JPS63303652A - Clad casting method - Google Patents

Abstract

PURPOSE:To uniformize joining condition of interface between a clad material and a solid member and to obtain the clad material having good quality by forming molten metal and fluoride series flux molten layer in mold space on a receiving table arranging an Al solid member at center thereof and descending the receiving table. CONSTITUTION:The molten metal 5 is poured into the mold space constituted of the movable receiving table 1 arranging the Al solid member 2 at the center part and the mold 10 from a pouring basin 9, and the flux is charged on the surface of the poured molten metal from flux bins 16 to form the fluoride series flux molten layer 6. Solidified part 4 solidifying by aid of injected cooling water 14 is developed according as descending the receiving table 1 to form the clad material. The molten metal 5 forms the uniform interface alloying layer having no oxide and minute gap with the Al solid member 2 by the molten flux 6 and they become firm joining condition and the clad material having good quality is cast.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Application Field) The present invention relates to a clad casting method, and relates to a casting technique for obtaining a clad ingot whose interfaces are uniformly alloyed and bonded.

(Prior art) A clad material made by combining materials with different compositions can combine the characteristics of each composite material, and can exhibit characteristics that cannot be achieved with a single material. Various studies have been carried out regarding its production.

That is, the general method for obtaining such a raft material is to cast each member individually, then face the ingot, or perform preforming such as rolling or extrusion, and then face it. It is made into a rod-shaped clad material by hot-cold forming or extrusion into a desired shape.

In addition, in contrast to such a general method, as a manufacturing method of clad material that omits the face-to-face process, clad casting is used in which molten metal from the other member is integrally cast into one member constituting the clad material. A method for forming clad ingots into clad material was published in Japanese Patent Publication No. 52-3181.
This is proposed in Publication No. 4.

In addition, when obtaining brazing parts with complex shapes from materials clad with brazing filler metal, it is important to note that the brazing filler metal is hard and difficult to bend and can only be used in straight pipes, and that flux As a method to avoid problems such as not being able to apply the coating accurately to the corners, a molten layer of brazing material and flux is formed in a container, and complex-shaped parts that have been molded into the final shape are inserted and immersed in this layer. JP-A-60-15088 discloses that a thin layer of brazing filler metal and flux is formed on the surface of the part by pulling it up.

(Problems to be Solved by the Invention) It is clear that the general method described above requires a considerable number of man-hours for preforming by facing, rolling, or extrusion.

Furthermore, even if the above-mentioned disadvantages can be avoided in the product according to Japanese Patent Publication No. 52-31814, it can be confirmed by naked eye observation that a partial micro gap 21 is generated at the cladding interface as shown in FIG. Microscopically, even in areas where microscopic gaps 21 are not recognized, as shown in Figure 5, oxides are present in the boundary areas and a boundary layer clearly exists. As shown in the figure, it has been confirmed through field studies by the present inventors that a part of the boundary layer ruptures and the molten metal flows into the area of one of the parts used in the molded body. Ru. In other words, as shown in Figure 6, the oxide ruptures at a thinner area, and the heat of the molten metal acts intensively on this ruptured area, melting the parts in that area and creating a non-uniform state. . In addition, as shown in Fig. 8, in the case of clad material obtained by hot forming a rad ingot, convex portions 23 of 1 to 2 Mφ and continuous convex portions 24 that are continuous are generated, resulting in poor quality. This will leave some defects.

The method disclosed in JP-A No. 60-15088 dip-coats parts into the final shape, and is charged from the lower end and immediately pulled out from the upper end after reaching the upper end. The time that the material remains in the bath, the heating during compaction, and the state of melting or alloying caused by the heating must be different for each part of the charged part. Even if the appearance relationship obtained as a covered product is the same, very different states are continuously changed and formed at the interface with the base material that becomes the final molded product. That is, the thickness of the formed brazing filler metal is uneven, and the formation condition and thickness of the alloy layer at the interface vary considerably. Furthermore, it is obvious that the process is a manual process and has poor productivity.

"Structure of the Invention" (Means for Solving Problems) A solid member made of aluminum or aluminum alloy is set in a mold having a movable pedestal, and melting is performed between the mold and the solid member or between the solid members. As the metal is injected, the movable pedestal is lowered to form and maintain a molten layer of fluoride flux on the surface of the molten metal bath, and the metal is cooled and solidified within the solid member and the mold or between the solid members. A solidified layer of the molten metal integrated with the solid member is continuously drawn out, and the surface of the solid member passing sequentially through the mold is brought into contact with the molten layer of flux, and then the molten metal is passed through the mold. A craft casting method characterized in that the solid member is cast while giving the outer surface of the solid member a substantially uniform thermal history due to the above-mentioned flux molten layer and molten metal.

