US3191292A - Method of producing rolled metal articles - Google Patents

Description

June 29, 1965 c. F. STROM METHOD OF PRODUCING ROLLED METAL ARTICLES 7 Sheets-Sheet 1 Filed July 16, 1963 m m m Wars 9! Miran June 29, 1965 c. F. STROM mmnon 0F PRODUCING ROLLED METAL ARTICLES '7 Sheets-Sheet 2 Filed July 16, 1963 INVENTORS. fizr/s .9 firm June 29, 1965 c. F. STROM 3,191,292

METHOD OF PRODUCING ROLLED METAL ARTICLES Filed July 16. 1963 v 7 Sheets-Sheet 3 IN VEN TORS 66 warzes 9. Mrmvn June 29, 1965 c. F. STROM 3,191,292

. METHOD OF PRODUCING ROLLED METAL ARTICLES Filed July 16. 1963 7 sh ets-sheet 4 IN V ENTORS War/2's firm June 29, 1965 c. F. STROM METHOD OF PRODUCING ROLLED METAL ARTICLES Filed July 16. 1963 7 Sheets-Sheet 5 WNW 3W mf Z,

June 29, 1965 c. F. STROM METHOD OF PRODUCING ROLLED METAL ARTICLES 7 Sheets-Sheet 6 Filed July 16, 1963 INVENTORS.

June 29, 1965 c. F. STROM METHOD OF PRODUCING ROLLED METAL ARTICLES Filed July 16, 1963 7 Sheets-Sheet 7 IN V EN TORS Kfiarls 9' tram 3,191,292 NETHOD F PRQDUCING RGLLED P/IETAL 11 Claims. (Cl. 29528) This invention relates to the production of metal articles, such as steel billets, blooms, or slabs, in pieces of desired cross-sectional dimensions and weights, directly from the molten metal and without the use of a primary mill.

This application is a continuation-in-part of my copending application Serial No. 25,498, now abandoned filed March 21, 1960 as a continuation-in-part of my application Serial No. 829,457, now abandoned, filed July 24, 1959, for Bottom Casting Articles in the name of Charles F. Strom.

According to prior art practices, steel ingots have been cast and stored in soaking pits. Such ingots have then been reheated, if necessary, and have been hot rolled in a primary mill to elongate the casting or ingot and reduce its cross-sectional area thereby forming a bloom having a length three or more times its maximum cross-sectional dimension and having a cross-sectional area not substantially in excess of 120 square inches. The blooms have then been rolled to form billets having a crosssectional area not substantially in excess of thirty six square inches and having a length three or more times the maximum cross-sectional dimension. Sometimes ingots are rolled by a primary mill into oblong slabs having a cross-sectional area of the order of from 48 square inches to 360 square inches and having a length three or more times the maximum cross-sectional dimension. Such billets and slabs have then been rolled to form commercial products such as rods, tubes and sheets.

Previous prior art attempts to eliminate ingots and the necessity for soaking pits by casting blooms, billets (including tube rounds) and/or slabs on a commercial basis have been unsuccessful, and according to the invention it has been discovered that such blooms, billets (including tube rounds) and/ or slabs can be cast by bottom pouring into an elongated graphite mold and can be directly rolled into commercial products.

For the purpose of this specification and claims, a bloom is hereby defined as a steel article having a substantially uniform cross-sectional area not substantially in excess of 120 square inches and a length three or more times its maximum cross-sectional dimension; a billet (including a tube round) is hereby defined as a steel article having a substantially uniform cross-sectional area not substantially in excess of thirty six square inches and a length three or more times its maximum cross-sectional dimension, and a slab is hereby defined as a steel article having a substantially uniform oblong cross-sectional area of from 48 square inches to 360 square inches and having a length three or more times its maximum cross-sectional dimension.

I have discovered that only the casting that can be successfully rolled directly into a commercial product, without the necessity for the previously described intervening steps, is one having an outer surface entirely free from external shrinkage voids or fissures.

