KR20200053190A - Casting Process Including Double Dip Process - Google Patents

Abstract

The present invention relates to a casting process including a double quenching process, capable of strengthening a mold. According to the present invention, the casting process including a double quenching process comprises: a melting step (S10); a first stirring step (S20); a dross removing step (S30); an alloy element filling step (S40); a second stirring step (S50); a degassing and foreign substance removing step (S60); a casting product producing step (S70); a cooling step (S80); a first quenching step (S90); an aluminum casting product separating step (S100); a scrap removing step (S110); an annealing step (S120); a second quenching step (S130); a washing and drying step (S140); a Kevlar coating step (S150); and an aging hardening step (S160).

Description

Casting Process Including Double Dip Process

The present invention relates to a casting process including a double immersion process. In more detail, after casting of aluminum, it is put into a primary immersion solution together with a mold to quench it at a slower rate than air quenching to protect both the mold and the casting. In addition, after the aluminum castings separated from the mold are tempered for 1 to 1.5 hours in a heat treatment furnace at which 320 to 350 ° C is maintained, they are put into a secondary immersion solution and quenched at a faster rate than water quenching. It relates to a casting process characterized by strengthening.

In general, when the weight of a car is reduced by 10%, it is possible to reduce fuel efficiency by 5 to 7% on average, and for this reason, aluminum that is lighter and has sufficient strength than conventional steel materials is in the spotlight in various industries. Until now, the proportion of aluminum materials used has been increasing, mainly among high-end automobile brands such as Audi, Jaguar, and Land Rover, but in recent years, the ratio of aluminum use has also increased in the general automobile manufacturing industry. Ducker Worldwide estimates that by 2025, the proportion of aluminum used in automobiles will more than double in 2015.

The reason that aluminum is in the spotlight along with its high specific strength, which is the most representative characteristic of aluminum, is that the alloys that can be added are very diverse. In particular, alloys such as Si, Cu, An, Mg, Li, Fe, Ti, Mn, and Sn are added to form an intermetallic compound, thereby acting as a solid solution strengthening agent and strengthening the strength of aluminum.

Another method of reinforcing aluminum strength is a heat treatment method. In particular, a method of quenching after heat treatment is used as a method of reinforcing most metal strength. This is a method of hardening a material by quenching a high-temperature metal to condense dislocations in the metal, which has an advantage of strong strength, but also has a disadvantage of increasing brittleness due to an increase in residual stress. Particularly, in the case of quenching performed to lower the temperature of the cast, there is a problem that brittle damage in the cast can occur.

Republic of Korea Registered Patent Publication No. 10-1998-0019541

Accordingly, the present invention is intended to solve the conventional problems, and after casting the aluminum into a furnace maintained at 250 to 300 ° C along with the mold, cooled for 10 to 20 minutes, and then placed in the primary immersion solution to protect both the mold and the cast. After that, after tempering for 1 to 1.5 hours in a heat treatment furnace at which 320 to 350 ° C is maintained, the object is to provide a casting process including a double immersion process in which the casting is cured by cooling in a second immersion solution.

The configuration of the method of the present invention as a means for achieving the above object, the step of dissolving an aluminum ingot (ingot) at a temperature of 700 ~ 750 ℃, the molten metal for the uniform heat transfer of the molten aluminum primary Stirring, removing the dross of the stirred aluminum molten metal, charging the alloy element into the aluminum molten metal from which the dross is removed, and stirring the aluminum molten metal in which the alloy element is charged is secondarily stirred. The step of generating a casting by injecting the degassing and removing foreign substances of the secondary stirred aluminum molten metal into the mold, and removing the degassing and removing foreign substances into the mold. Cooling the mold by putting it in a heat treatment furnace together with a mold, the primary immersion by cooling the cooled aluminum casting in the primary immersion solution together with the mold Quality step, separating the primary quenching-finished aluminum casting from the mold, removing scraps generated at the corners of the separating aluminum casting, and removing the scrap-removed aluminum casting into a heat treatment furnace to be released (Annealing) treatment step, the second quenching step of strengthening the surface of the casting product by immersing and cooling the annealed aluminum casting product in a second immersion solution, and the above-mentioned second quenching aluminum casting product is subjected to high pressure washing using alcohol. After drying, it is preferable to include the step of performing a kefra coating on the washed / dried aluminum cast, and curing the aluminum cast by performing the kefra coating operation at room temperature for about 4 days. .

