KR100662727B1 - Clad metal manufacturing method using steel and aluminum and centrifugal casting machine - Google Patents

Abstract

A method for manufacturing a clad metal of steel and aluminum is provided to economically manufacture a clad metal of steel and aluminum of which a bonding part has superior performance in a large quantity and a centrifugal casting machine for manufacturing the clad metal of steel and aluminum is provided. A method for manufacturing a clad metal of steel and aluminum comprises: a step(S500) of grinding the steel such that a surface of steel to be bonded have a determined roughness; a step(S510) of coating aluminum on the grinded surface of the steel by vacuum deposition to form a coating layer with a determined thickness on the grinded surface of the steel; a step(S520) of preheating the aluminum coated steel to a determined temperature; a step(S530) of contacting aluminum melt heated to a determined temperature with the aluminum coated surface of the steel while rotating the preheated steel to a determined rotation speed; and a step(S540) of cooling the aluminum coated steel surface contacted with the aluminum melt.

Description

Manufacturing method of steel and aluminum clad material and centrifugal casting machine for the same {CLAD METAL MANUFACTURING METHOD USING STEEL AND ALUMINUM AND CENTRIFUGAL CASTING MACHINE}

1 is a flow chart for explaining a method for producing a steel and aluminum clad material according to the present invention;

2 is a view for explaining an example of a centrifugal casting machine used for producing steel and aluminum clad material according to the present invention;

Figure 3a is a photographic view showing the microstructure when the cooling after injecting aluminum molten metal at 750 ℃ with the rotational speed of the centrifugal casting machine at 400 rpm while maintaining the preheating temperature of the steel at 480 ℃;

Figure 3b is a photographic view showing the microstructure when the cooling after injecting aluminum molten metal of 750 ℃ at a rotational speed of 400 rpm in the state of maintaining the preheating temperature of the steel at 530 ℃.

Explanation of symbols on the main parts of the drawings

1: steel material 2: aluminum (melt or adhesive layer)

3: iron and aluminum intermetallic compound layer

10 centrifugal casting machine 12 chamber

13: (chamber) opening 14: (chamber) inner space

15: heating element 16: cover

20: motor 22: shaft

30: molten metal injection hole 32: bonding process tube

33: molten metal furnace 34: (bonding process tube) opening

36: clamp 40: weight

The present invention relates to a method for producing steel and aluminum cladding material and a centrifugal casting machine for the same, and more specifically to joining steel and aluminum to a cladding material that can be used for home appliances, automobile parts, kitchenware, nuclear and petrochemical pressure vessels, and the like. The present invention relates to a method for producing a steel and aluminum clad material to be integrated by providing the same, and a centrifugal casting machine therefor.

Clad metal, which is a laminated composite material in which two or more materials are joined by metallization and integrated, has the advantage of maximizing the performance of materials and saving expensive materials. Therefore, a clad material formed by combining various materials has been proposed, and its field of application is also expanding. In particular, steel-aluminum cladding materials are widely used in home appliances and automobile parts, and are also applied to kitchen appliances, nuclear and petrochemical pressure vessels.

Republic of Korea Patent Publication No. 82-000650 "Method for joining aluminum base member and steel member" is a method of joining the aluminum base member and the steel member prepared by hot compression in a known manner the surfaces to be joined. In the process, the silicon particles are placed between the surfaces to be bonded before the compression operation, the silicon particles are protected from oxidation, and the pressure is applied to the interface at a temperature of 500 ° to 650 ° C. and sufficient pressure to remove at least a portion of the formed workpiece. The technique which processes as much as possible and then cools a joined body is proposed.

Korean Patent Laid-Open Publication No. 1997-0073813 "Method of manufacturing a main bearing for an automobile engine" proposes a technique for improving bonding and hardness by using a nickel coating layer between cast iron and aluminum on an outer diameter surface portion.

