Title:
APPARATUS FOR FABRICATING CONTINUOUS ELONGATED COMPONENTS
United States Patent 3744946


Abstract:
Apparatus for processing an elongated component characterized by being shrinkable upon sintering or reducting and sintering in which the elongated component passes through sintering and/or reducing and sintering furnace means in a manner so that the elongated component will pass through the furnace means without producing substantial buckling or fracturing of the elongated component.



Inventors:
LANG E
Application Number:
05/189709
Publication Date:
07/10/1973
Filing Date:
10/15/1971
Assignee:
NATIONAL STANDARD CO,US
Primary Class:
Other Classes:
419/3, 425/72.1, 425/73, 425/378.1
International Classes:
B22F3/00; B22F3/20; (IPC1-7): B22F3/16; B29F3/06
Field of Search:
425/122,79,378,384,387,72,73,449 164
View Patent Images:
US Patent References:
3608138N/A1971-09-28Marcovitch
3358743Continuous casting system1967-12-19Adams
3293692Apparatus for forming rigid porous metal body1966-12-27Rosenbaum
3149372Electromagnetic apparatus1964-09-22Stinger
3010148Rolling mill1961-11-28Dasher



Primary Examiner:
Spicer Jr., Robert L.
Parent Case Data:


RELATED U.S. APPLICATION

This application is a continuation-in-part of my pending application Ser. No. 41,912 filed Jun. 1, 1970.
Claims:
The invention claimed is

1. In a continuous extrusion apparatus the combination of furnace means comprising tube means extending therethrough, said tube means having an inlet at one end thereof and an outlet at the other end thereof, an extruder assembly ahead of said inlet of said tube having a die through which a continuous extrudate characterized by being subject to shrinkage when passing through said furnace means is fed into the inlet of said tube means, feed roll means for receiving the extrudate from the outlet of said tube, and means for driving said feed roll means and thus said extrudate at a speed relative to the speed of said extrudate at the extruder less the amount of the shrinkage of the extrudate through said furnace.

2. The apparatus of claim 1 for use with an extrudate composed of a metal compound compact subject to shrinkage when reduced and sintered characterized by said furnace means comprising heater means for reducing and sintering the extrudate, and means for supplying a reducing atmosphere to said tube means.

3. The apparatus of claim 1 for use with an extrudate composed of fine size metal particles and a lubricant characterized by heater means for evaporating the lubricant, means for supplying a protective atmosphere into said tube means to prevent ignition of the fine size metal particles, and heater means for sintering the extrudate in said tube means.

4. The apparatus of claim 1 in which said tube means extends on a straight line inclined downwardly from the extruder assembly at the inlet of said tube means through the outlet of said tube means.

5. The apparatus of claim 2 comprising a starter bar having a trailing end at said die for engaging the leading end of the extrudate from the die of said extruder assembly and extending through said tube means with its leading end extending out of the outlet of said tube means, and said feed roll means including control means for controlling the linear speed of said starter bar to compensate for the shrinkage of the extrudate in said tube means.

6. The apparatus of claim 3 comprising a starter bar having a trailing end at said die for engaging the leading end of the extrudate from the die of said extruder assembly, and said feed roll means including control means for maintaining the extrudate under compression in said tube means.

7. The apparatus of claim 1 in which said tube means is inclined upwardly through said furnace from the extruder assembly at the inlet of said tube means at the inlet of said furnace, and said tube means having an outer end portion extending downwardly at the outer end of said furnace means.

8. The apparatus of claim 7 characterized by the provision of endless conveyor means having a run extending through said tube means for receiving the extrudate from the die of said extruder assembly, and drive means for the conveyor means for moving the same through said tube means at a predetermined linear speed.

9. The apparatus of claim 7 for use with an extrudate composed of a metal compound compact subject to shrinkage when reduced and sintered characterized by a starter bar having a trailing end at said die for engaging the leading end of the extrudate from the die of said extruder assembly and extending through said tube means with its leading end extending out of the outlet of said tube means, and said feed roll means including control means for controlling the linear speed of said starter bar to compensate for the shrinkage of the extrudate in said tube means.

