CA1277855C - Grain refiner for aluminum containing silicon - Google Patents
Grain refiner for aluminum containing siliconInfo
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- CA1277855C CA1277855C CA000504223A CA504223A CA1277855C CA 1277855 C CA1277855 C CA 1277855C CA 000504223 A CA000504223 A CA 000504223A CA 504223 A CA504223 A CA 504223A CA 1277855 C CA1277855 C CA 1277855C
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- master alloy
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
- C22C1/03—Making non-ferrous alloys by melting using master alloys
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- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
ABSTRACT
Disclosed is an Al-Ti-B master alloy especially designed to grain refine cast aluminum alloys containing silicon. The alloy composition goes contrary to present known art. Present commercial master alloys contain a ratio of Ti to B exceeding 2.2 to promote a mixture of TiB2 and TiAl3 crystals. This invention provides an Al-Ti-B alloy wherein the Ti to B ratio is 1. It contains a preponderance of mixed boride crystals. The optimum composition of the alloy of this invention is Al-3Ti-3B.
Disclosed is an Al-Ti-B master alloy especially designed to grain refine cast aluminum alloys containing silicon. The alloy composition goes contrary to present known art. Present commercial master alloys contain a ratio of Ti to B exceeding 2.2 to promote a mixture of TiB2 and TiAl3 crystals. This invention provides an Al-Ti-B alloy wherein the Ti to B ratio is 1. It contains a preponderance of mixed boride crystals. The optimum composition of the alloy of this invention is Al-3Ti-3B.
Description
GRAIN REFINER FOR ALUMINUM CONTAINING SILICON
This invention relates to aluminum-titanium-boron grain refiners that are used to control the grain size of aluminum and its alloys during solidification. More particularly, it relates to a grain refiner especially suited for aluminum casting alloys containing silicon.
BACRGROUND AND PRIOR MT
1 0 PAT~:NTs Grain refiners ~or aluminum castings generally contain titanium and ~oron in an aluminum base. Examples of these refiners may be found disclosed in U. S. Patents Nos.
3,785,807, 3,857,705, 4,298,408 and 3,634,075. U. S.
Patent No. ~,676,111 discloses a methQ~ of refining aluminum base alloys by means of separate additions of boron and titanium. The invention teaches that (1) boron must be addea to the aluminum base alloy, then (2) titanium is aaded with additional boron as may be required.
Examples and suggestions of master alloy compositions for the titanium and boron additions in step (2) are limlted to the well-known Al-3%B alloy and Al-5% Ti-1%B master alloys. The ~inal cast alloy contains a Ti :8 ratio between 1.4 and 2.2.
12~7B55 _UBLICATIONS
The subject of the best titanium-to-boron ratio for grain refinement of aluminum has been the subject of several studies. Cornishl, Miyasaka and Namekawa2, and Pearson and Birch3 have all studied the question and concluded that the Ti:B ratio must be greater than 2.2 (the stoichiometric value for TiB2) for grain refine-ment to occur.
1 A. J. Cornish: Metal Science, 1975, Vol. 9, pg.
477-484.
This invention relates to aluminum-titanium-boron grain refiners that are used to control the grain size of aluminum and its alloys during solidification. More particularly, it relates to a grain refiner especially suited for aluminum casting alloys containing silicon.
BACRGROUND AND PRIOR MT
1 0 PAT~:NTs Grain refiners ~or aluminum castings generally contain titanium and ~oron in an aluminum base. Examples of these refiners may be found disclosed in U. S. Patents Nos.
3,785,807, 3,857,705, 4,298,408 and 3,634,075. U. S.
Patent No. ~,676,111 discloses a methQ~ of refining aluminum base alloys by means of separate additions of boron and titanium. The invention teaches that (1) boron must be addea to the aluminum base alloy, then (2) titanium is aaded with additional boron as may be required.
Examples and suggestions of master alloy compositions for the titanium and boron additions in step (2) are limlted to the well-known Al-3%B alloy and Al-5% Ti-1%B master alloys. The ~inal cast alloy contains a Ti :8 ratio between 1.4 and 2.2.
12~7B55 _UBLICATIONS
The subject of the best titanium-to-boron ratio for grain refinement of aluminum has been the subject of several studies. Cornishl, Miyasaka and Namekawa2, and Pearson and Birch3 have all studied the question and concluded that the Ti:B ratio must be greater than 2.2 (the stoichiometric value for TiB2) for grain refine-ment to occur.