(Function) A solid member made of aluminum or aluminum alloy is set in a mold having a movable pedestal, and molten metal is injected between the solid member and the mold, and fluoride flux is melted on the surface of the molten metal bath. While forming and maintaining the layer, the movable pedestal is lowered, and the molten metal solidified layer that is cooled and solidified in the solid member and the mold and is integrated with the solid member is successively extracted, thereby passing through the mold one after another. The outer surface of the solid member is sequentially brought into contact with the molten layer of flux to remove oxides on the outer surface of the solid member. Immediately following such oxide removal, it comes into contact with molten metal to form a solidified layer on its surface.

Thermal energy or heat history given by the flux molten layer and molten metal to the solid members that are sequentially introduced in this way is approximately uniform, and as described above, the molten metal formed on the solid member and its surface is Uniform alloying is achieved at the interface of the solidified metal layer, forming a strongly bonded interface.

When the clad ingot obtained in this way is hot- and cold-formed to produce a clad material, the thickness of each layer is constant and the interface is strong and stable, and no convexities occur on the surface. do not have. In other words, the protrusions that occur on the surface when a rad ingot is formed are caused by the presence of oxides on the surface of the solid member, which makes the bond between the solid member and the solidified molten metal layer uncertain, and the microscopic bumps that occur at the interface. It is presumed that the gas existing in the gaps expands, aggregates, and even peels off during subsequent hot processing, resulting in so-called blisters occurring on the surface of the cladding material. Moreover, by forming a uniform alloy layer at the interface, a strong bond is obtained, and there are no minute gaps, and the gas and unstable bonding parts that cause blisters as described above are not present. It is estimated to be.

To further explain the details of the present invention, the fluoride flux used in the present invention may be any flux as long as it has the effect of removing oxides from the surface of aluminum or aluminum alloy material, which is a solid member, in a molten state. For example, KF-Aj'F3
This KF-An system flux has a strong oxide removal effect (and has corrosion resistance against aluminum or aluminum alloys, so it is preferable). However, even if KF-AItF3 is contained in a proportion that is outside the eutectic point, if the injection temperature of the molten metal is set above the melting point of the flux, the flux will melt and oxides on the surface of the solid member can be removed. The F-Aj7F3-based flux has FSIl'F1 as the main ingredient, and CaF,...
NaF % LIF 5LtA I F4, Li, A
It is also possible to contain a fluoride such as IF. to F
-AIFW series Franks may be a simple compound of FSIIF3, or a complex compound of KF, AItF, for example, K
ANF KiA I! F.S.

It may be a single substance such as X3AβF3 or a mixture thereof.

The aluminum or aluminum alloy member described above is
For example, a casting method such as gravity casting or semi-continuous casting is used to form an ingot, such as a slab or a solid or hollow billet, and the ingot is processed as it is, face-milled, or subjected to a preliminary forming process to form the desired shape. Used as a dimension.

For clad casting, as shown in FIG. 1, a movable pedestal 1 is provided at the bottom of a mold 10, a solid member 2 made of aluminum or aluminum alloy is placed inside the mold 10, and this is set on the movable pedestal 1. Solid member 2 and mold 10
The molten metal 5 is injected into the mold space 3 between the mold 10 and gradually solidified by the cooling effect of the mold 10, and the solidified part 4 is supported and cooperated with the solid member 2 on the movable pedestal l and led out below the mold 10. However, in order to form and maintain a molten flux layer 6 on the surface of the molten metal 5 as described above, a coating layer 7 of a fluoride flux as described above is formed on a part or all of the circumferential surface of the solid member 2. are used to sequentially introduce them and replenish the flux layer 6.

Alternatively, as shown in FIG. 2, the solid member 2 is solidified by pouring it into the first water-cooled mold 11 from the gutter or tundish 12, and then set it on the movable pedestal l in the same manner as above.
The mold 10 is passed through the mold 10 which is a water-cooled mold.
The relationship is the same as that shown in FIG. 1, and the flux is supplied in the form of a powder or rod using an appropriate introducing means.

What is shown in FIGS. 1 and 2 are some examples of implementing the method of the present invention, and it goes without saying that the present invention is not limited to such equipment. The process can be carried out with the flux layer 6 formed and maintained on the surface of the molten metal 5, and the surface oxide of the solid member 2 is removed by contacting the surface of the solid member 2 with this flux layer 6. The flux for forming the coating layer 7 can be used in the form of a suspension in a liquid such as alniel or water, or can be applied by electrostatic coating or the like.

