JP2003166786A - Metal melting furnace and blending melting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal melting furnace capable of providing molten metal with desired compositions by using as raw material one or more materials of conventional standard materials, return materials or pure metallic materials and accepting chips as the raw material with compositions corresponding to the pure metallic materials or the standard materials and to produce molded products such as cast products, die casting products with excellent mechanical properties without defects by feeding the low-cost and quality-stable molten metal to a molding device in the rear step by the metal melting furnace at a low cost. <P>SOLUTION: This continuous type metal melting furnace has a blending function capable of providing the molten metal A with desired compositions by melting at least two kinds of pure metallic materials contained in a pure metallic material group X<SB>n</SB>constituted by an alloy material A and/or plural kinds of pure metallic materials. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a melting furnace used for melting metals and provided with a mixing means. More specifically, it has a function of blending a predetermined pure metal material to obtain a molten metal having the same composition as a desired molten metal obtained by melting a standard material,
As a raw material, in addition to standard materials and return materials (including scrap materials) of the same composition as standard materials, predetermined pure metal materials can be used, and any of these materials can be used as a raw material. The present invention relates to a metal melting furnace that can be used, and a compounding melting method.

[0002]

2. Description of the Related Art Every product has a preferable shape, and in order to obtain that shape, a fluid molding process in which a fluid is put into a mold and solidified, a viscous body molding in which a viscous body is heated and its viscosity is lowered, and then cooled and solidified. Processing such as processing, powder molding processing in which powder is put in a mold and compressed, and solid molding processing in which force is applied to a solid to cause plastic deformation are performed. Among them, fluid forming processing in which solid metal is melted into a fluid and put into a mold to be solidified is often used, and is known as a casting method or a die casting method.

Generally, in the fluid forming process, a metal material is often used as a raw material, and the metal material is melted and put into a mold as a fluid called a molten metal for molding. At this time, the molten metal as a raw material is often required to have a composition of a predetermined standard. This is because it is possible to suppress the possibility that the fluidity of the molten metal is lowered due to the change in the composition of the molten metal, the shape of the molded product is defective, and the mechanical properties of the molded product become unfavorable.

For example, when an aluminum wheel is manufactured as a product by a casting method, for example, an A356 aluminum alloy according to the AA standard is often used as a raw material metal material. A356 aluminum alloy means that Si (silicon) is 6.5 to Al (aluminum).
7.5 mass%, Mg (magnesium) 0.30 to 0.
It is an alloy containing 45% by mass and Ti (titanium) of 0.20% by mass or less. By constituting such a composition, the product obtained by the molding process has excellent mechanical properties and good resistance. Since it can be corrosive and has excellent castability, it is easy to meet various design and aesthetic requirements, and is suitable as an alloy material used as a raw material for an aluminum wheel under severe usage conditions.

As long as such an alloy material conforming to the standard (standard material) is used as a raw material, desired properties are imparted to the molded product, and a problem hardly occurs.

Further, in the case of producing a product by, for example, a casting method, in the casting process, a portion formed by a cavity which is a product shape forming space has an unnecessary portion as a product formed by a weir, However, this unnecessary portion is removed before it is made into a product and can be reused as a raw material. Alternatively, a product that fails the inspection, so-called scrap material, can be reused as a raw material. Since these have almost the same composition as the standard materials, they can be used as raw materials as they are, and by using return materials including scrap materials, raw material costs can be reduced and product costs can be reduced.

However, in recent years, in view of the fact that it is more environmentally preferable to suppress the discharge of waste materials, or due to demands from customers for further cost reduction, in addition to the above-mentioned return materials, it is possible to lower the cost. It has been desired to use a material other than a standard material having a predetermined cost-effective composition as a raw material.

For example, if a pure metal material is used as a raw material, a considerable cost reduction can be achieved as a raw material cost as compared with the case where an alloy material conforming to the standard is purchased as a raw material. More specifically, when manufacturing an aluminum wheel product, instead of the above-mentioned A356 aluminum alloy, high-purity Al is used as a main raw material, and Si, Mg, T
If i is used as an additive raw material and compounded and dissolved to obtain a desired molten metal, the cost can be further reduced.

Since each pure metal material preferably has high purity, it is possible to adopt a material that conforms to a predetermined standard as the pure metal material, but in that case as well,
In general, it can be cheaper than a standard material with a given composition. Further, if cutting powder can be used as the pure metal material or the standard material, the cost can be further reduced, and the waste material can be reused, which is even more preferable.

However, in a continuous melting furnace, in general, the amount of the main raw material input is not constant and the amount of the main raw material melted by the melting heat source cannot be grasped, so it is difficult to grasp the amount of the additional raw material to be mixed, and it is stable. It has been difficult to carry out compounding and melting so as to obtain a molten metal having a predetermined composition.
Therefore, a standard standard material such as an ingot is mainly used as a raw material. Further, the cutting powder is a chip generated by machining, and is a material that is easily oxidized and has a poor melting yield.

By the way, a melting furnace for batch processing is provided,
Although it is possible to use a means of using each pure metal material as a raw material in this batch processing melting furnace and compounding and melting to obtain a molten metal corresponding to a desired standard material, the batch processing melting furnace has poor melting efficiency, Since there are many losses in the operation method during operation and the cost for processing increases, it is difficult to obtain the total cost reduction effect even if the raw material cost can be reduced. It is almost equivalent to just performing the substitute of the standard material provider, and does not solve the problem. Incidentally, it seems that the prior art related to the present invention has not been proposed by the literature or the like.

[0012]

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to dissolve conventional standard materials and return materials as raw materials, In addition, it is possible to use a pure metal material as a raw material, mix and dissolve it to obtain a molten metal of a desired composition, and accept cutting powder of a composition corresponding to a pure metal material or a standard material as a raw material and mix it. Can be dissolved,
It is intended to provide a continuous metal melting furnace and a compounding melting method. Further, by this, it is possible to supply a molten metal of stable quality at a low cost to a molding device such as a casting device at a later stage, a die casting device and the like, which has excellent mechanical properties without defects, for example, casting. It is to make it possible to produce molded products such as products and die cast products at a lower cost. Based on the above, as a result of more detailed and deep research on the structure of the continuous melting furnace and the mixing and melting method, it was found that the above-mentioned objects can be achieved by the following means.

