG. 2, with respect to the lower die, for example, a slide material lower die 7 for skin material previously attached around the lower die 2 for the core material is pushed upward by the cylinder 8. Then, the upper die 9 for skin material is installed and casting is performed. By newly installing the fireproof heat insulating material 10 on the upper die 9 for skin material and performing hot-top casting, the contact time between the core material ingot and the molten metal can be lengthened, and the core material ingot and the skin material ingot can be obtained. The interface is preferable because it can be alloyed in a uniform state and can be reliably bonded.

The molten metal 18 for the skin material can be injected by using a float in the upper mold 9 for the skin material as in the case of injecting the molten metal 4 for the core material. If the space formed between the molds 9 is extremely narrow, the float becomes small and the stability of the float is lacking, and the upper surface of the molten metal in the mold is not stable. Casting by a casting method is preferable.
In addition, if the flow of the molten metal supplied in the mold is not strong, it is difficult to obtain a uniformly alloyed joint surface. Therefore, as illustrated in Fig. 3, it is suitable for hot top level pores with two or more molten metal pouring ports. It is preferable to perform casting using a casting device to reduce the flow of the molten metal.

(Example) Next, a specific example is described.

Example 1 JIS3003 alloy was melted by a conventional method and poured into the upper die 1 for a core material through a float 3, and cooling water 19 was directly fed from the lower portion of the upper die to the ingot peripheral length of 10 cm at 50 / min. At a casting rate of 100 mm / min, semi-continuous casting is performed, and the applied cooling water is provided at a number of slit type air nozzles 5 provided around the ingot at 70 cm / min per 10 cm ingot circumference. Of air and immediately remove it from the ingot onto the cover 6 and cross section 60 mm x
A core ingot having a length of 200 mm and a length of 1000 mm was obtained. At this time, the air nozzle 5 is 180 mm lower from the upper mold and 5 mm from the ingot,
It was installed at an angle of 30 ° upward. The surface temperature of the resulting ingot was 520 ° C in the upper part and 480 ° C in the lower part.

After casting the core material ingot 13, the ingot is raised, and as shown in FIG. 3, the upper die 9 for skin material having a cross section of 100 mm × 240 mm and the hot top casting capable of pouring from two directions The fireproof heat insulating material 10 is set, and at the same time, the lower die 2 for the core material is made into the lower die for the cover material on the side surface of the lower die for the core material by the air cylinder 8. After that, for the molten metal pool 12 provided on the peripheral side of the refractory insulation material 10 for hot-top casting, J
A molten IS4045 alloy was cast at a casting speed of 120 mm / min by a hot top level pore on the side surface of the core ingot. The clad ingot thus obtained is macroscopically and microscopically observed, and has a uniform and fine structure, and the ingot interface portion is alloyed in a uniform state,
A good bond was obtained. Also, from the clad ingot to the fourth
When a tensile test was carried out by cutting out the tensile test piece shown in the figure, the core material was fractured at the skin material portion 17 of the JIS 4045 alloy with the notch in the core material rather than the joint portion 16 of the core material and the skin material, and thus the core material It can be seen that the joining of the leather and the skin material is good. Further, it is found that when the obtained clad ingot is rolled, a straight clad plate is obtained without meandering, and a clad ingot which can be easily rolled is obtained.

(Example 2) In the same manner as in Example 1, 3 wt% Si-1 wt% Zn-0.5 wt% m
Cladding was performed using JIS 1050 alloy as a skin material on the outer periphery of a core ingot having a composition of g-0.5 wt% Fe-0.7 wt% Mn-0.1 wt% Cu-balance Al.

Observation of the obtained clad ingot revealed that both macro and micro had a uniform fine structure in the same manner as in Example 1, and the interface portion of the ingot was alloyed in a uniform state, and good bonding was obtained. Was obtained. Further, it was found that when the clad ingot was rolled, a straight clad plate was obtained without meandering, and a clad ingot which could be easily rolled was obtained.

(Effect) As described above, according to the clad casting method of the present invention, a clad ingot having a uniform fine metal structure and easy to roll can be obtained with high safety and reliability. It has various effects such that the interface portion of the ingot is alloyed in a uniform state and good bonding is obtained.

[Brief description of drawings]

1 and 2 are cross-sectional explanatory views showing an outline of an apparatus for carrying out the present invention. FIG. 3 is a schematic plan view of a two-pouring level-pore type hot-top structure casting machine used in the examples. FIG. 4 is a side view and a plan view of a tensile test piece for inspecting the joining state of the core material and the skin material cut out from the clad ingot. 1 ... Upper mold for core material, 2 ... Lower mold for core material, 3 ... Float, 4 ... Molten material for core material, 5 ... Air nozzle, 6 ... Cover, 7 ... Lower mold for skin material , 8 …… Cylinder, 9 …… Upper mold for skin material, 10 …… Fire top insulation for hot top casting, 11…
… Notches, 12 …… Molten pool, 13 …… Core material ingot, 14 ……
Float, 15 …… Gutter, 16 …… Joint of core and skin, 17…
… Test piece fracture, 18 …… Melt for skin material, 19 …… Cooling water, 20
…… Skin material mold, 21 …… Notch.

Claims (2)

[Claims] 1. A method for producing a clad ingot having aluminum or an aluminum alloy as a core material and a skin material by a direct water-cooling continuous casting method, in which the core material ingot is directly cast while cooling water is cast, The applied cooling water is immediately removed from the ingot, the casting is finished, the ingot is reheated, and the side surface of the ingot becomes a skin material while the temperature of the ingot is 400 ° C. or higher. A clad casting method characterized by continuously casting a molten metal to form an ingot which serves as a skin material. 2. When pouring a molten metal to be a skin material on the side surface of the ingot to be a core material to form an ingot to be a skin material, two pouring ports for the molten metal for the skin material to be supplied into the mold are provided. The clad casting method according to claim 1, which is formed by a hot top level pore casting method using the casting apparatus provided above.