Classifications

• • 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
  • C22C21/12—Alloys based on aluminium with copper 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
  • C22F1/057—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 with copper as the next major constituent
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
  • F05C2201/00—Metals
  • F05C2201/90—Alloys not otherwise provided for
  • F05C2201/903—Aluminium alloy, e.g. AlCuMgPb F34,37

Definitions

• Aluminium casting alloy method for the manufacture of a casting and cast component for combustion engines
• the invention relates to an aluminium casting alloy, which as well as aluminium, contains substantial constituents of Cu, Mn, Zr and Ti in respect of its properties.
• the invention relates to a method for the manufacture of castings from such an aluminium casting alloy.
• the invention relates to a cast component for internal combustion engines and preferred uses of the inventive alloy.
• the alloy composed in this way is intended to be easy to cast and nevertheless have particularly good strength values, such as high tensile strength, low inclination to material fatigue, and good fatigue and endurance strength at high temperatures .
• the combination of the said contents of Mn, V, and Zr in this case is ascribed as having a particularly favourable influence on the said properties.
• an aluminium casting melt which contained 6.0 % by weight Cu, 0.3 % by weight Mn, 0.10 % by weight V, 0.25 % by weight Zr, as well as 0.02 % by weight Ti and 0.005 % by weight B, were smelted and cast to make a bar, which was then not subjected to any further forming.
• the bars forged from the aluminium forging alloy are solutionized over a period of one to two hours at temperatures in the range from 510 - 537 2 C, while during the solutionizing of the bar produced from the casting alloy the annealing temperature was about 510 2 C. After the solutionizing, the bars were in each case quenched in water. All the bars were then hardened at a temperature of 190 a C for 12 hours.
• the object of the invention was to provide an aluminium casting alloy from which even complex-shaped castings can be cast with no problem and at high temperatures has good mechanical properties.
• a method be described for the manufacture of castings which allows for the operationally reliable manufacture of complex shaped castings for combustion engines in particular.
• a particularly advantageous uses be described of a casting alloy of the type according to the invention.
• such a casting alloy according to the invention contains (in wt.-%) 2 - 8 % Cu, 0.2 - 0.6 % Mn, 0.07 - 0.3 % Zr, maximum 0.25 % Fe, maximum 0.3 % Si, 0.05 - 0.2 % Ti, maximum 0.04 % V, and as the remainder Al and unavoidable impurities, wherein the total content of impurities amounts to a maximum of 0.1 % by weight.
• the content of each of the impurities is restricted to a maximum of 0.03 wt.-%.
• the contents of Cu, Mn, Zr, and Ti are restricted in each case to a range which is perceptibly more closely restricted than, for example, the prior art known from US 2,706, 680.
• vanadium as an impurity, is present only in a content which is of no effect with regard to influencing the properties of the alloy. Surprisingly, it has turned out that, with the maintaining of these narrow alloy limits specified by the invention, an aluminium casting alloy is obtained which allows for the production of castings with excellent strength properties .
• Mn in the contents specified according to the invention leads to a perceptible rise in the hot strength of the alloy according to the invention.
• the presence of Mn in the contents according to the invention in this situation impedes the speed with which the copper is diffused into the ⁇ -aluminium.
• Mh in this way stabilizes the strength of the alloy according to the invention even at high operating temperatures.
• This effect reliably occurs when, with an alloy according to the invention, the content of Mn lies within the range from 0.3 - 0.55 % by weight, in particular more than 0.3 % by weight. Particularly high strength values can be guaranteed in this situation, if the Mn content of the casting alloy according to the invention is 0.4 - 0.55 % by weight .
• Zr contents of 0.07 - 0.3 % by weigh favour the occurrence of disperse precipitations which, with castings cast from the casting alloys according to the invention, in addition to the effect of Mh, guarantee that the alloy according to the invention has high tensile strengths even at high temperatures and a minimised inclination to crack formation.
• Zr has a favourable effect on the creation of a fine-grain cast structure, which ensures that castings cast from the alloy according to the invention have good elongation and uniform property distribution. Accordingly, for castings cast from the alloy according to the invention a grain size of less than 100 ⁇ m can be guaranteed, without additional grain fining means needing to be added to the melt.
• the positive effects of the presence of Zr in the alloy according to the invention can be achieved in an optimized manner if the Zr content lies in the range of 0.18 - 0.25 % by weight.
• the formation of a fine-grain structure can also be supported in that titanium carbide in small amounts such as 2 kg Al3%TiO,15%C rod per ton Al-meltis added to the melt as a grain fining means .
• titanium carbide in small amounts such as 2 kg Al3%TiO,15%C rod per ton Al-meltis added to the melt as a grain fining means .
• the addition of TiC is particularly advantageous if the Zr content of an alloy composed according to the invention is located in the range of 0.07 - 0.15 wt.-% . Practical studies have shown that the addition of TiC has no effect if the Zr-content of inventive alloy amounts at least to 0.15 wt.-%.