[0013]

[Means for Solving the Problems] That is, according to the present invention, a continuous melting furnace for obtaining a molten metal A having a desired composition, comprising an alloy material A and / or a plurality of pure metal materials A metal melting furnace having a compounding function capable of melting at least two kinds of pure metal materials contained in a pure metal material group X _n composed of . In the present specification, the continuous melting furnace refers to a melting furnace capable of discharging the molten metal while receiving and melting the metal material as a raw material.

This blending function is performed by the amount Q of molten metal discharged from the melting furnace.
_outFirst means for obtaining the quantity and the input amount Q of the alloy material A_INATo
Set and melt, melt Y_ASecond means for obtaining pure metal
Material group X_nPure metal material X which is the main raw material contained in₁Input Q
_IN1Calculate the melt Y_AMelts into the melt Y₁Get the third
Means and pure metal material group X_nIs at least a component of
Pure metal material group X composed of one or more additive raw materials_mTo
Input Q of one or more pure metal materials included_INmAnd calculate
Te molten metal Y₁And a fourth means for obtaining molten metal A.
Preferably. Q_INAMay be 0. Also, Q
_IN1And Q _INmMay be 0.

In the metal melting furnace according to the present invention, it is preferable to provide a non-contact type level gauge for measuring the level of the molten metal A. Hot water discharge amount Q _out in the first means
Because it will be useful for seeking. A laser sensor can be cited as a non-contact level gauge.

The input amount Q _IN1 of the pure metal material X ₁ in the third means can be expressed by the following (Formula 1).

[0017]

[ _Equation 1] Q _IN1 = Q _out −Q _INA

Further, the pure metal material group X in the fourth means
_When the input amount Q _{INm of} one or more pure metal materials contained in _m is the content ratio P _m (mass%) of the pure metal material, it can be _expressed by the following (Equation 2).

[0019]

[ _Formula 2] Q _INm = Q _IN1 × P _m / 100

In the metal melting furnace according to the present invention, it is preferable to provide a stirring means for melting one or more pure metal materials contained in the pure metal material group X _m . Further, at least 2 contained in the alloy material A and / or the pure metal material group X _n
It is preferable that the one or more pure metal materials include cutting chips.
Further, it is necessary to provide a stirring means for dissolving the cutting chips in order to efficiently dissolve the chips.

The metal melting furnace according to the present invention is mainly composed of
It is suitably used for melting the molten metal A which is a lightweight metal made of aluminum, zinc or magnesium. Further, its main component is aluminum and silicon is 4-24.
It is suitably used for melting a molten metal A containing 1% by mass, 0.3 to 0.5% by mass of magnesium, and 0.05 to 0.25% by mass of titanium.

The metal melting furnace according to the present invention is preferably equipped with a composition analysis means for the melt A melted.

[0023] Also, in the metal melting furnace according to the present invention, to obtain a molten metal A dissolved alloy material A, and, to obtain a molten metal Y ₁ by dissolving pure metal material X _1, and capable of melting chamber , A holding chamber in which one or more kinds of pure metal materials contained in the pure metal material group X _m can be melted to obtain a melt A in the melt Y ₁ , and the alloy material A and the pure metal material X ₁ are placed in the melting chamber. A tower-shaped melting furnace comprising: a tower-shaped introduction part capable of discharging the exhaust heat of the melting chamber and / or the holding chamber through the tower-shaped introduction part. It is preferable that the material A or the pure metal material X ₁ can be preheated.

Further, in the metal melting furnace according to the present invention, instead of the alloy material A or in combination with the alloy material A, a return material having substantially the same composition as the alloy material A can be applied as a raw material. .

In the metal melting furnace according to the present invention, it is preferable that at least two types of raw material charging machines capable of dealing with a fixed raw material and an amorphous raw material, respectively, are provided.

Next, according to the present invention, there is provided a continuous melting method in which a molten metal A having a desired composition can be discharged while receiving and melting a metallic material as a raw material using a melting furnace. Or a predetermined amount of at least two pure metal materials contained in a pure metal material group X _n composed of a plurality of pure metal materials, respectively, to obtain a molten metal A by a predetermined amount. A method is provided.

In the blending dissolution method according to the present invention,
Comprised of alloy material A and / or a plurality of pure metal materials
Pure metal material group X_nAt least two kinds of pure contained in
It is a blending and melting method that melts metal materials to obtain molten metal A.
The amount of hot water discharged from the melting furnace Q_outThe first step of obtaining
Input amount Q of alloy material A_INASet and melt, melt Y_ATo
Second step of obtaining and pure metal material group X_nMain ingredients contained in
Pure metal material X ₁Input Q_IN1Calculate the melt Y_ADissolved in
Unravel, melt Y₁Third step for obtaining the pure metal material group X_nof
Consists of at least one additive raw material that is a constituent
Pure metal materials group X_mOne or more pure metal materials contained in
Amount of money Q_INmCalculate the melt Y ₁Melted into
A fourth step of obtaining,
Law is provided.

In the blending dissolution method according to the present invention,
The input amount Q _IN1 of the pure metal material X ₁ in the third step is Q
_IN1 = Q _out -Q _INA that can be shown in. The input amount Q _{I Nm} of one or more pure metal materials contained in the pure metal material group X _m in the fourth step is the content ratio P of the pure metal material X _{m.
When m} (mass%), it can be _expressed as Q _INm = Q _IN1 × P _m / 100.

In the blending dissolution method according to the present invention,
It is preferable to include a fifth step of analyzing the composition of the molten metal A after the fourth step.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the metal melting furnace and the compounding and melting method of the present invention will be specifically described, but the present invention is not construed as being limited to these, and Various changes, modifications and improvements can be made based on the knowledge of those skilled in the art without departing from the scope of the invention.

For example, in the present specification, the aluminum alloy material A356 is referred to as a standard material, that is, the alloy material A,
A of the pure metal material group X _n composed of a plurality of kinds of pure metal materials as an example of at least two kinds of pure metal materials, which constitutes A356.
l, Si, Mg, set a Ti, pure metal materials composed of pure metal material X ₁ of the main raw material contained in the pure metal material group X _n Al, from and added raw material component of the pure metal material group X _n Group X
Si, Mg, Ti with one or more pure metal materials contained in _m
However, the present invention, as one aspect, a continuous melting furnace capable of melting the alloy material to obtain a molten metal,
And / or a continuous-type melting furnace capable of melting a predetermined pure metal material having a mixing function to obtain a desired molten metal, and as a second aspect, a mixing melting method, of course, However, the metal as a standard material is
It may be an aluminum alloy other than the A356 alloy, or a lightweight metal other than the aluminum alloy, for example, an alloy such as titanium, magnesium, or zinc, and is not limited. Pure metal materials are also selected according to the composition of the alloy,
Not limited.

