JPS59100202A - Metal particle manufacture and device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates generally to the field of metallurgy, and more particularly to shot, powder, and particle generation.

The process of shot peening typically creates surface compressive stresses in stainless steel materials to prevent stress corrosion cracking, which otherwise occurs when the surface is exposed to hot water containing chlorides and subjected to surface tensile stresses, particularly or near the weld zone. used for The method is also used for improving fatigue resistance. This manufacturing technique for stainless steel shorts involved a later step to round the edges of the cut. , with or without wire cutting. This method is neither cost effective nor capable of producing truly spherical objects.

Stainless steel shorts were initially manufactured by cutting drawn wire, and in some cases the prior art conditioned the wire by rounding the edges of the cut. This prior art process was cost effective. well and does not produce the most desirable spherical shape for shot peening.Metal shot from some metal is produced where the molten metal is broken by screening and cooled by falling a given distance in a shot tower. Shots have also been made in the prior art by directing a stream of molten metal over a rotating disk where centrifugal force causes fracture of the metal.

Another attempt is U.S. Patent No. 2,308,584;
341,704; 2,523,454; 2,567,1
21;2,636,219;2,428,718;3,
891,730; and 3,951,577. All of the approaches disclosed in these patents involve the intersection of a molten metal stream with a reservoir fluid stream to break and produce shots of bath molten metal.

Powders used in compacting or sintering powder metallurgy are often fractured by high pressure water jets or may be produced by rotary motion equipment such as those used for some forms of shot.

The methods discussed above do not provide the adaptability and flexibility required for modern technology, nor do such methods provide the immediate ability to introduce modifying elements into the particles.

A method and apparatus embodying the teachings of the present invention provides a cost effective means of producing spherical metal particles with desirable properties such as stainless steel shot for short peening.

The operation of the apparatus implementing the teachings of the present invention is based on the Coanda effect. As used here, the Coanda effect means that “even if the wall is bent away from the axis of the jet,
The direction for the movement of the exiting gas or liquid from the jet is limited to ``closed'' to the wall contour.

In accordance with the present invention, a process is provided for producing metal particles by breaking a flow of molten metal in droplets and assimilating the droplets, the process comprising flowing a first fluid along a Coanda surface. positioning the second fluid adjacent to the Coanda surface with a flow of a third fluid influencing the second fluid to flow in a direction transverse to the first fluid, directing molten metal between the first and second fluids; flowing adjacent to and below the Coanda surface of the fluid but without preventing intersection of the first and second fluids;
and the first and second fluids to an intersecting position where the first and second fluids intersect and mix to break the metal flow into metal particles.
Characterize by flowing fluid.

The first and second fluids are preferably each gaseous and the molten metal stream is preferably in the form of a sheet.

The invention also includes apparatus for making the method of the invention effective. The invention therefore also provides an apparatus for carrying out the method of the invention, which apparatus comprises a Coanda surface C, a first
A slit opening 70 adjacent to the upper end of the Coanda surface C for forming a first fluid flow along the Coanda surface C to influence a second fluid directed to intersect with the fluid; Molten metal for shaping the flow of molten metal for introduction between first and second fluids to break the molten metal to form metal particles, but not to prevent fluid crossing; The reservoir 90 is characterized by:

In a preferred embodiment, the apparatus of the invention includes a hollow container into which various gases are forced under pressure.

The container has an arcuate surface on one of its sides forming a Coanda curve. A narrow adjustable slit is provided in the container to allow gas to escape at a selected rate and tangential to the curvature of the surface. The slit is of such size and dimension that the gas passing therethrough achieves a sufficiently high velocity that the gas flow contacts and follows a curved surface. (This gas flow is recognized as the initial gas flow.) In doing so,
The contacting gas causes the surrounding atmosphere to take up a volume several times the volume of the initial gas. When molten metal is introduced into the riding area from the reservoir, it is trapped between the initial gas flow and the riding gas stream, and is forced out of the curved surface after being broken into particles by the riding force. The molten metal is held back from the curved surface by the initial gas flow, which creates a protective barrier between the molten stream and the surface.

Particle size and shape are determined by metal temperature, gas pressure, slit opening, quenching medium, metal flow shape (which may be shaped by the restriction of the flow opening through which the flow is formed), curved shape (
The appendages may be affected by changes in the profile), the position of the slit into the curved profile, the orientation of the molten metal flow introduction, or the like.

Varying the gases used for the initial flow and for the ambient air makes it possible to derive desirable or less desirable properties and surface conditions. A distinct advantage of the presently disclosed device over the prior art device is the absence of moving parts and the greater protection feature results from the initial gas flow pairing effect which prevents erosion of the curvature by molten metal.