1 A. J. Cornish: Metal Science, 1975, Vol. 9, pg.
477-484.
2 y. Miyasaka & Y. Namekawa: Light Metals, 1975, pg. 197-211, AIME, New York 1975.
3 J. Pearson and M. E. J. Birch, Light Metals, 1984, pg. 1217-1229, AIME, New York 1984.
These patents and literature references relate to various modifications of titanium-boron contents to-gether with additional elements or certain processing steps.
The effectiveness of grain refinement is somewhat dependent upon the composition of the aluminum grain refiner and also the aluminum alloy being refined. For ~,~
1~77855 example, the most useful commercial aluminum-base graln refiners generally contain a titanium-to-boron ratio greater than about three. In practice, it was sometimes found that the effectiveness of these commercial grain 5 refiners was erratic and not predictable. Thus, it was necessary to determine the cause and ef~ect of this problem. It was found, however, that such standard commercial qrain refiners were ineffective when used in casting aluminum alloys containing about one percent or 10 more o~ dissolved silicon. It appears that the higher silicon contents found in casting alloys somehow interferes with the effect of titanium, and promotes that of boron, as a grain refiner.
A report entitled "Influence of Grain Refiner Master 15 Alloy Addition on A-356 Aluminum Alloy" publlshed in the Journal o$ the Chinese Foundryman's Association, June 1981, Vol. 29, pg. 10-18, discloses results of an investigation of this subject. Casting Alloy A-356 contains 6.5 to 7.5 percent sllicon, 0.2 to 0.4% magnesium, less than 0.2% each 20 of iron and titanium and the balance aluminum plus normal low-level lmpurities. The Chinese investigation determlned that an Al-4%B alloy was the best grain refiner for A-356 alloy, followe~ by Al-5% Ti-l~B alloy; then by Al-5% Ti alloy as the poorest grain refiner.
r lZ77~3S~S
The Cornish reference discloses a graphic relation-ship of Ti to B ratio. It can be determined from the Cornish reference that the ratio of Ti to B must be more than about 2 for effective results. All tests of alloys at a ratio of 1.48 indicated poor grain refinement (coarse grains). The best grain refiners were found to be with Ti to B ratios above 2.22 which is the stoi-chiometric proportion of TiB2.
The Pearson and Birch literature reference also teaches the Ti to B ratio to be over the stoichiometric value of 2.22. A grain refiner containing 3%Ti-1%B is reported to be the optimum composition.
Thus, the results of the Chinese study made in the Al-7%Si casting alloy (A-356) run counter to the results of Cornishl and Pearson and Birch3 for higher purity (low Si) aluminum. In our own laboratory studies, we have confirmed the results of the Chinese experiments, but plant trials of the Al-4%B alloy gave many prob-lems. So, it seemed as if there were no satisfactory grain refiners for the high silicon content aluminum casting alloys.
This invention seeks to provide a master alloy especially suitable for grain refining silicon-contain-ing aluminum alloys.
The invention also seeks to provide a master alloy that may be readily produced by processes known in the art.
' l~S5 .
SUMMARY OE THE INVENTION
The present invention provides a novel aluminum-titanium-boron master alloy that grain refines aluminum-silicon alloys more uniformly. Table 1 presents the composition ranges of the alloy of this invention.
In particular, the master alloy is one containing over 1% silicon, and in particular may have a Ti:B ratio of 1:1.
In anothex aspect of the invention, there is pro-vided a method of grain refining an aluminum alloy, particularly one containing over 1% silicon which com- , prises the addition of the master alloy of the inven-tion to a molten mass of the aluminum alloy.
In a particular embodiment the master alloy is produced at a reaction temperature of 725~C to 760C.
Ternary Al-Ti-B master alloys are well known in the art and the science of aluminum grain refining.
The gist of this invention resides in the critical ratio of Ti to B required to obtain grain refinement in aluminum alloys containing silicon.
The compositions in Table 1 contain aluminum plus impurities as balance. In the production of aluminum master alloys of this class, impurities from many sources i l!
_ 5 _ 1~7855 are ~ound ln the ~inal product. These so-called "impurities" are not necessarily always harm~ul and some may actually be beneficial or have an innocuous ef~ect, ~or example, iron and copper.
