Claims
- 1. A process of directly casting semi-finished products of a high-melting-point metal with constant cross sections in a permanent metal mold which has smooth sidewalls which form a casting cavity with a cross section corresponding to that of the products to be cast, comprising the steps of:
- (a) attaching to a plunger a thin, resilient metal band which extends above the top of the plunger;
- (b) disposing said plunger in the top portion of the casting cavity and placing the resilient metal band against the sidewalls of the mold so that the ends overlap;
- (c) forming on top of the plunger inside of the metal band a solid refractory barrier which holds the metal band against the sidewalls of the mold, which withstands the impact of the high-melting-point molten metal being poured upon it, which insulates the molten metal from the plunger, and which compresses to compensate for the forces generated by thermal expansion;
- (d) pouring molten metal of a high-melting-point into a reservoir disposed above the casting cavity and as the reservoir begins to fill, causing the plunger to descend relative to the mold toward the bottom of the cavity at a controlled rate of from 1/2 to 4 inches per second while keeping the reservoir supplied with molten metal, thereby causing molten metal to enter and fill the space being created above the plunger as it descends;
- (e) promptly after the plunger has completed its descent, and after the semi-finished metal product casting thus formed has cooled enough to have vertical strength, raising the plunger relative to the mold to lift the casting enough to break any adhesions with the sidewalls of the mold and prevent hanger cracks while maintaining the reservoir in communication with the casting so as to feed it as the metal solidifies and shrinks;
- (f) allowing the casting to continue to cool and further solidify enough to be handled; and
- (g) stripping the cast product from the mold without damaging the plunger so that the mold and plunger can be used again.
- 2. The process of claim 1, in which the semifinished products are rounds.
- 3. The process of claim 1, in which the semifinished products are slabs.
- 4. The process of claim 1, in which the high-melting-point metal is steel.
- 5. The process of claim 1, in which the high-melting-point metal is stainless steel.
- 6. The process of claim 1, in which the plunger is elevated enough to lift the casting and reservoir at least slightly out of the mold.
- 7. The process of claim 1, in which the plunger is pulled downwardly.
- 8. The process of claim 1, in which the mold is a steel mold.
- 9. The process of claim 1, in which the mold is a copper mold.
- 10. The process of claim 1, in which the refractory barrier is formed of silica sand with a suitable core binder which is rammed into the space above the plunger and then cured.
- 11. The process of claim 1, in which the metal band is steel with a thickness of less than 0.035 inch.
- 12. An apparatus for directly casting semifinished products of a high-melting-point metal of constant cross section which comprises:
- (a) a metal mold with smooth vertical sidewalls which define a casting cavity having a constant cross section which corresponds to the cross section of the products to be cast;
- (b) a plunger adapted to be lowered and raised in the casting cavity, the plunger having a cross section which is about the same as but slightly smaller than that of the casting cavity;
- (c) a resilient metal band attached to the plunger with overlapped ends and with upstanding portions which extend substantially above the top of the plunger and are disposed against the vertical sidewalls of the mold to make a sliding seal with the sidewalls;
- (d) a solid, slightly compressible, insulating refractory barrier on top of said plunger inside of said metal band which holds said band against the sidewalls of the mold but which, together with the shim band, has enough give to accommodate the thermal forces generated by expansion of said barrier and shim band so as to prevent binding up thereof within the mold;
- (e) a reservoir for molten ferrous metal on the top of the mold over the casting cavity for supplying molten metal to the cavity over the plunger; and
- (f) means for lowering and raising the plunger.
- 13. The apparatus of claim 12, in which silica sand is rammed into the space inside the metal band and is then cured in place to act as the refractory barrier.
- 14. The apparatus of claim 12, in which the metal band is steel shim stock with a thickness of between 0.015 and 0.035 inch.
- 15. The apparatus of claim 12, in which the metal mold is steel.
- 16. The apparatus of claim 12, in which the metal mold is copper.
- 17. An apparatus for casting rounds directly from molten, high-melting-point metal which comprises:
- (a) a tubular steel cylinder mounted vertically on a supporting platen with a smooth inside surface defining the casting cavity, the weight of the cylinder being at least one and one-half times the weight of the round to be cast;
- (b) a cylindrical plunger adapted to be lowered and raised in the casting cavity;
- (c) a thin, resilient steel band with upstanding portions placed against the inside surface of the casting cavity above the top of the plunger and which is attached to the plunger, the upstanding portions extending at least 11/2 inches above the top of the plunger;
- (d) a layer of rammed-up, cured-in-place silica sand on top of the plunger inside the steel band;
- (e) means for lowering and raising the plunger; and
- (f) a reservoir for molten metal on top of the tubular steel cylinder.
- 18. An apparatus for casting slabs directly from molten ferrous metal which comprises:
- (a) strongback steel side blocks mounted on a base;
- (b) strongback steel end blocks mounted on the base between said side blocks to define a slab casting cavity;
- (c) means to clamp the side blocks against the end blocks;
- (d) a plunger with substantially the same cross-sectional shape as that of the slab casting cavity adapted to be lowered and raised in said cavity;
- (e) a thin, flexible steel band with upstanding portions placed against the inside surface of the casting cavity above the top of the plunger and which is attached to the plunger, the upstanding portions extending at least 11/2 inches above the top of the plunger;
- (f) a layer of rammed-up, cured-in-place silica sand on top of the plunger inside the steel band;
- (g) means for lowering and raising the plunger; and
- (h) a reservoir for molten metal on top of the tubular steel cylinder.
Parent Case Info
This application is a continuation-in-part of my application Ser. No. 261,762, filed May 8, 1981, which in turn was a continuation-in-part of my application Ser. No. 106,391, filed Dec. 26, 1979, both are abandoned.
US Referenced Citations (3)
Foreign Referenced Citations (1)
Number |
Date |
Country |
379120 |
Aug 1932 |
GBX |
Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
261762 |
May 1981 |
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Parent |
106391 |
Dec 1979 |
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