I have further discovered that if such a casting is rolled at a temperature above the weld temperature of the metal in the casting, the internal shrinkage voids or fissures can be eliminated by the internal welding of the metal by the rolling operation. The reason for this is that the oxidation of the surfaces of the external fissures which United A States Patent 0 3,191,292 Patented June 29, 1965 are exposed to the atmosphere results in surface imperfections which can not be removed by internal welding. However, where all of the shrinkage fissures are internal, there is no problem of oxidation and the rolling will cause an internal welding to take place with the result that near perfect products can be produced by a direct rolling operation.

Further, I have discovered that a casting having no internal shrinkage voids communicating with an outer surface can be produced by forming the casting in a chill mold which serves to seal off the outer surface of the casting. In addition to using a chill mold it is necessary to insure that the end surfaces of the casting are also free of shrinkage fissures. This can be done by using a chill stopper at opposite ends of the mold cavity or by using a chill cut-off at one end of the mold cavity and using a special type riser at the other end of the mold cavity.

It is therefore a primary object of the invention to provide a method for producing a rolled metal product whereby a casting can be rolled into a finished product without the necessity for intermediate ingot and primary rolling operations.

A more specific object of the invention is the provision of a method for producing rolled metal products wherein a casting free of external shrinkage fissures is produced for direct rolling while it is at a temperature above the weld temperature of the metal.

The foregoing and other objects and advantages of the invention will become apparent from a consideration of the following specification and the accompanying drawings, wherein:

FIGURE 1 is a perspective view of a preferred embodiment of the invention utilized in the pouring of a conventional mold;

FIGURE 2 is a top plan view of the novel apparatus;

FIGURE 3 is a side elevational view thereof;

FIGURE 4 is an end elevational view taken from the right of FIGURE 3;

FIGURE 5 is a fragmentary horizontal sectional view taken on line 55 of FIGURE 4;

FIGURE 6 is a top plan view of a novel mold assembly;

FIGURE 7 is a vertical sectional view on line 77 of FIGURE 6;

FIGURE 8 is a side elevational view of the novel mold assembly;

FIGURE 9 is a fragmentary view partly in vertical section taken on line 9-9 of FIGURE 6;

FIGURE 10 is a side elevational view of the support means for the cut-01f power device;

FIGURE 11 is a vertical sectional view taken on line 1111 of FIGURE 10;

FIGURE 12 is an end elevational view taken from the left of FIGURE 10;

FIGURE 13 is a top plan View of the cut-off slide support;

FIGURE 14 is a vertical sectional view taken on line 1414 of FIGURE 13;

FIGURE 15 is a top plan view of the cut-ofi slide;

FIGURE 16 is a vertical sectional view taken on line 16-16 of FIGURE 15;

FIGURE 17 is a top plan view of the cut-off insert against which the mold gate seats;

FIGURE 18 is a vertical sectional view taken on line 18-18 of FIGURE 17;

FIGURE 19 is a side elevational view of a novel billet mold assembly to be utilized with the apparatus of FIG- URES 1-18;

FIGURE 20 is a vertical sectional View taken on line 20-20 of FIGURE 19;

FIGURE 21 is a top plan view of the bot-tom or drag mold frame shown in FIGURES 19 and 20;

o. FIGURE 22 is a bottom plan view of the top or cope mold frame shown in FIGURES 19 .and 20; and FIGURE 23' is a vertical sectional view taken on line 23,-23 of FIGURE 21.

In each of said figures, certain details have been omitted in the interest of clarity where adequately shown in 7 other views. I

Describing the. invention in detail, a mold assembly described, move together as a unit or assembly 2 and maybe interconnected in any desired manner.

The car ;6 comprises wheels 8 which roll on tracks 10 and also comprises a cut-off or gate closing device generally designated 12, ,The cut-off 12 is best seen in FIGURES '68 and 13-18 and includes a slide'suppor-t 14 havingan opening or hole 15 witha bushing 16 (FIG- I URE 7) which may be of any desired material such as graphite, baked clayor shell. The sl-ide'support 14 has a cut-out or slot 18 (FIGURE 13) partly defined by an inner edge 20 for a purpose hereinafter described.

