KR100758277B1 - Continuous cast aluminum alloy rod and production method and apparatus thereof - Google Patents

Abstract

The continuous casting aluminum alloy rod 101 is manufactured by the horizontal continuous casting method using the cylindrical mold which has a forced cooling means, keeping a central axis substantially horizontal. The rod has a Si-rich portion 104 having a thickness of 20 µm or more on the surface of the side surface of the rod having a central angle 103 of 30 degrees or more.

Description

Continuous casting aluminum alloy rod and manufacturing method and apparatus therefor {CONTINUOUS CAST ALUMINUM ALLOY ROD AND PRODUCTION METHOD AND APPARATUS THEREOF}

The present invention relates to a continuous cast rod of an aluminum alloy and to a method and apparatus for horizontally and continuously producing the cast rod.

In general, horizontal continuous casting of molten metal produces a stretch cast ingot of cylindrical, prismatic or hollow cylindrical form by the following method. Specifically, the molten metal preserved in the tundish, which is substantially horizontally stretched and forcedly cooled, and then cooled in a mold to form a solidification shell on the outer surface of the cooled molten metal, is passed through a fire resistant passageway. It is filled in a cylindrical mold. The coolant (eg water) is sprayed directly onto the ingot to advance the solidification inside the ingot, while the resulting cast ingot is withdrawn continuously from the mold. However, such a horizontal continuous casting process inevitably includes the following problems due to its inherent principle.

The first problem is described below. Since the mold is provided so that the center axis is substantially horizontal, the molten metal in the mold is press-molded under the mold inner circumferential wall by gravity. Thus, the molten metal is cooled in the mold in a non-uniform way. That is, the bottom of the molten metal cools faster than the top. As a result, it is finally solidified on the central axis of the continuous casting rod so that the casting ingot does not achieve a uniform metal structure.

The second problem is as follows. In order to prevent the molten metal from sticking to the inner circumferential wall, the lubricating oil is uniformly supplied to the entire inner circumferential wall through the mold inner circumferential wall portion near the inlet end of the mold, thereby acting on the gravity and lower surface acting on the upper surface of the casting ingot The lubricating oil rises from the bottom of the inner circumference wall to the top due to the difference between the gravity. In addition, the gas generated due to thermal decomposition of the lubricating oil rises to the upper portion of the inner circumferential wall. Therefore, the lubricating interface existing between the solidification shell formed on the outer circumferential surface of the molten metal or the casting ingot and the mold inner circumferential wall becomes non-uniform. As described above, in the lower part of the mold, since the molten metal is in close contact with the mold inner circumferential wall, there is no substantial space between the solidification shell and the mold inner circumferential wall. Thus, no lubricating oil is supplied to the solidified shell formed on the outer circumferential surface of the molten metal or the casting ingot, causing sticking between the molten metal and the mold inner circumferential wall. As a result, the solidification shell is broken, and outflow of unsolidified molten metal occurs, and large casting defects occur or breakage of the casting ingot occurs, thereby making the casting operation impossible. On the other hand, since there is an excess of the lubricating oil in the upper part of the mold, the molten metal is insufficiently cooled in the mold, and the unsolidified molten metal flows out of the upper part of the casting ingot.

Usually, various methods for solving such a fundamental problem contained in the horizontal continuous metal casting method have been proposed. For example, Japanese Patent Application Laid-open No. Hei 8-32356 discloses a casting method in which micropores or grooves are provided in the inner circumferential wall of the mold in order to prevent the supply of excess lubricant to the upper part of the mold.

However, conventional casting methods (including the proposed method) require that the casting conditions (e.g., supply of lubricating oil, casting temperature and casting speed) to be controlled very carefully, in particular, actually casting the casting. Since the rods are intricately associated with others in manufacturing operation control, it is difficult to prevent changes in the surface conditions of the continuous cast rods. As a result, sticking, breakout, and pits sometimes occur that cause casting defects.

In order to solve the above problems included in the conventional horizontal continuous casting method, an object of the present invention is to continuously cast an aluminum alloy, which prevents the occurrence of casting surface defects and breakouts, and enables stable continuous casting of a good quality casting ingot. It is to provide a rod and a method and apparatus for continuously manufacturing the cast rod horizontally.

The present invention relates to a continuous cast aluminum alloy rod manufactured by a horizontal continuous casting method using a cylindrical mold having a forced cooling means, the central axis of which is kept substantially horizontal, the side of the rod having a central angle of 30 ° or more. A continuous cast aluminum alloy rod comprising a Si rich portion having a thickness of at least 20 μm on a surface is provided.

In the continuous cast aluminum alloy rod, the Si rich portion has a Si fine structure containing primary α-Al having an area ratio of less than 50% as measured by an element distribution obtained from a radial cross section of the rod.

In the continuous cast aluminum alloy rod, the Si fine structure contains Si particles having an average particle size of 0.1 to 5 μm.

The continuous cast aluminum alloy rod contains Si in an amount of 7 to 14 mass%.

The continuous cast aluminum alloy rod contains Ca in an amount of 0.003% by mass or more.

The continuous cast aluminum alloy rod has a surface roughness Rmax of 50 µm or less, and does not have a tool mark on the surface when peeling after casting.

In addition, the present invention is a method for producing a continuous cast aluminum alloy rod using a cylindrical mold having a central axis substantially horizontal, and having a forced cooling means, the temperature of the molten aluminum alloy poured into the cylindrical mold A process for controlling the difference between its solidification temperatures, and a process for casting a rod to form a Si-rich portion having a thickness of 20 μm or more on the surface of the sidewall of the rod having a center angle of 30 ° or more; To provide.

The method of manufacturing the continuous cast aluminum alloy rod may further include a step of controlling the speed of drawing the rod from the cylindrical mold.

The method for producing a continuous cast aluminum alloy rod is obtained by using 7-14 mass% of Si and 0.003 mass% or more of Ca as a raw material, the casting speed of 200-1,500 mm / min, and the liquidus temperature of the alloy, or Controlled by the temperature of the molten aluminum alloy at a higher temperature, and as a cylindrical mold, made of one or two or more kinds of materials selected from aluminum, copper, and alloys thereof, and an effective mold length of 15 to 70 mm. It may further comprise using a mold having.

In the method for producing the continuously cast aluminum alloy rod, the molten aluminum alloy may be added with Ca in an amount of 0.003% by mass or more.

In the method for producing the continuous cast aluminum alloy rod, Ca to be added is metallic Ca having a purity of 99.9% or more.

In the method for producing the continuously cast aluminum alloy rod, the cylindrical mold is an annular permeable porous member having air permeability of 0.005 to 0.03 L / (cm ² × min) on the inner circumferential wall in close contact with the molten aluminum alloy. Included.

In the method for producing the continuously cast aluminum alloy rod, the permeable porous member is provided within a range of 5 to 15 mm of the effective mold length.