Some o~ the "impurities" may be present as residual elements resulting from certain processing steps, or adventitiously present in the charge materials: for example, silicon, manganese, sodium, lithium, calcium, magnesium, vanadium, zinc, and zirconium.
In actual practice, certain impurity elements are kept within established limits with maximum an~/or minimum to obtain uniform products as well known in the art and skill o~ melting and processing these alloys. Sodium, lithium, calcium, zlnc, and zirconium must generally be kept at the lowest possible levels.
Thus, the alloy of this invention may contain these and other lmpurities, within the limits usually associated with alloys o~ this class.
Although the exact mechanism of the invention is not ccmpletely understood, it is believed that the re~uired control o~ the titanium-to-boron ratio provides the proper balance o$ mixed aIuminum and titanium borides that is essential to effectively grain refine aluminum alloys containing silicon.
lZ77~5S
T~bl e Alloy Of This Invention ColT~position~ in wei~ percent Rroad Range ~ ~D~ Pr-~erred Rang~e Titaniun .1 to 9.81.5 to 72.5 to 3.5 Boron .1 to 7.01.5 to 72.5 to 3.5 Aluminun plus purities Balance Balance Balance Ratio Ti :B0.1 to 2 .10.25 to 1.80.7 to 1.4 ~tal AlB2 + TiB2 '50% >75% >90%
1~5 The invention is further explained by reference to the accompanying drawings in which:
Figure 1 il~strates graphically the relationship between Ti and B in the aforementioned Cornish reference, Figure ~ illustrates graphically the data of the aforementioned Chinese investigation with respect -to those prior grain refiners r Figures 3 and 4 illustrate graphically the superior average grain size results achieved with a grain refiner of the invention compared with two prior grain refiners.
With ~urther reference to Figure 1, this presents results derived from the Cornish reference.
In Fig. 1 the circles show the final alloy composition made by adding Ti and B as separate additions in the proper amount to 99.9~ aluminum. Dark circles show compositions of castings having fine grains; open circles are coarse grained; and half-filled circles show compositions of castings having only partial grain refinement.
- 7a -~ .> ~, .
~Z77~5 EXAMPLES
Five heats o~ experimental alloys were made by reacting a salt mixture o~ KBF4 and K2TiF6 with molten aluminum. This szlt mixture is called a "flux" herein.
Three ~lux compositions and three dif~erent reaction temperatures were employed, as shown in table 2 together with the compositions of the Al-Ti-B alloys made from the reaction.
Table 2 Fl~x_B~io and Alloy ~QmPQs'tion 40%R2TiF6/60%KBF4 20%K2TiF6/80%KBF4 1096K2TiF6/909~KBF4 Reaction Temp. (2,8~i-1.8%B) (1.4~T~= ~ %B) (0.7%~i-2.7%B) 725CHeat -29 Heat -31 Heat -39 800C - - Heat -37 - ---850oC Heat -40 The experimental alloys were used as grain refiners for an Al-7%Si alloy. Each was generally ef~ective as grain refiners. However; Heats 29, 40, 31 and 37 were outstanding because the products had cleaner mlcro-structures. Table 3 presents a tabular display of the test results.
~1~77F~iS
Tabl e 3 Hçat NQ~ ~,_~0~ Ef~ectiveness 29 about 1.5:1 excellent about 1.5:1 excellent 31 about 0.6:1 excellent 37 about 0.6:1 excellent 39 about 1:4 poorest Another series of alloys was prepared to examlne the effect o~ other flux ratios. Table 4 presents the flux ratios and reaction temperatures employed.
Table 4 Flux Ratio Reaction Heat No. !~L ~
20 54 25/75 760C (1400VF) 15/85 760C ~1400VF) 56 ' 30/70 760C (1400"F) 48 20/80 800C (1472''F) 1;~78~iS
A test o~ the grain refining effectiveness of these Al-Ti-B
master alloys in cast aluminum-7% silicon alloy revealed that Heat No. 56 was the outstanding master alloy of thls entire series. Heat 56 has a 30:70 flux ratio and a reaction temperature of 760C.
Results o~ the two series of tests suggest that the best practice of the invention lies between 0.7:1 and 1.4:1 ratios (preferably about 1:1 ratio) of Ti:B ana a flux ratio o~ 30:70. To verity this conclusion a 100 lb.
experimental alloy (No. 3-40) was made and tested. This alloy contained 3.1% titanium and 3.2~ boron. It was produced by reacting a 30:70 flux ratio at a temperature of 760C (1400F) as indicated for alloy 56 described above.
