US2338781A

US2338781A - Method and apparatus for continuously casting metal

Info

Publication number: US2338781A
Application number: US440370A
Authority: US
Inventors: Ralph B Porter
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-04-24
Filing date: 1942-04-24
Publication date: 1944-01-11
Anticipated expiration: 1961-01-11

Description

Jan. 11, 1944. R. B. PORTER METHOD AND APPARATUS FOR CONTINUOUSLY CASTING METALS Filed April 24 1942 2 Sheets-Sheet l INVENTOR PAL PHB. PORTER METHOD AND APPARATUS FOR CONTINUOUSLY CASTING METALS 1942 2 Sheets-Sheet 2 Filed April 24 INVENTOR ZQAL PHB. pop 759,

IVIVIIIIII Patented Jan. 11, 1944 BIETHOD AND APPARATUS FOR courrmn- OUSLY CASTING METAL Ralph 13. Porter, Johnstowmra. Application April 24, 1942, Serial No. 440,370

Claims;

This invention relates to the continuous casting of metal, and more particularly to the direct formation from molten metal of billets and bars of the desired cross-sectional contour.

It is among the objects of the present invention to reduce as much as possible the number and magnitude of operations necessary to produce metallic billets and bars of relatively small cross-sectional area.

Heretoi'ore there have been proposed a number of methods and apparatus for the continuous casting of molten metal into small ingots, billets, or bars of desired cross-sectional contour (i. e., round, square, oblong, or other shape) and of continuous, and therefore indefinite, length. Such methods and apparatus involve the continuous shaping of the liquid metal into cast forms of desired cross section, and the removal or dissipation of heat from the metal in order to obtain solidification. So far as I am aware,

the practices of the prior art have required the use of complex apparatus which is difllcult and expensive to maintain, whereby the resultant product has been characterized by high cost of production.

Another difliculty inherent in the practices of the prior art is that the resultant product does not possess the proper surfacecondition to permit of its being used in suflicient quantity to render operations commercially feasible.

The invention, then, comprises the features hereinafter fully described and as particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail a certain illustrative embodiment of the invention, this being indicative of one of the number of ways in which the principles of the invention may be employed.

In said drawings:

Figure 1 is an elevational view of the apparatus of the present invention, parts thereof being illustrated in section.

Figure 2 is a fragmentary sectional elevation illustrating some of the upper parts of the apparatus, particularly the compression chamber, compacting apparatus, extrusion chamber, moldforming mandrel, and teeming apparatus.

Figure 3 is a sectional view on the line IIIIII of Figure 2.

Referring more particularly to the drawings, the numeral 2 designates a horizontal pouring platform from which there depends a substantially vertical cylindrical housing 3 which comprises a compression chamber within which there is continuously formed a refractory mold of mold sand or other suitable granular material. Such granular mold material may comprise a mixture of foundry sand with the usual binding materials (1. e., flour, bentonite, and molasses). This compression chamber 3 carries in vertical dependency a cylindrical housing 4 of reduced diameter which connects and communicates therewith through a reducing section 8 of inverted frusto-conical shape. The lower cylindrical housing 4 comprises an extrusion chamber from which the refractory mold is continuously ejected in a manner which will be later described.

The upper end of the compression chamber 3 is provided with a closure 8 having a central aperture l in which there is carried a collar 8. The upper end of this collar 8 has a radial flange 8 which rests upon the closure 6. Disposed to extend through the collar 8 is a cylindrical tube III which carries at a position immediately below the closure 8 a radial flange Ii, between. which and the bottom of the closure 8 is an antifriction bearing l8. Secured to the upper end of the cylindrical tube l0, and resting upon the top of the radial flange 8 of the collar 8 is a bevel gear l8 through themedium of which the cylindrical tube l0 may be rotated.

Referring more particularly to Figure 2, the

cylindrical tube l0 extends through the com-.

pression chamber 8 and terminates within the reducing section 5. Formed on the periphery of the cylindrical tube i8 is a spiral screw l'l.