The present invention also provides a melting furnace for preserving a molten aluminum alloy and supplying the molten aluminum alloy; A casting portion having a cylindrical mold and cooling means, for casting the molten aluminum alloy into a solidified casting ingot; A drawing drive unit which draws the solidified casting ingot substantially horizontally from the cylindrical mold to form a continuous cast aluminum alloy rod having a Si-rich portion; A detector for detecting a region of the Si rich section and outputting a detected signal; A determination unit which compares the detection signal with a predetermined determination condition and outputs a determination signal; And a control unit for controlling the temperature of the molten aluminum alloy in the melting furnace, the cooling means of the casting unit, and the drawing speed of the drawing drive unit so that the detection signal is included in a predetermined determination condition based on the determination signal. Provided are devices for making rods.

The apparatus for manufacturing the continuous cast aluminum alloy rod further includes a Ca introduction portion controlled by a controller such that the detection signal is included in a predetermined determination condition based on the determination signal.

The apparatus for manufacturing the continuous cast aluminum alloy rod is an analysis unit for analyzing the composition of the molten aluminum alloy, and outputs a Ca amount measurement data signal to the determination unit based on the analysis result and the Ca amount is determined from the determination unit. The control unit further controls a Ca introducing unit to be included in a predetermined determination condition based on the signal.

According to the present invention, the cast aluminum alloy rod is continuously formed under the above conditions using a cylindrical mold having a central axis substantially horizontal and having a forced cooling means, thereby preventing breakage of the casting ingot or occurrence of casting defects. On the upper surface of the cast aluminum alloy rod, a string-shaped Si rich part having a relatively high strength may be formed in comparison with a general cast rod surface. That is, it is preferable to prevent the outflow of unsolidified molten metal due to friction between the surface of the casting rod and the mold inner circumferential wall.

1: is explanatory drawing of the continuous casting rod of this invention, FIG. 1 (a) shows the external appearance and FIG. 1 (b) shows the cross section of the radial direction.

2 is a schematic cross-sectional view showing a main part of a typical production apparatus used in the production method of the present invention.

3: is explanatory drawing of the Si-rich part of the continuous casting rod of this invention, FIG. 3 (a) shows the method of taking a test piece from the radial direction cross section of the said continuous casting rod, and FIG. 3 (b) is the said test piece An example of an enlarged element distribution diagram of Fig. 3 (c) shows an example of another enlarged element distribution diagram of the test piece.

It is explanatory drawing which shows the effective mold length of a cylindrical mold in the manufacturing apparatus of FIG.

5 is a schematic view showing the configuration of a typical manufacturing apparatus according to the present invention.

6 is a graph showing data obtained in Examples 1 to 4 of the present invention.

7 is a graph showing data obtained in Examples 5 to 8 of the present invention.

The continuous casting aluminum alloy rod of this invention is demonstrated below.

The continuous cast aluminum alloy rod of the present invention is manufactured through a horizontal continuous casting method using a cylindrical mold having a forced cooling means, the central axis of which is kept substantially horizontal (i.e., the transverse direction), and the cast rod is 10 to It has a diameter included in the range of 100mm. Casting rods having a diameter outside the above range can also be produced. However, when a casting rod having such a diameter is subjected to subsequent plastic working (for example, forging, roll forging, drawing, rotational working or impact molding), the size and diameter of the casting rod can be used for the plastic working. It is preferable to be included in the range. When changing the diameter of the cast rod to be produced, a separable cylindrical mold having an inner diameter corresponding to the changed diameter of the cast rod is used, and depending on the mold used, the molten alloy temperature and the casting speed are determined. If necessary, the amounts of cooling water and lubricating oil are appropriately determined.

As shown in Fig. 1 (a) and Fig. 1 (b), the continuous cast aluminum alloy rod 101 of the present invention is 30 ° or more (preferably 40 ° to 90 °) with respect to the center 102 of the rod. On the surface (outer circumferential surface) of the side surface of the rod having the center angle 103 of (), it has a longitudinal (axial) strip Si-rich portion 104 having a thickness of 20 µm or more (preferably 30 to 100 µm). The cast rod can prevent the outflow of the unsolidified molten alloy due to the friction between the surface of the cast rod and the mold inner circumferential wall, and the strip-shaped Si rich portion is not generated during subsequent plastic processing. It is desirable to have. If the center angle is less than 30 ° and the thickness is less than 20 mu m, sufficient effects of the present invention cannot be obtained. In addition, although a larger center angle is desired, the control of the casting conditions becomes more stringent as the center angle becomes larger.

In the present invention, the thickness of the Si rich portion is defined as follows. First, in order to obtain the said thickness, the said Si rich part is observed by the following method, for example.

(a) Sampling position, sampling method and preprocessing of sample:

A cast rod sample 101 was randomly collected from a continuously manufactured casting rod, and the specimen 306, 2-5 mm square, was drawn from the side surface of the sample 101 at a position corresponding to the top of the mold inner circumferential wall. It was cut as shown in (b). The test piece is cut into thin pieces using a microtome and each thin piece is used for observing the radial cross section of the rod sample. The reason for using the microtome is as follows. Since the observed test piece is obtained from the good surface of the cast rod sample, when the test piece is cut into thin pieces by a conventional cutting method, a roll off occurs in each piece, so that the piece cannot be reliably observed. As long as the above problems can be overcome, other cutting methods may be used.

In the same manner as above, the test piece is cut at various points on the circumferential side of the cast rod sample.

(b) Measuring device and measuring conditions:

Elemental Al or Si distributions were obtained from the radial side using a magnetic field emission Auger Electron Spectroscopy (FE-AES) device. The FE-AES device may be, for example, MICROLAB-310F (VG). The radial side surface is observed, for example, under the following conditions: acceleration voltage: 10 kV, current applied to the sample: 0.8-2.7 nA, magnification: 1,000.

For surface observation, a secondary electron microscope or EPMA may be used instead of an Auger electron spectrometer.

(c) Measurement of thickness and other data:

FIG. 3 (b) schematically shows an element distribution diagram obtained through observation of a test sample 306 obtained from the continuous casting rod 101 of FIG. 3 (a) using an Auger electron microscope. Obtaining an area ratio of α-Al 303 in any region (10 μm square) extending from the surface of the casting rod toward the center using the elemental distribution diagram thus obtained; An area where the area ratio of α-Al is less than 50% is defined as the Si rich portion 104; The width of the Si rich portion is defined as the thickness 302.

The area ratio of α-Al used herein refers to the area ratio of α-Al with respect to the area ratio of the above-mentioned region of the electron microscope element distribution diagram calculated by the point coefficient method.

The average size of the Si particles 304 in the Si rich portion obtained by the Auger electron microscope element distribution diagram is defined as the average particle size of the Si particles contained in the Si fine structure.

   In the continuous casting rod of the present invention, the Si rich portion 104 preferably has a Si fine structure having an area ratio of α-Al 303 of less than 50% as shown in FIG. 3 (c). When the area ratio of α-Al is less than 50%, the Si fine structure portion is preferably higher in hardness than the portions other than the fine structure portion, and the casting reliability is further improved.