A slide or plate. 22 preferably of cast iron, copper' or any other desired chill material, having the above mentioned minimum thermal conductivity coefiicien-t value,

is sl-idably mounted on the support '14 and comprises an opening or aperture24 having a bushing 26 similar in form andcomposition to bushing 16. The slide 22 is supported within a channel 28 (FIGURE 14) of, the support 14 and is seatedalong a surface 30 the-reof im- -mediately below shoulders or ledges 32 which define another channel 34 within which-is positioned a loose in .sert 36 (FIGURES '6-7 and 17-18) which is complementary to and removably mounted in an opening 38 of a top plate or panel 40-of the car 6.

guide, rails 71 (FIGURE, 1) which snugly confine therebetween'a pin 73 on panel 40 of car 6.1

When the assembly 2 is aligned with the t'op of tube a 58, the motor 64 is energized to lower the frame 60 until a tapered recess 74 in the bottom of the support 14 engages a complementary tapered'portion 76 of the upper end of' tube 58." The frame continues to l ower untilthe support 14 is clamped by force of gravity or by other means '(notshown) against the tapered portion of tube 58' to afforda substantially airtight seal between the tube and the support 14, whereupon the metal in which the tube 58 is immersed is pressurized (as for examplein the manner disclosed by U.S. Letters Patent No.s2,847,739 issued August 19, 195 8 to E. Q. Sylvester) to flowgthe metal'upwardly through apertures 15, 24

, and 50 and gate 54 until the mold has been filled. Tilting of the car-6 during pouring is limited by lugs .75 (FIGURE 1) mounted on the top of brackets 1 14, hereinaf-ter described p v T I v After ,themold'has been filled the slide 22 is actuated, as hereinafter described,ito cut-oh. flow of molten metal through the gate, whereupon pressure on the molten metal is released, the rail segments 10a are elevatedto mating relationship with rails 10, andthe assembly 2 is rolled ial ong the'r'a-ils past' the stop 56which has previously been pivoted to inoperative position. The stop 56 is 'then pivoted to operative position and another assembly '2 is rolled intopositi-on and poured as heretobefore described. 7

The-manner inwhi'ch the. cut-off 12 is actuated can 'best be seen in FIGURES 8 and 10-l2, wherein it will be seen that when theassembly 2 is supported on top of the tube 58, a power device 78 mounted on a cover 80 of a chamber or tank'81'containing'the molten metal is disposed between the slide 22 and an abutment 82 depend-ing from the underside of panel 40 so that actuation of the device 7-8, as by hydraulic or pneumatic pressure, to expand the device'78 to engage the abutment 82 and 7' a ram or piston member 86 of the'device 78 toengage The support 14 is releasably interlocked with the panel The insert 36 is provided with an opening or aperture:

"50 having a'bu-shing' 52 (FIGURE 7) 'simila-r to form and material to bushings 16 and 26, whereby when apertures 15, 2.4 and 68 are aligned, they define a continuous. passage for the flowaof molten metal into a gate 54 (FIGURE 7.) of .the mold 4. Y

The assembly 2 rolls along tracks 10 until one wheel strikes a retractibl'e stop 56 (FIGURE 4) pivoted at 55' to an car 57 on one rail segment ltla to locate the aper-' .tures I5, 24,;and. 50 in verticle alignment with the top of a pouring tube 58, the lower end of which comunicates with a source of material (not shown) to be cast, such as a ladle of molten metal, Under these conditions, the wheels 8 are supported by rail segments 19a which are separable from rails 10. and are vertically movable.

The segments 10a are supported by a frar'ne60 which i is inturn supported -a-tits corners, as'by, conventional worm gear screw jacks 62operativelyconnected to, a reversible electric motor 64. The jacks are mounted on' foundation-supported beams 66 (FIGURES 3 and 4) and raise or lower the frame 60 in response to rotation of the armature shaft 68 of motor 64in one direction or the other. The frame 60 is guided by rollers 70 '(FIGa URES 2 and '3) which are mounted on the frame and.