In some cases, the molten flux layer can be melted and spread on the surface of the molten metal within a short time even if the molten metal is injected into the mold 10 with flux pre-filled in the mold. It can be in any shape.

As the solid member 2 and the solidified part 4 are led out below the mold 10 together with the movable pedestal 1 as described above, the molten flux layer 6 and the molten metal 5 move relatively from the bottom to the top of the member 2. As a result, the molten flux layer 6
Since the flux floats on the molten metal 5 surface, there is no entrainment of flux and it does not interfere with subsequent processing. Moreover, when the molten flux layer 6 comes into contact with the surface of the solid member 2, the oxides on the surface of the solid member 2 are instantly dissolved and removed, improving the wettability between the member 2 and the molten metal 5, and making them tightly integrated. Solidified portions 4 are formed and bonded, and a uniform alloy layer is formed by a uniform thermal history to become strong and become a rad ingot. A concrete example of this situation is shown in the micrograph of FIG. 4, where the cladding interface between the member 2 and the solidified portion 4 is not clearly separated by the presence of oxides as shown in FIG. Furthermore, there is no need to form a portion into which molten metal has flowed as shown in FIG. 6, and the bonding becomes strong and stable through a uniform alloy layer having a substantially constant width. Of course, since such interfaces are precisely joined without leaving any room for minute gaps, protrusions (blisters) will not occur on the surface even if the ingot is rolled, extruded, or even stretched. Furthermore, even if parts with complex shapes are produced by strong bending, etc., the solidified portions 4 will not peel off, and a clad material of excellent quality can be obtained.

The invention can further be implemented in the manner shown in FIG. That is, the coils 18 are introduced along both inner surfaces of the mold 10 while being guided by guide rolls 19, and the molten metal 5 is placed between the coils 18 and 18, which are solid members.
At the same time, a molten flux layer 6 is injected onto the molten metal bath surface.
is formed and maintained, and the solidified and integrated portion is received on a movable pedestal l and sequentially guided out. That is, in the present invention, the solid member 2 may be made of a plurality of layers by craft casting the molten metal 4, and the solid member 2, particularly a thin plate, may be used as an example of molten metal or on both sides. Can be done. In this way, for example, the thin plate can be made of pure Al or A1 alloy with a clear composition and origin, and the molten metal 4 can be obtained from scrap etc., and the cost is low, and the surface of the craft material is Since it can have a clear composition and identity, it can be advantageously applied to various uses. Of course, the material is not limited to scrap, but may also be an alloy material with properties such as heat resistance or strength.

Note that if the temperature of the solid member 2 is high, the solidified layer 4 having the required alloy composition can be easily and reliably formed.
When the thickness of the molten metal 5 or its solidified portion 4 is relatively large compared to the thickness of the molten metal 5 or its solidified portion 4, or when its heat capacity is large, it is preferable to heat the member 2 in advance. The heating temperature for such a member 2 changes depending on the relative thickness difference, heat capacity difference, etc. - Although it cannot be determined generally, if it is desired to further thicken the interfacial alloy layer, the heating temperature is set higher, and the solid member becomes a molten metal. 5 or heated by the coagulation part 4,
It is preferable to preheat the molten metal layer 5 so that the temperature is near the solidus temperature or slightly higher than this temperature when it comes into contact with the molten metal layer 5.

As the solid member 2, aluminum or an aluminum alloy can be widely used, and its composition does not need to be particularly limited. Also, as the molten metal 5 forming the solidified layer 4, aluminum or aluminum alloy is used as solid Zns.
Cu alloy or the like may be used.

The casting atmosphere may be air, but may also be an inert gas atmosphere.

(Example) Specific examples of the present invention will be described below.

Example I A JIS 3003 alloy was melted by a conventional method and semi-continuously cast to obtain an ingot having a cross section of a Tsonx6o fin and a length of 1000 mm. After degreasing, the ingot was heated to a temperature of 480°C in a preheating furnace, and the heated ingot was set vertically on the movable pedestal 1 of a 200xlOOam semi-continuous casting mold as shown in Fig. 9, and the mold IO was heated. A refractory material 8 is provided on the upper part, and JI 34045 at 730° C. is separately melted for this molten metal reservoir 9 in a facility in which a molten metal reservoir 9 is provided on the circumferential side of the refractory material 8.
A molten metal 5 having a composition of
Flux bottle 16 to 75-t%KA I F4 on the surface
and 25-1%, a fluoride-based flux powder is supplied at a ratio of 8 lFh, that is, the flux is supplied at a ratio of 0.1 g/lllln per unit length of the heated ingot 2 introduced. Meanwhile, hot top casting was carried out at a casting speed of 200 am/sin.

