Continuously-cast aluminum alloy rod, and method for manufacturing the same

Abstract

To provide a continuously-cast aluminum alloy rod having fine primary crystalline Si dispersed therethroughout, the alloy rod capable of being efficiently utilized as a wear-resistant material from a center thereof to an outer peripheral surface thereof without removing an outer peripheral region, and a method for manufacturing the same.SOLUTION: The present invention relates to a cylindrical continuously-cast aluminum alloy rod in which, in a cross section perpendicular to a casting direction, primary crystalline Si located in a range of 10 μm or more and 70 μm or less outward from an equivalent circle diameter is present in a range of 5 or more and 15 or less per 0.25 cm2 within an area of 0.5 mm (vertical) and 0.5 mm (horizontal) from a casting skin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a continuously cast bar of an aluminum alloy and a method for manufacturing the continuously cast bar of an aluminum alloy.

Background Art

[0002] In recent years, aluminum alloys have been increasingly used as structural members for various products by taking advantage of their light weight. For example, steel has been used for general utensils, building materials such as panels, shipbuilding materials, and containers. On the other hand, in recent years, lightweight, corrosion-resistant, and high-strength aluminum alloy materials have been used.

[0003] Among these aluminum alloy materials, those used for sliding parts of machines and the like are required to have excellent wear resistance. Therefore, as aluminum materials, A390 series aluminum alloys, which are Al-Si hypereutectic alloys, are often used (for example, see Patent Document 1). The A390 series aluminum alloy is said to obtain excellent wear resistance by containing a large amount of Si.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional A390 series aluminum alloy, there is a reverse segregation layer formed during casting in the outer peripheral region within several millimeters from the outer peripheral surface to the inside. Since such a reverse segregation layer does not contain fine primary crystal Si for exhibiting wear resistance, conventionally, such an outer peripheral region has been removed in a process called peeling. For this reason, due to the disposal of the removed outer peripheral region (peeling chip), the portion that can actually be used as an alloy with wear resistance is less than the casting amount, and there is a problem that the yield of the product is low.

[0006] The present invention has been made in view of such a technical background, and in a continuous casting bar of an aluminum alloy in which fine primary crystal Si is dispersed, as a wear-resistant material, a continuous casting bar of an aluminum alloy that can be efficiently used from the center to the outer peripheral surface without removing the outer peripheral region, and an object of the present invention is to provide a method for manufacturing a continuous casting bar of an aluminum alloy.

Means for Solving the Problems

[0007] In order to solve the above problems, the present invention provides the following means.

[0008] (1) A continuous casting bar of a columnar aluminum alloy, in a cross section perpendicular to the casting direction, the primary crystal Si in the range of 10 μm or more and 70 μm or less outside the equivalent circle diameter is in an area of 0.25 cm in a range of 0.5 mm in length and 0.5 mm in width from the casting surface. 2 A continuous casting bar of an aluminum alloy, characterized in that it exists in a range of 5 or more and 15 or less per hit.

[0009] (2) Cast using a raw material for a continuous casting bar of an aluminum alloy having an alloy composition containing Si in the range of 10.0% by mass or more and 18.0% by mass or less, Fe in the range of 0.50% by mass or less, Cu in the range of 3.0% by mass or more and 6.0% by mass or less, Mn in the range of 0.35% by mass or more and 0.75% by mass or less, Ca in the range of 0.0010% by mass or less, and P in the range of 0.001% by mass or more and 0.1% by mass or less, with the balance being Al and unavoidable impurities. The continuous casting bar of the aluminum alloy according to (1).

[0010] (3) The continuous casting bar of the aluminum alloy according to (1) or (2), characterized in that it is used as a constituent material for a sliding part.