which engage vertical foundation-supported beams 72; The car is guided at each side thereof in aligned relationship with the top of tube 58' by foundation-mounted the cut-off slide 22. 1 The device 78 "has a limited stroke and at the end of said stroke, the-slide 22" is at a position whereat its aperture 24 is beyond edge 20 of the support14, whereupon molten metal in aperture 24 is dumped through slot 18 so that the bushing 26 need not'be replaced for each pouring operation. Also release of pressure on the molten metal in the tank 81 dumps the metal in bushing 16 so that it need not be replaced for each pouring operation. r The. devicel78is afforded a floating support so that,

upon actuation thereof the forces developed by the de- .vice 78 actuate the cut-off 12 to closedlposition are self- I a collar 109 of cylinder member 84*againsta stop plate 111 attached to bracket 88, thereby yieldingly holding the cylinder .memberf84'in proper alignment with the space. between slide 22' and abutment 82 as the assembly -2 is lowered to'or raised from the position shown in FIGURE 8. I

Upon energization of device 78, as heretofore described, the slide 94' permitsenough axial movement of the device 78rso that the forces developed thereby are self-contained within assemblyjZ and substantially no reactive forces are transmitted to bracket 88 or cover u .Uponr'emov'al of cylinder84 from the clamps 98, which can bela'ccomplished by manually lifting the. cylinder to compress spring 104, the spring 104 is held in position upon bosses 112 of levers 100 by a slight force provided by a tension spring 113 connected to the lower ends of levers 100.

It may be noted that the cover 80 may be clamped to the top of its container 81 by clamp means (not shown) mounted on foundation-supported brackets 114, and the rail segments a may be manually removed from, replaced upon, a frame 60 to accommodate insertion and removal of the cover 80 and a ladle (not shown) of molten metal into which the tube 58 extends. The construction of the container 81, the ladle (not shown), the cover 80 and tube 58 is per se no part of the present invention and may be of any other desired construc tion and arrangement, with the tube mounted on the cover or elsewhere in communication with the molten metal in the container 81.

It should be noted that bushings 16, 26, and 52 are flanged at their upper ends so that in their aligned position shown in FIGURE 7, the flange of bushing 16 engages slide 22, the flange of bushing 26 engages insert 36 and the flange of bushing 52 engages the mold 4 around its gate 54.

Referring now to FIGURES 19 to 23, which show a mold arrangement of the invention, a novel billet mold assembly 116 is disclosed for the casting of steel billets whichcan be rolled (without any surface conditioning and without any intermediate forming step such as forging or blooming) into commercial products such as Wire or rods.

The mold assembly 116 comprise a top frame 117 defined by longitudinal side channels 118 welded to transverse angles 120 and 121. A cope 122 formed of one or more blocks 124 of a chill material such as graphite having the previously described thermal conductivity characteristics is clamped against angles 120 and 121 by clamp bars 126 and bolt and nut assemblies 128. The cope blocks 124 are also clamped by a clamp bar 130 and bolt and nut assemblies 132 (one of which is shown at the left of FIGURE 19) against an abutment angle 134 welded or otherwise secured to the frame channels 118.

The mold assembly 116 also comprises a bottom frame 136 defined by longitudinal side channels 138 welded to longitudinal angles 140 and transverse angles 141 and 143. A drag 142 formed of one or more chill material blocks 144 is seated against the angles 140 and is clamped by a clamp bar 146 and bolt and nut assemblies 148 (one of which is shown at the left of FIGURE 19) against an abutment angle 147 welded or otherwise secured to frame The frames 117 and 136 are interconnected by readily releasable means, such as bolt and nut assemblies 149 to clamp the cope 122 and drag 142 together to define a casting cavity 151 in the shape of a conventional billet between twenty and thirty feet in length and approximately square in cross-section, measuring between two and six inches on a side.

In order to insure that the end of the casting opposite from the end adjacent the mold gate is free from shrinkage fissures, a special riser arrangement is povided.

The upper end of the mold assembly 116 is provided with a block 148:: of a chill material which has the previously mentioned thermal conductivity coefiicient value, such as graphite, having an opening 150 connected to cavity 151 and to a riser cavity 152 of another block 1423b of the chill material clamped on top of block 148a as by bolt and nut assemblies 153 one of which is shown at the left of FIGURE 19.

