Claims
- 1. In a method of forming a deposit on a surface of a substrate comprising the steps of:
- teeming a stream of molten metal, metal alloy or molten ceramic through an atomizing device;
- applying atomizing gas at said atomizing device for forming an atomizing gas flow field of a geometry which atomizes the stream into a spray of gas atomized molten metal, metal alloy or molten ceramic particles, said spray having a mean axis directed at the substrate;
- rotating the substrate about an axis of the substrate, and extracting heat in flight and/or on deposition from the atomized particles to produce a coherent deposit;
- imparting an oscillation to the gas flow field and thereby to the spray in the direction of the axis of the substrate such that an angle of the mean axis of the spray to the substrate and to the molten stream is varied, while the geometry of the atomizing gas flow field may remain substantially constant;
- oscillating the gas flow field at a speed of oscillation in excess of five cycles per second such that a layer of semi-solid/semi-liquid metal, metal alloy or ceramic is substantially maintained at a deposition surface of the deposit over an amplitude of oscillation to maintain a substantially uniform microstructure through the deposit; and
- varying a ratio of atomizing gas to molten metal, metal alloy or molten ceramic during deposition to give substantially uniform deposition conditions as the deposit increases in thickness, whereby a tubular billet deposit of discrete, semi-continuous or continuous length may be formed about the substrate.
- 2. A method according to claim 1, wherein the substrate is additionally moved in its axial direction relative to the spray, whereby a deposit of semi-continuous or continuous length may be formed.
- 3. A method according to claim 1, wherein the axis of the substrate is substantially perpendicular to the direction of the spray during a part of its oscillation.
- 4. A method according to claim 1, wherein the spray is moved at a speed which is varied during each cycle of oscillation.
- 5. A method according to claim 1, wherein the deposit formed is a tubular body generated about the axis of rotation.
- 6. A method according to claim 1, wherein a variable amount of heat is extracted in flight during the formation of the deposit to maintain said layer, and less heat is extracted in flight on initial deposition to reduce porosity.
- 7. A method according to claim 1, wherein metallic or non-metallic particles and/or fibers are introduced into the atomized spray to form a composite deposit.
- 8. A method of forming a deposit on a surface of an elongate substrate comprising the steps of:
- teeming a stream of molten metal, metal alloy or molten ceramic through an atomizing device;
- forming an atomizing gas flow field of a cooler atomizing gas;
- generating a spray of gas atomized molten metal, metal alloy or ceramic particles which are directed at the substrate by the application to the stream of the cooler atomizing gas flow field, the substrate being positioned with its longitudinal axis transverse to the spray and said spray having a mean axis directed at the substrate;
- rotating the substrate about its longitudinal axis;
- oscillating the spray over an amplitude of oscillation so that the spray is moved over at least a part of the surface of the substrate, said oscillating comprising varying an angle of the mean axis of the spray to the substrate and to the molten stream while geometry of the atomizing gas flow field may remain substantially constant;
- extracting a controlled amount of heat in flight and on deposition from the atomized particles by the relatively cold atomizing gas, and oscillating the spray at a speed of oscillation in excess of five cycles per second, to produce and maintain a layer of semi-solid/semi-liquid metal, metal alloy or ceramic at a deposition surface of the deposit over an amplitude of the oscillation throughout the deposition operation to produce a deposit which has a non-particulate microstructure and is free from macro-segregation; and
- varying a ratio of atomizing gas to molten metal, metal alloy or molten ceramic during deposition to give substantially uniform deposition conditions as the deposit increases in thickness, whereby a tubular billet deposit of discrete, semi-continuous or continuous length may be formed about the substrate.
