US1491846A - Steel process, mold, and ingot - Google Patents

Description

A ril 29 1924. 1,491,846

R. G. COATES STEEL PROCESS, MOLD, AND INGOT Filed 001:. 6 1920 2 Sheets-Sheet. 1

April 29 i924.

R. G. COATES s'rsm. PROCESS, MOLD, AND meow Filed Oct. 6, 1920 2 Sheets-Sheet 2 illll 7 IIIII IlHh w,

Patented Apr. 29, 1924.

UNITED OFFICE.

RAY G. COATES, OF PASADENA, CALIFORNIA, ASSIGNOR TO VALLEY IVIOULD AND IRON CORPORATION, OF SHARPSVILLE, PENNSYLVANIA, A CORPORATION OF NEW YORK.

STEEL PROCESS, MOLD, AND INGO'T.

Application filed October 6, 1920. Serial No. 415,089.

T 0 all whom it may concern.

Be it known that I, RAY G. COATES, a citizen of the United States, and a resident of the city of Pasadena, in the county of Los Angeles, State of California, have invented new and useful Improvements in Steel Processes, Mo1ds,'and Ingots, of which the following is a specification.

This invention relates broadly to metallurgy and more particularly to a method and apparatus for casting steel ingots in a covered mold.

More especially the present invention relates to casting steel ingots in a chill mold and comprises a method and apparatus for localizing blow holes inthe middle of the ingot. 4 I An important object of the present invention is the method of casting steel ingots in a covered mold and causing the blow hole bubbles to be trapped in the middle of the ingot a sufficient distance from the surfaces of the ingot to prevent the cavities from breaking out during rolling. v

A further object of the present invention is a method and apparatus for casting steel ingots having all sides thereof chilled and wherein bubbles are trapped in the middle of the ingot a suflicient distance from the surfaces of the ingot to prevent the cave .ities from breaking out during rolling.

A still further object of the present invention is a method and apparatus for easting steel ingots having all sides thereof chilled and wherein bubbles are trapped in the middle of the ingot in such manner that the cavities caused by the bubbles will weld together during rolling operations.

Another further and important object of the present invention is a method and appa-ratus for casting steel ingots in a covereed chill mold by providing a substantially horizontal mold arranged with trunnions which rest upon suitable tracks or supports so that the ingot may be released by inverting the mold and freeing the cover. A still further andimportant object of the present invention is the method of casting steel ingots which comprises pouring molten steel into a covered chill mold, permitting a solidified cup to form, continuing the pouring until the metal contacts with the chilled top, thereby sealing said cup, and then inverting the mold and causing gas bubbles to be sealed against the bottom of the originally formed cup.

A still further object of the present invention is a method and apparatus for easting steel ingots wherein zones of isocrystallization are arranged centrally around the axis of the ingot and with the central zone enclosing any blow hole cavities that may occur in the ingot.

A still further object of the present invention is an article of manufacture having a metal body with all sides thereof chilled and with any blow hole openings that 00- cur located in the middle central axis and remote from the ends thereof.

A still further object of the present invention is an ingot of steel or the like comprising a body portion having zones of crystallization arranged as cups on one side of the ingot and as closed areas on the other side thereof and with blow hole openings substantially in the middle of the ingot.

' Other and further objects of the present be embodied in and practiced by other means than those specifically shown and described, I desire such disclosure to be understood as illustrative and not in the limiting sense.

Figure 1 illustrates the first period in the method of carrying out the process and shows crystallization building up in the bottom and sides of the mold;

Figure 2 illustrates the second period in which the pouring is finished and crystallization has begun at the top of the ingot;

Figure 3 illustrates the third period when the mold is turned to degrees on its longitudinal axis.

Figure 4 illustrates the 4th period when all of the metal in the ingot has crystallized;

Figure 5 illustrates one form of mold for carrying out the present invention;

Figure 6 illustrates a transverse section through the middle of an ingot made in accordance with the present invention;

Figure 7 illustrates the operation of the mold when the cover and ingot are dropped.