The lower end of the cope 122 is provided with a block 152 of the chill material having a gate 155 connected to the lower end of the cavity 151 and to apertures 15, 24, and 50 (FIGURE 7) of the cut-01f 12 on a car 2a substantially identical with the car 2 previously described except that the car 2a preferably has only one pair of wheels 8a because the drag 142 is pivotally supported at its opposite end by a pivot bar 154 welded to channels 138 and pivotally mounted in a V-shaped channel 156 of a car 158 having wheels 160 mounted on the rails 10. The rail segments 10a and their elevating and lowering mechanism, as well as the pouring and cut-off mechanism are disclosed in FIGURES 1 to 18, and are not shown in detail in FIGURES l9 and 21.

Thus it will be understood that when the rail segments 10a are lowered to connect the gate with the pouring tube 58, as heretofore described, a pivoting action takes place between assembly 116 and rail segments 10a by means of wheels 8a and also pivoting action takes place between car 158 and assembly 116 by means of pivot bar 154.

In actual practice, billets and slabs have been poured at a metal flow rate of about sixty-five pounds per second. These billets were approximately thirty feet in length and were square in cross-section, approximately 3% inches on a side. The cope 122 and drag 142 forming the mold in which such billets were cast were formed of graphite blocks machined on their mating surfaces as seen in FIGURE 20 to define the mold cavity 151. It has been discovered that graphite produces a very fine dendritic structure at the surface of the casting, and according to the invention it is critical that the mold and riser, as well as the cut-oft slide, be formed of a chill material which has the previously mentioned thermal conductivity coeflicient value of at least 0.1 cal./sec./cm. C./cm. for pressure pouring of products such as blooms, billets, or slabs which are to be directly rolled.

The riser may, however, be connected to an upwardly facing opening of the mold at some point other than the extreme upper end of the mold, in which case said upper end is closed by a plate which is provided with tiny vent apertures permitting escape of air from the mold as it is filled with the molten steel. In such an arrangement, air also escapes through the riser as the mold is filled with the molten steel. The plate is also formed of such a chill material to cause rapid freezing of the molten steel as it contacts the plate.

In a mold having a cavity of about thirty feet in length or more, the longitudinal axis of the mold is preferably at an angle of the order of 24 or less with respect to horizontal.

To describe the complete process of producing a rolled metal product in accordance with the teachings of the invention, it will be understood that the casting is first formed by bottom pressure pouring, at a non-turbulent flow rate, as previously described, by the application of superatmospheric pressure on the metal in the container.

After the mold and riser cavities are filled and the flow of molten metal into the mold is cut-off by the slide mechanism previously described, the casting is then permitted to cool to the point where it has solidified sufficiently to permit its removal from the mold.

At this stage of the operation it will be understood that the entire outer surface of the casting, with the possible exception of the surface of the riser which has been ex posed to the atmosphere, has been in contact with a chill surface of the mold, and/ or cut-off slide, and is therefore entirely free of external shrinkage voids of fissures. Also, because of the riser arrangement, the end portion or up per end of the casting is, for a depth of several inches, free of shrinkage fissures.

At this point the riser end of the casting is cut-oil to eliminate the sprue and to provide the desired length for the casting. The casting is cut through the portion which is free of shrinkage voids so that the outer end surface of the casting is, like the rest of the casting surface, free of shrinkage voids.

In the event that the temperature of the casting throughout its entirety has fallen below the weld temperature of the metal, and this is usually the case, the casting is reheated until the temperature throughout the casting is above the weld temperature of the metal. ,7 The castingis then ready to be rolled directly into a commercial product. During the rolling operation any internal shrinkage voids or fissures in the casting will be:

molten steel in a container to force the molten'steel up-- wardly at a nont urbulent flow rate through a pouring tube into a bottom gate of an'elongated chill mold having a thermal conductivity coefiicient value at 18 C. of the order of 0.1 cal./sec./cm. C./cm., or greater, said mold having a riser at its upper end to seal internal shrinkage of the steel for a limited depth from the top of the mold; then, when the mold has been filled withrsaid molten steel, closing said gate by a chill having a thermal conductivity coefficient value at 18 C. of the order'of 0.1 r

or. greater; then, after the steel in the mold has solidified amines tureuntil all internal "shrinkage has been eliminated by internal welding and the desired product is produced.