Alloy 3-40 was used to refine the grain of commercial alloy no. 356, which contains 7%Si, .3% Mg, .1% Fe, and .02% Ti. The casting temperature was 725C (1350F) and the time the grain refiner was in contact with the melt before casting was 5 minutes.
Prior art alloys, 5%Ti-1%B, and A1-3%B were used under the same conditions as the experimental alloy 3-40.
Results of the test are shown graphically in Figure 3. The average grain size of the prior art alloys are plotted as ~277~
curve (a); the average grain size of alloy 3-40 is plotted as curve (b). Clearly, these data show the alloy of thls invention to be superior over the prior art alloys.
In further testing, commercial aluminum alloy no. 319 (which contains 6%5i, 3.5%Cu, 1%Fe, 1%Zn and 0.5%Mn) was also grain refined by the three master alloys mentioned above. Figure 4 is a graphic presentation of the test results. Here, also the alloy of this invention alloy (No.
3-40) was superior over the prior art alloys. Prior art alloy 5~Ti-1%B is a well known commercial master alloy with a Ti to B ratio of 5:1.
A metallographic study of all master alloys described above was made. The alloy described in this invention contained a preponderance of mixed al~minum and titanium borides, that is from about 50% to over 90% mlxed borides.
This is in contradiction with the known art whlch teaches that solely titanium boride phases (especially TiB2) and titanium aluminides ~TiA13) are preferred.
These patents and literature references relate to various modifications of titanium-boron contents to-gether with additional elements or certain processing steps.
The effectiveness of grain refinement is somewhat dependent upon the composition of the aluminum grain refiner and also the aluminum alloy being refined. For ~,~
1~77855 example, the most useful commercial aluminum-base graln refiners generally contain a titanium-to-boron ratio greater than about three. In practice, it was sometimes found that the effectiveness of these commercial grain 5 refiners was erratic and not predictable. Thus, it was necessary to determine the cause and ef~ect of this problem. It was found, however, that such standard commercial qrain refiners were ineffective when used in casting aluminum alloys containing about one percent or 10 more o~ dissolved silicon. It appears that the higher silicon contents found in casting alloys somehow interferes with the effect of titanium, and promotes that of boron, as a grain refiner.
A report entitled "Influence of Grain Refiner Master 15 Alloy Addition on A-356 Aluminum Alloy" publlshed in the Journal o$ the Chinese Foundryman's Association, June 1981, Vol. 29, pg. 10-18, discloses results of an investigation of this subject. Casting Alloy A-356 contains 6.5 to 7.5 percent sllicon, 0.2 to 0.4% magnesium, less than 0.2% each 20 of iron and titanium and the balance aluminum plus normal low-level lmpurities. The Chinese investigation determlned that an Al-4%B alloy was the best grain refiner for A-356 alloy, followe~ by Al-5% Ti-l~B alloy; then by Al-5% Ti alloy as the poorest grain refiner.
r lZ77~3S~S
The Cornish reference discloses a graphic relation-ship of Ti to B ratio. It can be determined from the Cornish reference that the ratio of Ti to B must be more than about 2 for effective results. All tests of alloys at a ratio of 1.48 indicated poor grain refinement (coarse grains). The best grain refiners were found to be with Ti to B ratios above 2.22 which is the stoi-chiometric proportion of TiB2.
The Pearson and Birch literature reference also teaches the Ti to B ratio to be over the stoichiometric value of 2.22. A grain refiner containing 3%Ti-1%B is reported to be the optimum composition.
Thus, the results of the Chinese study made in the Al-7%Si casting alloy (A-356) run counter to the results of Cornishl and Pearson and Birch3 for higher purity (low Si) aluminum. In our own laboratory studies, we have confirmed the results of the Chinese experiments, but plant trials of the Al-4%B alloy gave many prob-lems. So, it seemed as if there were no satisfactory grain refiners for the high silicon content aluminum casting alloys.
This invention seeks to provide a master alloy especially suitable for grain refining silicon-contain-ing aluminum alloys.
The invention also seeks to provide a master alloy that may be readily produced by processes known in the art.
' l~S5 .