[0011] (4) A method for manufacturing a continuously cast bar of any one of the aluminum alloys (1) to (3), comprising a cylindrical mold body having one end as a molten metal inlet and the other end as a casting outlet of an ingot, and a carbon ring disposed on the inner peripheral surface of the mold body, wherein the carbon ring is configured by stacking a first ring portion disposed on the one end side and a second ring portion disposed on the other end side, and performing continuous casting using a continuous casting mold. A method for manufacturing a continuously cast bar of an aluminum alloy, characterized in that.

[0012] (5) The mold body has a lubricating oil supply path connected to the second ring portion and a gas supply path connected to the second ring portion and disposed apart from the lubricating oil supply path, and a connection supply portion connecting the lubricating oil supply path and the second ring portion is disposed closer to the first ring portion than a connection supply portion connecting the gas supply path and the second ring portion. A method for manufacturing a continuously cast bar of an aluminum alloy according to (4), characterized in that.

[0013] (6) A groove through which the lubricating oil supplied from the lubricating oil supply path leaks to the molten metal side is formed on a surface of the second ring portion that overlaps the first ring portion. A method for manufacturing a continuously cast bar of an aluminum alloy according to (5), characterized in that.

[0014] (7) When viewed from the direction connecting the one end and the other end, the connection portion between the lubricating oil supply path and the second ring portion and the connection portion between the gas supply path and the second ring portion are arranged to overlap. A method for manufacturing a continuously cast bar of an aluminum alloy according to (5) or (6), characterized in that.

[0015] (8) A lubricating oil flow groove through which the lubricating oil supplied from the lubricating oil supply path passes is formed along the inner peripheral surface of the second ring portion. A method for manufacturing a continuously cast bar of an aluminum alloy according to any one of (5) to (7), characterized in that.

[0016] (9) The method for manufacturing a continuous casting rod of an aluminum alloy according to any one of (5) to (8), characterized in that a gas flow groove through which the gas supplied from the gas supply path passes is formed along the inner peripheral surface in the second ring portion.

[0017] (10) The method for manufacturing a continuous casting rod of an aluminum alloy according to any one of (4) to (9), characterized in that the length in the direction connecting the one end and the other end is such that the second ring portion is longer than the first ring portion.

[0018] (11) Among the first ring portion and the second ring portion, at least the second ring portion has a bulk density of 1.65 to 1.9 g / cm 3 and is made of a graphite material having a bending strength of 30 MPa to 98 MPa. The method for manufacturing a continuous casting rod of an aluminum alloy according to any one of (4) to (10), characterized in that.

[0019] (12) The method for manufacturing a continuous casting rod of an aluminum alloy according to any one of (4) to (11), characterized in that the supply amounts of the lubricating oil and the gas are independently controlled.

Advantages of the Invention

[0020] According to the present invention, in a continuous casting rod of an aluminum alloy in which fine primary crystal Si is dispersed, as a wear-resistant material, a continuous casting rod of an aluminum alloy that can be efficiently used from the center to the outer peripheral surface without removing the outer peripheral region, and a method for manufacturing a continuous casting rod of an aluminum alloy can be provided.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show the characteristic parts enlarged for the sake of easy understanding of the characteristics, and the dimensional ratios of each component are not necessarily the same as the actual ones. Also, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not necessarily limited thereto, and it can be appropriately changed and implemented within the range that does not change the effect.

[0023] [Continuous Casting Rod of Aluminum Alloy] The continuous casting rod of the aluminum alloy of the present embodiment is obtained by continuous casting using the material for the continuous casting rod of the aluminum alloy described later with the continuous casting mold for the aluminum alloy described later.

[0024] The continuous casting rod of the aluminum alloy of the present embodiment corresponds to a 390 series aluminum alloy in that it contains a large amount of Si.

[0025] The continuous casting bar of the aluminum alloy of this embodiment (hereinafter, may be simply referred to as the continuous casting bar) is a continuous casting bar of a columnar aluminum alloy. In a cross section perpendicular to the casting direction, the primary Si in the range of 10 μm or more and 70 μm outside the equivalent circle diameter is in an area of 0.25 cm in the range of 0.5 mm in length and 0.5 mm in width from the casting surface 2 and exists in the range of 5 or more and 15 or less per hit.