" 4. In a method of producing'commercial rolled metal product directly from cast billets, bloO-ms or slabs, the steps of: providing an air-tight avenue of communication "between ana-ir-tight container and an ingate at the lower end of an inclined elongated chill mold formed of a material having a thermal conductivity coefiicient value at 1 8 C.v of at least 0.1 cal./.sec./cm. C./cm.' and having at its upper end a riser for sealing internal shrinkage of' the casting for. a limited depth from the upper end 1 of the mold; applying superatmospheric pressure to into arcasting', cutting off the riser at an area of the casting above said depth which is entirely solid and spaced from' internal shrinkage cavities in said casting; then heating the casting to a temperature at'least as great as its welding temperature; and them, without otherwise conditioning its outer surface, rolling the casting before it has cooled to a value below said welding temperature until all internal shrinkage has beeneliminated by internal welding and the desired product is produced. 7,

2.In a method of producing commercial rolled steel product directly from cast steel billets, blooms or slabs,

the steps of: applying pressure against molten steel'in a container to force the molten steel upwardly at a non-.

molten met-alin the container to force it from the container into the mold; after the mold has been filled, closing the gate with a chill member'formed of a composition having a thermal conductivity value at 18 C. of at' least 011; after the metal in the mold has solidified into a casting, cutting of a portion of the upper end of the casting" at an area above said depth which is entirely free from internal shrinkage cavities; heating the casting 'until theitemperature throughout its entirety is above the weld temperature of the metal; and then, before the temperavure of the casting has fallen below said weld temperature, rolling the casting until all internal shrinkage cavities vhave been eliminated by internal welding and the desired product is j produced.

5. In a method of producing commercial rolled metal product directly from cast'billets, blooms or slabs, the steps of:' providing an air-tight avenue of communication between an air-tight container and an ingate at one end of an elongated chill mold formed of a material having turbulent flow rate through a pouring tube intoa bottom I gate of an elongated chill mold formed of a material having a thermal conductivity coefficient value at 18 C. of

the order of 0.1 cal./sec./cm. C./cm., or greater, and having at its upper end a riser to seal internal shrinkage of the steel for a limited depth from the top of the mold; after the mold has been filled with said molten steel, closing said gate by a chill member formed of a material having a thermal conductivity coetficient value at 18 C. of

the order of 0.1 or greater; after the steel in thevmold has solidified into a casting, cutting off the upper end of the casting at an area of the casting, above said depth, which is entirely solid and spaced from internal shrinkage cavif ties in said casting; heating the casting to a temperature at least as great as its welding temperature; and then rollingthe casting, before it has cooled to a value below said I welding temperature, until all internal shrinkage has been eliminated by internal welding and the desired product is produced.

3. In a method of producing commercial rolled metal 1 product directly from cast billets, blooms or slabs, the

material having a thermal conductivity coefficient value at 18 C. of not less than 0.1;after the steel in the mold has solidified into a casting, cutting off the upper end of the casting at an area of the casting, above said depth,' which is entirely solid and free from internal-shrinkage cavities; heating the casting to a temperature at least as great as its welding temperature; and then rolling the casting be,

fore it has cooled to a value below said welding temperaa thermal conductivity coeflicient value at 18 C. of at least 0.11 ca-l./,sec./cm. C./.cm. and having at its other end a riser for sealing internal shrinkage of the casting for a limited depth from theupper end of the mold; applyring isuperatmospheric pressure to molten metal in the container'toforce it from the container into the mold; after the mold has been filled, closing the gate with a chill member ,formed of a composition having a thermal conductivity value at 18. C. of at least 0.1; after the metal in theim'old has solidifiedinto a casting, cutting of a portion, of said other end of the casting at an area above said depth'which is entirely free from internal shrinkage cavities; heating the casting until the temperature throughout its entirety is above the weld temperature of the: metal; and'then, before the temperature of the casting has fallen below said weld temperature, rolling the casting until all internal shrinkage cavities have been eliminated by internal welding and the desired product is produced.