That is, when the flux powder supplied as described above comes into contact with the molten metal 5, it immediately melts and forms a molten flux layer 6 on the molten metal 5, and the ingot 2 is transferred to the molten metal 5 through the molten flux layer 6. The ingot 2 was passed through the mold 10 and cooled by the mold 10, and then the solidified part 4, which is a craft layer, was formed on the circumferential surface of the ingot 2, and the ingot 2 was led out by the movable pedestal 1.

FIG. 4 shows a microscopic observation of the interface between the ingot 2 and the solidified portion 4 of the craft ingot thus obtained, and shows that a uniform alloy layer is formed and is strong and stable. It was confirmed that they were connected. Further, the macroscopic cross-sectional structure of such an ingot was as shown in FIG. 10, and as shown in FIG. 6, there were no gaps 21 that could be observed with the naked eye.

In addition, this clad ingot was solidified using a conventional method, and then hot and cold rolled to form a plate with a thickness of 0.2 ms. A kraft material of excellent quality was obtained which was smooth and had no protrusions.

In addition, compared to the above-described one according to the present invention, as a comparative example (2), the supply of flux powder was discharged, and therefore the flux layer 6 was formed and the heated ingot 2 was heated by this flux layer 6.
A clad ingot was obtained by a method that complied with the above conditions except that there was no effect on the ingot, and when this clad ingot was observed, it was found that there was a macroscopic gap 21 between the ingot 2 and the solidified part 4. It was happening all over the place.

In addition, the preheating temperature of the JI33003 alloy ingot mentioned above was set to 560°C.
℃, and other conditions were the same as above, and the clad ingot was obtained in Comparative Example 2.The boundary between the ingot 2 and the solidified part 4 was macroscopically observed. Even though there were some areas where it was not observed, gaps 21 were observed at a rate of nearly 60%. Moreover, as a result of microscopic observation of the part where the gap 21 is not recognized, an oxide layer as shown in Fig. 4 was confirmed, and as shown in Fig. 5, the oxide was broken and the molten metal became a JIS 3003 alloy ingot. A portion that appears to have flowed into the region No. 2 was confirmed, and uniform bonding was not obtained and alloying was also non-uniform.

Furthermore, when these clad ingots were solidified as in the above-described embodiments of the present invention, and then hot-rolled and cold-rolled, 10 or more convex portions were generated per ingot in the hot-rolled material. Although the shape of the cold-rolled material was slightly different, the same number or more of convex portions were generated, and the quality was different from that of the present invention in terms of spacing.

Example 2 Fe: 0.44%, Si: 0.25%, Cu: 0.13
%, Mn: 0.82%, Mg: 1.2%, a molten aluminum alloy with a composition of 180 x 6
An ingot with a length of 1000 cranes was obtained with 0 cranes. After degreasing the ingot, its surface was coated with KAlF: 80 wt% and 3 A.
IFh: 5wt% and Lis Aj! Fi: 1
A slurry of 5wt% fluff powder suspended in water at a rate of 30g/l was sprayed with a spray gun at 400+Il/l.
It was applied at a rate of rrf. After drying the ingot coated with this flux, it is heated to 480°C in a preheating furnace, and the heated ingot is heated and melted at 720°C using molten metal having a composition of JIS 1080 in the lower casting apparatus shown in Example 1. Craft cast.

That is, the flux applied to the ingot melted immediately upon contact with the molten metal, and casting was carried out in the same manner as in Example 1 under the conditions that the flux was spread and coated as a molten layer on the surface of the molten metal.

When the obtained clad ingot was observed, good bonding was obtained in both macroscopic and microscopic terms as in Example 1, and a uniform alloy layer was formed at the interface, making it strong. It was confirmed that it was connected to

Example 3 A JIS 3003 alloy was cast into a billet with a diameter of 125 mm and a length of 1000 mm using a semi-continuous casting method.

The billet was made into a diameter of 120flφ, degreased, and then heated to 300°C in a preheating furnace.The heated billet was placed vertically on a movable pedestal in a semi-continuous casting mold of 160mm diameter, and heated to 730°C JIS. 1 by pouring 1050 molten metal
Tru-top casting was performed at a casting speed of 20 m/win.