[0026] Here, the longitudinal direction is the direction along the casting direction of the continuous casting bar, and the transverse direction is the diameter direction perpendicular to the casting direction of the continuous casting bar.

[0027] In addition, the equivalent circle diameter (HEYWOOD) is represented by the following formula (1) when the area of a substantially circular cross section perpendicular to the casting direction of a columnar object with unevenness on the outer peripheral surface, such as a continuous casting bar, is Area. HEYWOOD = √(4 / π × Area) ···(1)

[0028] (The primary Si is 5 or more and 15 or less per 0.25 cm area in the range of 0.5 mm in length and 0.5 mm in width from the casting surface 2 ) Fine primary Si contributes to the improvement of wear resistance. In this embodiment, by setting the primary Si in the outer peripheral region to 5 or more per 0.25 cm area, the wear resistance can be improved also in the outer peripheral region of the continuous casting bar. On the other hand, by setting the primary Si in the outer peripheral region to 15 or less per 0.25 cm area, an excessive decrease in tensile strength can be suppressed. 2 2

[0029] According to the continuous casting bar of the aluminum alloy of this embodiment having the above configuration, fine primary Si for exhibiting wear resistance is also in an area of 0.25 cm in the outer peripheral region within a range of several millimeters from the outer peripheral surface 2Since it exists in the range of 5 or more and 15 or less per hit, there is no need to remove, by means of a peeling process, a reverse segregation layer in which primary crystal Si formed in the outer peripheral region does not exist as in the prior art. For this reason, it becomes possible to efficiently use, without waste, the continuously cast bar after continuous casting as a wear-resistant material up to the outer peripheral surface.

[0030] Since the continuously cast bar of the aluminum alloy of the present embodiment is excellent in wear resistance, it can be suitably used, for example, as a constituent material of sliding parts such as bearings.

[0031] [Material for continuously cast bar of aluminum alloy] The material for a continuously cast bar of an aluminum alloy, which is a manufacturing material of the continuously cast bar of the aluminum alloy of the present embodiment, has the following composition. It contains Si in the range of 10.0 mass% or more and 18.0 mass% or less, Fe in the range of 0.50 mass% or less, Cu in the range of 3.0 mass% or more and 6.0 mass% or less, Mn in the range of 0.35 mass% or more and 0.75 mass% or less, Ca in the range of 0.0010 mass% or less, and P in the range of 0.001 mass% or more and 0.1 mass% or less, and the balance is composed of Al and inevitable impurities.

[0032] (Si: 10.0 mass% or more and 18.0 mass% or less) Si crystallizes as fine primary crystal Si, thereby having an effect of improving the wear resistance of the aluminum alloy. By setting the content rate of Si to 10.0 mass% or more, fine primary crystal Si can be crystallized up to the outer peripheral region of the continuously cast bar of the aluminum alloy. On the other hand, by setting the content rate of Si to 18.0 mass% or less, a decrease in the tensile strength of the aluminum alloy can be suppressed.

[0033] (Fe: 0.50 mass% or less) Fe has the effect of improving the tensile strength of aluminum alloys by crystallizing in the aluminum alloy as fine crystals including intermetallic compounds such as Al-Mn-Fe-Si, Al-Fe-Si, and Al-Mn-Fe. By keeping the Fe content within the above range, it is possible to manufacture the desired processed products without reducing the machinability and workability of the aluminum alloy material.

[0034] (Cu: 3.0 mass% or more and 6.0 mass% or less) Cu has the effect of finely dispersing Mg-Si compounds in the aluminum alloy and the effect of improving the tensile strength of the aluminum alloy by precipitating as an Al-Cu compound. By keeping the Cu content within the above range, the tensile properties can be improved without deteriorating the workability.