6. In a method of producing commercial rolled steel roduct directly from cast billets, blooms or slabs, the steps of: applying pressure against the upper surface of molten steel in a container to force the molten steel upwardly at a nonturbulent flow rate through a pouring tube into a bottom gate ofan elongated'chill mold having a thermal-conductivity coefficient value at'18 C. of the order of 0.1 cal./sec./cm. /-"-C./cm., or greater, said mold having an air vent inits upper end and means comprising a riser connected at its lower end to an upwardly facing opening of the mold to alford escape of atmosphere in the mold and to seal internal shrinkage of the steel for a limited depth from said opening of the I rnold; then, when the mold has been filled with said molten .steel, closing saidgate by a chill having a thermal conductivity coefilcient value at 18 C. of the order of 0.1 or greater; then, after the steel in the mold and riser has solidified'into la casting, cutting ofi? the riser at an area of thecasting above said depth which is entirely solid and spacedfrom internalsh-rinkage cavities in said casting; then heating the casting to a temperature at least as great as its welding temperature'; and then, without otherwise conditioning its outer surface, rolling the castingbefore it has cooled to a value below said welding temperature until all internal shrinkagev has been elim- 9 inated by internal welding and the desired product is produced.

7. In a method of producing commercial rolled steel product directly from cast billets, blooms or slabs, the steps of: applying pressure against molten steel in a container to force the molten steel upwardly at a nonturbulent flow rate through a pouring tube into a bottom gate of an elongated chill mold formed of a material having a thermal conductivity coeflicient value at 18 C. of the order of 0. 1 cal./sec./cm. C./cm., or greater, said mold having an air vent in its upper end and means comprising a riser connected at its lower end to an upwardly facing opening of the mold to afford escape of atmosphere in the mold and to seal internal shrinkage of the steel for a limited depth from said opening of the mold; after the mold has been filled with said molten steel, closing said gate by a chill member formed of a material having a thermal conductivity c-oeflicient value at 18 C. of the order of 0.1 or greater; after the steel in the mold and riser has solidified into a casting, cutting olf the steel of the riser at an area of the casting, above said depth, which is entirely solid and spaced from internal shrinkage cavities in said casting; heating .the casting to a temperature at least as great as its welding temperature; and then rolling the casting, before it has cooled to a value below said welding temperature, until all internal shrinkage has been eliminated by internal welding and the desired product is produced.

8. In a method of producing commercial rolled metal product directly from east billets, blooms or slabs, the steps of: applying pressure against molten metal in a container to force it upwardly at a nonturbulent flow rate through a pouring tube into a bottom gate of an elongated chill mold formed of a material having a thermal conductivity coefi'icient value at 18 C. of not less than 0.1 cal./sec./cm. C./cm., said mold having means to alford escape of all atmosphere in the mold comprising an air vent aperture in the upper end of the mold and also comprising a riser connected at its lower end to an upwardly facing opening of the mold to afford escape of said atmosphere from the mold and to seal internal shrinkage of the metal for a limited depth from said opening of the mold; after the mold has been filled, closing said gate by a chill member formed of a material having a thermal conductivity coeflicient value at 18 C. of not less than 0.1; after the metal in the mold and riser has solidified into a casting, cutting off the metal of said riser at an area of the casting, above said depth, which is entirely solid and free from internal shrinkage cavities; heating the casting to a temperature at least as great as its welding temperature; and then rolling the casting before it has cooled to a Value below said welding temperature until all internal shrinkage has been eliminated by internal welding and the desired product is produced.

9. In a method of producing commercial rolled steel product directly from east billets, blooms or slabs, the steps of: applying superatmospheric pressure against molten steel in a container to force it upwardly at a nonturbulent flow rate through a pouring tube into a bottom gate of an elongated chill mold formed of graphite blocks having a thermal conductivity coeflicient value at 18 C. of not less than 0.1 ca-l./sec./cm. C./-cm., means to afford escape of all atmosphere in the mold comprising an air vent aperture in the upper end of the mold and also comprising a riser connected at its lower end to an upwardly facing opening of the mold for affording escape of said atmosphere and for sealing internal shrinkage of the steel for a limited depth from said opening of the mold; after the mold has been filled, closing said gate by a chill member formed of a material having a thermal conductivity coeflicient value at 18 C. of not less than 0.1 cal./sec./1cm. C./cm.; after the steel in the mold and riser has solidified into a casting, cutting off the steel of the riser at an area of the casting above said depth which is entirely solid and free from internal shrinkage cavities; heating the casting to a temperature at least as great as its welding temperature; and then rolling the casting before it has cooled to a value below said welding temperature until all internal shrinkage has been eliminated by internal welding and the desired product is produced.