• the alloy according to the invention does not contain any vanadium because it has been surprisingly ascertained that taking into consideration the alloy prescribed by the invention the presence of Vanadium does not increase the mechanical properties of an aluminium alloy according to the invention in an noteworthy manner. Accordingly the invention proposes to abstain from adding V as an alloying element in order to provide a lower-cost product, which is easy to cast and has very good mechanical properties . This awareness and proposal is in direct contrast to the skilled knowledge documented in US 2,706,680 for example.
• the effect of Cu which enables the precipitation hardening by forming AI 2 CU and enhances the strength at high temperatures in an aluminium casting alloy according to the invention reliably occurs when the Cu content is 6 - 8 % by weight, in particular 6.5 - 7.5 % by weight. It was proved in practical tests, for example, that in particular with Cu contents of 7 + 0.5 % by weight, in combination with the other alloy elements, with good casting capacity, even after long application at high temperatures, high strength values are guaranteed with components cast from an alloy according to the invention.
• Ti is contained in an alloy according to the invention in contents from 0.05 - 0.2 % supports the precipitation hardening of the inventive alloy. In addition to that it enhances the grain refinement in combination with Zr.
• the aluminium casting alloy according to the invention after solutionizing at a solutionizing temperature of more than 485 2 C, controlled cooling, and, following the cooling, soaking of the casting at a temperature of 160 - 240 a C over an annealing time of 3 - 14 h, it has a superior tensile strength at room temperature of at least 270 MPa, a yield strength of at least 250 MPa, and an elongation of 0,5 - 10 %.
• the alloy according to the invention after an application lasting at least 400 h at a temperature of at least 250 a C, at a test temperature of 250 a C has a tensile strength of at least 160 MPa, in particular of at least 200 MPa, and a yield strength of at least 100 MPa, in particular of at least 150 MPa.
• the heat-treated casting at an elongation of 0.5 - 10 %, has a tensile strength of at least 270 MPa and a yield strength of at least 250 MPa.
• the effort associated with the method according to the invention is minimised accordingly.
• the castings manufactured from a casting alloy alloyed according to the invention have superior strength and elongation properties . Tests have shown that this effect can surprisingly be particularly effectively used if the solutionizing temperature amounts to at least 530 - 545 3 C, especially in the range of 538 - 542 0 C.
• the solutionized casting is cooled under controlled conditions.
• This controlled cooling can, for example, be carried out with a suitable quenching liquid, such as water, or with the aid of an air flow, in which the respective casting is cooled in an accelerated manner.
• Quenching with water or comparable media leads to a particularly strong structure. Surprisingly, it has transpired that, for castings cast from an alloy according to the invention and quenched with water, even after an application lasting for at least 400 h, during which the castings are subjected to a temperature of at least 250 2 C, at a test temperature of 250 2 C a tensile strength of at least 200 MPa and a yield strength of at least 150 MPa is guaranteed.
• a temperature loading of 250 2 C over, for example, 500 h, or 290 a C over 400 h corresponds to the thermal load which the components of a typical car internal combustion engine are subjected to overall in the course of their average service life. Accordingly, particularly high- value castings for internal combustion engines can be manufactured from the alloy according to the invention and in the manner according to the invention, for which it is guaranteed over their entire service life that they will satisfy even the most stringent demands on their mechanical properties .
• the alloy according to the invention can be used for the manufacture of filigree- shaped cylinder heads or engine blocks for internal combustion engines, with which, even after a long period of use at high temperatures, superior high strength values and elongation properties are still guaranteed. This applies in particular if the method according to the invention is applied during the casting production of these engine castings .
• the castings cast from the alloy according to the invention are soaked after controlled cooling at temperatures of 160 - 260 0 C. Particularly good results from this precipitation hardening are achieved if the cast component is soaked for an annealing time of 4 to 12 h, at a temperature of 180 - 220 2 C. With regard to the saving of costs short soaking times of 4 to 10 h are preferred.
• the bars were re-melted, degassed and cleaned in a commercial rotary melt cleaning unit.
• the casting temperature was constantly kept at 750 0 C for all castings. After complete solidification the cylinder heads Cl/1 to CIO/3 were given a solution annealing at 540 0 C for 8 hours .
• the cylinder heads would be exposed during there life cycle as part of a combustion engine for a vehicle the cylinder heads C3/1 to C3/3 and C6/1 to C6/3 were subjected to a post-aging heat treatment during which they were held at 250 0 C for 500 hours.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Cylinder Crankcases Of Internal Combustion Engines (AREA)

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• 2006
  • 2006-12-13 NO NO20065767A patent/NO20065767L/no unknown
• 2007
  • 2007-12-10 WO PCT/NO2007/000433 patent/WO2008072972A1/en not_active Ceased
  • 2007-12-10 EP EP07860907A patent/EP2097551A4/de not_active Withdrawn

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