10. The apparatus of claim 7 for use with an extrudate composed of fine size metal particles and a lubricant comprising a starter bar having a trailing end at said die for engaging the leading end of the extrudate from the die of said extruder assembly, and said feed roll means including control means for maintaining the extrudate under compression in said tube means.

11. The apparatus of claim 7 including control means for the drive means for the conveyor and control means for the feed roll means at the outlet of said tube means for effecting uniform linear speed of movement of said conveyor means and the linear speed of movement of said extrudate at feed roll means after passage of said starter bar through said feed roll means.

12. The apparatus of claim 10 including control means for the drive means for the conveyor and control means for the feed roll means at the outlet of said tube means for effecting uniform linear speed of movement of said conveyor means and the linear speed of movement of said extrudate at feed roll means after passage of said starter bar through said feed roll means.

13. An apparatus for heat treating an elongated component, the combination of furnace means comprising tube means extending therethrough, said tube means having an inlet at one end thereof and an outlet at the other end thereof, means ahead of said inlet of said tube for forming a continuous elongated component characterized by being subject to shrinkage upon passing through said furnace means for feeding into the inlet of said tube means, feed roll means for receiving the continuous elongated component from the outlet of said tube means, and means for driving said feed roll means and thus said extrudate at a speed relative to the speed of said extrudate at the extruder less the amount of the shrinkage of the extrudate through said furnace.

14. The apparatus of claim 13 characterized by said furnace means comprising heater means for reducing and sintering the continuous elongated filament, and means for supplying a reducing atmosphere to said tube means.

15. The apparatus of claim 13 for use with a continuous elongated component composed of fine size metal particles and a lubricant characterized by heater means for evaporating the lubricant, means for supplying a protective atmosphere into said tube means to prevent ignition of the size metal particles, and heater means for sintering the continuous elongated component in said tube means.

16. The apparatus of claim 13 in which said tube means is inclined upwardly through said furnace from the means for forming said continuous elongated component at the inlet of said tube means at the inlet of said furnace, and said tube means having an outer end portion extending downwardly at the outer end of said furnace means.

17. The apparatus of claim 16 characterized by the provision of endless conveyor means having a run extending through said tube means for receiving the continuous elongated component from the means for forming the same, and drive means for the conveyor means for moving the same through said tube means at a predetermined linear speed.

Description:
BACKGROUND OF THE INVENTION

In the fabrication of continuous elongated components such as wire, tubing or strip formed, for example, by forming means such as an extruder for extruding a body composed of small metal particles, with or without a binder, through a die for passage through a sintering or reducing and sintering furnace means, it is essential that the continuous component in passing through the furnace means does not buckle to any substantial extent or fracture when reduced and sintered. After sintering of such elongated component, it is of good mechanical strength and no longer is it necessary to carefully handle the elongated component.

One typical metal compound compact with which the present invention may be employed was produced in the following manner. The by-product iron oxide, from spent pickle recovery was milled in a conventional manner until 50 percent of the iron oxide particles were less than 8/10 th microns and 50 percent being in a range of from 8/10th microns to 10 microns. The aforementioned micron sizes were determined by a Coulter Counter measurement and it is to be understood that the expression "particle size" as used herein means size as determined by coulter counter measurement. A binder was then prepared by adding 15 grams of corn starch to 100 milliliters of water and heating the solution to 160° F until a gel was formed. Then 4.2 grams of this binder was added to 22.7 grams of the milled iron oxide powder, and the combination was then mixed intimately in a mix-muller. The mixture of iron oxide and binder was then put into the cavity of an extrusion die having an opening of 0.115 inches in diameter and a pressure of 12,000 p.s.i. applied which formed an elongated green metal compound component of nominal mechanical strength. A green metal compound component of the character noted may be introduced into furnace means having a reducing section providing an atmosphere of hydrogen at a temperature of about 1,100° F for a period of 30 minutes, and then a sintering section in which at a temperature of 2,100° F for about 60 minutes effects sintering of the extrusion.