As for the average particle size of Si particle | grains contained in the said Si microstructure, 0.1-5 micrometers is preferable. If the average particle size is within the above range, the Si fine structure strengthens the solidification shell formed on the side surface of the casting rod to prevent the outflow of unsolidified molten metal due to friction between the surface of the casting rod and the mold inner circumferential wall. In addition, the cast rod does not cause other problems during subsequent plastic working. The surface of the cast rod having the Si microstructure has a metallic luster.

When the continuous casting rod of the present invention is manufactured by a long-term casting process, it is possible to prevent sticking between the casting rod and the inner circumferential wall of the mold, breaking of the casting rod, or leakage of the molten alloy. As a result, the frequency of adjustment of the operating conditions (e.g., the amount of lubricant supplied and the casting speed) can be reduced, so that a reliable casting operation can be performed.                 

The assumed mechanism by which the effect is obtained is as follows. Since the continuous casting rod of this invention has a Si-rich part which has a thickness of 20 micrometers or more on the surface of the side surface of the said rod which has a center angle of 30 degrees or more, the surface hardness of the casting rod is higher than the surface hardness of the conventional casting rod. Therefore, the solidification shell becomes stronger against the adhesion resistance between the casting rod and the inner circumferential wall of the mold, and it can be considered that the occurrence of casting defects (for example, sticking) is suppressed. The portion of the cast rod having the Si fine structure has a metallic luster and has a hardness higher than that of other portions of the rod. On the other hand, the upper part of the casting rod (that is, the portion corresponding to the upper inner circumferential wall of the cylindrical mold that is substantially horizontally stretched) is insufficiently cooled because excess lubricant is present in the portion. When the Si-rich portion is formed on the upper part of the cast rod, the upper part is solidified reliably, so it can be considered that the outflow of the unsolidified molten alloy can be prevented.

The continuous cast rod of the present invention preferably contains Ca in an amount of 0.003% by mass or more (more preferably, 0.003 to 0.05% by mass, most preferably 0.006% by mass or more, particularly 0.006 to 0.04% by mass). This is because if the casting rod contains Ca in the above amount, the surface hardness of the casting rod can be further increased. As a result, the above effect can be further improved.

The continuous casting rod of the present invention is used as a series of plastic working materials such as forging, roll forging, drawing, rotational processing or impact molding. In addition, the cast rod is used as a machining material, such as bar machining or punching, or a similar process material. When the cast rod is subjected to plastic working or machining, the Si fine structure is removed from the cast rod by peeling, if necessary, before the post-processing as described above. Since the cutting tool used for peeling (for example, a turning tool) and the said Si rich part does not show a big difference in hardness, peeling of the continuous casting rod of this invention can be performed easily. In the case of peeling the cast rod, the pieces are broken at the Si-rich portion, so that problems during peeling such as entanglement of the pieces and the cutting tool can be avoided. As a result, the cast rod of the present invention exhibits improved machinability, good finish after peeling and good forging during subsequent forging processes, so that, for example, the quality (eg, dimensional accuracy) of the casting rod and the endurance life of the forging rod are improved. When peeling off the surface of the said continuous casting rod, it is preferable that the obtained casting rod has surface roughness Rmax of 50 micrometers or less, and there is no tool mark. Here, "tool mark" means the scratch formed by the piece which entered the cutting tool (for example, a turning tool) used in a peeling process detected by visual inspection.

The entire casting rod, including the upper outer circumferential surface having a high metallic luster, has a very smooth casting surface. In addition, the cast rod does not contain a cavity therein and is suitable for use as a forging material.

Even when proper heat treatment is performed without peeling off the continuous cast rod of the present invention, the cast rod exhibits the mechanical properties required for post-processing.

A typical apparatus used in the present invention and a manufacturing method using the apparatus will be described. The horizontal continuous casting method used in the present invention may be a known horizontal continuous casting method. Supplying at least one fluid selected from a gaseous lubricant, a liquid lubricant and a gas obtained by pyrolysis of the liquid lubricant to the inner circumferential wall of the cylindrical mold having, for example, forced cooling means and maintained so that the central axis is substantially horizontal; A molten aluminum alloy containing Si is poured into the cylindrical mold through the first stage to form a cylindrical molten alloy body; Solidifying the main body in the cylindrical mold to form a casting ingot; The casting ingot is taken out from the second end of the cylindrical mold.

2 shows a typical continuous casting apparatus near the mold used in the present invention.

The tundish 250, the fire-resistant plate-shaped body 210 and the cylindrical mold 201, and the molten alloy 255 stored in the tundish 250 are fire-resistant plate-shaped bodies 210 as the cylindrical mold 201. Install to pour through). The cylindrical mold 201 is maintained such that the central axis 220 is substantially horizontal. Means for forcibly cooling the mold inside the cylindrical mold to solidify the molten alloy into the casting ingot 216, and means for forcibly cooling the casting ingot to an outlet of the cylindrical mold. Install. As shown in Fig. 2, a coolant-shower device 205 is provided, which is an example of means for forcibly cooling the casting ingot. In the vicinity of the exit of the cylindrical mold, a drive device (not shown) is provided so as to continuously pull out the casting ingot 216 forcedly cooled from the mold at a predetermined speed. Moreover, a tuning cutter (not shown) is provided in order to cut the casting rod thus drawn out to a predetermined length.

As shown in FIG. 2, the cylindrical mold 201 is hold | maintained so that the center axis | shaft 220 may be substantially horizontal. In addition, the cylindrical mold 201 supplies a means for forcibly cooling the mold and a cooling water 202 to the cooling water cavity 204 of the mold, thereby cooling the inner circumferential wall of the mold to bring the molten metal into close contact. Means for removing heat from the cylindrical molten alloy 215 filled in the mold through a mold inner circumferential wall to form a solidified shell on the surface of the molten alloy; And forced cooling means installed to solidify the molten alloy in the mold by releasing the cooling water from the shower device 205 to apply water to the casting ingot directly to the outlet of the mold. The cylindrical mold is connected to the tundish 250 through the fire resistant plate-like body 210 at the end opposite to the outlet of the shower device. As shown in FIG. 2, the cooling water for forcibly cooling the mold and the cooling water for forcibly cooling the casting ingot are supplied through a cooling water supply pipe 203. However, the two types of cooling water may be supplied separately. It is preferable that the forced cooling means and the coolant shower device of the cylindrical mold can control their functions by a control signal.

The effective mold length (see letter L in FIG. 4) is defined as the length measured from the position where the central axis of the outlet of the coolant shower device crosses the surface of the casting ingot to the contact surface between the mold and the refractory plate-like body. As for the said effective mold length, 15-70 mm is preferable. This is because when the effective mold length is in the above range, the Si rich portion having a thickness of 20 µm or more is sufficiently formed on the surface of the portion of the continuous casting rod having a central angle of 30 ° or more. If the effective mold length is less than 15 mm, no good coating is formed on the molten alloy, so that the casting of the molten alloy is not performed. On the other hand, if the effective mold length exceeds 70 mm, the effect of forced cooling is not obtained. Therefore, the inner circumferential wall of the mold prevents the solidification of the molten alloy and the adhesion resistance between the mold and the molten alloy or the solidification shell increases. This results in undesirable casting (eg, cracking on the casting surface, or breakage of the casting ingot in the mold).