10. In a method of producing commercial rolled metal product directly from cast billets, blooms, or slabs, the steps of: providing an air-tight avenue of communication between an air-tight container and an ingate at one end of an elongated chill mold formed of graphite and having at its other end a riser for sealing internal shrinkage of the casting for a limited depth from the upper end of the mold; applying superatmospheric pressure to molten metal in the container to force it from the container into the mold; after the mold has been filled, closing the gate with a chill member; after the metal in the mold has solidified into a cast-ing, cutting of a portion of said other end of the casting at an area above said depth which is entirely free from internal shrinkage cavities; heating the casting until the temperature throughout its entirety is above the weld temperature of the metal; and then, before the temperature of the casting has fallen below said weld temperature, rolling the casting until all internal shrinkage cavities have been eliminated by internal welding and the desired product is produced.

11. In a method of producing commercial rolled metal product directly from east billets, blooms or slabs, the steps of: providing an air-tight avenue of communication between an air-tight container and an ingate at the lower end of an inclined elongated chill mold formed of a material having a thermal conductivity coeflicient value at 18 C. of at least 0.1 cal./sec./crn. /C./cm., said mold having means for affording escape of all atmosphere in the mold comprising an air vent aperture in the upper end of the mold and also comprising a riser connected at its lower end to an upwardly facing opening of the mold for affording escape of said atmosphere from the mold and for sealing internal shrinkage of the casting for a limited depth from said upwardly facing opening of the mold; applying superatmospheric pressure to molten meta-l in the container to force it from the container into the mold; after the mold has been filled, closing the gate with a chill member formed of a composition having a thermal conductivity value at 1 8 C. of at least 0.1; after the metal in the mold and riser has solidified into a casting, cutting off the metal of said riser at an area above said depth which is entirely free from internal shrinkage cavities; heating the casting until the temperature throughout its entirety is above the weld temperature of the metal; and then, before the temperature of the casting has fallen below said weld temperature, rolling the casting until all internal shrinkage cavities have been eliminated by internal welding and the desired product is produced.

References Cited by the Examiner UNITED STATES PATENTS 1,172,506 2/16 Vickers 22213 X 1,455,197 5/23 Gathmann 222l3 1,908,168 5/33 Nangle et a1 29-528 2, 847,76 9 8 5 8' Sylvester.

WHITMORE A. WILTZ, Primary Examiner.

Claims (1)

1. IN A METHOD OF PRODUCING COMMERCIAL ROLLED STEEL PRODUCT DIRECTLY FROM CAST BILLETS, BLOOMS OR SLABS, THE STEPS OF; APPLYING PRESSURE AGAINST THE UPPER SURFACE OF MOLTEN STEEL IN A CONTAINER TO FORCE THE MOLTEN STEEL UPWARDLY AT A NONTURBULENT FLOW RATE THROUGH A POURING TUBE INTO A BOTTOM GATE OF AN ELONGATED CHILL MOLD HAVING A THERMAL CONDUCTIVITY COEFFICIENT VALUE AT 18*C. OF THE ORDER OF 0.1 CAL./SEC./CM.2* C./CM., OR GREATER, SAID MOLD HAVING A RISER AT ITS UPPER END TO SEAL INTERNAL SHRINKAGE OF THE STEEL FOR A LIMITED DEPTH FROM THE TOP OF THE MOLD; THEN, WHEN THE MOLD HAS BEEN FILLED WITH SAID MOLTEN STEEL, CLOSING SAID GATE BY A CHILL HAVING A THERMAL CONDUCTIVITY COEFFICIENT VALUE AT 18*C. OF THE ORDER OF 0.1 OR GREATER; THEN, AFTER THE STEEL IN THE MOLD HAS SOLIDIFIED INTO A CASTING, CUTTING OFF THE RISER AT AN AREA OF THE CASTING

Images