[0035] (Mn: 0.35 mass% or more and 0.75 mass% or less) Mn has the effect of improving the tensile strength of the aluminum alloy by forming fine granular precipitates including intermetallic compounds such as Al-Mn-Fe-Si, Al-Mn-Fe, Al-Mn, Al-Mn-Si, etc. By keeping the Mn content within the above range, the mechanical properties of the aluminum alloy material at room temperature can be improved.

[0036] (Inevitable impurities) Inevitable impurities are impurities that are inevitably mixed into the aluminum alloy from the raw materials or manufacturing process. Examples of inevitable impurities include Ni, Sn, Be, etc. The content of these inevitable impurities is preferably not more than 0.1 mass%.

[0037] [Manufacturing method of aluminum alloy continuous casting rod] Next, a method for producing a continuously cast aluminum alloy rod of the above-mentioned embodiment will be described. First, a continuous casting mold used in the method for producing a continuously cast aluminum alloy rod of the present embodiment will be described. (Continuous casting mold) FIG. 1 is a schematic cross-sectional view of a mold for continuous casting. FIG. 2 is an explanatory view for explaining a method of manufacturing a continuous casting bar of an aluminum alloy using a vertical continuous casting apparatus equipped with the mold for continuous casting shown in FIG. 1. FIG. 3 is a schematic enlarged cross-sectional view of the vicinity of the carbon ring.

[0038] The continuous casting mold 100 shown in FIG. 1 is a continuous casting mold used for continuous casting, and includes a cylindrical mold body 20 having openings at both ends, one end being the molten metal inlet 21 and the other end being the casting outlet 22 of the ingot, and a carbon ring 10 disposed on the inner peripheral surface 20A of the mold body 20. The carbon ring 10 is configured by stacking a first ring portion 10a disposed on one end side and a second ring portion 10b disposed on the other end side.

[0039] In FIG. 1, the direction in which the first ring portion 10a and the second ring portion 10b are stacked (the direction connecting one end and the other end) is defined as the Z direction, the direction orthogonal to the Z direction and parallel to the paper surface is defined as the X direction, and the direction orthogonal to the Z direction and orthogonal to the paper surface is defined as the Y direction. Hereinafter, the carbon ring composed of the first ring portion and the second ring portion may be referred to as a "split type carbon ring".

[0040] The continuous casting apparatus equipped with the continuous casting mold 100 is a vertical continuous casting apparatus that supplies molten metal L from the upper side of a cylindrical mold body 20 that is open in the vertical direction, and continuously draws out an ingot S that has been cooled and solidified by the supply of cooling water H from the lower side of the mold body 20.

[0041] In the vertical continuous casting apparatus equipped with the continuous casting mold 100, for example, it can be used when continuously casting an ingot S of an aluminum alloy such as a slab (rectangular cross-section) of an aluminum alloy or a billet (circular cross-section) of aluminum. Note that the type of the ingot S is not limited to the above-described aluminum alloy, and any metal that can be continuously cast using this vertical continuous casting apparatus may be used.

[0042] The mold body 20 has a lubricating oil supply path 31 connected to the second ring portion 10b and a gas supply path 32 connected to the second ring portion 10b and arranged at a distance from the lubricating oil supply path 31. The connection supply portion 31a connecting the lubricating oil supply path 31 and the second ring portion 10b is arranged closer to the first ring portion 10a than the connection supply portion 32a connecting the gas supply path 32 and the second ring portion 10b in the Z direction. Examples of the gas supplied from the gas supply path 32 include air, a mixed gas (e.g., oxygen + inert gas), and an inert gas.

[0043] Since the lubricating oil supply path 31 for supplying lubricating oil into the mold and the gas supply path 32 for supplying gas are arranged separately and do not share, it is possible to prevent the influence (interference, backflow, etc.) due to the pressure difference based on the respective supply amounts of the lubricating oil and the gas. Also, since the lubricating oil supply path 31 and the gas supply path 32 are provided independently, the supply amounts of the lubricating oil and the gas can be controlled independently.