The material of the above mold is preferably one or a combination of two or more selected from aluminum, copper and alloys thereof. Combinations of these species can be determined in terms of thermal conductivity, heat resistance or mechanical strength.

It is preferable that the said mold contains the annular permeable porous member 222 which exhibits self-lubrication on the inner peripheral wall in close contact with a molten alloy. The annular member is provided over the entire inner circumferential wall of the cylindrical mold. The air permeability of the permeable porous member is preferably 0.005 to 0.03 L / (cm ² × min) (more preferably 0.007 to 0.02L / (cm ² × min)). There is no particular limitation on the thickness of the permeable porous member, but the thickness thereof is preferably 2 to 10 mm (more preferably 3 to 8 mm). This is because if the thickness is in the above range, the Si rich portion having a thickness of 20 µm or more is sufficiently formed on the surface of the side surface of the continuous casting rod having a central angle of 30 ° or more. The permeable porous member may be made of graphite having air permeability of, for example, 0.008 to 0.012 L / (cm ² × min). The breathability is obtained by measuring the amount of air passing through the test piece (thickness: 5 mm) per minute under the application of ² kg / cm ² pressure.

In the cylindrical mold, the permeable porous member is preferably provided within the range of 5 to 15 mm of the effective mold length. This is because, when the permeable porous member is provided within the above range, the Si rich portion having a thickness of 20 µm or more is sufficiently formed on the surface of the side surface of the continuous casting rod having a center angle of 30 ° or more. Preferably, the O-ring 213 is provided on the surface where the fire-resistant plate-shaped body, the cylindrical mold, and the permeable porous member are in close contact with each other.

The radial side surface of the inner circumferential wall of the cylindrical mold may be assumed to be a circular shape, a triangular shape, a rectangular shape, or an irregular shape having neither a symmetry axis nor a symmetry plane. When manufacturing a hollow casting ingot, the core may be formed in the said cylindrical mold. The cylindrical mold has an opening. The molten alloy is poured into the mold through the first end of the mold (via the inlet installed in the refractory plate-like body), and the solidified casting ingot is extruded or drawn out from the second end of the mold.

The inner diameter of the mold is increased toward the casting ingot withdrawal direction such that the elevation angle between the mold inner circumferential wall and the central axis 220 is preferably 0 to 3 ° (more preferably 0 to 1 °). If the elevation angle is less than 0 °, a resistance is applied to the casting ingot at the outlet of the mold during the withdrawal of the casting ingot from the mold and casting cannot be performed. On the other hand, when the elevation angle exceeds 3 °, the molten alloy is in intimate contact with the mold inner circumferential wall, and the mold insufficiently exerts the effect of removing heat from the molten alloy or the solidified shell, thereby causing the molten alloy Coagulation of is insufficient. As a result, there is a high probability of casting problems. For example, a remelting surface is formed on the casting ingot or unsolidified molten alloy flows out of the end of the mold.

The tundish includes a molten alloy inlet 251, a molten alloy reservoir 252 and an outlet 253 in which the molten alloy is poured into a mold. The tundish introduces a molten aluminum alloy whose composition is preset by a melting furnace or the like provided outside the casting apparatus, through an inlet. In the tundish, the level 254 of the molten alloy is maintained at a position above the top surface of the mold cavity. When a plurality of castings are performed, the molten alloy is stably poured from the tundish into a plurality of molds. The molten alloy stored in the molten alloy storage portion of the tundish is poured into the mold through the molten alloy inlet 211 provided in the refractory plate-like body. It is preferable that the said melting furnace or tundish is equipped with Ca induction apparatus, and since this controls the amount of Ca introduce | transduced by a control signal, it is preferable.

The fire resistant plate-like member 210 is provided to separate the tundish from the mold. The plate-shaped body may be made of a material of fire resistance and heat insulation. Examples of such materials include Lumiboard (manufactured by Nichias Corporation), Insural (manufactured by Foseco Ltd.), and Fiber Blanket Board (manufactured by Ibiden Co., Ltd.). The refractory plate-like member has a shape in which a molten alloy inlet can be formed. One or more molten alloy inlets may be formed in the portion of the refractory plate-like body extending inwardly from the inner circumferential wall of the cylindrical mold.

Reference numeral 208 denotes a fluid supply pipe for supplying a fluid. Examples of the fluid to be supplied include lubricating fluids. The fluid may be one or more selected from gaseous lubricants and liquid lubricants. The gaseous lubricant supply pipe and the liquid lubricant supply pipe are preferably installed separately. The fluid which is pressurized and supplied through the fluid supply pipe 208 passes through the annular passage 224 and is supplied to a gap between the cylindrical mold and the fire resistant plate-like member. Preferably, the gap of 200 micrometers or less is formed in the part in which the said mold and fire-resistant plate-shaped object are in close contact with each other. The gap has a size such that the molten alloy does not enter the gap and the fluid can flow along the mold inner circumferential wall. As shown in FIG. 2, the annular passage 224 is formed on the outer circumferential surface of the porous porous member 222 provided in the cylindrical mold. The fluid to which the pressure is applied is permeated through the permeable porous member in close contact with the molten alloy and supplied to the inner circumferential wall 221 of the cylindrical mold. The liquid lubricant may be decomposed into a gas by heating, and the gasified lubricant may be supplied to the inner circumferential wall of the cylindrical mold.

As a result, it is possible to improve the lubricity between the outer circumferential surface of the cylindrical molten alloy body or the outer circumferential surface of the metallic mass, which is the outer circumferential surface of the solidification shell, and the porous porous surface of the cylindrical mold. Since the annular permeable porous member is formed on the mold inner circumferential wall, excellent lubricating effect is obtained, and has a Si-rich portion (thickness: 20 μm or more) formed on the surface of the side of the continuous casting rod having a central angle of 30 ° or more. Continuous cast aluminum alloy rods can be easily manufactured.

The corner space 230 is formed in the presence of at least one selected from a feed gas phase or a liquid lubricant, and a gas obtained by decomposition of the liquid lubricant.

Hereinafter, the manufacturing method of this invention is demonstrated.                 

As shown in FIG. 2, the molten alloy in the tundish 250 is poured into the cylindrical mold 201, which is maintained such that the central axis is substantially horizontal, through the fire-resistant plate-like body 210. It is forced to cool at the exit of the mold and solidify to form a casting ingot 216. The casting ingot 216 is continuously drawn out from the mold at a predetermined speed by using a drive device provided near the outlet of the mold to form a casting rod. The cast bar obtained is cut into pieces of predetermined length using a tuning cutter.