Granular mold material is introduced to the compression chamber 3 adjacent the top thereof through an aperture [9 which communicates with an outboard hopper 28. According to the fore,- going construction and arrangement, it will be seen that the introduction of the granular mold material into the hopper 20 and the rotation of the bevel gear l5 will result in the compacting of the mold material within the compression cham-v ber 8 and the forcing of the said compacted material into and through the reducing section 5 and extruding chamber 4. Preferably the granular mold material must not only be capable of resisting heat, plastic, and porous, but also capable of reuse. In its movement through the reducing section 5 and into the extrusion chamber 4 it is bottom 01' the cylindrical tube I0. A cylindrical tube 25 of enlarged diameter is carried on the lower end of the elongate cylindrical tube 24 through the medium of an intermediate enlarging section 21 of frusto-conical shape. The elongate cylindrical tube 24, its conical pouring funnel 25, the larger cylindrical tube 25, and the frusto-conical enlarging section 21 are continuously lined throughout with a refractory material 28 which is capable of withstanding protracted periods of contact with the molten metal to be cast.

It is to be particularly noted that the lower end of the cylindrical tube 24 terminates at the bottom of the reducing section 5. and that the larger cylindrical tube 25 and enlarging section 2'! lie within the extruding section 4. Such construction permits the spiral screw H to force the granular mold material downwardly through the compression chamber 3 and reducing section 5 before the diametrically larger portions (21-26) at the bottom of the elongate cylindrical tube 24 are encountered. This enables the desired compressing relationship prior to the movement of the compressed or compacted mold material over the diametrically larger portions of the mandrel at the bottom of the elongate cylindrical tube 24. In the manner aforesaid, thelower end of the elongate cylindrical tube 24, the expanding section 21, and the larger cylindrical tube 25 provide a mandrel which affords interior support for the granular mold material being extruded; and the mold, designated hereinafter at X, emerges from the lower end of the extruding chamber 4 with an interiorly formed cylindrical bore which forms the mold cavity or matrix.

Disposed on the pouring platform 2 is a conveyor 29 which is capable of continuously feeding the granular mold material to the hopper 20. Disposed adjacent the conical pouring funnel 25 is a motor 30, and an associated speed reducer 3| having a driven bevel gear 32 which meshes with the bevel gear I5 on the upper end of the cylindrical tube Ill. The motor 30 thus continuously rotates the cylindrical tube It and the spiral screw I'I within the compression chamber 5, while the granular mold material is continuously teemed into the conical pouring funnel 25 and flows through the refractory lining 23 which extends through the bottom of the cylindrical tube 26 and into the cylindrical matrix provided in the refractory mold X which is continuously extruded from the bottom of the extruding chamber 4. At the beginning of the teeming operation a refractory plug (not shown) is disposed in the cylindrical matrix of the extruded refractory mold X, and as the said refractory mold moves out of the lower end of the extruding chamber 4, molten metal is teemed into the conical pouringv funnel 25 at a rate commensurate with the rate of extrusion aforesaid. Thus the mold and billet move in synchronism. The porosity of the extruded mold X permits quick removal of heat from the cast metal, and the outer surfaces of the billet are quickly frozen.

' Disposed below the extrusion chamber 4 is a assure-1 tarding rolls 40. These retarding rolls are suitably shaped to accommodate the contour of the solidified billet. Above and below the retarding rolls 45 are suitable water sprays 4| which serve to chill the surfaces of thesolidified casting.

It will be understood thatas the solidified casting leaves the retarding rolls40, it may be moved in any direction and given any desired processing treatments. In the embodiment shown, a guide 43 is disposed below the retarding rolls 45, the same being constructed and arranged to' divert the downwardly-moving continuous casting into a horizontal path. Immediately beyond the guide 43 is a pair of pinch rolls 44' which direct the horizontally moving continuous casting onto a bed of carrier rolls 45. From the carrier rolls 45 the continuous casting may, for example, be transferred to a shearing mechanism (not shown) which may be used to cut the continuous casting into billets of desired length, after which the said billets may be additionally rolled with or without reheating, as desired.

It will be understood by those skilled in the art that while the continuously extruded refractory mold X and continuously cast billet within the matrix thereof are shown as being of cylindrical shape, they may take other forms such as the round, square, oblong, or other shapes referred to hereinbefore.