The present invention also has utility for utilization with tubing formed from a green metal compound elongated component made from the same formulation as to the wire component above described but extruded through a conventional tube forming die to form a tubular green metal component having an outside diameter of 0.115 inches and an internal diameter of 0.065 inches. Such tubing may be reduced and sintered by subjecting the same in a furnace in a hydrogen atmosphere at 1,100° F for 30 minutes to effect reduction of the green metal component, and then subjecting the elongated extrusion to sintering in the sintering section of the furnace at a temperature of 2,100°*20 F for a period of 60 minutes.

It will be understood that the foregoing examples are only illustrative of the class of extruded metal compound compacts that require reducing and sintering with which the present invention has utility. It is characteristic of the foregoing metal compound compacts that they shrink a substantial extent upon reduction and/or sintering.

The apparatus of invention also has utility for use with elongated green metal components formed by forming means other than an extruder. By way of example, elongated components of metal compound compacts may be formed into green preforms for elongated components by depositing slurry-like metal compound compacts upon forming means having a surface in which at least one longitudinally extending groove is formed for receiving the slurry material so that the slurry material is shaped to form at least one elongated component and set therein. The groove of the forming means is fabricated of material from which the shaped and set material in the groove may be easily separated from the groove without fracturing the shpaed and set material, and then reducing and/or sintering the shaped and set material as aforedescribed.

The slurry material for the purposes last noted may be composed, in part, of a reducible metal compound such as metal oxide powder which may be reduced and sintered to provide metal wire. The metal oxide compound powders of the slurry material may comprise oxide particles of which at least 35 percent are of a particle size of 10 microns or less as determined by coulter counter analysis. Thus the particle size distribution will be considerably below the maximum 35 percent under 10 microns, and may have a means particle size no greater than about 6 microns and at least 25 percent by weight, the particles will be below 2.5 microns in diameter. Optimum results are obtained when the apparent average particle of the powder is less than one micron in diameter.

That the average particle is less than one micron in diameter may be determined by coulter counter measurement where agglomeration is not a factor. However, where the particles tend to agglomerate, accurate particle size determination by means such as coulter counter measurement is not possible. It has been found, however, that such determination may be made by surface area determination. By determining the total surface area of a given powder one can readily deterimnie the average particle size if one assumes perfectly smooth, spherical particles. Such determination may be made through the utilization of the formula:

D = K/d × SA

where

D = average diameter in microns of perfect spheres

K = the constant 6

d = density in grams per cubic centimeter

SA = surface area of the particles in square meters per gram.

For example, if one determines the surface area of iron oxide (Fe2 O3) to be 5 m 2 /g and the density to be 5.24 g/cc then:

D = 6/5.24 × 5

or

D = 0.23 microns

There are a number of known means for determining the surface area of powders each differing to some extent in results. It is found that the BET method developed by Dr. Paul Emmet and his associates in the late 1930's for use in measuring the available surface area of catalysts to be the most reliable for determining the surface of metal compound powders.

In the BET method the surface of the particles is coated with a monomolecular layer of adsorbed gas. This is accomplished by passing a known quantity of gas, such as nitrogen, through a measured specimen at the boiling point of the gas (-195° C for nitrogen). Under these conditions the gas molecules form a tightly packed monomolecular layer on the surface of the specimen. A determination of the gas consumed by the specimen by monomolecular adsorption as compared to standard specimens readily yields a relatively accurate determination of the surface area of the powder.

For purposes of the foregoing, particle size determination of less than one micron shall be interpreted in accordance with BET measurements.

A suitable slurry material for forming a continuous elongated green metal component may be composed of the aforementioned oxide powders together with a binder to provide the slurry material of a consistency to enable the ready deposit of the slurry material onto a grooved belt. A typical binder for iron oxide powder of the particle size range aforenoted may be a PVA-glycerine binder composed of a mixture of polyvinyl alcohol and glycerine in a 80 to 20 ratio mixed with the oxide powder to provide a slurry material of a consistency enabling its deposition onto the forming means as described to fill the groove in the forming means on the belt.