When the continuous cast aluminum alloy rod is manufactured, the temperature and composition of the molten alloy are set such that the Si rich portion having a thickness of 20 μm or more is formed on the surface of the side of the continuous cast rod having a central angle of 30 ° or more. Therefore, it is thought that the state of the solidification interface 217 of the said molten alloy and the state of the trunk are stabilized. As a result, stable casting operation can be performed. The effective mold length is set such that a Si rich portion having a thickness of 20 µm or more is formed on the surface of the side surface of the continuous casting rod having a central angle of 30 ° or more.

The composition of the molten aluminum alloy 255 stored in the tundish is described below. The molten aluminum alloy is preferably 7 to 14% by mass of Si (more preferably 8 to 13% by mass, most preferably 12 to 13% by mass) and at least 0.003% by mass of metallic Ca (more preferably 0.003%). To 0.04 mass%, most preferably 0.003 to 0.03 mass%). In addition to the above components, the molten alloy preferably contains iron (0.1 to 0.5 mass%), copper (2.0 to 9.0 mass%), manganese (0 to 0.5 mass%), and magnesium (0.2 to 1.0 mass%).                 

The molten aluminum alloy containing Si in an amount of 8 to 13% by mass exhibits excellent mechanical properties due to the formation of a thin microstructure by aluminum and silicon contained in the casting ingot, and the casting ingot is formed by the presence of hard silicon. It is particularly preferred because of its improved wear resistance.

The relationship between the Ca content of the alloy and the amount of Ca added will be described.

When Ca is inevitably contained in the alloy, the Ca content of the alloy as measured by the analysis is (1) Ca inevitably contained in the raw material of the alloy (The Ca is mainly from the Ca mixed metallic silicon which is a raw material Derived) and (2) the total amount of Ca added to the molten alloy. For example, when Ca is not added to the molten alloy, Ca detected in the obtained casting ingot is derived from a raw material and inevitably contained in the casting ingot. On the other hand, when Ca is added to the molten alloy, the amount of Ca added is obtained by subtracting the amount of Ca inevitably contained from the total amount of Ca contained in the casting ingot.

In the present invention, the amount of Ca contained in the alloy is preferably 0.003% by mass or more. In particular, the amount of Ca added to the alloy is preferably 0.003% by mass or more. The total amount of Ca added to the casting ingot and inevitably added Ca is preferably 0.004% by mass or more (more preferably, 0.004 to 0.05% by mass, most preferably 0.05% by mass or less). This is because if the total amount of Ca is in the above range, the formation of the Si-rich portion is promoted, and the silicon particles of the casting ingot become fine, thereby improving the mechanical properties of the casting ingot.                 

It is considered that metallic silicon, which is a raw material of the molten aluminum alloy, inevitably contains Ca and exists in the form of calcium silicate. Inevitably, Ca added to the molten aluminum alloy is not an oxide form in the alloy. Therefore, in the casting ingot, in order to refine the silicon particles and to promote the formation of the Si rich portion, the amount of Ca added is preferably adjusted to 0.003 mass% or more, more preferably 0.003 to 0.03 mass%. Do.

As Ca added to the alloy, metallic Ca having a purity of 99.9% or more is preferable. The Ca is preferably in the form of particles from the viewpoint of ease of operation. After adjustment of elemental components other than Ca of the molten alloy is completed, Ca particles are added to the molten metal. In order to prevent oxidation of the Ca particles during the addition, it is preferable to coat the particles with aluminum foil before the addition.

The composition ratio of the alloy component of the casting ingot can be confirmed by a method classified by JIS H 1305 using, for example, an optical emission spectrometer (eg PDA-5500, manufactured by Shimadzu Corporation) based on photoelectric photometry.

The height difference between the level 254 of the molten metal stored in the tundish and the upper surface of the mold inner circumferential wall is preferably 0 to 250 mm (more preferably, 50 to 70 mm). This means that if the height difference is within the above range, the pressure of the molten alloy poured into the mold is well balanced with the pressure of the liquid lubricant and the gas obtained by gasification of the lubricant, so that the castability is improved, and the center angle of 30 ° or more is improved. It is because the continuous casting aluminum alloy rod which has the Si-rich part (thickness: 20 micrometers or more) formed on the surface of the side surface of the continuous casting rod which has is easy to manufacture. When a level sensor is installed on a tundish to measure and monitor the level of the molten alloy, the level of the alloy can be precisely controlled to maintain the difference at a height of a predetermined value.

The liquid lubricant may be a vegetable oil functioning as a lubricating oil. Examples of the vegetable oils include rapeseed oil, castor oil and salad oil. The use of such vegetable oils is preferred since it reduces adverse effects on the environment.

The supply amount of the lubricating oil is preferably 0.05 to 5 mL / minute (more preferably, 0.1 to 1 mL / minute). This is because, when the supply amount is within the above range, the Si rich portion having a thickness of 20 µm or more is sufficiently formed on the surface of the side surface of the continuous casting rod having a center angle of 30 ° or more. If the feed amount is too small, breakage of the casting ingot occurs due to poor lubricity, while if the supply amount is too large, excessive lubricant enters the casting ingot and causes internal defects of the ingot.

The speed (ie, casting speed) at which the casting ingot is drawn out from the mold is preferably 200 to 1500 mm / minute (more preferably, 400 to 1,000 mm / minute). This means that if the casting speed is within the above range, the Si-rich portion having a thickness of 20 μm or more is sufficiently formed on the surface of the side of the continuous casting rod having a center angle of 30 ° or more, and as a result, the castability is not impaired even if the manufacturing conditions are varied. This is because a casting ingot having a fine and uniform structure can be obtained at a high cooling rate.

The volume of the cooling water per mole supplied from the cooling water shower device to the mold is preferably 5 to 30 L / min (more preferably, 25 to 30 L / min). If the amount of cooling water is too small, an Si rich portion having a thickness of 20 μm or more is insufficiently formed on the surface of the side of the continuous casting rod having a central angle of 30 ° or more. As a result, breakout occurs and the surface of the casting ingot is remelted to internally form a non-uniform structure in the casting ingot. On the other hand, if the amount of cooling water is too large, a large amount of heat is removed from the mold and casting cannot be performed.

Since the average temperature of the molten alloy poured from the tundish into the mold is sufficiently formed on the surface of the side of the continuous cast rod having a center angle of 30 ° or more, the Si-rich portion having a thickness of 20 µm or more is preferably 600 to 750 ° C. (More preferably, 640-680 degreeC). If the temperature of the molten alloy is too low, large crystal products are formed in the mold or upstream of the mold, and the product causes internal defects in the casting ingot. On the other hand, if the temperature of the molten alloy is too high, a large amount of hydrogen gas is taken into the molten alloy to generate many voids (ie internal defects) in the casting ingot.

A method of detecting and measuring the string-shaped Si rich portion formed vertically on the surface of the continuous casting rod according to the present invention will be described below with reference to FIG.

5 is a schematic diagram showing the configuration of one embodiment of an apparatus 501 for producing a continuous cast rod of an aluminum alloy according to the present invention.