The metal melting furnace according to the present invention not only melts an alloy material conforming to a predetermined standard, but also mixes and melts a pure metal material as a raw material to obtain a molten metal having a desired composition,
It is a melting furnace that can be supplied to a molding processing device such as a general casting device or a die casting device in the latter stage. The metal melting furnace according to the present invention holds a melting chamber that receives and melts a standard material, a return material, or a main raw material of a pure metal material, and a molten metal obtained in the melting chamber. The main constituent equipment is a holding chamber for melting and adding powder.

In the present specification, the pure metal material refers to a metal in which the total amount of impurities is a certain ratio or less. Further, when simply referred to as a standard material, it means an alloy material in which a plurality of metals are mixed in advance in a predetermined ratio.

In the metal melting furnace according to the present invention, although it is a continuous melting furnace, a molten metal having a composition corresponding to a molten metal obtained by melting a desired alloy material is obtained from, for example, two or more kinds of pure metal materials. The feature is that it has a compounding function. Another characteristic is that the melting of the alloy material and the melting of two or more kinds of pure metal materials can coexist. By providing such characteristics, it is possible to further reduce the raw material cost, not only cost competitiveness can be imparted to the metal product produced through the metal melting furnace according to the present invention, but also the composition is clear. If so, for example, it is easy to effectively use waste materials such as cutting chips, it is possible to reduce the chances that the waste materials are discharged and left, and it is possible to prevent environmental degradation.

The metal melting furnace according to the present invention will be described in detail below with reference to the drawings.

The metal melting furnace according to the present invention is located at the first stage in the manufacturing process by the casting method of metal products, which includes the steps of melting, cleaning, heat retention, and molding with a metal, for example. It is an apparatus used for metal dissolution processing including.

FIG. 5 is a block flow diagram showing an example of the overall configuration of the metal melting furnace according to the present invention. As shown in FIG. 5, the metal melting furnace 11 preferably includes a melting furnace main body 10, additional four systems of raw material feeders, and a composition analysis device 20 for the molten metal 3 discharged. The four-system raw material feeders are two types of main raw material feeders 31, 32.
It is preferable that it is composed of an additive raw material feeder 33 and a swarf raw material feeder 34.

First, the raw material feeder will be described.

The main raw material supply device 31 includes a stock conveyor 61 and a capsule type raw material feeding device 62, and is a device for feeding the fixed material 25 into the melting furnace main body 10. The stock conveyor 61 is a carrier that prepares the fixed-form material 25 to be charged into the melting furnace main body 10 and puts it on standby, and deposits the fixed-form material 25 in sequence to the capsule-type raw material supply device 62. It is also preferable to provide an automatic weighing device next to the stock conveyor 61 and weigh the fixed material 25 before depositing. This is because the amount of input material can be controlled regardless of the composition. The capsule-type raw material feeder 62 moves the fixed-form material 25 received from the stock conveyor 61 to the carry-in port of the melting furnace main body 10 by gripping and placing it, and puts it into the melting-furnace main body 10 and gently charges it. The main raw material feeder 31 does not have an impact when the main raw material is charged, and does not damage the inner surface of the melting furnace main body 10.

The fixed material 25 is, for example, a body formed by assembling a single rod-shaped ingot material into a fixed shape, and is usually an alloy material 8 that meets a predetermined standard, or
The pure metal material 1 as the main raw material used for the blending corresponds to this.

The main raw material feeder 32 includes an elevator-type raw material feeding device 63, and is a device for feeding the amorphous material 26 into the melting furnace body 10. Elevator type raw material feeder 6
3, the box or basket containing the amorphous material 26 is lifted to the carry-in port of the melting furnace main body 10 by an elevator,
Throw in. The elevator system is not limited, and a hydraulic system, a rope system, or the like may be adopted.

The shape of the main raw material is not limited, and the product that fails the inspection, that is, the scrap material 6, the waste material 5 that is molded in a portion other than the product cavity at the time of casting and removed by the trimming process, etc. Return material 2 can be added. The alloy material 8 which does not form the body of the ingot and conforms to a predetermined standard, or the pure metal material 1 as the main raw material used for the compounding is also the main raw material supply device 32.
Can be charged into the melting furnace main body 10.

The additive raw material supply device 33 includes a hopper 64 and a metering supply device 65, and is a device for introducing the trace amount metal material 9 into the melting furnace main body 10. A certain amount of the trace amount metal material 9 is on standby in the hopper 64, and the metering feeder 65 measures the required amount according to the main raw material and puts it in the stirring chamber 53 of the melting furnace body 10. Hopper 64 and metering device 65
The method and the like are not limited. For example, a hopper 64 that is an inverted cone with a mortar bottom shape and the opening provided at the bottom cuts out with a vibrating feeder, or a load cell is installed in a container with a certain amount, and it can be subtracted up to a set amount by cutting out The machine 65 can be adopted.

The trace amount metal material 9 is usually a small piece or a lump of a pure metal material 12 different from the main raw material. For example, when the pure metal material 1 is used as the main raw material, a molten metal obtained by melting is desired. The material is added in the required amount so as to have the above composition.

The swarf material feeder 34 is provided with a hopper 66 and a metering feeder 67 for feeding the swarf 4 to the melting furnace body 1
It is a device to be input to 0. A certain amount of the cutting powder 4 is on standby in the hopper 66, the amount of the cutting powder 4 is measured by the metering and supplying device 67, and the cutting powder 4 is put into the stirring chamber 54 of the melting furnace body 10.
The system and the like of the hopper 66 and the metering and supplying device 67 are not limited, and the same system as the hopper 64 and the metering and supplying device 65 described above can be adopted.

The cutting powder 4 is a machining waste and is usually
It is preferable to use an alloy material that meets a predetermined standard. The amount available is limited, but if used, material loss can be reduced, which greatly contributes to the reduction of raw material costs.