In addition, the temperature of the aluminum molten metal that has been subjected to the degassing treatment and the removal of foreign substances in the configuration of the present invention is preferably 670 to 700 ° C.

In addition, with the configuration of the present invention, the temperature of the heat treatment furnace at the time of charging the aluminum casting and the mold in the step of cooling the aluminum casting together with the mold into the heat treatment furnace is 250 to 300 ° C, and furnace cooling for about 10 to 20 minutes. Therefore, it is preferable if the temperature of the surface of the mold and the heat treatment furnace are similar.

In addition, the annealing treatment described above with the configuration of the present invention is preferably performed at a temperature of 190 to 240 ° C. for 1 to 1.5 hours.

In addition, it is preferable that the above primary immersion solution is composed of 20 parts by weight of brightstock and 5 parts by weight of terpene polymer resin in 100 parts by weight of paraffin-based mineral oil.

In addition, the secondary immersion solution described above is composed of 2 to 8 parts by weight of polyalkylene glycol in 100 parts by weight of water, and the polyalkylene glycol is 50 to 100 parts by weight of oxyethylene in 100 parts by weight of oxyethylene. It is preferable to be synthesized including a part.

In the case of aluminum castings completed according to the casting process of the present invention, the first immersion process is performed together with the mold to protect both the mold and the casting, thereby extending the life of the mold and reducing the internal defect rate such as brittle fracture in the case of casting. In addition, in the case of a casting product that has been processed up to the second immersion process, a high-strength casting product can be obtained as compared to an aluminum casting product that is completed according to an existing casting process.

1 is a flow diagram of a casting process including a double immersion process according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to describe in detail that a person skilled in the art to which the present invention pertains can easily implement the present invention. Advantages of the objects, actions, and effects of this invention will become more apparent by the description of preferred embodiments.

For reference, the embodiments disclosed herein are merely selected and presented as the most preferred embodiments to assist the skilled person in understanding among the possible examples, and the technical spirit of the present invention is not necessarily limited or limited by the presented embodiments , Various changes, additions, and modifications including equivalents or substitutes are possible without departing from the technical spirit of the present invention.

In addition, the expressions of terms or words used in the specification and claims of the present application are defined on the basis of the principle that the inventor can appropriately define the concept of terms in order to best describe his or her invention. However, it should not be interpreted as being limited to only ordinary or dictionary meanings, but should be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

1 is a flow chart of a casting process including a double immersion process according to an embodiment of the present invention.

The configuration of the casting process flow diagram including the double immersion process according to this embodiment of the invention, as shown in Figure 1, the configuration of the method of the present invention as a means for achieving the above object, the aluminum ingot (ingot) 700 Step of dissolving at a temperature of ~ 750 ℃ (S10), the step of first stirring the molten metal for uniform heat transfer of the molten aluminum (S20), removing the dross (Dross) of the stirred aluminum molten metal Step (S30), the step of charging the alloy element in the aluminum molten metal dross is removed (S40), the second step of stirring the molten aluminum alloy element (S50), the secondary agitation Degassing treatment of aluminum molten metal and removal of foreign substances (S60), injecting the degassing treatment and the aluminum alloy molten metal from which foreign substances have been removed into a mold to produce a casting (S70), and molding the produced aluminum casting Cooling by putting in a heat treatment furnace together with (S80), a primary quenching step (S90) of immersing the cooled aluminum casting in a primary immersion solution together with a mold, and cooling the aluminum casting after the primary quenching. And separating step (S100), removing the scrap generated in the corner of the separated mold (S110), the annealing process of annealing (S120) by inserting the scrap removed aluminum casting into the heat treatment furnace (S120) , A second quenching step (S130) of strengthening the surface of the cast product by cooling the annealed aluminum casting product in a second soaking solution, and then drying the aluminum cast product after the second quenching using alcohol under high pressure. Step (S140), a step of performing a kefra coating on the washed / dried aluminum casting (S150), and the aluminum casting on which the above-mentioned kefra coating operation was performed at room temperature 4 Allowed to stand for about preferably comprising including the step (S160) of curing aging.

At this time, the temperature of the step of dissolving the aluminum ingot (S10) is preferably 700 to 750 ° C. When this temperature is less than 700 ° C, aluminum may not be sufficiently dissolved, and when it exceeds 750 ° C, hydrogen is excessive in the subsequent stirring process. It is undesirable because it is filled and it is impossible to obtain the correct molten aluminum.