The said manufacturing apparatus 501 has the melting furnace 502 which manufactures a molten aluminum alloy, the Ca introduction apparatus 503 which introduces Ca into the said melting furnace 502, and the structure shown in FIG. A casting device 504 to which molten aluminum alloy is supplied, a drawing drive device 505 for pulling out the continuous casting rod 101 of the aluminum alloy cast by the casting device 504 from the casting device 504, and the continuous casting A detection unit 506 which detects a region of the Si-rich portion formed on the surface of the rod 101, outputs a detection signal, and analyzes the continuous casting rod 101 in the composition, and outputs a Ca content measurement data signal ( 507, a determination unit 508 for comparing output signals from the detection unit 506 and the analysis unit 507 with preset determination conditions, and outputting a determination signal based on the comparison, and a determination in which the determination signal is preset. Based on the output signal to be included in the condition And a control unit 509 for controlling each unit. Here, the analysis unit may be omitted, and the control unit may include a plurality of control units arranged by a dispersion method.

The melting furnace 502 includes a heater (not shown) and a temperature detector (not shown). The heater is controlled by the controller 509 to maintain the furnace internal temperature at a predetermined temperature, and the temperature detector detects the furnace internal temperature and outputs the detected temperature to the controller 509. In addition to the Ca introduction device, a device (not shown) for introducing a metal component into the melting furnace 502 for forming a molten aluminum alloy is provided. Each introduction device including the Ca introduction device 503 is provided with a detector (not shown) and an introduction mechanism (not shown) for detecting the introduced amount. Each introduction mechanism is controlled by the control unit 509 so that each metal is introduced into the melting furnace 502, and each detector detects the introduction amount and outputs the detection amount to the control unit 509. The casting device 504 includes lubrication means (not shown), cooling means for metal components (not shown), and a temperature detector (not shown). The lubrication means and the cooling means are controlled by the control unit 509 to cool the molten aluminum alloy with the continuous casting rod 101 of aluminum alloy, and the temperature detector is configured to adjust the tundish internal temperature and the mold internal temperature. It detects and outputs the detected temperature to the control part 509. The drawing drive device 505 includes a speed detector (not shown) for detecting the drawing speed, and is controlled by the detecting unit 509 to continuously cast an aluminum alloy from the casting device 504. The speed detector detects the drawing speed and outputs the detected speed to the control unit 509.

In view of the fact that the Si rich portion of the continuous casting rod 101 made of aluminum alloy differs from other portions, the detector 506 can use any detector as long as it can detect the difference. Since the surface of the Si rich portion has metallic luster and / or other roughness, a detector for detecting reflectance and / or surface roughness can be used, for example, to detect metallic luster and / or roughness. In particular, optical, ultrasonic or charge-capacitive detectors are advantageous because they can detect in a non-contact phase. Since the detector detects a region of the Si-rich portion, it is required to have a function of covering the entire surface of the continuous casting rod of aluminum having the surface characteristic to be detected or a function of scanning a detection range.

The detection signal corresponding to the surface characteristic and the position result of the Si-rich portion of the continuous casting rod 101 of the aluminum alloy detected by the detection unit 506 is output to the determination unit 508.

The determination unit 508 has a predetermined determination condition, the detection signal from the determination unit 506 to the Si rich unit, and the analysis result from the analysis unit 507 based on the predetermined determination condition, that is, , Compare Ca amount measurement data signal. For example, a portion where a difference occurs in the surface characteristic result as a boundary between the Si rich portion and the other portion is detected to determine the Si rich portion region. It also has a function of feeding back a control signal for controlling casting conditions based on the comparison and determination results to the control unit 509.

Signal processing, determination processing, and condition setting processing can be performed using either an analog or digital signal.

The conditions for determining the Si rich portion include surface roughness and reflectance of a region corresponding to the side surface of the continuous casting rod 101 of aluminum alloy having a center angle of 30 ° or more.

In casting, molten aluminum alloy temperature and casting speed are controlled. Thus, based on the signal of the continuous casting rod 101 of the aluminum alloy detected by the detection unit 506 and manufactured by the casting device 504, for example, by increasing the molten aluminum alloy temperature, the portion having metallic luster is expanded. You can. The reason is considered that the difference between the aluminum alloy melting temperature and the solidification temperature causes a difference in the solidification state and can be controlled in the form of metallic luster. It is thought that the same effect can be applied to the casting speed. The molten aluminum alloy temperature may be adjusted by controlling the heating temperature of the melting furnace 502, the heating during the supply of the tumbled dish, and the heating inside the tundish to insulate the metal component. The casting speed can be adjusted using a device capable of adjusting the forced cooling of the mold, the amount of cooling water from the coolant shower device, the draw rate of the draw drive device 505 and the molten aluminum alloy temperature.

As the object to be controlled in the casting, it is preferable to further include the amount of Ca added as it increases the degree of freedom in setting the casting conditions. As shown in FIG. 5, the Ca introduction device 503 arranges the introduction device (not shown) as a Ca addition method in parallel in order to introduce a metal component for forming a molten aluminum alloy into the metal furnace 502. . By doing in this way, the quantity of Ca and metal component which are introduce | transduced can be controlled easily. The addition function of Ca reduces the solidification temperature, changes the difference between the melting temperature and the solidification temperature and increases the difference in the solidification state. It is believed that this makes it possible to control the formation of controlled metallic luster. If Ca is directly introduced into the tundish, the same effect can be obtained.

In order to more precisely manage the amount of Ca added, an analysis unit 507 is provided for transferring data of the Ca amount measurement result obtained through the analysis of the casting product composition to the determination unit 508, and the It is desirable to control the molten aluminum alloy temperature, the casting rate and the amount of Ca added based on the measurement result and the amount of Ca added data. This is because the amount of Ca added at 0.003% by mass or more can be precisely controlled, and the region of the Si rich portion can be controlled.

As long as the amount of Ca can be detected, there is no particular limitation on the compositional analysis method. Either the method of performing initial analysis of Ca amount from the surface of a rod immediately after casting, or the method of measuring Ca amount offline after removal of a sample may be sufficient. The method using the measurement time of 1 hour or less is preferable. For example, luminescence spectroscopy can be enumerated for Ca amount measurement.

Using this apparatus, a continuous cast aluminum alloy rod having a Si-rich portion having a thickness of 20 µm or more on the surface of the side of the rod having a center angle of 30 ° or more can be easily manufactured.

Since the Si rich portion formed on the upper surface of the continuous cast aluminum alloy rod is suppressed from sticking and breakout, the continuous cast aluminum alloy rod can be stably manufactured.

The method for producing a continuous cast aluminum alloy rod using the manufacturing apparatus includes controlling the difference between the molten aluminum alloy temperature and the solidification temperature, or controlling the difference and the rate at which the continuous cast aluminum alloy rod is drawn out of the cylindrical mold, It is easy to manufacture a continuous cast aluminum alloy rod having a Si-rich portion having a thickness of 20 mu m or more on the surface of the side surface of the rod having a center angle of 30 degrees or more.

Since the Si rich portion formed on the upper surface of the continuous cast aluminum alloy rod is suppressed from sticking and breakout, the continuous cast aluminum alloy rod can be stably manufactured.

