Package making – Methods – With contents treating
Reexamination Certificate
1999-12-08
2002-06-18
Sipos, John (Department: 3721)
Package making
Methods
With contents treating
C053S467000, C053S122000, C053S235000
Reexamination Certificate
active
06405512
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. §119 of Austrian Patent Application No. 2066/98, filed on Dec. 9, 1998, the disclosure of which is expressly incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and to a process to create input material for parts to be manufactured using powder metallurgy. More particularly, the instant invention relates to a device for manufacturing metal powder from a molten mass that includes at least one metallurgical vessel for treating and/or preparing the liquid metal, an atomizing chamber having a nozzle part for sputtering the liquid metal, and a separator for classifying the metal powder formed. The device also includes an encapsulating facility for introducing and enclosing the formed metal powder in a container, a conveyance and connecting unit for powder transport-in the device, and lines with regulators and connections for preparing the atomizing media.
Moreover, the invention relates to a process for manufacturing metal powder from molten mass which includes liquid metal being introduced from a metallurgical vessel into an atomizing chamber, sputtering the liquid metal via a gaseous medium, and allowing it to solidify. The metal powder formed in this way is classified and filled into capsules, which are closed or supplied for further processing.
2. Discussion of Background Information
Work pieces and parts that are produced using powder metallurgy have a consistently fine-grained isotropic structure and, therefore, also advantageously similar material properties independent of the direction of stress. The favorable structural characteristics and, e.g., mechanical property characteristics are compared with conventional goods, which are essentially improved with high-alloy PM materials, because they do not have rough primary precipitations even if the respective content of the elements causing these precipitations is high. Powder metallurgical manufacturing of work pieces takes place essentially by way of a metal molten mass being introduced in a thin stream into a cavity, a so-called “atomizing chamber,” and the molten mass stream is split into small droplets by a gas stream coming from nozzles having or causing a high kinetic energy. In further passing through the chamber, the droplets solidify in an extremely short time and are collected as powder particles. Finally, additional cooling takes place and, if necessary, classification of the metal powder, which can be enclosed in a metal capsule, can occur by subjecting the capsules to a pressing cycle at high temperature. This hot pressing can be executed by forging or rolling the capsules brought to the deformation temperature, by high-temperature isostatic pressing (HIP-process), or by baking the powder particles and by eliminating the cavities between these particles. In this manner, a completely dense work piece with an extremely fine-grained all-round homogeneous structure can be created.
A device for manufacturing metal powder can have an essentially vertical or an essentially horizontal atomizing chamber depending upon the atomizing type or direction that is planned for the metal molten mass.
If the gas stream sputtering the liquid metal in the direction of the molten mass stream is guided downward, as in a device disclosed, e.g., in SE-AS-421758, an atomizing chamber with its longitudinal axis aligned vertically can be used advantageously. However, such types of atomizing devices as a whole have a considerable height, which is something that can have negative effects on facilities and hall costs.
An atomizing chamber that has a length that is essentially horizontally aligned preferably finds application with a sputtering process in which the gas stream laterally impacts the metal stream introduced into the chamber at an angle of approximately 90°, as disclosed in, e.g., International Publication No. WO 89/05197. While such horizontal chambers are built low in terms of installation, most of the time, they require additional gas inlets and/or other devices to convey or bring about the solidification of the metal droplets and the powder transport, and to diminish its thermal load.
In the case of all devices for manufacturing metal powder from a molten mass, air admission should be avoided to the greatest extent possible during the entire preparation process leading up to powder encapsulation. This requirement necessitates great facility-related and procedural expenditures such that only absolutely necessary vessel openings with especially effective seals are provided for in the device, which often impedes some service work.
After processing a molten mass into powder, residues can remain in the device which are output with the subsequent batch and are further processed with it. If necessary, this blending of the residual quantities is tolerable, if, in the future, the same kind of molten mass or molten mass of a same quality of steel arrives for processing within the prescribed narrow range of the chemical composition. Otherwise, an expensive and time-consuming cleaning of the atomizing chamber is required and/or the first runnings or the first partial incidence of powder must be scrapped and assigned to the waste pile.
When splitting the molten mass stream in the atomizing chamber, the size of the droplets formed with unchanged gas precipitation depends on the temperature of the molten mass and, in particular, on either the speed or the ferrostatic pressure with which it is guided into the chamber. Therefore, if the temperature of the bath and/or the metal bath height in the metallurgical vessel are not kept largely constant over the atomizing period, different powder particle classifications can be formed according to the dependencies and, in the future, can be stored in layers in the capsule, such that non-homogeneities are created with higher residual cavities at least in its longitudinal direction.
SUMMARY OF THE INVENTION
Based upon the state of the art, the present invention provides a device for manufacturing metal powder from a molten mass favoring preferred solidification criteria of the metal droplets. The device includes a special atomizing chamber, and, using an advantageous simple powder transfer into the device, makes the densest possible powder particle packing available for filling capsules and has a low structural device height as well as high economic efficiency in terms of device preparation.
In addition, the present invention provides a process in which powder can be manufactured from liquid metal in a simple and economical manner, and capsule inserts with a high density and homogeneity can be prepared from this powder.
According to the present invention, the device can include, in addition to certain features of the device generally discussed above, an atomizing chamber connected on a feed side of a metallurgical vessel, which is designed to be inclined downwards at an angle in its longitudinal extension. Further a diverting part cooperates with a discharge side metallurgical vessel, such that a pipe is coupled to the discharge side and pointed upwardly in a continuation of a conveyance path for the powder. The ascending pipe opens into a disintegrator arranged in front of a separator, such that the separator is connected to the disintegrator through a deflection valve. A collecting basin is coupled to the separator, and can be brought into connection with an encapsulating facility or a powder capsule through a shut-off device.
Certain advantages of the present invention are apparent in that the individual parts of the device can be optimized in terms of their respective functions relative to the high requirements on the metal powder or the final powder, and can be coordinated synergistically with one another. Further, the device has high economic efficiency, operating safety, and overall availability. According to arrangement of the device, an inclined position of the atomizing chamber can cause an extension of a
Böhler Edelstahl GmbH & Co. KG
Greenblum & Bernstein P.L.C.
Sipos John
LandOfFree
Apparatus and process for manufacturing metal powder in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and process for manufacturing metal powder in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and process for manufacturing metal powder in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2976113