Republic of Korea Patent Publication No. 10-0274404 "Iron and aluminum joining method and joints" when the iron is immersed in the aluminum molten metal, the aluminum molten metal temperature is controlled to 620 ~ 720 ℃, the iron immersion time is 5 ~ By controlling the thickness of the compound layer to 20 to 50 μm by controlling it to 7 minutes, a technique for improving the bonding force by the fine concave-convex portions formed by inducing the electromagnetic compound bond at the interface when joining steel and aluminum is proposed.

Korean Patent Laid-Open Publication No. 2002-0046844 "Method for manufacturing a bearing metal" proposes a technique for joining aluminum strips and steel plates made of aluminum alloy by pressure welding in a semi-used state.

Republic of Korea Patent Publication No. 10-0376555 "Manufacturing method of triple clad plate of stainless steel-aluminum" is a preheating temperature in the range of 300 ~ 500 ℃, by rolling in a range in which the stainless steel sheet is stretched to 1-2% A technique for producing a stainless steel plate / aluminum plate / stainless triple clad plate through hot rolling is proposed.

As such, the methods mainly used to manufacture steel and aluminum clad materials to date include diffusion bonding, explosion welding, and hot rolling. However, when manufacturing the steel-aluminum cladding material using the diffusion bonding, the performance of the joint is excellent, but the bonding time is long, and the price is expensive, there is a disadvantage in the economic efficiency. In addition, explosion welding has a problem that noise problems, mass production is difficult due to the use of gunpowder. In addition, the most economical and mass-produced hot rolling is a kind of solid state joining, and the surface treatment before joining to remove foreign substances such as scale, oil, etc. existing on the joining surface is very important. In order to protect the interface, it is difficult to roll in a vacuum atmosphere or in a reducing gas atmosphere in order to protect the interface in the commercial process of mass production of the product. Scales form and cause problems in bonding.

Accordingly, the present invention is to solve the above problems, to provide a new type of steel and aluminum cladding material manufacturing method and centrifugal casting machine for providing a steel and aluminum cladding material with economical and large-scale excellent performance of the joint. .

According to a feature of the present invention for achieving the above object, the present invention provides a method for producing a steel and aluminum cladding material, the method comprising: polishing the surface of the steel to be bonded to have a predetermined roughness; Coating aluminum by vacuum deposition to have a predetermined thickness on the polished surface of the steel; Preheating the aluminum coated steel to a predetermined temperature; Rotating the preheated steel at a predetermined speed to allow the aluminum molten metal heated to a predetermined temperature to come into contact with the aluminum-coated surface of the steel, followed by cooling.

In such a method of manufacturing steel and aluminum clad material according to the present invention, the surface of the steel material has a roughness polished using abrasive paper up to # 2000, the thickness of the aluminum coating layer is 1 ~ 2㎛, the preheating temperature of the steel Is 480 ~ 520 ℃, the rotation speed of the steel is 300 ~ 400rpm, the temperature of the aluminum molten metal may be 700 ~ 800 ℃.

According to a feature of the present invention for achieving the above object, the present invention is a centrifugal casting machine for the production of steel and aluminum cladding material, the chamber having an inner space having an upward opening therein; A lid for closing the opening of the chamber; A heating element installed around the upper side of the chamber to heat the upper inner space of the chamber; A shaft which is connected to a motor provided below the inner space in the chamber and is rotated by the motor by extending vertically above the inner space; It is horizontally coupled from the upper side of the shaft so as to be located in the upper inner space of the chamber in which the heating element is installed, the steel is coupled to one side is formed an opening in which the joining surface of the steel is in contact, the other side in accordance with the weight of the steel A weight is coupled to adjust the center of rotation, and the molten aluminum flows from the molten metal inlet coupled to the upper includes a joining process tube formed with a molten metal flows to the opening combined with the steel.

1 is a flowchart for explaining a method for manufacturing a steel and aluminum clad material according to the present invention.