Examples of the present invention are listed below, but the present invention is not limited to these examples.

(Example)

Examples 1-4:

Metallic Ca was added to the aluminum alloy containing Si in an amount of 12 mass% (Ca content: 0.003 mass% in Example 1, 0.006 mass% in Example 2, 0.01 mass% in Example 3 and Example 4 0.03 mass%). The molten alloy thus obtained is subjected to horizontal continuous casting using the apparatus shown in FIG. 2 to form a billet (diameter: 30 mm). A permeable porous member made of graphite having a breathability of 0.01 L / (cm ² × min) is used for the mold. Casting conditions are as follows.

(1) the height difference between the level of the molten alloy in the tundish and the upper part of the mold inner circumferential wall: 150 mm

(2) Lubricant oil: Seed oil

(3) Supply amount of lubricant oil: 0.2 mL / min

(4) casting speed: 900mm / min

(5) Supply of cooling water: 25L / min

(6) Average temperature of molten alloy in tundish: 660 ° C

Comparative Example 1:

Except not adding metallic Ca to the said aluminum alloy, the process of Example 1 was repeated and horizontal continuous casting was performed.

6 is a graph showing the relationship between the frequency of occurrence of casting problems (the number of problems occurring within 30 minutes) on the vertical axis and the casting time on the horizontal axis, for each Example and Comparative Example 1. FIG. Here, the "casting problem" refers to the stopping of casting operation due to breakout or breakage of the billet. After the mold was replaced immediately after stopping the casting operation, the casting operation was then resumed.

In each of Examples 1-4 (total number of actual casting operations: 100), the casting conditions were stabilized and the frequency of occurrence of the casting problems (eg, leakage of molten alloys or breakage of billets) was reduced. It was found that the cast rod thus produced had a very smooth cast surface containing a portion having a high metallic luster on the upper portion of the outer circumferential surface portion, and had no cavity on the inner surface of the cast rod.

The structure of the metallic luster was observed, and the portion was found to have a Si microstructure containing α-Al in an area ratio of less than 50%.

In Comparative Example 1 (total number of actual casting operations: 100), the casting conditions were not stabilized, and a change occurred in the casting surface conditions. Elongation between the casting rod and the mold inner circumferential wall, breakage of the casting rod, or such breakdown caused the outflow of the molten alloy from the mold. When such a problem occurs, the casting operation is stopped, and either the supply amount of the lubricating oil or the casting speed requires regulation, and the production efficiency is deteriorated. The surface of the thus produced casting rod was visually observed. As a result, it was found that the upper casting surface of the rod had a periodic scaly pattern, and the lower casting surface had large and small raised portions. Such abnormal surface conditions adversely affect the deep interior of the casting rods.

Tables 1-3 show the results of the physical properties of the Si-rich portion in Tables 2 and 3, specifically, as a result of the Examples and Comparative Examples 1, specifically, the analysis results of the alloy compositions in Table 1.                 

Si-rich portion thickness (µm) Ca addition amount (mass%) Example 1 18 0.003 Example 2 25 0.006 Example 3 23 0.01 Example 4 32 0.03 Example 5 20 0.003 Example 6 23 0.006 Example 7 28 0.01 Example 8 35 0.03 Comparative Example 1 10 0 Comparative Example 2 0 0

Glossy Part Angle (°) Ca addition amount (mass%) Example 1 50 0.003 Example 2 59 0.006 Example 3 55 0.01 Example 4 72 0.03 Example 5 38 0.003 Example 6 46 0.006 Example 7 55 0.01 Example 8 63 0.03 Comparative Example 1 19 0 Comparative Example 2 0 0

Examples 5-8:

Metallic Ca was added to an aluminum alloy containing 12% by mass of Si, 4% by mass of Cu, and 0.5% by mass of Mg (Ca content: 0.003% by mass in Example 5, 0.006% by mass in Example 6) 0.01 mass% in Example 7, and 0.03 mass% in Example 8). Horizontal molten casting was performed on the obtained molten alloy using the apparatus shown in FIG. 2, and the billet (diameter: 50 mm) was formed. A permeable porous member made of graphite having air permeability of 0.01 L / (cm ² × min) was used for the mold. Casting conditions are as follows.

(1) the height difference between the level of the molten alloy in the tundish and the upper part of the mold inner circumferential wall: 170 mm

(2) Lubricant oil: Seed oil                 

(3) Supply amount of lubricating oil: 0.3 mL / min

(4) casting speed: 900mm / min

(5) Supply of coolant: 30L / min

(6) Average temperature of molten alloy in tundish: 660 ° C

Comparative Example 2:

Except for not adding metallic Ca to the aluminum alloy, the process of Example 5 was repeated to perform horizontal continuous casting.

FIG. 7 is a graph showing the relationship between the casting time on the horizontal axis and the frequency of occurrence of casting problems on the vertical axis in each Example and Comparative Example 2. FIG. As in the case of Example 1, the results of the continuous casting performed in each example were excellent. In other words, casting defects were greatly reduced. In each example (total number of casting operations: 100), the casting conditions were very stable, and the frequency of occurrence of operational problems (eg, outflow of molten alloy or destruction of billets) was reduced.

The hardness of the portion with high metallic luster formed on the top surface of the cast rod was measured. It was found that the surface of each of the cast rods of Examples 5 to 8 in which the metallic Ca was added to the alloy had a relatively high hardness as compared to the cast rod of Comparative Example 2 in which the metallic Ca was not added to the alloy. The metallic luster portion formed on the upper surface of only the cast rod containing metallic Ca has a relatively higher hardness than the other portions of the cast rod. If a metallic polish is formed on top of the casting rod, the presence of excess lubricant can prevent the outflow of unsolidified molten alloy from the top of the casting rod, corresponding to the top of the mold inner circumferential wall where the molten alloy is insufficiently cooled. have.

The structure of the metallic gloss was observed, and the part was found to have a Si fine structure containing α-Al in an area ratio of less than 50%.

Unlike the case of the above example, in Comparative Example 2 (total number of casting operations: 100), the casting conditions were unstable, and a change occurred in the casting surface state. Elongation between the casting rod and the mold inner circumferential wall, breakage of the casting rod, or such failure caused the outflow of molten alloy from the mold. When such a problem occurs, the casting operation is stopped and it is necessary to control either the supply amount of the lubricating oil or the casting speed, resulting in poor production efficiency. It was found that the upper surface of the cast bar of Comparative Example 2, in which metallic Ca was not added to the molten alloy, had a periodic scaly pattern. It was also found that the upper surface of the cast rod was not the Si rich portion, and the structure of the upper surface was found to be the same as the interior of the cast rod.

Tables 1-3 each show the result of the Example and the comparative example 2, specifically, the analysis result of the said alloy composition, and the measurement result of the physical characteristic of the said Si rich part.

Table 4 shows the measurement result of the average particle size of Si particle contained in the Si fine structure of the casting rod of each Example.

