Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/12—Accessories for subsequent treating or working cast stock in situ
  • B22D11/124—Accessories for subsequent treating or working cast stock in situ for cooling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
  • B22D11/0605—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two belts, e.g. Hazelett-process
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
  • C22F1/05—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions

Definitions

• the present invention concerns an aluminum alloy for die casting, and particularly concerns an aluminum alloy for casting that may be used optimally for the casting of members for which high rigidity and a low linear thermal expansion coefficient are particularly required, such as ladder frames, perimeter frames, and cases for various types of vehicles such as automobiles.
• cast iron was used for members such as automobile frames that require particularly high rigidity, but in recent years, from the standpoint of energy conservation, the need for weight reduction of automobiles has increased, and attention has been paid to aluminum alloy as a material that can meet these needs.
• Japanese Unexamined Patent Publication No. H01-180938 discloses an aluminum alloy with improved wear resistance, but the aluminum alloy disclosed therein has the problem that when substituted for cast iron products being used for automobile frames and the like, its rigidity is low, and its linear expansion coefficient is too high. Additionally, Japanese Unexamined Patent Publication No. H03-199336 also similarly discloses an aluminum alloy with improved wear resistance, but the aluminum alloy disclosed therein also has the problem that when substituted for cast iron products being used for automobile frames and the like, its rigidity is low, and its linear expansion coefficient is too high, and further, sticking to the die occurs easily. [Patent Document 1] Japanese Unexamined Patent Publication No. H01-180938 [Patent Document 2] Japanese Unexamined Patent Publication No. H03-199336
• the present invention offers an aluminum alloy for die casting having excellent rigidity and a low linear expansion coefficient, containing 13-25% by mass of silicon, 2-8% by mass of copper, 0.5-3% by mass of iron, 0.3-3% by mass of manganese, 0.001-0.02% by mass of phosphorus, and the remainder comprising aluminum and inevitable impurities, wherein the total amount of iron and manganese is 3.0% by mass or greater. and nickel 3.0% by mass or greater.
• 0.1-1.0% by mass of chromium 0.05-1.5% by mass of magnesium, 0.01-1.0% by mass of titanium, 0.0001-1.0% by mass of boron, 0.1-1.0% by mass of zirconium, 0.1-1.0% by mass of vanadium, or 0.01-1.0% by mass of molybdenum may be contained.
• the alloy of the present invention prefferably be cast at a cooling rate of 30 degrees C per second or greater, and in order to cast at a high cooling rate, it is desirable to do the casting by the die casting method.
• the inventors of the present invention discovered that there is a correlation between the area ratio of crystallized products and the rigidity and linear expansion coefficient of aluminum alloys, and as a result of further research, discovered that by the alloy composition described above, it was possible to disperse minute crystallized particles of Al-Cu, Al-Fe-Si, Al-Fe-Mn, or Al-Si-Mn compounds, and the necessary high rigidity and low linear expansion coefficient was realizable.
• the effects of each component in said aluminum alloy shall be described.
• Iron + Manganese 3.0% by mass or greater
• Iron and manganese crystallize as Al-Fe-Mn, Al-Fe-Si, and Al-Si-Fe-Mn compounds, contribute to the improvement of rigidity, and have the effect of reducing the linear expansion coefficient. Additionally, they have the effect of improving heat resistance. This effect becomes marked when iron+manganese is 3% by mass or greater, but since at greater than 12% by mass, the crystallized products become coarse, and the rigidity improving effect is lessened, it is desirable to keep the total amount of iron + manganese at 12% by mass or less.
• Phosphorus has the effect of miniaturizing and dispersing uniformly the primary silicon. This effect is marked at 0.001% by mass or greater, but at greater than 0.02% by mass, the viscosity of the molten metal increases, and castability becomes worse.
• Mg dissolves in solid solution in the matrix and contributes to the improvement of rigidity. This effect is marked at 0.05% by mass or greater, but at greater than 1.5% by mass, elongation is reduced, and castability markedly worsens. More desirably, magnesium should be 0.4% by mass or less.
• Chromium 0.1-1.0% by mass
• Chromium crystallizes as Al-Si-Fe-Mn-Cr compounds, and contributes to the improvement of rigidity. Additionally, it has the effect of dispersing primary silicon minutely and uniformly. Said effect is marked for 0.1% by mass or greater of chromium, but at greater than 1.0% by mass, coarse compounds are formed, and elongation is reduced.