- 9. In a method of forming a deposit on a surface of a substrate comprising the steps of:
- generating a spray of gas atomized molten metal, metal alloy or molten ceramic particles by means of an atomizing device forming an atomizing gas flow field, said spray having a mean axis directed at the substrate;
- rotating the substrate about an axis of the substrate;
- extracting heat in flight and/or on deposition from the atomized particles to produce a coherent deposit;
- the improvement comprising;
- supporting the atomizing device for movement, effecting movement of the atomizing device at a speed of movement, whereby:
- the spray is oscillated in the direction of the axis over an amplitude of oscillation, an angle of the mean axis of the spray to the substrate is varied, and geometry of the atomizing gas flow field may remain substantially constant;
- controlling the speed of movement of the atomizing device, whereby the oscillation of the spray is in excess of five cycles per second to maintain a layer of semi-solid/semi-liquid metal or ceramic at a deposition surface of the deposit over the amplitude of oscillation; and
- varying a ratio of atomizing gas to molten metal, metal alloy or molten ceramic during deposition to give substantially uniform deposition conditions as the deposit increases in thickness, whereby a tubular billet deposit of discrete, semi-continuous or continuous length may be formed about the substrate.
- 10. A method according to claim 1, comprising controlling the rate and amplitude of the oscillation of the spray to favorably influence the angle of impingement of the atomized particles on the forming deposit.
- 11. A method according to claim 9, wherein the movement of the atomizing device comprises tilting of the whole atomizing device.
- 12. In a method of forming a deposit on a surface of a substrate comprising the steps of:
- teeming a stream of molten metal, metal alloy or molten ceramic through an atomizing device;
- generating a spray of gas atomized molten metal, metal alloy or molten ceramic particles by the application to the stream of an atomizing gas flow field at a temperature less than that of the said molten metal, metal alloy or molten ceramic, and said spray having a mean axis directed at the substrate, and extracting heat in flight and/or on deposition from the atomized particles by said cooler atomizing gas to produce a coherent deposit
- the improvement comprising oscillating the spray over an amplitude of oscillation at a speed of oscillation in excess of five cycles per second whereby;
- (a) an angle of the mean axis of the spray to the substrate and to the molten stream is varied;
- (b) geometry of the atomizing gas flow field may remain substantially constant;
- (c) a deposition profile of the spray is modified by elongation across the surface of the substrate or a deposition surface of the deposit forming thereon;
- (d) a layer of semi-solid/semi liquid metal or ceramic is maintained at a deposition surface of the deposit over the amplitude of oscillation; and,
- a ratio of atomizing gas to molten metal, metal alloy or molten ceramic is varied during deposition to give substantially uniform deposition conditions as the deposit increased in thickness, whereby a tubular billet deposit of discrete semi-continuous or continuous length may be formed about the substrate.
- 13. A method of forming a deposit according to claim 12, wherein the oscillation of the spray is effected by movement of the atomizing device.
Priority Claims (2)
Number |
Date |
Country |
Kind |
852783 |
Nov 1985 |
GBX |
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8527854 |
Nov 1985 |
GBX |
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Parent Case Info
This is a continuation of application Ser. No. 07/877,195, filed May 1, 1992, now abandoned, which is a continuation of application Ser. No. 07/612,512, filed Sep. 20, 1990, now U.S. Pat. No. 5,110,631; which is a continuation of application Ser. No. 07/323,158, filed Mar. 15, 1989, now abandoned; which is a continuation of application Ser. No. 07/083,788, filed Jul. 1, 1987, now abandoned, which was a national stage application of PCT/GB86/00698, filed Nov. 12, 1986.
US Referenced Citations (5)
Foreign Referenced Citations (4)
Number |
Date |
Country |
2043882 |
Feb 1974 |
DEX |
1379261 |
Jan 1975 |
GBX |
1472939 |
May 1977 |
GBX |
1599392 |
Sep 1981 |
GBX |
Continuations (4)
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Number |
Date |
Country |
Parent |
877195 |
May 1992 |
|
Parent |
612512 |
Sep 1990 |
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Parent |
323158 |
Mar 1989 |
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Parent |
83788 |
Jul 1987 |
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