The metal melting furnace 11 according to the present invention is equipped with the above-described four systems of raw material feeders 31 to 34, and each can independently operate arbitrarily. Therefore, in one metal melting furnace 11, if the compositions of the raw materials that are simultaneously charged from the main raw material feeders 31 and 32 are the same, for example,
General melting using an alloy material 8 that meets a predetermined standard as a raw material, compounding melting using a predetermined two or more kinds of pure metal materials 1 and 12 as raw materials, and melting using cutting chips 4 as a raw material so,
Alternatively, they can be carried out simultaneously.

That is, any material such as a fixed alloy material 8 such as an ingot, an amorphous return material 2, and chips 4 can be charged as a raw material regardless of the shape, and the optimum material can be used depending on the shape of the raw material. Means can be used. Since the raw materials can be simultaneously supplied to the melting furnace main body 10 from the four-system raw material feeders 31 to 34, the main raw material and the additional raw material can be blended and dissolved, and at this time, the cutting powder 4 is included in either the main raw material or the additional raw material. Even if it is, it is possible to mix and dissolve.
When the main raw material feeders 31 and 32 are simultaneously operated, it is preferable that the compositions of the main raw materials to be fed are the same. The main raw material feeders 31 and 32 are simultaneously operated, and
If the composition of the main raw materials to be input is not the same, separately
It is necessary to provide a metering device and determine the input amount of each main raw material.

Next, the melting furnace body will be described with reference to FIGS. 1 to 3 in addition to FIG.

FIG. 1 is a view showing an embodiment of a metal melting furnace 11 according to the present invention, and is a horizontal sectional view of a melting furnace main body 10. 2 is a BB of the melting furnace body 10 shown in FIG.
FIG. 3 is a vertical sectional view showing a section, and FIG. 3 is a vertical sectional view showing an AA section of the melting furnace body 10 shown in FIG. 1.

The melting furnace body 10 includes a tower-shaped introduction part 55,
The dissolution chamber 51 is connected to the tower-shaped introduction section 55, and the holding chamber 52 is connected to the dissolution chamber 51. The holding chamber 52 is provided with a stirring chamber 53 that also functions as a charging port for the trace amount metal material 9 and a stirring chamber 54 that also functions as a charging port for the cutting chips 4 in addition to the tower-shaped introduction section 55 that is a charging port for the main raw material. It is preferable. This is because it is possible to promote the dissolution of the trace amount metal 9 and the cutting chips 4 and prevent defective dissolution. Further, it is possible to avoid a problem that may occur when the trace amount metal 9 and the cutting powder 4 are introduced from the tower-shaped introduction section 55. For example, the trace amount metal 9 is added to the tower-shaped introduction part 5
When charged together with the main raw material from No. 5, it stops on the wall surface of the tower-shaped introduction section 55 or on the main raw material waiting for dissolution in the tower-shaped introduction section 55,
Variation in the time required for melting and mixing with other materials in the holding chamber 52 may occur, which is not preferable.
Further, when the cutting powder 4 is introduced from the tower-shaped introduction part 55, in addition to the same problem as in the case of the trace amount metal 9, the exhaust heat that rises the tower-shaped introduction part 55 due to the exhaust heat of the melting chamber 51 or the holding chamber 52. It is not preferable because a part of the material is wound up and discharged to the outside of the furnace and melted to cause a variation in the amount mixed with other raw material in the holding chamber 52.

When the main raw material which is the regular raw material 25 or the irregular raw material 26 is introduced from the tower-like introduction part 55, by the melting heat source, for example, by the melting burner 71 shown in FIG.
It is melted in the melting chamber 51, and further flows into the holding chamber 52 by gravity, for example, and if necessary, the stirring chamber 53.
A desired molten metal 3 is obtained by mixing the trace amount metal material 9 which is the added raw material introduced through the above, or the cutting powder 4 as the main raw material or the added raw material which is introduced through the stirring chamber 54. In the holding chamber 52, the molten metal 3 is kept at a constant temperature by a holding heat source, for example, by a holding burner 72 shown in FIG. 3, and after staying for a predetermined time, it is tapped from a tap 56 shown in FIG.

Although the shapes and sizes of the tower-shaped introduction part 55 and the melting chamber 51 are not limited, the main raw material is put into the tower-shaped introduction part 55 and is sequentially melted in the melting chamber 51 by the melting heat source. It is preferable to configure so as to proceed. In the examples shown in FIGS. 2 and 3, as the main raw material,
For example, the fixed material 25, which is the alloy material 8 and is assembled into an ingot, is stacked in the melting chamber 51 and the tower-shaped introduction part 55. The main raw material is a melting burner 71 which is a heat source for melting.
It begins to melt from the lower part near and flows into the holding chamber 52. As described above, the tower-shaped introduction part 55 and the melting chamber 51 are integrated, and the tower-shaped introduction part 55 is preferably a longer and narrower tower-shaped one as long as it can accept the main material having the maximum outer shape.
This is because the material preheating zone becomes longer and the waste heat can be recovered more effectively. By doing so, the installation area of the metal melting furnace 11 can be further reduced.

It is also preferable that the tower-shaped introduction part 55 is provided with a photoelectric tube switch or the like so that the amount of the main raw material charged can be sensed to grasp the material filling level. It is also preferable that the alloy material 8 and the like can be automatically charged by the main material feeders 31 and 32 when the amount of the main material becomes small.

Further, an exhaust port 57 is provided at the upper part of the tower-shaped introduction part 55.
Is preferably provided. Exhaust heat of the melting chamber 51 and the holding chamber 52 is also discharged through the tower-shaped introduction part 55, and the exhaust heat heats the main raw material waiting for the melting in the tower-shaped introduction part 55 in advance and required for melting. This is because the amount of heat generated by the melting heat source can be reduced and a more energy-saving effect can be exhibited. By increasing the capacity of the tower-shaped introduction part 55, the tower-shaped introduction part 55 functions as a buffer together with the capacity of the holding chamber 52, and the main raw material input amount can be leveled even if the amount of hot water discharged changes.