Depending on the temperature required for the various metals, the device may be constructed of high temperature metals, ceramics, alumina components, or the like. The equipment is continuously cooled by the gas required during the process. Cooling of the particles also affects shape, with more spherical particles being created when the particles are allowed to solidify in a gaseous atmosphere rather than being quenched into a liquid.

The entire process is tubed in a container forming a large chamber with a reservoir at the bottom to hold the coolant/incineration liquid filled with various gases.

Due to the high volumetric nature of this device, extensive breakup of the melt flow occurs due to the introduction of a relatively small volume of gas.

The particles produced by the process employing the present invention have properties that allow the invention to be applied to cold molding processes, forging or the like, allowing for better and more uniform molding possibilities. It will be done.

The generation of powders and particles required in powder metallurgy or molding may also be enhanced by this process due to gas impingement (due to its properties and/or the possibility of surface deformation as well as shape and size). I don't know.

The invention will be further described by way of example with reference to the accompanying drawings, in which: FIG.

Referring to the drawings, shown in FIG. 1 is an apparatus 10 for producing particles of various shapes, sizes, and compositions.

The device 10 includes a top 11, a bottom 16, sides 18 and 20,
It includes a hollow diamber defining the housing 12 which includes a planar rear wall 22.

Additionally, the housing includes a serpentine front section 30 best seen in FIG. 2 including an operating top section having a radius of curvature R1 that smoothly and completely mates an operating bottom section having a radius of curvature R2. . , as shown in Figure 2,
The front portion 30 forms an ogee shape with radii R1 and R2 creating opposite bends with R2 exceeding R1. The top portion 32 has an end edge 40 located inside a chamber 42 defined within the housing 12, and the bottom portion 36 has a lower end edge fully connected to the housing bottom 16.

As seen in FIG. 2, the arcuate top 32 has an outer surface 50 and the bottom 36 has an outer surface 52 with surfaces 50 and 52 forming a continuous arcuate, meandering surface. This surface forms a boil and is hereinafter designated as Coanda surface C, and is shaped to produce the previously mentioned Coanda effect according to fluid mechanics and boundary layer principles known to those skilled in the art. and dimensioned.

The Coanda effect as well as many of the relevant flow effects utilized in the practice of the present invention are not due to the fluid properties themselves, but are due to static or fluid conditions such as stagnation pressure, temperature, enthalpy, density, and the like. is influenced and governed by the surface characteristics of the housing, such as the nature of the casing, as well as the coefficient of friction, dimensions and the like.

The selection of these parameters will be governed by theories, relationships, formulas and the like known to those skilled in the fluid mechanics and metallurgical arts. This disclosure will provide instruction to those skilled in the art regarding results, operations, functions, and the like, and these skilled technicians may wish to consult basic textbooks such as: Library of Congrcss. C
atalogCard No. Mechani by Irving Shaner, published by McGraw-Hill Book Co., Ltd. with 61-18731.
cs of Fluids; Victor L. Str
cctcr, University of Michi
Handboo edited by gan Press
k of Fluid Dynamics;A. B. C
ambel and B. H. Jennings, No.
rthwestern University, McGr.
aw-Hill Scrics in Mcchani
Gas Dyna by calEngineering
mics; Hcrman Schlicting, Uni
versity of Braunschwcig,G
crmany translated by J. Ke
stem, Brown University, McGr
ow-Hill Serics in Mechani
Boundary by calEngincering
Layer Theory. 4th edition; Aschcr
H. Shapiro, The Ronald Press
The Dynamies by Company,
andThermodynamics of Comp
Ressible Fluid Flow, Volume
1 and 2; and the like, paper or U.S. Patent Nos. 2,052,869; 4,014,487; 3
,999,696;4,035,870;4,136,
Patents such as No. 808 and No. 4,147,287, which are for other teachings related to details of practicing the invention based on this disclosure. A complete discussion of the considerations required to accurately design a Coanda surface C is not present here in view of the existence of teachings in the above-mentioned textbooks, papers, patents, and the like. The precise design of such surfaces, and the selection of other elements in the fluid to produce particular results, may be learned from the subsequent disclosure to and by those skilled in the art concerned. Depends on parameters that are obvious from knowledge.

As shown in FIG. 2, the top outer surface 50 is spaced from the housing top 14 to define a gap 60. As shown in FIG. Since the top 14 of the gap 60 is flat, the surface 50
having the dimensions and shape as determined by the dimensions and shape of.