[0044] In the illustrated example, both the connection supply portion 31a and the connection supply portion 32a are portions arranged annularly in the mold body 20 along the outer peripheral surface of the annular carbon ring 10 (second ring portion 10b). However, the lubricating oil supply path 31 may be inserted into the second ring portion 10b and the connection supply portion 31a may be arranged inside the carbon ring 10. Similarly, the gas supply path 32 may be inserted into the second ring portion 10b and the connection supply portion 32a may be arranged inside the carbon ring 10. It is also possible to arrange one or both of the connection supply portion 31a and the connection supply portion 32a inside the carbon ring 10.

[0045] In the illustrated example, when viewed in plan from the Z direction, they are arranged at positions that do not overlap with the connection supply portion 31a and the connection supply portion 32a, but they may be arranged to overlap.

[0046] In the second ring portion 10b, a lubricating oil flow groove through which the lubricating oil supplied from the lubricating oil supply path 31 passes may be formed in a circumferential shape. The circumferential shape can be one turn or less than one turn. A gas flow groove through which the gas supplied from the gas supply path 32 passes may be formed in a circular shape inside the second ring portion 10b. The circular shape can be one turn or less than one turn.

[0047] In the Z direction, since the connection supply portion 31a connecting the lubricating oil supply path 31 and the second ring portion 10b is arranged on the upper stage side of the second ring portion 10b, and the connection supply portion 32a connecting the gas supply path 32 and the second ring portion 10b is arranged on the lower stage side of the second ring portion 10b, the following operational effects are achieved.

[0048] The lubricating oil supplied from the lubricating oil supply path 31 descends by its own weight along the inner peripheral surface 10bAA of the second ring portion 10b via the connection supply portion 31a. On the other hand, the gas supplied from the gas supply path 32 is discharged from the inner peripheral surface 10bAA of the second ring portion 10b via the connection supply portion 32a, and due to the effect of the gas (air bubbling made dense by the porosity of the carbon material), the gas is discharged from the wide surface of the second ring portion 10b made of carbon. By discharging the gas in this state, the lubricating oil that has descended by its own weight becomes foamy lubricating oil, forms a heat insulation layer near the molten metal contact surface of the mold, and becomes a seal layer for the supplied molten metal, so that the molten metal is in a non-contact state with the inner surface of the mold, and a continuous casting rod with a smooth outer surface can be obtained. Also, the primary cooling is prevented by the synergistic effect, and the reverse segregation layer around the surface becomes thinner. Furthermore, since it does not penetrate and discharge through the carbon ring 10, there is no restriction on the type of oil, and as long as there is no damage, it can be used maintenance-free for a long time.

[0049] The carbon ring 10 is an annular member made of carbon. The carbon ring 10 is configured such that the first ring portion 10a and the second ring portion 10b are stacked, and the lubricating oil sent from the lubricating oil supply path 31 is supplied to the inner peripheral surface of the mold through the gap G where the first ring portion 10a and the second ring portion 10b are stacked, as will be described in detail later.

[0050] Thus, since the carbon ring 10 is not configured such that lubricating oil oozes out onto the inner peripheral surface of the mold through the holes in the graphite material like a conventional graphite ring, it is not essential for the carbon ring 10 material to have holes through which lubricating oil oozes. However, the lubricating oil may not only come from the gap where the first ring portion 10a and the second ring portion 10b overlap, but also be a material that oozes out onto the inner peripheral surface of the mold through the holes in the material like a conventional graphite ring. Also, from the perspective of heat resistance to the molten metal, it remains preferable that the carbon material constituting the carbon ring 10 is graphite (graphite), but it is not limited to this. Further, the carbon ring 10 may be manufactured by compacting fine graphite particles by extrusion or isostatic pressing so as to have a predetermined pore structure.