SUMMARY OE THE INVENTION
The present invention provides a novel aluminum-titanium-boron master alloy that grain refines aluminum-silicon alloys more uniformly. Table 1 presents the composition ranges of the alloy of this invention.
In particular, the master alloy is one containing over 1% silicon, and in particular may have a Ti:B ratio of 1:1.
In anothex aspect of the invention, there is pro-vided a method of grain refining an aluminum alloy, particularly one containing over 1% silicon which com- , prises the addition of the master alloy of the inven-tion to a molten mass of the aluminum alloy.
In a particular embodiment the master alloy is produced at a reaction temperature of 725~C to 760C.
Ternary Al-Ti-B master alloys are well known in the art and the science of aluminum grain refining.
The gist of this invention resides in the critical ratio of Ti to B required to obtain grain refinement in aluminum alloys containing silicon.
The compositions in Table 1 contain aluminum plus impurities as balance. In the production of aluminum master alloys of this class, impurities from many sources i l!
_ 5 _ 1~7855 are ~ound ln the ~inal product. These so-called "impurities" are not necessarily always harm~ul and some may actually be beneficial or have an innocuous ef~ect, ~or example, iron and copper.
Some o~ the "impurities" may be present as residual elements resulting from certain processing steps, or adventitiously present in the charge materials: for example, silicon, manganese, sodium, lithium, calcium, magnesium, vanadium, zinc, and zirconium.
In actual practice, certain impurity elements are kept within established limits with maximum an~/or minimum to obtain uniform products as well known in the art and skill o~ melting and processing these alloys. Sodium, lithium, calcium, zlnc, and zirconium must generally be kept at the lowest possible levels.
Thus, the alloy of this invention may contain these and other lmpurities, within the limits usually associated with alloys o~ this class.
Although the exact mechanism of the invention is not ccmpletely understood, it is believed that the re~uired control o~ the titanium-to-boron ratio provides the proper balance o$ mixed aIuminum and titanium borides that is essential to effectively grain refine aluminum alloys containing silicon.
lZ77~5S
T~bl e Alloy Of This Invention ColT~position~ in wei~ percent Rroad Range ~ ~D~ Pr-~erred Rang~e Titaniun .1 to 9.81.5 to 72.5 to 3.5 Boron .1 to 7.01.5 to 72.5 to 3.5 Aluminun plus purities Balance Balance Balance Ratio Ti :B0.1 to 2 .10.25 to 1.80.7 to 1.4 ~tal AlB2 + TiB2 '50% >75% >90%
1~5 The invention is further explained by reference to the accompanying drawings in which:
Figure 1 il~strates graphically the relationship between Ti and B in the aforementioned Cornish reference, Figure ~ illustrates graphically the data of the aforementioned Chinese investigation with respect -to those prior grain refiners r Figures 3 and 4 illustrate graphically the superior average grain size results achieved with a grain refiner of the invention compared with two prior grain refiners.
With ~urther reference to Figure 1, this presents results derived from the Cornish reference.
In Fig. 1 the circles show the final alloy composition made by adding Ti and B as separate additions in the proper amount to 99.9~ aluminum. Dark circles show compositions of castings having fine grains; open circles are coarse grained; and half-filled circles show compositions of castings having only partial grain refinement.
- 7a -~ .> ~, .
~Z77~5 EXAMPLES
Five heats o~ experimental alloys were made by reacting a salt mixture o~ KBF4 and K2TiF6 with molten aluminum. This szlt mixture is called a "flux" herein.
Three ~lux compositions and three dif~erent reaction temperatures were employed, as shown in table 2 together with the compositions of the Al-Ti-B alloys made from the reaction.
Table 2 Fl~x_B~io and Alloy ~QmPQs'tion 40%R2TiF6/60%KBF4 20%K2TiF6/80%KBF4 1096K2TiF6/909~KBF4 Reaction Temp. (2,8~i-1.8%B) (1.4~T~= ~ %B) (0.7%~i-2.7%B) 725CHeat -29 Heat -31 Heat -39 800C - - Heat -37 - ---850oC Heat -40 The experimental alloys were used as grain refiners for an Al-7%Si alloy. Each was generally ef~ective as grain refiners. However; Heats 29, 40, 31 and 37 were outstanding because the products had cleaner mlcro-structures. Table 3 presents a tabular display of the test results.