Referring to FIG. 1, in the method of manufacturing steel and aluminum clad material according to the present invention, first, the surface of the steel to be bonded is polished to have a predetermined roughness (S500). The steel whose surface is to be bonded is polished to form an aluminum coating layer through vacuum deposition (S510). At this time, the thickness of the aluminum coating layer is to have the same thickness as the preferred embodiment of the present invention to be described later. Next, the aluminum-coated steel is preheated to a predetermined temperature (S520), and while the preheated steel is rotated at a predetermined speed so that the aluminum molten metal heated to the predetermined temperature is brought into contact with the aluminum-coated surface of the steel (S530). Cooling (S540) to form a steel and aluminum glad material.

As described above, in the method of manufacturing the steel and the aluminum cladding material according to the present invention, the aluminum molten metal is injected into a centrifugal casting machine, and the coated surface is coated with aluminum while giving the desired roughness to the steel surface in order to improve the bonding property. By controlling the preheating temperature of the steel, the rotational speed of the centrifugal casting machine and the temperature of the aluminum molten metal in the inside, it is possible to suppress the formation of intermetallic compounds that are vulnerable to the steel and aluminum interface and to have excellent bonding characteristics. According to the present invention, since the steel and aluminum cladding can be bonded using a centrifugal casting machine according to a preferred embodiment of the present invention to be described later, when manufacturing steel and aluminum clad material compared to other manufacturing methods (welding, welding, etc.) Its simple process makes it easy to assign various dimensions and shapes, and is suitable for the production of small quantity items. In addition, since the steel surface is coated with aluminum by vacuum deposition, the generation of scale generated by surface oxidation during steel preheating is suppressed, and the bonding characteristics are maximized without special vacuum equipment during the bonding process.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, FIGS. 2 to 3B, and like reference numerals denote like elements for performing the same functions in FIGS. 2 to 3B. Meanwhile, the illustration and detailed description of the technical details of the centrifugal casting method and the vacuum deposition method which are usually performed are parts that can be easily understood by those skilled in the art, and thus, the descriptions are briefly omitted or omitted and the parts related to the present invention are shown.

Figure 2 is a view for explaining a preferred embodiment of the centrifugal casting machine used to manufacture the steel and aluminum clad material according to the present invention.

Referring to FIG. 2, the centrifugal casting machine 10 according to the preferred embodiment of the present invention includes a chamber 12, a cover 16, a heating element 15, a shaft 22, and a joining process tube 32. The chamber 12 is formed with an internal space 14 having an opening 13 upward. Such a chamber 12 is usually formed in a cylindrical shape as a function of a frame like a centrifugal casting machine. The cover 16 is configured to close the opening 13 of the chamber 12 so as to block heat release to the outside in the process of preheating the steel 1. The heating element 15 is installed around the upper side of the chamber 12 and configured to heat the upper side of the internal space 14 of the chamber 12. Such a heating element 15 will be able to have a heating structure that is usually used in a heating furnace and the like. The shaft 22 is rotated by the motor 20 by being connected to the motor 20 provided below the inner space 14 in the chamber 12 and extending vertically above the inner space 14. Such a shaft 22 may be configured in connection with a clutch, a brake, etc. for controlling the driving of the motor 20.

The original casting machine 10 according to the present embodiment having such a configuration has a specially designed joining process tube 32. The bonding process tube 32 is horizontally coupled on the upper side of the shaft 22 so as to be located above the internal space 14 of the chamber 12 in which the heating element 15 is installed. And the opening (34) is joined to one side of the steel 1 is joined to the joint surface of the steel (1) is formed, the weight 40 for adjusting the center of rotation in accordance with the weight of the steel (1) on the other side Combined. In this case, various types of clamps 36 for fixing the steel 1 will be applied. In addition, the joining process tube 32 is formed of a molten metal path 33 so that the aluminum molten metal introduced from the molten metal injection hole 30 coupled to the upper portion flows to the opening 34 to which the steel material 1 is coupled.