Although the size of the holding chamber 52 is not limited, the molten metal melted in the melting chamber is lower than the molten metal temperature in the holding chamber, and the molten metal in the holding chamber fluctuates due to tapping and melting. Since it is repeated, an appropriate capacity that can maintain the holding temperature in the shortest time is required. The shape of the holding chamber 52 is also not limited, but it is preferable that the bottom surface is a substantially flat surface, the side surface is a vertical surface, and the horizontal cross-sectional shape is as simple as possible such as a quadrangle. If there is almost no change in the sectional area in the depth direction and the area of the molten metal surface is known, for example, the holding chamber 5
This is because by attaching a level gauge to 2 and measuring the level variation in the holding chamber 52, the amount of hot water discharge can be easily calculated by the difference of the level of the molten metal × difference in variation of the molten metal level.
Since the upper part of the molten metal is also high in temperature along with the molten metal, it is preferable to adopt a non-contact type such as a laser sensor for the molten metal level gauge.

The melting heat source and the holding heat source are not limited to the burner. For example, the melting heat source includes electrical resistance, electrical induction,
An electric heat source such as an arc or an electronic heating method such as a laser or an electron beam may be used.

Further, for example, a heater can be used as the holding heat source. In this case, it is preferable to use the immersion heater because heat can be directly transferred to the molten metal, which is more efficient.

Also, the fuel that generates heat is not limited,
It can be liquid, solid or gas. No matter which fuel or heat source is used, alloy material 8 which is a main raw material at room temperature,
In order to reduce the manufacturing cost, it is preferable that the heat loss is suppressed as much as possible by directly heating the waste heat as described above instead of directly melting it.

The stirring chambers 53 and 54 are provided with stirring means, respectively. In the stirring chamber 53, it is possible to increase the rate of dissolution of the trace amount of metal material 9 introduced by stirring, and to stabilize the composition of the molten metal 3 discharged at an early stage. Also, the stirring chamber 5
In No. 4, it is possible to swirl the cutting chips 4 into the molten metal promptly by stirring, and promote the dissolution of the cutting chips 4 while preventing oxidation loss.

The stirring means provided in the stirring chambers 53 and 54 is not limited, but in order to prevent the molten metal 3 from being oxidized, it is agitated by an inert gas, or as shown in FIG. 1, for example, has a thin impeller. Motor driven agitator 7
It is preferable to install 3,74 substantially at the center of the agitation chambers 53, 54 and perform rotational agitation. Alternatively, it is preferable that the mechanism is such that it can be quickly caught by electromagnetic induction or the like.

Next, referring to FIG. 5, the composition analyzer will be described.

The composition analyzer 20 can analyze the composition of the melt 3 after blending and melting, or the melt 3 discharged from the holding chamber 52. The composition analyzer 20 is preferably provided after the holding chamber 52 and before the next step of sending the molten metal 3 for quality control. For example, it is possible to monitor and measure whether or not there is a problem in the quality of the molten metal 3 by taking a sample of the molten metal 3 before the tap hole 56 of the holding chamber 52, obtaining the component ratio of the constituent metals. If there is a problem, an alarm is issued to stop the molten metal 3 from coming out, and further, before the problem occurs, the holding chamber 52
In addition, it is also preferable to add a pure metal material or a trace amount of metal material as a main raw material in a necessary amount and automatically readjust the content so as to obtain a desired component ratio.

If the composition analyzer 20 is provided and the quality of the molten metal 3 discharged is monitored, not only the alloy material 8 and the pure metal materials 1 and 12 having a predetermined composition are used as raw materials but also those generated from other factories. It is easy to recycle the scrap materials such as the so-called scrap material 6 and the unnecessary material 5 as raw materials. Of course, in that case, it is preferable to investigate the source of the scrap material 6 or the unnecessary material 5 and clarify the original material type. However, even if an unexpected material is mixed in, the quality of the molten metal 3 will be deteriorated by the composition analyzer 20. It can prevent becoming stable. Composition analyzer 2
As 0, for example, an emission analyzer can be applied.

Next, an example of a metal product manufacturing process including the metal melting furnace 11 according to the present invention will be described below.

FIG. 4 is a block flow diagram showing an example of a metal product manufacturing process by the casting method.
Is located in the first stage of the manufacturing process. The manufacturing process 41 shown in FIG. 4 includes, in addition to the metal melting furnace 11, a holding furnace 13 that holds and stores at least the temperature of the molten metal 3 obtained in the metal melting furnace 11, and a molding process of the molten metal 3 by casting. A casting device 14 for removing the unnecessary portion of the cast product that does not become a product, and a heat treatment device 19 for improving the mechanical properties of the product. It is also preferable to have an inspection device 21 that confirms the presence or absence of defects in the pre-shipment product.

The holding furnace 13 immediately after the metal melting furnace 11 is
Usually, a heater is provided and the temperature of the molten metal 3 is maintained until it is sent to the casting apparatus 14.

The casting device 14 is for injecting the molten metal 3 into a mold and solidifying the molten metal 3 to obtain a cast product. Casting equipment 14
Then, since solidification of the molten metal 3 is completed early and the throughput is improved, it is preferable to use a material having a higher thermal conductivity for the mold.

The obtained cast product is generally cooled and then separated by a trimming device 18 into a pre-product and a waste material 5. The pre-product is then heat-treated by the heat-treatment device 19 to improve the mechanical properties and become the final metal product 7. The waste material 5 separated by the trimming device 18 returns to the metal melting furnace 11 and is reused as a raw material. In addition, the final metal product 7 is also the inspection device 2
The defect found in 1 returns to the metal melting furnace 11 as scrap material 6 and is reused as a raw material. Although not shown, of course, the trimming device 18 and the inspection device 2
It is also possible to accept unnecessary materials and scrap materials generated in other than 1 in the metal melting furnace 11 and use them again as raw materials.

Next, various melting methods including compounding using the metal melting furnace according to the present invention will be described below with examples.

Using the metal melting furnace 11 having the entire configuration shown in FIG. 5, for example, an aluminum wheel as a product, the composition of which is 7% by mass of Si, 0.4% by mass of Mg, and 0.15% by mass of Ti. % Al alloy (A356
(Equivalent to aluminum alloy). Here, a molten metal level gauge is provided in the holding chamber 52 of the metal melting furnace 11 to continuously measure the molten metal level, and at least the molten metal level H
(High level) and the molten metal surface L (low level) can be detected.
The holding chamber 52 has a constant cross-sectional shape in the depth direction, and the molten metal surface area S is known.

At this time, the raw materials that can be handled by the four-system raw material feeders of the metal melting furnace 11 are as follows.