~1~77F~iS
Tabl e 3 Hçat NQ~ ~,_~0~ Ef~ectiveness 29 about 1.5:1 excellent about 1.5:1 excellent 31 about 0.6:1 excellent 37 about 0.6:1 excellent 39 about 1:4 poorest Another series of alloys was prepared to examlne the effect o~ other flux ratios. Table 4 presents the flux ratios and reaction temperatures employed.
Table 4 Flux Ratio Reaction Heat No. !~L ~
20 54 25/75 760C (1400VF) 15/85 760C ~1400VF) 56 ' 30/70 760C (1400"F) 48 20/80 800C (1472''F) 1;~78~iS
A test o~ the grain refining effectiveness of these Al-Ti-B
master alloys in cast aluminum-7% silicon alloy revealed that Heat No. 56 was the outstanding master alloy of thls entire series. Heat 56 has a 30:70 flux ratio and a reaction temperature of 760C.
Results o~ the two series of tests suggest that the best practice of the invention lies between 0.7:1 and 1.4:1 ratios (preferably about 1:1 ratio) of Ti:B ana a flux ratio o~ 30:70. To verity this conclusion a 100 lb.
experimental alloy (No. 3-40) was made and tested. This alloy contained 3.1% titanium and 3.2~ boron. It was produced by reacting a 30:70 flux ratio at a temperature of 760C (1400F) as indicated for alloy 56 described above.
Alloy 3-40 was used to refine the grain of commercial alloy no. 356, which contains 7%Si, .3% Mg, .1% Fe, and .02% Ti. The casting temperature was 725C (1350F) and the time the grain refiner was in contact with the melt before casting was 5 minutes.
Prior art alloys, 5%Ti-1%B, and A1-3%B were used under the same conditions as the experimental alloy 3-40.
Results of the test are shown graphically in Figure 3. The average grain size of the prior art alloys are plotted as ~277~
curve (a); the average grain size of alloy 3-40 is plotted as curve (b). Clearly, these data show the alloy of thls invention to be superior over the prior art alloys.
In further testing, commercial aluminum alloy no. 319 (which contains 6%5i, 3.5%Cu, 1%Fe, 1%Zn and 0.5%Mn) was also grain refined by the three master alloys mentioned above. Figure 4 is a graphic presentation of the test results. Here, also the alloy of this invention alloy (No.
3-40) was superior over the prior art alloys. Prior art alloy 5~Ti-1%B is a well known commercial master alloy with a Ti to B ratio of 5:1.
A metallographic study of all master alloys described above was made. The alloy described in this invention contained a preponderance of mixed al~minum and titanium borides, that is from about 50% to over 90% mlxed borides.
This is in contradiction with the known art whlch teaches that solely titanium boride phases (especially TiB2) and titanium aluminides ~TiA13) are preferred.
Claims (23)
1. A master alloy characterized by being capable of grain refining commercial aluminum alloys containing over 1% silicon consisting essentially of, in weight percent, 1.5 to 7 titanium, 1.5 to 7 boron, and the balance aluminum plus impurities wherein the Ti:B
ratio is between 0.25 to 1.8 and over 75% of the borides in said master alloy are in the form of mixed borides.
ratio is between 0.25 to 1.8 and over 75% of the borides in said master alloy are in the form of mixed borides.
2. The master alloy of claim 1, wherein said weight percent of titanium is 3 and said weight percent of boron is 3.
3. The master alloy of claim 1, wherein the ratio of Ti:B is about 1:1.
4. The grain refined cast alloy of claim 1 wherein said mixed borides comprise aluminum and titanium borides.
5. The master alloy of claim 1 wherein over 90% of the borides in said master alloy are in the form of mixed borides.
6. The master alloy of claim 1 produced by reacting an about 30:70 flux ratio of K2TiF6:KBF4 with molten aluminum.
7. The master alloy of claim 1 wherein the commercial aluminum alloy is selected from the group consisting of Alloy 319, Alloy A-356 and Alloy Al-7%Si.
8. The master alloy of claim 1, wherein the Ti:B ratio is between 0.7 to 1.4.
9. The master alloy of claim 6, produced at a reduction temperature of about 725°C to 760°C.
10. A method of grain refining an aluminum alloy containing over 1% silicon comprising the addition of the master alloy of claim 1, 2 or 3 to a molten mass of said aluminum alloy.
11. A method of grain refining an aluminum alloy containing over 1% silicon comprising the addition of the master alloy of claim 4, 5 or 6 to a molten mass of said aluminum alloy.