Upon deposition of slurry material as aforenoted the separated and set green metal elongated component is subjected to reduction and sintering to form elemental wire. Typically, the separated and set green metal elongated component may be suitably passed through a reduction and sintering furnace in which the reduction is effected in an atmosphere of hydrogen at about 1,000° F for 5 minutes, and sintering at a temperature of about 2,100° F for about 5 minutes. It will be understood that the reduction and sintering time is dependent on the size and cross section of the material being treated.

In addition to the foregoing example of a slurry material suitable for fabricating metal wire, it will be understood that the apparatus of the present invention is applicable to any reducible metal compound, particularly those susceptible to reduction with hydrogen which have standard free energies of reaction with hydrogen less than about +15 kilo calories (per atom) of hydrogen at the reduction temperature. The metal compounds of particlar interest in connection with the foregoing are the metal oxides such as the oxides of Fe, Co, Ni, Cu, Mo, and W, and combinations thereof.

Although the use of hydrogen to provide the environment for reducing the foregoing slurry materials to elemental metal is preferred, other reducing materials may be employed. For example, the above recited metal compounds, and particularly iron oxide, can be reduced by partially or wholly substituting carbon monoxide for the hydrogen reducing environment.

Any metal compound powders having particles of any general shape (i.e. spherical, oblong, needles, or rods, etc.) and originated from any source (i.e. ore deposits, or concentrates, precipitates, etc.) may be employed in providing the slurry material for the present invention for forming elongated green metal components, for example in a groove of an endless belt, and subsequent reduction and sintering.

The sintered elongated component so derived will possess a substantially pore free structure, a smooth surface and can be made to exhibit densities in excess of 90 percent of completely dense material.

It will be understood that the foregoing examples are only illustrative of metal compound compacts that shrink when reduced and/or sintered, and that the apparatus of the present invention has utility for the many other materials of the class that shrink when reduced and/or sintered.

The apparatus of the invention further has utility in the powder metallurgy art in which a body of material consisting essentially of metal of fine particle size is formed as afore described in the from of wire, tubing or strip, but which need only be sintered to render the extrudate of good mechanical strength to provide a satisfactory end product.

THE INVENTION

The invention comprehends the formation of an elongated component of the foregoing noted character into the entrance of suitable furnace means together with the provision of feed roll means at the exit of the furnace means rotationally driven at a speed equal to the linear speed of the elongated component at the exit of the furnace means.

In one form of the invention, suitable for utilization with the aforedescribed metal compound compact containing reducible metal particles, the elongated component is of sufficient green strength to be self-sustaining in passing through a reducing and sintering furnace means on a straight line inclined downwardly from the extruder to provide during passage of the elongated component therethrough to allow for the resulting shrinkage of the elongated component without substantial buckling or fracturing thereof, and in which at the exit of the reducing and sintering furnace means is engaged by the aforementioned feed roll means operating at a rotational speed equal to the linear speed of the elongated component, and which feed rolls may typically provide for feeding the reduced and sintered elongated component onto a take-up reel.

In other forms of the invention applicable for elongated components of the above described metal compound compacts or bodies of fine particle sizes of metal, one end of a starter bar or wire for starting up the apparatus is inserted into the leading portion of the elongated component and extends through the furnace means with its other end wound around a take-up reel. The aforementioned feed roll means is in driving engagement with the end of the starter bar or wire projecting outwardly of the exit end of the furnace for effecting movement of the starter rod or wire through the furnace. Known conventional variable speed drive means is associated with the feed roll means to dirve the feed roll means at a speed to compensate for the shrinkage in the reducing and sintering of an extruded body of fine metal particles under compression so that upon reducing and sintering of the former, and sintering of the latter, the elongated component at the outer end of the furnace means is of the substantial mechanical strength for an end product such as wire, tubing or strip.