Through such a configuration, the centrifugal casting machine 10 according to the present embodiment uses the clamp 36 to fix the steel 1 having the aluminum coating layer formed on the joining surface to the joining process tube 32, and then preheats the aluminum melt. The bonding process and the cooling process are performed.

Figure 3a is a photographic view showing the microstructure when the cooling after injecting aluminum molten metal of 750 ℃ with the rotational speed of the centrifugal casting machine to 400rpm while maintaining the preheating temperature of the steel at 480 ℃, Figure 3b Is a photographic diagram showing the microstructure of the aluminum centrifugal casting machine at a rotational speed of 400rpm while maintaining the temperature at 530 ° C and injecting 750 ° C molten aluminum after cooling.

1 to 3B, the steel and aluminum clad material according to the present embodiment is manufactured using the centrifugal casting machine 10 configured as described above. In the centrifugal casting machine 10, the steel 1 to be processed is coated with aluminum on the surface to be joined. Then, the aluminum molten metal is installed in the centrifugal casting machine 10 and preheated to 480 ° C. to 520 ° C. and the rotation speed of the joining process tube 32 is set to a range of 300 to 400 rpm, and then heated to 700 ° C. to 800 ° C. It is made by injecting and solidifying the molten metal inlet 30.

In the method of manufacturing steel and aluminum clad material according to the present embodiment, first, a process of applying roughness to a steel surface in order to improve bonding strength between steel and aluminum and to remove an oxide film formed on the surface of the steel is performed (S500). That is, the process of polishing up to # 2000 with sand paper on the steel surface. At this time, the abrasive paper is polished up to # 2000 because when the roughness of the abrasive paper is less than # 2000, there is a problem that the bonding strength between the steel and aluminum decreases due to a decrease in the surface area where the two materials react in the process of joining steel and aluminum. In addition, when the abrasive exceeds # 2000, a large increase in the surface area of the two materials reacts to produce a large amount of Fe-Al-based intermetallic compound (3), which is very vulnerable to the steel and aluminum interface, resulting in deterioration of the mechanical properties of the clad material. Because it causes.

When the process of applying roughness to the steel surface is completed, when the steel is preheated, an aluminum coating layer having a thickness of 1 to 2 μm is applied to the surface of the steel by using a vacuum deposition method to suppress the generation of an oxidative scale generated on the surface. To form (S510). The reason for limiting the coating material to aluminum is that in the process of joining steel and aluminum, foreign matter is minimized between the two materials, thereby improving the bonding strength. The reason for limiting the thickness of the aluminum coating layer to 1 to 2 μm is that when the thickness of the coating layer is less than 1 μm, the thickness of the aluminum coating layer is too thin to promote generation of an oxidized scale during preheating, thereby significantly reducing the bonding strength. When the thickness of the coating layer exceeds 2 μm, the aluminum coating layer is so thick that the Fe-Al-based intermetallic compound (3) is formed on the surface of the steel during preheating, thereby reducing the mechanical properties of the cladding material.

Thus, the steel material 1 in which the aluminum coating layer of 1-2 micrometers was formed in the surface is fixed by the clamp 36 to the joining process pipe 32 of the centrifugal casting machine 10. As shown in FIG. At this time, the steel 1 is fixed so that the bonding surface is in close contact with the opening 34 of the bonding process tube (32). After fixing the steel (1) to the joint process tube 32 to adjust the weight 40 to maintain the horizontal level of the joint process tube (32). In addition, the cover 16 is covered to block heat release to the outside during the preheating process. Next, preheating (S520) of the steel material 1 by operating the heating element 15, wherein the preheating temperature is limited to the range of 480 ~ 520 ℃. At this time, when the preheating temperature is lower than 480 ° C, the flowability of the aluminum molten metal decreases, making it difficult to join aluminum and steel, thereby forming pores or unfilled regions at the interface, and thus deteriorating the bonding characteristics. As can be seen, the interdiffusion is much easier than the cladding material fabricated at the temperature below that, and the Fe-Al-based intermetallic compound (3), which is very vulnerable to the steel and aluminum interface, is produced, thereby significantly reducing the mechanical properties of the cladding material. Because it becomes.