12. A method of grain refining an aluminum alloy containing over 1% silicon comprising the addition of the master alloy or claim 7, 8 or 9, to a molten mass of said aluminum alloy.
13 13. A method of making a master alloy capable of grain refining commercial aluminum alloys contain-ing over 1% silicon comprising the steps of:
reacting molten aluminum with a mixture of a titanium-containing salt and a boron-containing salt by stirring said mixture into said aluminum to produce a molten alloy consisting essentially of aluminum, titanium and boron; and casting said molten alloy to produce said master alloy, wherein the ratio of said titanium-containing salt to said boron-containing salt is such that the Ti:B ratio in said master alloy is between 0.25 to 1.8 and wherein a sufficient amount of said mixture is used to produce a master alloy consisting essentially of, in weight percent, 1.5 to 7 titanium, 1.5 to 7 boron and the balance aluminum plus impurities, said master alloy being further characterized by having over 75% of its borides in the form of mixed borides.
reacting molten aluminum with a mixture of a titanium-containing salt and a boron-containing salt by stirring said mixture into said aluminum to produce a molten alloy consisting essentially of aluminum, titanium and boron; and casting said molten alloy to produce said master alloy, wherein the ratio of said titanium-containing salt to said boron-containing salt is such that the Ti:B ratio in said master alloy is between 0.25 to 1.8 and wherein a sufficient amount of said mixture is used to produce a master alloy consisting essentially of, in weight percent, 1.5 to 7 titanium, 1.5 to 7 boron and the balance aluminum plus impurities, said master alloy being further characterized by having over 75% of its borides in the form of mixed borides.
14. The method of claim 13, wherein said Ti:B
ratio in said master alloy is between 0.7 and 1.4.
ratio in said master alloy is between 0.7 and 1.4.
15. The method of claim 13, wherein said Ti:B
ratio in said master alloy is approximately 1:1.
ratio in said master alloy is approximately 1:1.
16. The method of claim 13, wherein said weight percent of titanium is approximately 2.5 to 3.5 and said weight percent of boron is approximately 2.5 to 3.5.
17. The method of claim 13, wherein said ratio of the weight percents of said titanium-containing salt to said boron-containing salt is 30 + 6 to 70 +
14.
14.
18. The method of claim 13, wherein said titanium-containing salt is K2TiF6 and said boron-containing salt is KBF4.
19. The method of claim 18, wherein the ratio of the weight percents of said K2TiF6 to said KBF4 is about 30:70.
20. The method of claim 13, wherein said 90% of said borides in said master alloy are in the form of mixed borides.
21. A method of making a master alloy capable of grain refining commercial aluminum alloys contain-ing over 1% silicon comprising the steps of:
reacting molten aluminum with a mixture of K2TiF6 and KBF4 by stirring said mixture into said molten aluminum, wherein the flux ratio of K2TiF6:KBF4 is about 30:70, to produce a molten alloy consisting essentially of aluminum, titanium and boron; and casting said molten alloy to produce said master alloy having a Ti:B ratio of about 1:1, wherein a sufficient amount of said salt is used to produce a master alloy consisting essentially of, in weight percent, 2.5 to 3.5 titanium, 2.5 to 3.5 boron, and the balance aluminum plus impurities, said master alloy being further characterized by having over 90% of its borides in the form of mixed borides.
reacting molten aluminum with a mixture of K2TiF6 and KBF4 by stirring said mixture into said molten aluminum, wherein the flux ratio of K2TiF6:KBF4 is about 30:70, to produce a molten alloy consisting essentially of aluminum, titanium and boron; and casting said molten alloy to produce said master alloy having a Ti:B ratio of about 1:1, wherein a sufficient amount of said salt is used to produce a master alloy consisting essentially of, in weight percent, 2.5 to 3.5 titanium, 2.5 to 3.5 boron, and the balance aluminum plus impurities, said master alloy being further characterized by having over 90% of its borides in the form of mixed borides.
22. The master alloy of claim 1, wherein the weight percent of titanium is from 2.5 - 3.5 and the weight percent of boron is from 2.5 - 3.5.