The main raw material feeder 31 capable of charging the fixed material 25 handles A356 alloy ingots and pure Al metal ingots. The main raw material feeder 32, which can supply the amorphous material 26, handles defective aluminum wheels (scrap material 6). Waste material 5
Alternatively, A356 alloy that is not an ingot and pure Al metal can be handled, but they are excluded from this example. Further, the additive raw material supply device 33 handles pure Si metal lumps, pure Mg metal lumps, and pure Ti metal lumps as the trace metal material 9 which is the pure metal material 12. The swarf raw material supply machine 34 uses A356 alloy swarf which is swarf 4, pure Si swarf, pure Mg
Chips and pure Ti chips are handled.

(Case 1)

Pure A is used as a raw material by the main raw material feeder 31.
l Metal ingot is charged and melted, and the additive raw material feeder 33
Thus, a pure Mg metal blob and a pure Ti metal blob are charged and melted as raw materials, and a pure Si metal blob as a raw material is charged and melted by the cutting material feeder 34. No other ingredients are used.

It is necessary to manage the amount of hot water discharged, Q _out , and mix it. The hot water discharge amount Q _out is obtained from the hot water surface area S and the hot water surface levels H and L by the following equation (3).

[0077]

[Equation 3] Q _out = S × (HL)

In the holding chamber 52, when the molten metal level gauge detects the molten metal level L, the melting burner 71 is ignited to start melting the pure Al metal ingot. Then, the pure Si metal small mass is weighed in the stirring chamber 53 provided in the holding chamber 52, and the charged amount Q _{IN Si} represented by the following (Formula 4) is charged and melted. Here, the content ratio P
_mSi = 7 (mass%).

[0079]

[Number 4] _{Q INSi = Q out × P mSi} / 100

The pure Si metal lumps are agitated and mixed with the molten metal which has been kept at a high temperature by the holding burner 72 and is already in the holding chamber 52, and melted. Input of pure Si metal blob is pure Al
It is preferable to carry out the treatment in a plurality of times in accordance with the rise in the molten metal level accompanying the melting of the metal ingot.

In parallel, the stirring chamber 5 provided in the holding chamber 52
A small amount of pure Mg metal and a small amount of pure Ti metal are respectively weighed in 3, and the respective input amounts Q _INMg and Q _INTi shown in the following (Equation 5) and (Equation 6) are added and dissolved. Here, the content ratios _{Pm Mg} = 0.4 (mass%) and P _mTi = 0.15 (mass%).

[0082]

[ _Formula 5] Q _INMg = Q _out × P _mMg / 100

[0083]

[ _Equation 6] Q _INTi = Q _out × P _mTi / 100

The pure Mg metal blobs and the pure Ti metal blobs are agitated and mixed with the molten metal which has been kept at a high temperature by the holding burner 72 and is already in the holding chamber 52 to be melted. It is preferable that the pure Mg metal lumps and the pure Ti metal lumps are charged in a plurality of times in accordance with the rise of the molten metal level of the pure Al metal ingot.

When the molten metal level gauge detects the molten metal level H, the melting burner 71 is stopped. By repeating this, the raw materials are mixed and melted to obtain the molten metal 3. The composition of the obtained molten metal 3 is analyzed by the composition analyzer 20.
Therefore, it is preferable to start the hot water discharge if there is no problem. If there is a problem, an alarm will be issued and pure Al metal ingot as the main raw material, or pure Si metal small lumps, pure Mg metal small lumps, and pure Ti metal small lumps as the additive raw materials will be added in the required amounts. However, it is also preferable to readjust automatically so that the desired component ratio is obtained.

(Case 2)

Pure A is used as a raw material by the main raw material feeder 31.
l Metal ingot is charged and melted, and the additive raw material feeder 33
Then, a pure Si metal blob, a pure Mg metal blob, and a pure Ti metal blob as a raw material are charged and melted, and an A356 alloy swarf as a raw material is charged and melted by a swarf material feeder 34.
No other ingredients are used.

It is preferable to manage the amount of hot water outflow Q _out and mix. The hot water discharge amount Q _out is obtained from the above-mentioned expression (3) from the surface area S and the surface level.

In the holding chamber 52, when the molten metal level gauge detects the molten metal level L, the melting burner 71 is ignited to start melting the pure Al metal ingot. Next, the A356 alloy cutting powder is weighed and put into a stirring chamber 54 provided in the holding chamber 52 to melt it. The A356 alloy swarf is agitated and mixed with the molten metal which has been kept at a high temperature by the holding burner 72 and is already in the holding chamber 52, and melted. Q _INA is the amount of A356 alloy swarf. The A356 alloy swarf can be added independently of the melting of the pure Al metal ingot. If A356 alloy cutting powder is more than hot water Q _out output, it is possible to cope with it by hot water Q _out corresponds dissolved out only A356 alloy cutting powder.

Then, pure Al is obtained by the above equation (1).
After _obtaining the input amount Q _IN1 of the metal material, a pure Si metal blob, a pure Mg metal blob, and a pure T are placed in the stirring chamber 53 provided in the holding chamber 52.
i Each small amount of metal is weighed, and each input amount Q is expressed by the following equations (7), (8) and (9).
_INSi , Q _INMg , Q _INTi are added and dissolved.

[0091]

[Equation 7] _{Q INSi = Q IN1 × P mSi} / 100

[0092]

[ _Equation 8] Q _INMg = Q _IN1 × P _mMg / 100

[0093]

[ _Equation 9] Q _INTi = Q _IN1 × P _mTi / 100

Pure Si metal nodules, pure Mg metal nodules, pure T
The i-metal small lumps are agitated and mixed with the molten metal which has been kept at a high temperature by the holding burner 72 and is already in the holding chamber 52 to be melted. The introduction of pure Si metal blobs, pure Mg metal blobs, and pure Ti metal blobs should be performed in multiple times in accordance with the rise in the molten metal level due to the melting of the pure Al metal ingot and the A356 alloy cutting chips. Is preferred.

When the melt level gauge detects the melt level H, the melting burner 71 is stopped. At the time of the molten metal surface H, the mixing of the appropriate composition is completed, and the molten metal 3 is obtained. Correspondence regarding the composition analysis and the analysis result of the obtained molten metal 3 is based on Case 1.

(Case 3)

A3 is used as a raw material by the main raw material feeder 31.
56 alloy ingot is added and melted. No other ingredients are used. The process is similar to that of a general continuous melting furnace.