• Titanium 0.01-1.0% by mass
• the inventors of the invention of the present application manufactured the aluminum alloys according to the present invention, and confirmed experimentally the relationship between composition and crystalline structure, rigidity and linear expansion coefficient, and the results shall be described herebelow.
• the composition of the aluminum alloys used in the experiment is shown in table 1.
• the aluminum alloy used in the experiment after being cast in a 200x200x10 mm planar form at a casting temperature of 720 degrees C, was aged by maintaining at 200 degrees C for 4 hours, and then the rigidity (Young's modulus) and the linear expansion coefficient (thermal expansion coefficient) were measured.
• Alloys No. 9-15 are aluminum alloys according to the present invention, and alloys No. 1-8 and 16 18-24 are comparative examples that do not satisfy at least one of the conditions for the range of the compositions described above. Compositions that do not satisfy the conditions are shown underlined. [Table 1] No.
• the criterial value is taken to be 90 GPa, and any composition with a value above this is judged to satisfy the criterion, and regarding the coefficient of linear thermal expansion, the criterial value is taken to be 18 ⁇ 10 -6 /°C, and any composition with a value lower than this is judged to satisfy the criterion.
• Alloy No. 18 has a Young's modulus of 80 GPa so has a lower value than the criterial value (90 GPa), and at the same time, its coefficient of linear thermal expansion is 20.0 ⁇ 10 -6 /°C, higher than the criterial value (18 ⁇ 10 -6 /°C), and neither value satisfies the criteria.
• the cause is thought to be the fact that the contained amount of any of silicon, copper, and nickel + iron + manganese is insufficient, and therefore is below the range described above.
• Alloy No. 19 similarly with Alloy No. 18, satisfies the criteria neither for the Young's modulus nor the coefficient of linear thermal expansion.
• the cause is thought to be the fact that, although the content of copper is within the range described above, the contained amount of both silicon and nickel + iron + manganese is insufficient (below the range described above).
• Alloy No. 20 has a Young's modulus lower than the criterial value, and the cause is thought to be the fact that the total contained amount of nickel + iron+ manganese is 2.0% by mass, and this is below the condition described above of a total nickel + iron + manganese content of 3.0% by mass.
• Alloy No. 21 satisfies the criteria for Young's modulus and coefficient of linear thermal expansion, but caused sticking to the die.
• the cause is thought to be the fact that iron was not substantially added, and this did not satisfy the conditions described above.
• Alloy No. 22 had insufficient elongation, and since the test piece broke within the elastic deformation region, the Young's modulus was not measurable. This is thought to be because manganese was not substantially added, and the conditions described above regarding the composition were not satisfied.
• Alloy No. 23 does not satisfy the criteria for either Young's modulus or coefficient of linear thermal expansion.
• the cause is thought to be the fact that the copper content is insufficient at 1% by mass (is below the range described above).
• Alloy No. 24 also does not satisfy the criteria for either Young's modulus or coefficient of linear thermal expansion.
• the cause is thought to be the fact that the silicon content is insufficient at 12% by mass (is below the range described above).
• aluminum alloys No. 1-17 of the present invention satisfying the range of composition described above, as shown in table 1, have Young's moduli and coefficients of linear thermal expansion that satisfy the criteria.
• the aluminum alloy for die casting of the present invention may be used optimally for the casting of members particularly requiring a high rigidity and low linear expansion coefficient.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Body Structure For Vehicles (AREA)
• Continuous Casting (AREA)

Applications Claiming Priority (2)

Publications (3)

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• 2004
  • 2004-03-23 JP JP2004084256A patent/JP4665413B2/ja not_active Expired - Lifetime
• 2005
  • 2005-03-22 MY MYPI20051266A patent/MY139116A/en unknown
  • 2005-03-23 KR KR1020067021516A patent/KR20060130753A/ko not_active Withdrawn
  • 2005-03-23 WO PCT/JP2005/005225 patent/WO2005090624A2/ja active Application Filing
  • 2005-03-23 EP EP05726972.2A patent/EP1728882B1/en not_active Expired - Lifetime
  • 2005-03-23 US US10/593,338 patent/US20070193663A1/en not_active Abandoned
• 2010
  • 2010-08-02 US US12/848,859 patent/US20100296964A1/en not_active Abandoned

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