During this casting, the boundary between the billet and the molten metal contains 754% KA I Fa and 25% 3A j! A fluoride flux powder consisting of F was supplied at a rate of 0.06 g/ca-1IIin per unit length of the boundary. That is, this flux melted immediately upon contact with the molten metal to form a molten flux layer on the surface of the molten metal, and the billet was introduced into the molten metal through the flux layer.

When the kraft ingot obtained as described above was observed, it was found that similar to the one in Example 1, good macro and micro bonding was obtained, and the interface was a uniform alloy layer, resulting in strong bonding. I confirmed that

In addition, this clad ingot was preheated to 400°C before and after the face to 1500φ, extrusion speed was 3.711I/1IIin, and surface pressure was 53.
．． The material was extruded at 5 kg/w" to obtain an extruded material of 16 tmφ, but no convexities were observed in the extruded material, and a clad material of excellent quality could be obtained. In contrast, molten metal In the case of a comparative example in which no flux layer was provided on top of the clad ingot obtained under the same conditions, the occurrence of macroscopic gaps at the boundary was 2 times the boundary length.
It was observed at a rate of nearly 5%, and it was clear that the quality was inferior.

"Effects of the Invention" According to the present invention as explained above, the desired clad ingot can be obtained through an advantageous process that omits the face-to-face process, and oxides at the clad interface can be effectively removed, and oxides at the clad interface can be effectively removed. This eliminates the occurrence of minute gaps and forms a uniform alloy layer to achieve a strong bonding state. Therefore, in products obtained by further molding,
This invention does not produce defects such as small convex portions of 2 cranes φ and produces a cladding material of excellent quality, and is industrially highly effective.

[Brief explanation of the drawing]

The drawings show the technical contents of the present invention, and FIGS. 1 and 2 are cross-sectional explanatory diagrams showing an outline of the equipment for carrying out the method of the present invention, and FIG. 3 is a diagram showing another method of the present invention. A cross-sectional explanatory diagram of the outline of the equipment for carrying out the method; FIG. 4 is a micrograph showing the metal structure at the boundary between the member and the cladding layer of the clad ingot obtained by the present invention;
Figures 5 and 6 show the fourth example of the conventional method, respectively.
A microscopic photograph similar to the one shown in the figure, Fig. 7 is a sectional view showing the macroscopic cross-sectional structure of an ingot produced by the conventional method, and Fig. 8 shows defects on the surface of the clad material obtained by processing and forming the ingot using the conventional method. FIG. 9 is an explanatory view of the casting equipment employed in the example, and FIG. 10 is a cross-sectional view of the ingot obtained in the example. In these drawings, 1 is a movable pedestal, 2 is a solid member, 3 is a mold space, 4 is a solidified part, 5 is a molten metal, 6 is a molten flux layer, 7 is a flux coating layer, 8 is a refractory material, 9 is a molten metal reservoir, 1o is a mold, 16 is a flux pin, 18 is a coil, 19 is a guide roll, and 21 is a gap. Patent applicant: Nippon Light Metal Co., Ltd. Inventor: Sho Mochizuki Joint
Yoshitoshi Sagisaka Sakae
Jun Oshiro --'34 Illustration procedure amendment (voluntary) Showa 42.7. January 2nd, Commissioner of the Japan Patent Office) IXllllst Person 1, Indication of the case Showa tyu year patent Ill No. 1 J'77-21 2, Winter of Invention Name 7 U...J"Jj Manushii Mitsumi 3 , Person making the amendment Name of the patent applicant related to the case (name) Japan Light Metal Flooring Company 2 Company 4, Agent 1939 Month/Date Contents of the shipping amendment 1, In the middle part of the specification, page 16, line 4: "Figure 6" has been corrected to "Figure 7." 2. On page 22, lines 3 to 4, it says "10 is the mold," and then "14 is the cooling water, and add j." Correction to the Drawings 11 "Figure 9" in the original drawings at the beginning of the application is attached as an attachment. (Correction.

Claims (1)

[Claims] A solid member made of aluminum or aluminum alloy is set in a mold having a movable pedestal, and molten metal is injected between the mold and the solid member or between the solid members and a fluoride-based material is poured onto the molten metal bath surface. While forming and maintaining a molten layer of flux, the movable pedestal is lowered to form a solidified layer of the molten metal that is cooled and solidified between the solid member and the mold or between the solid members and is integrated with the solid member. The surface of the solid member that is continuously led out and sequentially passes through the mold is brought into contact with the above-mentioned flux molten layer, and then passed through the molten metal, and the above-mentioned flux molten layer and the molten metal are brought into contact with the surface of the solid member. A clad casting method characterized by casting while giving a substantially uniform thermal history to the metal.