23. The method of claim 13, wherein said ratio of the weight percents of said titanium-containing salt to said boron-containing salt is 30 to 70.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US71532885A | 1985-03-25 | 1985-03-25 | |
| US715,328 | 1985-03-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1277855C true CA1277855C (en) | 1990-12-18 |
Family
ID=24873591
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000504223A Expired - Lifetime CA1277855C (en) | 1985-03-25 | 1986-03-17 | Grain refiner for aluminum containing silicon |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS61223156A (en) |
| BR (1) | BR8600976A (en) |
| CA (1) | CA1277855C (en) |
| DE (1) | DE3608713A1 (en) |
| FR (1) | FR2579227B1 (en) |
| GB (1) | GB2174103B (en) |
| NL (1) | NL8600394A (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NO174165C (en) * | 1992-01-08 | 1994-03-23 | Elkem Aluminium | Method of refining aluminum and grain refining alloy for carrying out the process |
| ZA938824B (en) * | 1992-12-07 | 1994-06-30 | Rheinfelden Aluminium Gmbh | Grain refiner for aluminium casting alloys, in particular aluminium-silicon casting alloys. |
| DE50208178D1 (en) * | 2001-06-07 | 2006-11-02 | Bayerische Motoren Werke Ag | Cleaning of aluminum casting alloys by adding boron |
| US7201210B2 (en) | 2003-12-02 | 2007-04-10 | Worcester Polytechnic Institute | Casting of aluminum based wrought alloys and aluminum based casting alloys |
| TR200504376A2 (en) * | 2005-11-02 | 2008-05-21 | T�B�Tak-T�Rk�Ye B�L�Msel Ve Tekn�K Ara�Tirma Kurumu | A process for producing grain-reducing pre-alloys |
| JP6011998B2 (en) * | 2012-12-25 | 2016-10-25 | 日本軽金属株式会社 | Method for producing aluminum alloy in which Al-Fe-Si compound is refined |
| RU2644221C1 (en) * | 2016-12-27 | 2018-02-08 | Общество с ограниченной ответственностью "Безотходные и малоотходные технологии" (ООО "БМТ") | Aluminium-titanium-boron master alloy |
| EP4098382B9 (en) * | 2020-02-06 | 2024-07-10 | UACJ Corporation | Aluminum alloy ingot and method for manufacturing same |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1041695B (en) * | 1955-03-29 | 1958-10-23 | Metallgesellschaft Ag | Grain refinement of cast aluminum |
| GB802071A (en) * | 1957-04-15 | 1958-10-01 | Kawecki Chemical Company | Improvements in aluminium-base alloys |
| GB1244082A (en) * | 1968-03-13 | 1971-08-25 | Kawecki Berylco Ind | Improvements in introducing a grain refining or alloying agent into molten metals and alloys |
| SE349331B (en) * | 1970-04-28 | 1972-09-25 | Svenska Aluminiumkompaniet Ab | |
| US3676111A (en) * | 1971-03-01 | 1972-07-11 | Olin Corp | Method of grain refining aluminum base alloys |
| JPS5143011B2 (en) * | 1972-02-14 | 1976-11-19 | ||
| LU67355A1 (en) * | 1973-04-04 | 1974-11-21 | ||
| US4298408A (en) * | 1980-01-07 | 1981-11-03 | Cabot Berylco Inc. | Aluminum-titanium-boron master alloy |
-
1986
- 1986-02-17 NL NL8600394A patent/NL8600394A/en not_active Application Discontinuation
- 1986-03-06 GB GB8605589A patent/GB2174103B/en not_active Expired
- 1986-03-06 BR BR8600976A patent/BR8600976A/en not_active IP Right Cessation
- 1986-03-15 DE DE19863608713 patent/DE3608713A1/en not_active Ceased
- 1986-03-17 CA CA000504223A patent/CA1277855C/en not_active Expired - Lifetime
- 1986-03-19 JP JP6193486A patent/JPS61223156A/en active Granted
- 1986-03-24 FR FR8604191A patent/FR2579227B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0159345B2 (en) | 1989-12-15 |
| NL8600394A (en) | 1986-10-16 |
| FR2579227B1 (en) | 1988-11-25 |
| BR8600976A (en) | 1986-11-18 |
| JPS61223156A (en) | 1986-10-03 |
| GB2174103A (en) | 1986-10-29 |
| DE3608713A1 (en) | 1986-10-09 |
| FR2579227A1 (en) | 1986-09-26 |
| GB2174103B (en) | 1989-06-21 |
| GB8605589D0 (en) | 1986-04-09 |
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