Si average particle size (µm) Ca addition amount (mass%) Example 1 1.0 0.003 Example 2 1.1 0.006 Example 3 0.9 0.01 Example 4 1.1 0.03 Example 5 0.9 0.003 Example 6 0.8 0.006 Example 7 1.1 0.01 Example 8 1.2 0.03

Examples 9, 10, 11 and 12:

The process of Example 5 was repeated and the horizontal continuous casting was performed except having used the following permeable porous member which has the following breathability: In Example 9, it was 0.008 L / (cm <^2> * min), Example in the 10, 0.012L / (cm ² × min), according to example 11. in the 0.001L / (cm ² × min), or example 12, 0.1L / (cm ² × min).

In Example 9 and 10, the result equivalent to Example 5 was obtained. In Example 11, the frequency of occurrence of casting problems (i.e., stopping of the casting operation) was not greatly increased, but the lubricant effect was obtained insufficiently, sticking on the surface of the casting rod, breaking of the casting rod and unstable casting. In some cases, problems such as driving were caused. In Example 12, the incidence of casting problems (i.e., stopping of the casting operation) did not increase significantly, but there was an excess of the lubricant in the mold, the outflow of the molten alloy due to insufficient cooling, the surface of the casting rods, or Problems such as intrusion of inclusions and unstable casting and operation were sometimes caused inside.

As described above, the present invention provides a method for producing a continuous cast aluminum alloy rod having a Si rich portion having a thickness of 20 μm or more on the surface of the side of the rod having a central angle of 30 ° or more. In addition, according to the present invention, a stable casting operation can be realized.

Claims (18)

A continuous cast aluminum alloy rod manufactured by a horizontal continuous casting method using a cylindrical mold having a forced cooling means, the center axis of which is kept horizontal, The aluminum alloy rod is a composition containing 8% by mass to 13% by mass of Si and 0.004% by mass to 0.05% by mass of Ca, The rod has a Si-rich portion having a thickness of 20 μm or more on the surface of the side of the rod having a central angle of 30 ° or more with respect to the center of the rod, The Si rich portion contains Si as the primary α-Al having an area ratio of less than 50% in any 10 μm square region extended from the surface of the rod toward the center of the rod, measured by an element distribution obtained from the radial cross section of the rod. Has a fine structure, A continuous cast aluminum alloy rod, characterized in that the average particle size of the Si particles contained in the Si rich portion is 0.1 to 5㎛. delete delete delete delete The method of claim 1, The said rod has a surface roughness Rmax of 50 micrometers or less, and does not have a tool mark on the surface, when the said Si-rich part is removed by the peeling process after casting, The continuous casting aluminum alloy rod. A method of manufacturing a continuous cast aluminum alloy rod using a cylindrical mold having a central axis horizontally and having forced cooling means, By adding 0.003 mass% or more of Ca, the composition of a molten aluminum alloy is adjusted so that 8 mass%-13 mass% of Si, and 0.004 mass%-0.05 mass% are contained as a composition, respectively, Using a cylindrical mold made of a material of one kind or a combination of two or more kinds selected from aluminum, copper, and alloys thereof and having an effective mold length of 15 to 70 mm, In the cylindrical mold, a permeable porous member having a breathability of 0.005 to 0.03 L / (cm ² × min) and formed into an annular shape is provided over the entire inner circumferential wall of the cylindrical mold in close contact with the molten aluminum alloy. , The average temperature of the molten aluminum alloy flowing into the cylindrical mold is controlled to 600 to 750 ° C. so as to be equal to or higher than the liquidus temperature of the aluminum alloy. By controlling the continuous cast aluminum alloy rod to be withdrawn from the cylindrical mold at a drawing speed of 200 mm / min to 1500 mm / min, A method of producing a continuous cast aluminum alloy rod, characterized in that for producing a continuous cast aluminum alloy rod having a Si-rich portion having a thickness of 20㎛ or more on the surface of the side of the rod having a center angle of 30 ° or more with respect to the center of the rod. delete delete delete The method of claim 7, wherein the Ca added to the composition of the molten aluminum alloy is a metallic Ca having a purity of 99.9% or more. delete The method of claim 7, wherein A method for producing a continuous cast aluminum alloy rod, wherein the permeable porous member uses a cylindrical mold provided within a range of 5 mm to 15 mm of the effective mold length. A melting furnace 502 for preserving a molten aluminum alloy and supplying the molten aluminum alloy; A casting part (504) having a cylindrical mold (201) and cooling means (202) for casting the molten aluminum alloy into a solidified casting ingot; A drawing drive unit 505 for drawing the solidified casting ingot horizontally from the cylindrical mold to form a continuous cast aluminum alloy rod 101 having a Si rich portion 104; A detector 506 for detecting a region of the Si rich portion and outputting a detected signal; A judging section 508 for judging and determining the reflectance or surface roughness of the surface of the side surface of the rod having a center angle of 30 ° or more with respect to the center of the casting rod as a judgment condition, and outputting a judgment signal; A control unit (509) for controlling the melting temperature of the melting furnace, the cooling means of the casting unit, the drawing speed of the drawing drive unit, and the amount of Ca added so that the detection signal from the detection unit is included in the determination condition based on the determination signal; And And a Ca introduction portion (503) controlled by the control portion so that the detection signal from the detection portion is included in the determination condition on the basis of the determination signal from the determination portion. delete The method of claim 14, An analysis unit 507 for analyzing the composition of the molten aluminum alloy and outputting a Ca amount measurement data signal to the determination unit based on the analyzed result; The control unit controls the Ca introduction unit so that the amount of Ca is 0.004% by mass to 0.05% by mass based on the determination signal from the determination unit and the data of Ca addition amount. A method of manufacturing a continuous cast aluminum alloy rod using a cylindrical mold having a central axis horizontally and having forced cooling means, Ca is added to the molten aluminum alloy by the Ca introduction portion, From the melting furnace in which molten aluminum was preserve | saved, the said molten aluminum alloy is supplied to a cylindrical mold, By the casting part provided with a cylindrical mold and cooling means, the said molten aluminum alloy is made into the solidification casting ingot, By the drawing drive part, the solidification casting ingot is drawn out horizontally from the cylindrical mold to form a continuous cast aluminum alloy rod having a Si-rich part, A detection section detects an area of the Si rich section and outputs the detection signal; The determination unit determines the reflectance or surface roughness of the surface of the side surface of the rod having a center angle of 30 ° or more with respect to the center of the casting rod as a determination condition, and compares the detection signal with the determination condition, and outputs the determination signal. The control unit controls the melting temperature of the melting furnace, the cooling means of the casting unit, the extraction speed of the extraction drive unit, and the amount of Ca added from the Ca introduction unit so that the detection signal from the detection unit is included in the determination condition based on the determination signal. Method for producing a continuous cast aluminum alloy rod. The method of claim 17, The analysis unit analyzes the composition of the molten aluminum alloy and outputs the Ca amount measurement data signal to the determination unit based on the analyzed result, The control unit controls the amount of Ca to be added such that the amount of Ca is 0.004% by mass to 0.05% by mass, based on the determination signal and the data of the amount of Ca addition from the determination unit.

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