It is not necessary to manage the hot water discharge amount Q _out . Regardless of the amount of hot water output Q _out , in the holding chamber 52, when the level gauge has cut off the level H, the melting burner 71 is ignited and A3
The melting of the 56 alloy ingot is started, and when the molten metal level gauge detects the molten metal level H, the melting burner 71 is stopped. Repeat this,
The raw materials are melted to obtain the molten metal 3 and the molten metal is discharged.

(Case 4)

A3 is used as a raw material by the main raw material feeder 31.
A 56 alloy ingot is charged and melted, and an A356 alloy cutting powder is charged and melted as a raw material by a cutting powder raw material feeder 34. No other ingredients are used. This is processing according to Case 3.

It is not necessary to manage the hot water discharge amount Q _out . Regardless of the amount of hot water output Q _out , in the holding chamber 52, when the level gauge has cut off the level H, the melting burner 71 is ignited and A3
The melting of the 56 alloy ingot is started, and when the molten metal level gauge detects the molten metal level H, the melting burner 71 is stopped. Repeat this,
The raw materials are melted to obtain the molten metal 3 and the molten metal is discharged. Also, the holding chamber 5
When the molten metal surface of No. 2 is less than the molten metal surface H, the A356 alloy swarf is put into the stirring chamber 54 provided in the holding chamber 52. A35
The 6-alloy cutting powder is already mixed in the holding chamber 52 and is stirred by the holding burner 72 with the molten metal 3 maintained at a high temperature to be mixed and melted. A356 alloy ingot input and A
It can be carried out independently from the addition of the 356 alloy cutting chips.

(Case 5)

A defective aluminum wheel as a raw material is charged by a main raw material feeder 32 and melted, and a pure Si metal blob, a pure Mg metal blob, and a pure Ti metal blob are fed and melted as a raw material by an additive raw material feeder 33. Then, pure Al metal swarf as a raw material is charged and melted by the swarf raw material feeder 34. No other ingredients are used.

It is preferable to manage the amount of hot water discharged, Q _out , and mix it. The hot water discharge amount Q _out is obtained from the above-mentioned expression (3) from the surface area S and the surface level.

In the holding chamber 52, when the level H of the level gauge is cut off, the melting burner 71 is ignited to start melting the defective aluminum wheel product. Next, the pure Al metal shavings are weighed and put into a stirring chamber 54 provided in the holding chamber 52 and melted. The input amount of pure Al metal cutting chips is _designated as Q _IN1 . The pure Al metal swarf is agitated and mixed with the molten metal which has been kept at a high temperature by the holding burner 72 and is already in the holding chamber 52 to be melted. The addition of the pure Al metal cutting powder can be performed independently of the melting of defective aluminum wheel products. If the defective aluminum wheel is more than the hot water output Q _out ,
It is possible to deal with this by melting only defective aluminum wheels corresponding to the hot water discharge amount Q _out .

Next, the stirring chamber 53 provided in the holding chamber 52
A pure Si metal blob, a pure Mg metal blob, and a pure Ti metal blob are weighed respectively, and the respective input amounts Q shown in the formulas (7), (8) and (9) are given. _INSi , Q _INMg ,
_Add Q _INTi and dissolve.

Pure Si metal nodules, pure Mg metal nodules, pure T
The i-metal small lumps are agitated and mixed with the molten metal which has been kept at a high temperature by the holding burner 72 and is already in the holding chamber 52 to be melted. It is preferable that the pure Al metal swarf, the pure Si metal lumps, the pure Mg metal lumps, and the pure Ti metal lumps be charged in multiple times.

When the melt level gauge detects the melt level H, the melting burner 71 is stopped. At the time of the molten metal surface H, the mixing of the appropriate composition is completed, and the molten metal 3 is obtained. Correspondence regarding the composition analysis and the analysis result of the obtained molten metal 3 is based on Case 1.

As described above, in order to obtain a desired molten metal in one metal melting furnace, for example, general melting using an alloy material that meets a predetermined standard as a raw material, and predetermined two or more kinds of pure metals The compounding dissolution using the material as the raw material and the dissolution using the cutting powder as the raw material can be performed independently or simultaneously. Of course, it is not limited to the above cases 1 to 5.

The materials of the equipment constituting the metal melting furnace according to the present invention will be described below.

The temperature of the molten metal is maintained at a high temperature of around 720 ° C., for example, when an aluminum-based alloy is used as a raw material, so it is preferable to pay particular attention to corrosiveness. It is preferable to use a regular refractory, an irregular refractory, or the like on the inner surface of the main body that is in contact with the molten metal. Ceramics, graphite, and the like can be applied to the equipment installed in the metal melting furnace, such as a burner and a stirrer. An iron plate may be used for a raw material feeder that does not directly touch the molten metal, but it is preferable to apply a coating having heat resistance and corrosion resistance.

[0112]

As described above, according to the metal melting furnace and the compounding and melting method of the present invention, in addition to melting the standard material or the return material as the raw material to obtain the molten metal as in the conventional method, the pure metal material is added. It is possible to obtain a molten metal having a desired composition by using it as a raw material and mixing and melting it. Furthermore, a molten metal having a desired composition can be obtained by accepting and using a cutting powder having a composition corresponding to a pure metal material or a standard material as a raw material. Therefore, there is an excellent effect that a molten metal having a stable quality can be supplied to a molding processing device such as a casting device and a die casting device at a later stage while reducing the raw material cost.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of a metal melting furnace according to the present invention, and is a horizontal sectional view of a melting furnace main body.

FIG. 2 is a view showing an embodiment of the metal melting furnace according to the present invention, and is a vertical sectional view showing a BB cross section of the melting furnace main body shown in FIG.

FIG. 3 is a view showing an embodiment of the metal melting furnace according to the present invention, and is a vertical sectional view showing an AA cross section of the melting furnace main body shown in FIG.

FIG. 4 is a block flow diagram showing an example of a metal product manufacturing process by a casting method including a metal melting furnace according to the present invention.

FIG. 5 is a block flow diagram showing an example of the overall configuration of a metal melting furnace according to the present invention.