IN THE DRAWINGS

FIG. 1 is a largely diagrammatic view of one form of apparatus of the invention for utilization with reducible metal compound compacts;

FIG. 2 is a largely diagrammatic view of another form of apparatus of the invention which may be utilized with reducible metal compound compacts or extruded bodies of fine metal particles showing a starter rod in initial position in starting up the apparatus;

FIG. 3 is a view similar to FIG. 2 but showing an advanced position of the starter rod in the furnace means of the apparatus;

FIG. 4 is a diagrammatic sectional view of another form of apparatus of the invention in which a starter rod is employed for initially starting up the operation of the apparatus;

FIG. 5 is a side elevational view similar to the apparatus of FIG. 4 but embodying conveyor means for conveying a starter rod and subsequently an extrudate through suitable furnace means;

FIG. 6 is a side elevational view of a portion of one form of conveyor suitable for use with the apparatus of FIG. 5;

FIG. 7 is a detail vertical sectional view taken along the line 7--7 on FIG. 6 looking in the direction indicated by the arrows;

FIG. 8 is a largely diagrammatic view of another form of apparatus for forming an elongated component for practicing the present invention; and

FIG. 9 is a plan view of a portion of the appartus shown in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

Referring now to FIG. 1 the appartus of the invention there shown comprises furnace means 5 having a conventional extruder assembly 6 at the upper end thereof and feed roll means 7 at the lower end thereof. The furnace means 5 includes a cylindrical tube 8, and embodies a reducing section 10 and a sintering section 12 heated by conventional heaters as diagrammatically indicated at 14. The extruder assembly 6 includes a die, as at 16, which is provided with an appropriate die orifice for forming a metal compound compact contained in chamber 17 typically of the composition above described, into desired configuration such as wire, tubing or strip. The extruder head assembly includes any suitable known extruder screw or plunger (not shown) for forcing the material in the chamber through the die orifice at the entry end of the furnace means 5. As shown, an inlet, as at 20, for reducing gas, such as hydrogen, is provided at the lower outer end of tube 8, and a reducing gas outlet for the tube 8 is provided at the upper end thereof as at 22, and at which the escaping reducing gas may be burned off during operation of the apparatus.

A take-up reel 25 driven by suitable known varible drive means 26 serves to receive the extrudate from the feed roll means 7 to accumulate the reduced and sintered extrudate. It will be especially noted that the tube 8 within the furnace means is inclined downwardly away from the extruder assembly 6 to the feed roll means 7 on a substantially straight line.

In operation of the foregoing described apparatus the extrudate from the die orifice of die 16 enters the entry or upper end of tube 8 of furnace means 5. The extrudate is of sufficient green strength to pass along an inclined straight line through the tube 8 extending downwardly from the extruder assembly 6 to the feed roll means 7 with gravity acting to prevent buckling or fracturing of the extrudate. As the extrudate passes through the tube 8 it is first reduced and then sintered with considerable shrinkage taking place. At the exit end of tube 8 the extrudate after being reduced and sintered is of substantial mechanical strength and is no longer subjected to substantial shrinkage. Thus, at the exit end of the tube 8 the feed roll means 7 is driven at a rotational speed equal to the linear speed of the extrudate thereat for coiling onto the reel 25. The inclined path of travel of the extrudate through the furnace means 5 is such that the extrudate will pass through the tube 8 without producing substantial stress upon the extrudate. In view of the shrinkage characteristics of the metal compound compact the feeding rate of the metal compound compact at the extruder is obviously greater than the rate of linear travel of the extrudate at the exit end of tube 8.

Referring now to FIGS. 2 and 3 there is shown another embodiment of the present invention having utility for use with the aforedescribed typical metal compound compacts or of bodies of material consisting essentially of metal of fine particle size commonly employed in the powder metallurgy art.

The parts of the apparatus of FIGS. 2 and 3 common to the parts of the apparatus described in connection with FIG. 1 bear the same reference numerals as described in connection with FIG. 1. However, in the apparatus of FIGS. 2 and 3, feed roll means, as indicated at 30, include known variable speed drive control means 32 for controlling the speed of rotation of the feed rolls 33.

As will be seen in FIG. 2, a starter rod or wire 35 has its upper end 36 extending into the die orifice of the die 16. The lower end portion of the rod or wire 35 is wrapped around the take-up reel 25 in sufficient amount to anchor it to the reel 25. Assuming the material extruded through the die 16 is of the aforegoing described metal component compound compact, operation of the extruder assembly 6 forces the material from the chamber through the die, and the feed roll means 30, by the variable drive control means 32, is energized so that the rate of travel of the starter rod or wire 35 is such as to compensate for the shrinkage of the metal compound compact as it is reduced and sintered in passing through furnace means 5 as before described. When the extrudate reaches the lower open end of the tube 8 the variable drive controlling means 32 has been adjusted so that the rotational speed of feed rolls 33 substantially equals the linear speed of the extrudate thereat for delivery to the take-up reel 25.