Accordingly, the size and shape of the Coanda surface C is further influenced by the shape and effect of any fluid flow flowing in the gap 60 as is clear from this disclosure. The gap 60 is the lip 6 from the top 14 as shown in FIG.
It is closed along the side etsude by 4. Thus,
Gap 60 defines an exit slit 70 and any fluid flowing therein can contact its surface 50. The location of impingements, separation points, or the like is governed by the shape of surface 50 as well as the flow vector of the fluid flowing through gap 60.

The gas inlet means includes an inlet conduit attached to the +a section 18 of the housing and extends through the slit 7 as indicated by arrow GF.
Suitable valves, fill spaces, gauges and the like used to regulate the flow of fluid into the interior or housing to limit the pressure for that fluid suitable to establish the desired flow through the A fluid source that has passed through one (
(not shown) to the interior of the housing.

Due to the surrounding U surrounding the device 10 (θ between the flow GF and the gas at −) friction and the like, the flow gradient of the surrounding gas is established by the flow GF, as indicated by the arrow EFG. Ru.

This flow gradient generally has a shape that is influenced by the shape of the Coanda surface C which rotates in the direction of the gas flow GF and thus influences the shape of the gas flow GF.

The surrounding debris is thus dissolved in the gas in the flow GF in the direction of +tr
Since it dissolves in the gas at F, it can be recognized as a power gas. The gas in the gradient EFG is Lυ concave in the region J of Figure 2.
It contacts the gas in the flow GF at a position recognized as . As a result of the shape of surface C, flows GF and EF
G tends to be good at communication. Crossing and mixing will occur later but does not interfere.

As shown in FIGS. 1 and 2, reservoir 90 includes a channel 92 disposed proximate housing 12 and fluidly coupled to a respective exhaust portion 94. As shown in FIGS.

The flute 92 is funnel-shaped in cross section and has an elongated discharge port 96 connected to the discharge portion 94 and the opening 92 and located near the Coanda face C and the slit 70.

Molten metal M is placed in reservoir 90 and flows out of entry port 96 as indicated by reference indicator MF in FIG. An example is a car power flow.

Exhaust port 96 is arranged so that molten metal is directed near Coanda surface C and resides at or near location J. The molten metal flows past IL and the scum flows GF and E start at position J and mix separately from each other.
Separate FG. The exhaust port is vertically connected to create the most efficient operation of the device - the Coanda surface C near location J for suction into the molten metal at the corner.
It is oriented in relation to the posture of the person.

As mentioned above, the size, shape and location U of the discharge port 96, flow MF are shown in FIG. selected to be influenced by. Appropriate dimensional spacing and flow parameters for flow MF and discharge port 96 are determined according to appropriate and desired flow MC considerations. and determined in accordance with the teachings provided by the relevant prior art material.
, because the metal in stream MF is denser than the fluid in stream GF, and because of the placement of the evacuation ports associated with Coanda surface C, the flow GF influenced by the Coanda surface portion 50 intersecting the metal flow is As shown in the figure, a protective layer of gas GL is contained between the molten metal stream MF and the Coanda surface C without creating a protective layer. Due to the presence of molten metal flow MC, flow GF
and EFG's previously discussed mixing is prevented from occurring at or near location J. However, the flow of the three fluids is subject to normal cooling parameters such as pressure, temperature, coefficient of friction, and the like as well as the physical properties of flow and flow.
Flow G until position B3 is reached by three flows at
F and EFG continue along the crossroads - C flow G
7 combinations of F and EFG are later, 7, and this one 1
After this, the flow GF and EFG will be mixed later, but there is no interference.

Due to the effects of gravity, flow separation effects, and the like]
Thus, fluid streams GF and EFG are optimally mixed at position B. This ratio between fluid GF and EFG is
A particle flow PF occurs as the molten metal flow MC breaks into a large number of particles P flowing in a direction and at a velocity O determined by conventional fluid theory. This rupture may occur quickly or gradually depending on flow parameters and the like. However, it is understood that location B may be a zone and the break may be gradual. The distinct delimitations shown in FIG. 2 for locations J and B are not intended to be limiting, as will be understood by those skilled in the art.

The entire process is managed within a container 100 that has an associated reservoir (not shown) to collect the particles. Container 100 is shown partially removed to show the presence of a suitable reservoir underneath device 10. Container 100 is also filled with a suitable gas at a suitable pressure and temperature to establish the desired flow EFG for the ambient gas. The gas within container 100 is ambient gas in such cases.