[Explanation of symbols]

1, 12 ... Pure metal material, 2 ... Return material, 3 ... Molten metal,
4 ... Cutting chips, 5 ... Waste material, 6 ... Scrap material, 7 ...
Metal product, 8 ... Alloy material (standard material), 9 ... Trace metal material, 10 ... Melting furnace body, 11 ... Metal melting furnace, 13 ... Holding furnace, 14 ... Casting device, 18 ... Trimming device, 19 ... Heat treatment furnace, 20 ... Composition analysis device, 21 ... Inspection device, 25 ...
Standard material (main raw material), 26 ... Non-standard material (main raw material), 3
1, 32 ... Main raw material feeder, 33 ... Additive raw material feeder, 34
... Chips raw material feeder, 41 ... Manufacturing process, 51 ... Melting chamber,
52 ... Holding chamber, 53, 54 ... Stirring chamber, 55 ... Tower-like introduction part, 56 ... Hot water outlet, 57 ... Exhaust port, 61 ... Stock conveyor, 62 ... Capsule type raw material feeder, 63 ... Elevator type raw material feeder, 64, 66 ... Hopper, 65, 67 ... Metering feeder, 71 ... Melting burner, 72 ... Holding burner, 73,
74 ... Stirrer.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4K045 AA04 BA03 DA03 RA12 RB12                       RB22                 4K056 AA05 BB01 CA04 EA11 FA01                       FA11 FA17                 4K063 AA04 BA03 CA03 CA07 GA02                       GA09

Claims (19)

[Claims] 1. A continuous melting furnace comprising: Consist of alloy material A and / or plural kinds of pure metal materials
Pure metal materials group X _nAt least 2 kinds included in
Of pure metal material to obtain molten metal A with the desired composition.
Metal melting characterized by having a compounding function capable of
Furnace. 2. The compounding function comprises a first means for obtaining an amount Q _out of molten metal from a melting furnace, and a second means for melting by setting an input amount Q _INA of the alloy material _A to obtain a molten metal Y _A. And a pure metal material X ₁ as a main raw material contained in the pure metal material group X _n.
Calculates a charged amount Q _IN1 dissolved in the melt Y _A, the molten metal Y
Third means for obtaining a _1, insertion of the one or more pure metal material contained in the pure metal material group X _m and consisting of at least one or more additives material which is a component of the pure metal material group X _n 4. A metal melting furnace according to claim 1, further comprising: a fourth means for calculating a quantity Q _INm and melting it in the melt Y ₁ to obtain a melt A. 3. The metal melting furnace according to claim 1, further comprising a non-contact type melt level gauge for measuring a melt level of the melt A. 4. The pure metal material X _{1 according to} the third means.
3. The metal melting furnace according to claim 2, wherein the input amount Q _IN1 is expressed by the following equation: Q _IN1 = Q _out −Q _INA . 5. The pure metal material group X in the fourth means.
_When the input amount Q _{INm of} one or more pure metal materials contained in _m is the content ratio P _m (mass%) of the pure metal material, it is expressed by the following equation: Q _INm = Q _IN1 × P _m / 100 The metal melting furnace according to claim 4. 6. A stirring means for melting one or more pure metal materials contained in the pure metal material group X _m.
Or the metal melting furnace according to 2. 7. The metal melting furnace according to claim 1, wherein the alloy material A and / or at least two or more kinds of pure metal materials contained in the pure metal material group X _n contain cutting chips. 8. The metal melting furnace according to claim 7, further comprising stirring means for melting the cutting chips. 9. The main component of the molten metal A is aluminum,
The metal melting furnace according to claim 1, which is a lightweight metal made of either zinc or magnesium. 10. The molten metal A contains aluminum as a main component, contains 4 to 24 mass% of silicon, 0.3 to 0.5 mass% of magnesium, and 0.05 to 0.25 mass% of titanium. The metal melting furnace according to any one of claims 1 to 8. 11. The metal melting furnace according to claim 1, further comprising a composition analysis unit for the molten metal A. 12. to obtain the molten metal A by dissolving the alloy material A, and the obtain a molten metal Y ₁ by dissolving pure metal material X _1, and melting chamber which is capable, the net in the melt Y ₁ A holding chamber capable of melting one or more pure metal materials contained in the metal material group X _m to obtain the molten metal A, and the alloy material A and the pure metal material X ₁ may be placed in the melting chamber. A tower-shaped melting furnace comprising a possible tower-shaped introduction section, wherein the exhaust heat of the melting chamber and / or the holding chamber is configured to be discharged via the tower-shaped introduction section, The metal melting furnace according to claim 2, wherein the alloy material A or the pure metal material X ₁ can be preheated. 13. A return material having substantially the same composition as the alloy material A can be applied as a raw material instead of the alloy material A or in combination with the alloy material A. The metal melting furnace according to claim 1. 14. The metal melting furnace according to claim 1, further comprising at least two kinds of raw material charging machines for a regular raw material and an amorphous raw material. 15. A metal material as a raw material is received by using a melting furnace.
A series that can discharge molten metal A with a desired composition while pouring and melting
A continuous dissolution method, Consist of alloy material A and / or plural kinds of pure metal materials
Pure metal materials group X _nAt least 2 kinds included in
Each of the pure metal materials of
A method of blending and dissolving which is characterized by obtaining. 16. A first step of obtaining a molten metal output Q _out from the melting furnace, a second step of setting a melting amount Q _INA of the alloy material A and melting the molten alloy to obtain a molten metal Y _A , pure metal material X ₁ of the main raw material contained in the pure metal material group X _n
Calculates a charged amount Q _IN1 dissolved in the melt Y _A, the molten metal Y
A third step of obtaining a _1, insertion of the one or more pure metal material contained in the pure metal material group X _m and consisting of at least one or more additives material which is a component of the pure metal material group X _n The fourth step of calculating a quantity Q _INm and dissolving it in the molten metal Y ₁ to obtain a molten metal A. 17. The pure metal material X in the third step
The blending dissolution method according to claim 16, wherein the input amount Q _{IN1 of 1} is represented by the following formula: Q _IN1 = Q _out −Q _INA . 18. The input amount Q _{INm of} one or more pure metal materials contained in the pure metal material group X _m in the fourth step is:
The blending and dissolving method according to claim 17, wherein the content ratio P _m (mass%) of the pure metal material X _m is represented by the following formula: Q _INm = Q _IN1 × P _m / 100. 19. The blending and dissolving method according to claim 16, further comprising a fifth step of analyzing the composition of the molten metal A after the fourth step.