AL-CASTING ALLOY

Abstract

The invention relates to an Al casting alloy.

Claims

1. An Al casting alloy containing at least five of the following alloy constituents: Si: 3.0% to 3.8% by weight Mg: 0.3% to 0.8% by weight Cr: 0.05% to 0.35% by weight Fe: <0.18% by weight Mn: <0.06% by weight Ti: <0.16% by weight Cu: 0.006-0.015% by weight Sr: 0.010% to 0.030% by weight Zr<0.006% by weight Zn<0.006% by weight Impurities: <0.1% by weight and is supplemented by Al to an extent of 100% by weight in each case.

2. The Al casting alloy as claimed in claim 1, wherein Si is present with a content of more than 3.1% by weight, preferably of more than 3.3% by weight, more preferably of more than 3.4% by weight.

3. The Al casting alloy as claimed in claim 1, wherein Si is present with a content of less than 3.7% by weight, preferably of less than 3.5% by weight.

4. The Al casting alloy as claimed in claim 1, wherein Mg is present with a content of more than 0.40% by weight, preferably of more than 0.50% by weight, more preferably of more than 0.55% by weight.

5. The Al casting alloy as claimed in claim 1, wherein Mg is present with a content of less than 0.70% by weight, preferably of less 0.60% by weight.

6. The Al casting alloy as claimed in claim 1, wherein Cr is present with a content of more than 0.10% by weight, preferably of more than 0.15% by weight, more preferably of more than 0.20% by weight, most preferably of more than 0.25% by weight.

7. The Al casting alloy as claimed in claim 1, wherein Cr is present with a content of at most 0.30% by weight, preferably of less than 0.30% by weight.

8. The Al casting alloy as claimed in claim 1, wherein Fe is present with a content of more than 0.01% by weight, preferably of more than 0.05% by weight, more preferably of more than 0.07% by weight.

9. The Al casting alloy as claimed claim 1, wherein Fe is present with a content of less than 0.15% by weight, preferably of less than 0.12% by weight.

10. The Al casting alloy as claimed in claim 1, wherein Mn is present with a content of more than 0.01% by weight, preferably of more than 0.02% by weight.

11. The Al casting alloy as claimed in claim 1, wherein Mn is present with a content less than 0.15% by weight, preferably of less than 0.12% by weight, more preferably of less than 0.10% by weight.

12. The Al casting alloy as claimed in claim 1, wherein Ti is present with a content of more than 0.01% by weight, preferably of more than 0.03% by weight, more preferably of more than 0.04% by weight.

13. The Al casting alloy as claimed in claim 1, wherein Ti is present with a content of less than 0.10% by weight, preferably of less than 0.08% by weight, more preferably of less than 0.065% by weight, most preferably of less than 0.055% by weight.

14. The Al casting alloy as claimed in claim 1, wherein Cu is present with a content of more than 0.006% by weight, preferably of more than 0.007% by weight, more preferably of more than 0.008% by weight, most preferably at least 0.009% by weight.

15. The Al casting alloy as claimed in claim 1, wherein Cu is present with a content of less than 0.015% by weight, preferably of less than 0.013% by weight, more preferably of less than 0.012% by weight, most preferably of less than 0.011% by weight.

16. The Al casting alloy as claimed in claim 1, wherein Sr is present with a content of more than 0.015% by weight, preferably of more than 0.020% by weight.

17. The Al casting alloy as claimed in claim 1, wherein Sr is present with a content of less than 0.030% by weight, preferably of less than 0.025% by weight.

18. The Al casting alloy as claimed in claim 1, wherein Zr is present with a content of more than 0.001% by weight.

19. The Al casting alloy as claimed in claim 1, wherein Zr is present with a content of less than 0.005% by weight, preferably of less than 0.004% by weight, more preferably of less than 0.003% by weight.

20. The Al casting alloy as claimed in claim 1, wherein Zn is present with a content of more than 0.001% by weight, preferably of more than 0.002% by weight.

21. The Al casting alloy as claimed in claim 1, wherein Zn is present with a content of less than 0.005% by weight, preferably of less than 0.004% by weight.

22. The Al casting alloy as claimed in claim 1, wherein impurities are present with a content of less than 0.05% by weight, preferably less than 0.035% by weight.

23-32. (canceled)

33. A cast component produced from an Al casting alloy as claimed in claim 1, wherein the cast component after a heat treatment has a yield point R.sub.P0.2 of 300 to 330 MPa, preferably of >320 to 330 MPa, and/or an elongation at break A5 of 7% to 11%, preferably of 8.5% to 10%, more preferably of 9% to 9.5%, and/or a tensile strength R.sub.m of 350-375 MPa, preferably of >360-375 MPa.

Description

EXAMPLE

[0034] To ascertain the mechanical properties of an alloy of the invention containing 3.4% by weight of Si, 0.6% by weight of Mg, 0.27% by weight of Cr, 0.09% by weight of Fe, 0.03% by weight of Mn, 0.05% by weight of Ti, 0.009% by weight of Cu, 0.022% by weight of Sr, 0.002% by weight of Zr, 0.003% by weight of Zn and impurities of less than 0.1% by weight, in each case supplemented to 100% by weight with Al, what is called a French tensile specimen according to DIN 50125 is cut out of a swivel bearing produced by means of a counterpressure diecasting (CPC) method, the swivel bearing having received a heat treatment (solution annealing at 540 C. for 8 h, quenching in water, age hardening at 180 C. for 6.5 h) beforehand. The casting of comparative examples (AlSi3Mg0.5 and AlSi3Mg0.5Cr0.3) and subsequent heat treatment are effected under the same conditions. The alloys to be compared differ solely in the chromium content. The specimen is taken at the same position in the swivel bearing. The mechanical properties of tensile strength R.sub.m, yield point R.sub.p0.2 and elongation at break A5 according to DIN10002 are ascertained.

TABLE-US-00001 R.sub.m [MPa] R.sub.p0.2 [MPa] A5 [%] AlSi3Mg0.5 327 263 9.3 Alloy of the invention 369 322 9.12 AlSi3Mg0.5Cr0.3 358 308 6.9

[0035] Against the background of DE 10 2013 108 127 A1 and the upper limit for copper of 0.006% by weight which is specified as critical for the mechanical indices, the achievement of the abovementioned mechanical indices for the alloy of the invention was not to be expected.