[0051] There is no particular limitation on the method of attaching the carbon ring 10 to the mold body 20. For example, it can be attached to the mold body 20 by shrink fitting using the difference in the coefficient of thermal expansion between the mold body 20 and the carbon ring 10. Since carbon has a smaller coefficient of thermal expansion than the metal constituting the mold body 20, at room temperature, the inner diameter of the mold body 20 is set smaller than the outer diameter of the carbon ring 10, and when the carbon ring 10 is press-fitted into the mold body 20 whose inner diameter has expanded by heating, the carbon ring 10 is fixed in a state of being clamped by the mold body 20 due to the temperature drop of the continuous casting mold 100.

[0052] When attached by shrink fitting, the mold body 20 and the carbon ring 10 are in close contact with each other and no gap is formed between them, so heat transfer from the carbon ring 10 to the mold body 20 occurs promptly during continuous casting. Also, since the mold body 20 and the carbon ring 10 are in close contact over the entire circumferential direction, non-uniform cooling in the circumferential direction does not occur.

[0053] The carbon ring 10 has a structure in which the first ring portion 10a and the second ring portion 10b overlap (a combined structure), but the first ring portion 10a and the second ring portion 10b may be made of carbon materials having the same characteristics or carbon materials having different characteristics. Of the first ring portion 10a and the second ring portion 10b, at least the second ring portion 10b may be a graphite material with a bulk density of 1.65 to 1.9 g / cm 3 and a bending strength of 30 MPa to 98 MPa. The ring portion made of a graphite material having such characteristics allows the gas supplied from the gas supply path 32 to sufficiently permeate and has sufficient strength for use in continuous casting of an aluminum alloy.

[0054] The carbon ring 10 may be configured such that an integral carbon ring is divided into two parts, i.e., a first ring portion 10a and a second ring portion 10b.

[0055] In the carbon ring 10, the length in the Z direction is such that the length of the second ring portion 10b (reference symbol L2 in FIG. 3) is longer than the length of the first ring portion (reference symbol L1 in FIG. 3).

[0056] FIG. 4(a) is a schematic cross-sectional view showing the first ring portion 10a and the second ring portion 10b constituting the carbon ring 10 separated from each other for convenience of explanation. As shown in FIG. 3, when fitted to the inner peripheral surface of the mold body 20, there is only a slight gap G (see FIG. 3) formed according to the flatness of each mating surface (stacking surface, overlapping surface) 10aA, 10bA between the first ring portion 10a and the second ring portion 10b. On the other hand, the mating surface 10bA of the second ring portion 10b may be configured to have grooves or recesses (three of which are indicated by reference symbol 10ba) through which the lubricating oil supplied from the lubricating oil supply path 31 leaks to the molten metal side, as shown in FIG. 4(b).

[0057] In the example shown in FIG. 4(b), grooves with the centers of the holes facing O in a plan view from the Z direction are formed at equal intervals, but the number of grooves is not limited to this, and there may be some non-uniformly spaced grooves, or all the grooves may be non-uniformly spaced. From the viewpoint of uniformly supplying the lubricating oil to the inner peripheral surface 20A of the mold body 20, it is preferable that a plurality of grooves are arranged at equal intervals. The depth of the groove 10ba can be, for example, about 0.015 mm to 2 mm.

[0058] FIG. 5 is a conceptual diagram for conceptually explaining the function and effect of the mold for continuous casting. In the continuous casting mold 100 shown in FIG. 1, in the Z direction, the connection supply part 31a connecting the lubricating oil supply path 31 and the second ring part 10b is arranged on the upper stage side of the second ring part 10b, and the connection supply part 32a connecting the gas supply path 32 and the second ring part 10b is arranged on the lower stage side of the second ring part 10b. Further, the carbon ring 10 has a configuration in which the first ring part 10a and the second ring part 10b are stacked in the Z direction.

[0059] The lubricating oil supplied from the lubricating oil supply path 31 is supplied to the inner peripheral surface 10bAA of the second ring part 10b from the gap G between the first ring part 10a and the second ring part 10b via the connection supply part 31a. The lubricating oil LUB supplied to the inner peripheral surface 10bAA of the second ring part 10b descends by its own weight along the inner peripheral surface 10bAA. On the other hand, the gas supplied from the gas supply path 32 is discharged from the inner peripheral surface 10bAA of the second ring part 10b via the connection supply part 32a, and the gas is discharged on the wide surface of the second ring part 10b by the air bubbling effect.