When the preheating process is completed, the motor 20 is operated to maintain the rotational speed per minute (rpm) at 300 to 400 rpm, and then the aluminum molten metal in the temperature range of 700 to 800 ° C. is injected into the molten metal inlet 30 ( S530). At this time, when the temperature of the aluminum molten metal is lower than 700 ° C, the fluidity of the molten metal decreases, and the bonding property of the steel and aluminum is lowered. When the temperature of the aluminum molten metal is higher than 800 ° C, the gas availability of the molten metal is rapidly increased, resulting in poor casting quality and Properties are degraded. After the aluminum molten metal maintained at such a temperature is injected into the injection hole 30, the temperature is maintained in a range in which steel and aluminum can be bonded, and then cooled (S540) to minimize the intermetallic compound vulnerable to the steel and aluminum interface. It forms as a steel-clad material with excellent bonding properties.

As described above, the method of manufacturing steel and aluminum clad material according to a preferred embodiment of the present invention and a centrifugal casting machine therefor are shown in accordance with the above description and drawings, but this is merely described as an example and does not depart from the spirit of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the present invention.

According to the manufacturing method of the steel and aluminum cladding material according to the present invention and the centrifugal casting machine therefor, it is possible to provide the steel and aluminum cladding material which suppresses the formation of intermetallic compounds vulnerable to the steel and aluminum interface and has excellent bonding properties. In addition, a specially designed centrifugal casting machine can be used to bond steel and aluminium, thus saving manufacturing time and manufacturing cost compared to other manufacturing methods (welding, hot rolling, etc.) when manufacturing steel and aluminum clad materials. In addition, since the steel surface is coated with aluminum by vacuum deposition, the generation of scale generated by surface oxidation during steel preheating is suppressed, and the bonding properties are maximized without special vacuum equipment during the bonding process.

Claims (3)

In the manufacturing method of steel and aluminum cladding material, Polishing the surface of the steel to be bonded to have a predetermined roughness; Coating aluminum by vacuum deposition to have a predetermined thickness on the polished surface of the steel; Preheating the aluminum coated steel to a predetermined temperature; And rotating the preheated steel at a predetermined speed to bring the aluminum molten metal heated to a predetermined temperature into contact with the aluminum-coated surface thereof, and then cooling the steel and aluminum clad material. The method of claim 1, The surface of the steel is to have a roughness polished using abrasive paper up to # 2000, the thickness of the coating layer of aluminum is 1 ~ 2㎛, the preheating temperature of the steel is 480 ~ 520 ℃, the rotation speed of the steel 300 to 400 rpm, the temperature of the molten aluminum is 700 ~ 800 ℃ characterized in that the manufacturing method of steel and aluminum clad material. In the centrifugal casting machine for the production of steel and aluminum cladding material, A chamber in which an inner space having an opening upward is formed therein; A lid for closing the opening of the chamber; A heating element installed around the upper side of the chamber to heat the upper inner space of the chamber; A shaft which is connected to a motor provided below the inner space in the chamber and is rotated by the motor by extending vertically above the inner space; It is horizontally coupled from the upper side of the shaft so as to be located in the upper inner space of the chamber in which the heating element is installed, the steel is coupled to one side is formed an opening in which the joining surface of the steel is in contact, the other side in accordance with the weight of the steel Manufacturing of steel and aluminum clad material, characterized in that it comprises a joining process tube coupled to the weight to adjust the center of rotation, the molten metal flowing from the molten metal inlet coupled to the upper flows to the opening in which the steel is combined; Centrifugal casting machine.

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