The method and apparatus of fire present invention may be adapted to the production of billets of tubular form by the simple device of. disposing within the conical pouring funnel 25, and to extend throughout the elongate cylindrical tube 24, a suitable mandrel (not shown) the purpose of which is to form the interior wall of the tube.

This mandrel may be provided with a slight taper throughout its length to permit shrinkage of the cast metal as it solidifies. such a mandrel might be of hollow formation and supplied with a cooling fluid introduced from above the cylindrical pouring funnel 25 and carried in interior channels throughout its length and back to a point of exit above the said pouring funnel.

Another modification contemplates the introduction of a lubricant to the inner walls of a compression chamber 3 and extrusion chamber 4. Such a lubricant could be introduced through small apertures (not shown) arranged in a horizontal plane around the said compression chamber. However, when using a molding mixture of suitable consistency, such a lubricant is ordinarily unnecessary.

conventional sand stripper 35 which removes the mold X from around the cast billet. Immediately above the sand stripper 35 is a system of water jets 35 which facilitate the stripping operation. The sand or other granular material of which the mold X is composed, after stripping, falls into a collector 31 from which it is moved by a conveyor 38 to the conveyor 29 on thepouring platform 2 which feeds the hopper 20. Disposed below the sand stripper 35 is a pair of re- While I have shown and described several specific embodiments of the present invention, it will be seen that I do not wish to be limited exactly thereto, since various modifications may be made without departing from the scope of the invention as defined in the appended claims.

I claim:

1. The method of continuousLv casting metal billets and the like, ously extruding a hollow bonded granular refractory mold, continuously teeming said mold, permitting the teemedmetal to solidify within the continuously extruded mold, and removing the continuously extruded mold from around the continuously cast billet.

2. The method of continuously casting metal billets and the like, which comprises continuteemed metal to solidify within the continuously extruded mold, and removing the continuously which comprises continue extruded mold from around the continuously cast billet.

3. The method of continuously casting metal billetsgand the like, which comprises continuously extruding ahollow bonded granular re- 5 fractory mold, continuously teeming said mold during the extrusion thereof and at a rate which I is substantially the same as the rate of extrusion, permitting the 'teemed metal to solidify within the continuously extruded mold, and removing 10 the continuously extruded mold from around the continuously cast billet.

4. The method of continuously casting metal billets and the like, which comprises continuously extruding a hollow bonded granular re- 5 fractory mold, continuously teeming said mold, permitting the tcemed metal to solidify within the continuously extruded mold, removing the continuously extruded mold from around the continuously cast billet, and chilling the said billet go after the mold has been removed therefrom.

5. The method of continuously casting metal billets and the. like, which comprises continuously extruding a hollow bonded granular refractory mold, continuously teeming said mold a during the extrusion thereof, permitting the te'exnled metal to solidify within the continuously -extruded mold, removing the continuously extruded mold irom around the continuomly cast billet, and chilling the said billet after the mold 3 has been removed therefrom. 6. The method of continuously casting metal billets and the like, which comprises continu-' ously extruding a hollow bonded granular-refractory mold, continuously teeming said mold a moving the continuously extruded mold from around the continuously cast billet, and chilling the said'billet after the mold has been removed therefrom.

7. Apparatus for continuously casting metal billets and the like comprising, in combination, means for continuously extruding a bonded granularrefractory mold, means for continuously teeming molten metal into said mold, and means for removing said mold from the cast billet after the solidification thereof.

8. Apparatus for continuously casting metal billets and thelike comprising, in combination, means for continuously extruding a bonded granular refractory mold, means for continuously teeming molten metal into said mold during the extrusion thereof, and means for removing said mold from the cast billet after the solidification thereof.

9. Apparatus for continuously casting metal billets and the like comprising, in combination,

means for continuously extruding a bonded granular refractory mold, means for continuously teeming molten metal into said mold, means for removing said mold from the cast billet after the solidification thereof, and means for chilling said billet after the moldhas been removed therefrom.

10. Apparatus for continuously casting metal billets and the likeloomprising, in combination, means for continuously extruding abonded granular refractory mold, means for continuously teeming molten metal into said mold during the extrusion thereof, means for removing said mold from the cast billet after the solidification thereof, and means for-chilling said billet after the mold has been removed therefrom.

, RAIPHEPORTER.