The various shapes and dimensions for the Coanda surface C, pressure and other parameters for the EFG as well as the fluid flows MF and GF will affect the production rate of the particles P as well as the production rate of the particles P.
can be selected to establish the desired particle size and shape. The pressure, temperature, physical parameters, and other state characteristics and flow-affecting parameters of both fluids as well as the molten metal flow are varied according to known theories to create the desired particles. A complete discussion of such parameter selection is available to those skilled in the art of metallurgy and/or fluid mechanics in order to determine such conditions based on the teachings provided by this disclosure. Unfortunately, standard related substances can be investigated, so they are not given here.

The process thereby establishes the stream EFG and then the stream M
The flow of establishing F begins by establishing GF.

Even if the flow MF is generated at °C, the process of riding the flow EFG is continuous, because it creates the above-mentioned frictional effect on the flow sheet of the MF, and its Jf: friction effect is equal to the flow EF
G is also the first to be established between the flows MC and EFG. The direction of flow gradient EFG remains misdirected even if flow MC is present because flows GF and EFG still tend to mix. The previously discussed principles as well as agitation and fluid moments cause this continuous nodding mixing of flows GF and EFG. Thus, once started, the process continues to produce metal particles P.

Dedicated hardening means or the like may be included to transform the particles P into suitable metal particles. Other means may also be used without departing from the scope of this disclosure.

The required quenching is achieved by using a time optimization of the particles P in the surrounding fluid used as a source of the stream EFG.

In summary of this disclosure, the present invention provides an improved direction for forming individual particulate metals from metals using the Coanda effect. Modifications are possible within the scope of this invention.

[Brief explanation of drawings]

FIG. 4 is a perspective view of an apparatus constructed in accordance with one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line 2--2 in FIG. 10... Device 12... Housing 14.
...Top 16...Bottom 18...Side part
20...Side part 22...Flat rear wall 30.
...Front part 32...Top part 36...Bottom part 4
0...end edge 42...chamber 50...
Outer surface 52... Surface 60... Gap
64...Rip 70...Slit 90...
Reservoir 92... Thread 94... Discharge portion 96... Discharge boat 100... Container patent applicant Teledyne Industries. Incorporated representative attorney Wakabayashi Tadashi procedure amendment (self-motivated) July 1930/[l Patent Office 1 (Government 1, Chuo Ino 1 display Showa (II 3 '7 6"Jl)
,'lIl+(11th 2091J7shioυ3, Sodeichi wo I3 ゛11i'1 Relationship with Applicant TE L-gain rnstries, Inchoho L・1
-7-7NoI・4, Agent address: 8th floor, Kowa Building 16, 9-20, Akasaka 1-chome, Minato-ku, Tokyo, , s, FTllt's 1st agent 46. 1i11: Clarify j! 11. fl, 1, 1 person) out i1. +lOne person's assignment □'s finger and Figure 11
'llc+ Contents of 6 volumes 11'
11.・Submitted 67 letters and translations-4
Ru. Heat (:2) 11Y as shown in the attached sheet i'+li
+l', -4ru, -1t31 +1 Submit formula drawing.

Claims (6)

[Claims] 1. In a method for breaking a stream of molten metal into droplets and solidifying the droplets to produce metal particles, a first fluid stream along a Coanda surface and a first fluid stream for flowing in a direction transverse to the first fluid are provided. With the flow of the first fluid affecting the two fluids, the second fluid is positioned adjacent to the Coanda surface so that the intersection of the first and second fluids occurs later but does not impede the flow of the first and second fluids. the first and second fluids at an intersecting location where the first and second fluids intersect and mix to flow the molten metal adjacent to the Coanda surface between the first and second fluids and thereby break the molten metal stream into metal particles; A method for producing metal particles characterized by flowing two fluids. 2. J) Method according to claim 1, characterized in that the first and second fluids are gaseous. 3. 3. A method as claimed in claim 1 or 2, characterized in that the molten metal flow is in the shape of a bath molten metal. . 4. Claims 1 to 3 characterized in that the molten metal intersects the flow of the first and second fluids at a location where the first fluid first affects the second fluid. Method described. 5. In an apparatus for carrying out a method for producing metal particles,
a Coanda surface (C) defining one external surface of the gas chamber (12), directing the first fluid flow along the Coanda surface (C) to influence a second fluid flow towards the intersection with the first fluid; a slit opening adjacent the upper end of the Coanda surface (C) for forming, and first and second slit openings for leaving behind but not impeding the intersection of the fluids and for fracturing the molten metal to form metal particles; Apparatus for the production of metal particles characterized by a reservoir (90) of bath molten metal for forming a stream of molten metal for introduction into a fluid. 6. Apparatus characterized in that the reservoir (90) comprises an elongated discharge portion (94) of the reservoir forming the molten metal in the form of a sheet.