[0060] When the gas is discharged in this state, the lubricating oil that has descended by its own weight becomes foamy lubricating oil FLUB, becomes a heat insulating layer near the molten metal contact surface of the mold, and becomes a seal layer for the supplied molten metal, so that the molten metal is in a non-contact state with the inner surface of the mold, and a continuous casting bar with a smooth outer surface can be obtained.

[0061] FIG. 6 is a graph comparing the transition of the pressure (lubricating oil pressure) for lubricating oil supply according to the number of times of use of the mold when using the continuous casting mold provided with the split carbon ring according to the present invention and when using the conventional continuous casting mold provided with an integral carbon ring. The material of the carbon ring is graphite.

[0062] In the graph of FIG. 6, the horizontal axis is the number of times of use of the mold (that is, the number of times of manufacturing the continuous casting bar), and the vertical axis is the ratio of the use pressure at each number of times of use when the initial pressure of the lubricating oil pressure is 1. It is determined that clogging occurs when the ratio of the operating pressure to the initial pressure of the lubricating oil pressure is 1.5.

[0063] When using a conventional integral carbon ring, the lubricating oil pressure exceeds the clogging determination pressure during the fourth use. In contrast, when using a split carbon ring, the ratio of the operating pressure to the initial pressure increased to about 1.03 during the third use, and the lubricating oil pressure remained unchanged even after the twelfth use. As described above, when using a split carbon ring, it can be seen that the clogging of the carbon ring is significantly reduced compared to when using a conventional integral carbon ring.

[0064] The method for manufacturing a continuously cast bar of an aluminum alloy according to this embodiment can be carried out by introducing the molten metal of the material for the continuously cast bar of the aluminum alloy having the alloy composition described above into the continuous casting mold 100 for continuous casting and performing continuous casting. An example of the casting conditions by the vertical continuous casting apparatus during such continuous casting is shown in Table 1.

[0065]

Table 1

[0066] According to the method for manufacturing a continuously cast bar of an aluminum alloy according to this embodiment as described above, primary Si exists in the range of 5 or more and 15 or less per area of 0.25 cm² in the range of 0.5 mm in length and 0.5 mm in width from the casting surface. 2 It becomes possible to manufacture a continuously cast bar of an A390 series aluminum alloy. As a result, the peeling process for the outer peripheral portion becomes unnecessary, and a continuously cast bar of an aluminum alloy that can be efficiently used as a wear-resistant material can be manufactured.

[0067] The embodiments of the present invention have been described above. These embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, as well as in the invention described in the claims and the equivalent scope thereof.

Example

[0068] Next, verification examples of the present invention will be described, but the present invention is not particularly limited to these verification examples.

[0069] [Example, Comparative Example] Continuous casting rods of aluminum alloys for the example and the comparative example were produced under the casting conditions shown in Table 2.

Table 2

[0070] Next, regarding the continuous casting rods of aluminum alloys obtained in the example and the comparative example, the distribution state of fine primary Si in the range of about 1.5 mm in the depth direction from the outer peripheral surface was observed. An optical microscope was used for the observation. The results are shown in a photograph in Fig. 7.

[0071] According to the results shown in Fig. 7, it can be seen that in the outer peripheral region (the rectangular frame part in the photograph of Fig. 7) from the outer peripheral surface of the continuous casting rod to a depth of about 400 μm, fine primary Si indicated by black particles is dispersed in the example. On the other hand, in the comparative example, there is almost no fine primary Si indicated by black particles in such an outer peripheral region. From these results, it was confirmed that the continuous casting rod of the aluminum alloy of the present embodiment has fine primary Si dispersed up to the outer peripheral surface, and can be efficiently used as a wear-resistant material including the outer peripheral region without performing a peeling process.