In utilizing the apparatus of FIGS. 2 and 3, in which the chamber contains a body of material consisting essentially of metal particles of fine particle size, and without a binder, the starter rod of wire 35 is programmed through the variable drive means 32 of feed roll means 30 to maintain the extrudate through the die and the furnace means under compression. In most instances, bodies of material of the character last noted only requiring sintering to provide the extrudate with sufficient mechanical strength to be self-supporting and adequate for the desired end use of the formed extrudate. Thus in sintering such an extrudate formed from a body consisting essentially of metal particles of fine size, a reducing atmosphere is not necessarily employed and the heater means indicated at 14 need only be energized to effect sintering of the extrudate. However, as is conventional the upper end of the furnace may constitute a lubricating evaporation section and a protective gas to prevent ignition of the fine metal particle may be passed through the furnace means through the inlet and outlet pipes 20 and 22. The feed roll means 30 is controlled so that the feed roll means 33 feed the sintered extrudate onto the take-up reel 25.

Referring now to FIG. 4 the embodiment of the invention therein shown comprises furnace means 40 suitable for use with the aforedescribed metal compound compact or a body of material consisting essentially of metal of fine particle size. A tube 42 extends through the furnace means 40 and an extruder assembly 43 is arranged at the inlet end of the tube 42. As shown in FIG. 4 the furnace means 40 and tube 42 are inclined upwardly from the extruder assembly 43 with the tube 42 at the outer end thereof being formed with a curved end 45 extending vertically downwardly providing an outlet as at 46. Heater means 47 are embodied in the furnace and gas inlet and outlet tubes 48 and 49 are provided, respectively, at the lower and upper ends of the furnace means 40. A starter rod 50, as before, is initially disposed into the die opening at the discharge end of the extruder assembly 43 and passes through the tube 42 between a pair of feed rolls 51 of feed roll means 52 which also embodies variable speed control means 53 for controlling the rate of rotation of the feed rolls 51. In the position of the parts as shown in the drawing, the feed rolls 51 under the control of the variable speed drive means 53 has advanced the starter rod 50 to the position shown at a rate to provide or compensate for the shrinkage of the extrudate from the die of the extruder assembly 43. When the extrudate is composed of the foregoing described metal compound compacts, a reducing atmosphere may be admitted through the inlet 48 and exited at 49 and with the heaters 47 being energized to first effect reduction of the extrudate followed by subsequent sintering of the extrudate. Thus, when the extrudate reaches the feed rolls 51 the feed roll means 52 has been suitably controlled so that the roational speed of the feed rolls 51 substantially equals the linear speed of the extrudate leaving the exit end of the tube 42.

Referring now to FIG. 5, the embodiment of the invention there shown comprises furnace means 40, tube 42, heater 47 and pipes 48 and 49 as described in connection with FIG. 4. The apparatus of FIG. 5 is suitable for use with the aforedescribed metal compound compacts or a body of material consisting essentially of metal of fine particle size.

In the apparatus of FIG. 5, however, conveyor means indicated at 60 is supported on suitable drive and guide rollers 63 and 64, respectively, and provides an upper run 65 for passage through the tube 42. An extruder assembly 66 is disposed adjacent the inlet opening of the tube 42 having a suitable die for the disposal of a continuous elongated extrusion onto the conveyor at the linlet of tube 42. A starter rod or bar initially has its inner or trailing end disposed into the die opening of the extruder assembly 66 for purposes aforedescribed.

The outer or leading end of starter bar or rod 70 passes through the exit end of the tube 42 and as shown the leading end of the starter bar or rod passes between feed rolls 72 of feed roll means 74 including variable speed control means 75 for controlling the speed of rotation of the feed rolls 72.