In addition, in this step, the temperature of the molten metal in the step (S70) of injecting the aluminum molten metal from which the foreign matter has been removed is preferably 670 to 700 ° C. If this temperature is less than 670 ° C, the aluminum molten metal is solidified before being injected into the mold. Problems may occur, and if it exceeds 700 ° C, hardness, strength, and elongation may decrease, which is undesirable.

In addition, in this case, the temperature of the heat treatment furnace in the step (S80) of cooling the aluminum casting together with the mold in the heat treatment furnace is preferably performed at 250 to 300 ° C for 10 to 20 minutes, and when the heat treatment temperature is less than 250 ° C, the strength of aluminum is It may fall, and if it exceeds 300 ℃, cold shock may be given to the mold in the first quenching step (S90), and if the cooling time is less than 10 minutes, sufficient furnace cooling is not achieved and residual stress in the aluminum casting cannot be sufficiently resolved. , If it exceeds 20 minutes, it may cause a problem that the strength in the cast is lowered, which is not preferable.

In addition, at this time, the annealing temperature is preferably 1 to 1.5 hours at 190 to 240 ° C in an annealing step (S120) by placing the aluminum casting after scrap removal into the heat treatment furnace, and when the heat treatment temperature is less than 190 ° C, the strength of the cast product If it does not have a sufficient effect on, and if it exceeds 240 ° C, it may cause cracking of the casting in the second quenching step, and if the annealing time is less than 1 hour, it does not have a sufficient effect on the strength change of the casting and 1.5 hours. If exceeded, it may cause a problem that the strength of the aluminum casting is lowered, which is not preferable.

Claims (6)

Dissolving the aluminum ingot (ingot) to a temperature of 700 ~ 750 ℃;
First stirring the molten metal for uniform heat transfer of the molten aluminum melt;
Removing the dross of the stirred aluminum molten metal;
Charging an alloy element in the aluminum molten metal from which the dross is removed;
A second stirring of the molten aluminum in which the alloy element is charged;
Degassing and removing foreign substances from the secondary stirred aluminum molten metal;
Generating a cast by injecting the degassing treatment and the aluminum alloy molten metal from which the foreign matter has been removed into a mold;
Cooling the produced aluminum casting in a heat treatment furnace together with a mold;
A primary quenching step of dipping and cooling the cooled aluminum casting together with a mold in a primary immersion solution;
Separating the primary quenching finished aluminum casting from the mold;
Removing scraps generated at the corners of the separated aluminum casting;
Step of annealing the aluminum scrap after removal of the scrap is put in a heat treatment furnace;
A second quenching step of strengthening the surface of the cast by immersing the cooled aluminum casting in a second soaking solution and cooling;
Washing the aluminum casting after the second quenching using an alcohol under high pressure and drying;
Performing a kefra coating on the washed / dried aluminum casting;
A casting process comprising a double immersion process comprising; the step of curing the aging by leaving the aluminum casting product subjected to the kefra coating operation at room temperature for about 4 days. According to claim 1,
The temperature of the aluminum molten metal after the degassing treatment and the foreign material removal step is completed,
Casting process comprising a double immersion process, characterized in that 670 ~ 700 ℃. According to claim 1,
In the step of cooling the aluminum castings together with the mold in a heat treatment furnace,
When charging aluminum castings and molds, the temperature of the heat treatment furnace is 250 ~ 300 ℃,
Casting process including a double immersion process characterized in that the temperature of the surface of the mold and the heat treatment furnace are similar by furnace cooling for about 10 to 20 minutes. According to claim 1,
The annealing process described above,
Casting process comprising a double immersion process characterized in that it lasts for 1 to 1.5 hours at a temperature of 190 to 240 ℃. According to claim 1,
The primary immersion solution described above,
Casting process including a double immersion process characterized in that it is synthesized by including 20 parts by weight of light stock and 5 parts by weight of terpene polymer resin in 100 parts by weight of paraffinic mineral oil. According to claim 1,
The secondary immersion solution described above,
It is synthesized with 2 to 8 parts by weight of polyalkylene glycol in 100 parts by weight of water,
The polyalkylene glycol is a casting process comprising a double immersion process characterized in that the synthesis comprises 50 to 100 parts by weight of oxypropylene to 100 parts by weight of oxyethylene.

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