Explanation of Reference Signs

[0072] 10… Carbon ring 10a… First ring part 10b… Second ring part 20… Mold body 21… Pouring inlet 22… Casting outlet 31… Lubricating oil supply path 32… Gas supply path

Claims

1. A continuous casting bar of a cylindrical aluminum alloy, wherein in a cross section perpendicular to the casting direction, the primary crystal Si in the range of 10 μm or more and 70 μm or less from the outer side of the equivalent circle diameter is in an area of 0.25 cm ２ per hit in the range of 5 or more and 15 or less in the range of a surface of 0.5 mm in length and 0.5 mm in width from the casting skin. A continuous casting bar of an aluminum alloy, characterized in that it exists in the range of 5 or more and 15 or less.

2. The aluminum alloy continuous casting rod according to claim 1, characterized in that it is cast using a material for a continuous casting rod of an aluminum alloy having an alloy composition containing Si in the range of 10.0% by mass or more and 18.0% by mass or less, Fe in the range of 0.50% by mass or less, Cu in the range of 3.0% by mass or more and 6.0% by mass or less, Mn in the range of 0.35% by mass or more and 0.75% by mass or less, Ca in the range of 0.0010% by mass or less, and P in the range of 0.001% by mass or more and 0.1% by mass or less, with the balance being Al and unavoidable impurities.

3. The aluminum alloy continuous casting rod according to claim 1 or 2, characterized in that it is used as a constituent material for sliding parts.

4. A method for manufacturing a continuous casting rod of an aluminum alloy according to claim 1 or 2, characterized in that continuous casting is performed using a continuous casting mold comprising a cylindrical mold body having one end as a molten metal inlet and the other end as an ingot outlet, and a carbon ring disposed on the inner peripheral surface of the mold body, wherein the carbon ring is configured by stacking a first ring portion disposed on the one end side and a second ring portion disposed on the other end side.

5. The method for manufacturing a continuous casting rod of an aluminum alloy according to claim 4, characterized in that the mold body has a lubricating oil supply path connected to the second ring portion and a gas supply path connected to the second ring portion and disposed apart from the lubricating oil supply path, and a connection supply portion connecting the lubricating oil supply path and the second ring portion is disposed closer to the first ring portion than a connection supply portion connecting the gas supply path and the second ring portion.

6. The method for manufacturing a continuous casting rod of an aluminum alloy according to claim 5, characterized in that a groove through which the lubricating oil supplied from the lubricating oil supply path leaks to the molten metal side is formed on a surface of the second ring portion that overlaps the first ring portion.

7. The method for manufacturing a continuous casting rod of an aluminum alloy according to claim 5, characterized in that the connection portion between the lubricating oil supply path and the second ring portion and the connection portion between the gas supply path and the second ring portion are arranged to overlap when viewed in the direction connecting the one end and the other end.

8. The method for manufacturing a continuous casting rod of an aluminum alloy according to claim 5, wherein a lubricating oil flow groove through which the lubricating oil supplied from the lubricating oil supply path passes is formed along the inner peripheral surface in the second ring portion.

9. The method for manufacturing a continuous casting rod of an aluminum alloy according to claim 5, wherein a gas flow groove through which the gas supplied from the gas supply path passes is formed along the inner peripheral surface in the second ring portion.

10. The method for manufacturing a continuous casting rod of an aluminum alloy according to claim 4, wherein the length in the direction connecting the one end and the other end is such that the second ring portion is longer than the first ring portion.

11. Among the first ring part and the second ring part, at least the second ring part has a bulk density of 1.65 to 1.9 g / cm ３ and is made of a graphite material having a bending strength of 30 MPa to 98 MPa. The method for manufacturing a continuous casting rod of an aluminum alloy according to claim 4, characterized by this.

12. The method for manufacturing a continuous casting rod of an aluminum alloy according to claim 4, wherein the supply amounts of the lubricating oil and the gas are independently controlled.

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