The feed roll means 63 also includes variable known speed control means 77 with the arrangement being such that the feed roll means 63 drives the conveyor 65 at the rate of an extrudate composed of a metal compound compact onto the conveyor from the extruder assembly 66. The feed roll means 74 through the variable speed control means 75 provides for rotation of feed rolls 72 at the same rate as the travel of the conveyor in the initial starting up operation thereof so that the starter bar is fed outwardly away from the lower end of the tube 42 at the same linear rate as the conveyor. After initial starting up of the apparatus the feed roll means 74 is driven at a controlled rate so as to equal the linear speed of the extrudate as it passes out of the lower end of the tube 42.

In operating the apparatus of FIG. 5 with an extrudate from the extruder assembly 66 composed of metal of fine particle sizes the extrudate is maintained under compression. Again the heater 47 may be energized for evaporating a lubricant for the extrudate and for sintering the extrudate in the furnace. As before, a protective gas may be circulated through the tube 42 through the pipes 48 and 49. The aforedescribed conveyor 65 may be of a construction as shown in FIGS. 6 and 7 defined by a plurality of serially connected links of heat resistant material as shown at 90 in FIGS. 6 and 7. The links at one end are formed of spaced apart lugs as at 91 between which a lug 92 of an adjacent link 6 is disposed. A pin 93 extends through the several lugs to provide a pivotal connection at the ends of adjacent links to enable the links to pass around the drive and guide rolls of the last described apparatus. The several links are formed with a U-shaped groove as at 94 which, when the links are abutted as when passing through the reducing and sintering section of the furnace, form a continuous groove to receive and support the starter bar and the extrudate from the extruder. The drive and guide rolls are formed with suitable spaced apart transverse grooves to receive the several pins 93 for driving and guiding the endless conveyor through the described apparatus.

It is believed that it will be apparent that the last described apparatus as shown in FIG. 5 may be operated to reduce and sinter a metal compound compact such as above described, or the arrangement is adaptable in the manner already described for utilization with material from the extruder consisting of metal of fine particle size with the pipes 48 and 49 in the reducing and sintering operation serving for supplying a reducing gas to the section of the tube 42 within the furnace or, in the sintering of material consisting essentially of metal of fine particle size for the introduction of a protective atmosphere to prevent ignition of an extrudate of metal of fine particle sizes.

In FIGS. 8 and 9 there is illustrated an apparatus embodying forming means 100 in lieu of an extruder as shown, for example, in FIG. 5, at 66 for forming and delivering elongated components of the metal compound commpact as aforedescribed to the inlet of furnace means 40. The reference numerals applied to the furnace means of FIG. 8 are the same as those aforedescribed in connecton with FIG. 5 and need not be repeated here. The forming means 100 may, by way of example, be in the form of an endless belt means 102 mounted between a pair of spaced apart end roller means, only one of which is shown at 103, which may constitute a drive roller for the endless belt means 102 which may be driven by drive chain 104 extending between the drive roller means 103 for the endless belt means 102 driven off the drive gear 105 keyed to the shaft 106 of the endless belt means 102 from left to right as viewed in FIGS. 8 and 9. The endless belt means 102 is formed with at least one indentation, such as a continuous groove 108, which may be of any desired cross sectional configuration. Hopper means 107 is suitably supported above the upper run of the endless belt means 102 by conventional means, not shown, for depositing the aforementioned metal compound compact material upon the belt for filling the groove 108 in the belt. Doctor blade means 110 may be supported in any suitable manner downstream from the hopper means 107 to assure filling of the groove 108 with the metal compound compact material. Downstream of the doctor blade the upper run of the endless belt means 102 passes through heater means, as at 112, so as to set the material in the groove of the endless belt when heat is required for setting. After passage of the upper run of the endless belt 102 through the heating means 112, the set material in the groove 108 is discharged from the endless belt means at its discharge end directly onto the conveyor belt 60 of furnace means 40 in which the elongated component is processed as described in connection with FIG. 5.

The endless belt means 102 is preferably fabricated of the material from which the formed and set green metal elongated component may be readily separated from the groove without fractruing, for example, a material having low adhesive characteristics such as Teflon or polyethylene.