Claims
- 1. A method for producing silica sand-based foundry shapes useful in forming metal castings, said method comprising the steps of:
providing a foundry sand, adding an anti-veining composition comprising bentonite to said foundry sand to form a mineral composition, and adding a foundry resin to said mineral composition to form a sand-based foundry composition; and shaping said sand-based foundry composition to form a desired pattern, wherein said anti-veining composition reduces veining in metal castings prepared from said sand-based foundry composition.
- 2. The method of claim 1 wherein said bentonite is selected from the group consisting of sodium bentonite, calcium bentonite and combinations thereof.
- 3. The method of claim 2 wherein said anti-veining composition further comprises another clay mineral wherein said mineral is selected from the group consisting of hectorite, illite, smectites, shale, and mixtures thereof.
- 4. The method of claim 1 wherein said sand-based foundry composition contains from about 95% to about 99.5% by weight of said mineral composition and from about 5% to about 0.5% by weight of a polymerizable or curable foundry resin appropriate for sand cores and molds, and said mineral composition contains from about 1% to about 10% by weight of said anti-veining composition based on said mineral composition.
- 5. The method of claim 4 wherein said foundry resin is selected from the group consisting of phenolic hot box, phenolic urethane, furan, sodium silicate systems, polyester binders, acrylic binders, alkaline binders, epoxy binders and furan warm box systems.
- 6. The method of claim 1 wherein said bentonite is utilized in a granular form having an average particle size of from about 74μ to about 3.4 mm.
- 7. The method of claim 6 wherein said bentonite has a moisture level of from about 0.1% to 15%.
- 8. The method of claim 1 wherein said anti-veining composition contains up to about 10% stearate wherein said stearate increases tensile properties.
- 9. The method of claim 8 wherein said stearate is selected from the group consisting of calcium stearate, magnesium stearate, sodium stearate and aluminum stearate.
- 10. The method of claim 1 wherein said anti-veining composition contains up to about 50% coal slag wherein said coal slag increases tensile properties.
- 11. The method of claim 10 wherein said anti-veining composition further comprises a stearate.
- 12. A method of making a metal casting from sand-based foundry compositions comprising the steps of:
providing a foundry sand, adding an anti-veining composition comprising bentonite to said foundry sand to form a mineral composition, and adding a foundry resin to said mineral composition to form a sand-based foundry composition; shaping said sand-based foundry composition to form a desired pattern, wherein said anti-veining composition reduces veining in metal castings prepared from said sand-based foundry composition; and pouring molten metal into the pattern formed in said sand-based foundry composition to produce a metal casting having little or no veining.
- 13. The method of claim 12 wherein said foundry composition comprises a matrix of sand and foundry resin having bentonite particles uniformly dispersed therethrough, wherein said foundry composition matrix reduces thermal expansion defects.
- 14. The method of claim 12 wherein said bentonite is selected from the group consisting of sodium bentonite, calcium bentonite and combinations thereof.
- 15. The method of claim 14 wherein said anti-veining composition further comprises another clay mineral wherein said mineral is selected from the group consisting of hectorite, illite, smectites, shale, and mixtures thereof.
- 16. The method of claim 12 wherein said sand-based foundry composition contains about 95% to about 99.5% by weight of said mineral composition and from about 5% to about 0.5% by weight of a polymerizable or curable foundry resin appropriate for sand cores and molds, and said mineral composition contains from about 1% to about 10% by weight of said anti-veining composition based on said mineral composition.
- 17. The method of claim 16 wherein said foundry resin is selected from the group consisting of phenolic hot box, phenolic urethane, furan, sodium silicate systems, polyester binders, acrylic binders, alkaline binders, epoxy binders and furan warm box systems.
- 18. The method of claim 12 wherein said bentonite is utilized in a granular form having an average particle size of from about 74μ to about 3.4 mm.
- 19. The method of claim 18 wherein said bentonite has a moisture level of from about 3% to 15%.
- 20. The method of claim 12 wherein said anti-veining composition contains up to about 10% stearate wherein said stearate increases tensile properties.
- 21. The method of claim 20 wherein said stearate is selected from the group consisting of calcium stearate, magnesium stearate, sodium stearate, and aluminum stearate.
- 22. The method of claim 12 wherein said anti-veining composition contains up to about 50% coal slag, wherein said coal slag increases tensile properties.
- 23. The method of claim 22 wherein said anti-veining composition further comprises a stearate.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional Application Ser. No. 60/414,809, filed Sep. 30, 2002 and U.S. Provisional Application Ser. No. 60/332,679, filed Nov. 14, 2001.
Provisional Applications (2)
|
Number |
Date |
Country |
|
60414809 |
Sep 2002 |
US |
|
60332679 |
Nov 2001 |
US |