Heretofore in the art of casting steel ingots from blow hole steel, that is steel having a considerable gaseous content, diificulties have been encountered, particularly where the casting was done in a covered mold. Where the ingot was cast in a horizontal covered mold the metal chilled on the long sides, the bottom and the top, as well as the ends of the ingot, since the first metal run into the mold covered these portions first and therefore had a longer time to chill. Immediately gases began to be released as the metalcrystallized and these gases escaped through the top surface of the metal until the mold was sufficiently filled so that the metal touched the cover, or top. As soon as the top was reached a chilled skin was formed over the molten metal and the solidified metal grew in all directions from the chilled portions of the mold, except under the bubbles, toward the central molten mass. Those surfaces which were first in contact with the mold, because of the longer contact time, naturally built up more crystallization than the surfaces which made contact later. Therefore the bottom being the first in contact had a thicker solidified portion than either the top or the sides. The gases tendingto escape from the cooling steel being lighter than the steel, moved upwardly and were entrapped in the ingot beneath the upper skin thereof. Under normal conditions these bubbles formed subcutaneous cavities which would break out in rolling and permit air to strike the hot side walls of the cavity and oxidize.

the same, so that the cavities were not likely to weld together during rolling operation.

Where the metal was particularly Wild the bubbles tended to coalesce and finally reach such proportions as to cause large subcutaneous blow holes which caused the bloom to show scabs, cold shuts and other serious defects which rendered the metal unsuitable for many purposes. These subcutaneous blow holes are a great detriment. whereas blow holes deeply seated in the body of the ingot are relatively harmless because such blow holes may be closed and welded together in rolling operations before any air strikes the side walls of such blow holes. The gas entrapped in such deep seated blow holes is absorbed in the surrounding metal when the'ingot is highly heated and rolled into a bloom.

The present invention overcomes the difiiculties of the known art by the method and apparatus which will later be described in detail and wherein the gas bubbles are caused to collect in the middle of the ingot and are suiiiciently deeply embedded in solid metal to prevent breaking out in rolling so that the cavities may be welded together as has been found to be possible and highly desirable. In carrying out the present invention the teeming operation is carried on slowly, preferably in' a horizontal mold, so that crystallization builds up from the bottom and the side Walls to a considerable thickness before the molten metal comes into contact with the chilled cover, which seals the ingot against further discharge of gases. At this point both the gas escape and the runner are chilled by placing cold bodies against the same providing these portions have not chilled sufiiciently bynaturally cooling; the fountain having been removed before the runner is chilled. From this time on expelled gases are trapped in the still molten steel as crystallization is growing from all of the various interior surfaces of the chilled steel except those surfaces around the blow holes, since the presence of the gas bubbles prevent any supply of liquid metal adding to the thickness of the thin metal over the blow holes. In order to remove these gas bubbles from beneath the top, I invert the mold, that is, in

a horizontal mold I turn the mold through.

180 degrees around its longitudinal axis. The thick bottom now becomes the new top and the old thin top now becomes the new bottom. The bubbles which were sealed in next to the original top now rise upwardly and are entrapped in the bottom of the inverted cup formed of the chilled metal that has crystallized over the bottom and sides of the mold. These bubbles are now embedded a safe distance from the ingot surfaces and the liquid metal settles into contact with the inner chilled surface of the new bottom so that crystallization may grow rapidly from this new bottom upwards. The old subcutaneous blow holes have disappeared and new deep seated blow holes have formed about the middle axial line of. the ingot. It will be evident that the thickness of the original bottom crystallization that may be allowed to form, before the ingot is turned over, is such that may be closely controlled as soon as the time of teeming and crystallization for any paroutside surface, including the chilled ends, and such blow holes as are in the ingot,

are harmless because of being deeply seated which illustrate a horizontal two part mold as being a preferred form for carrying out the present invention. It is recognized that multi-part molds may be used where desired and furthermore it is also recognized that the present method is not necessarily confined to being carried out in horizontal molds. Where a two part horizontal mold is used the body portion 1 may be provided with a suitable chill cover 2, which may be provided with clamp lugs 4, that are arranged adjacent clamp lugs 5 on the body portion. uitable clamps 6 are adapted to be driven over the lugs and thus securely lock the cover in position. The cover also is provided with an opening 8 through which the runner 9 may extend and a fountain. 10 may be mounted adjacent the runner to direct molten metal into the mold. Preferably the opposite end of the mold is provided with a riser 11 which may be partly within the cover and partly within the body portion. The ends of the body portion are also preferably provided with trunnions 12 and 14 and these trunnions are mounted on suitable rails or stands 15 and 16 respectively. The trunnions may be provided with flat surfaces 17 and 18 which tend to stabilize the mold when in either erect or in verted posit-ion. \Vhen the mold is filled with steel the whole device becomes substantially a solid mass of metal of which the longitudinal gravity axis may be easily found and the trunnions may be located with reference to this axis so that a relatively small amount of force is required to turn the mold over on the said axis through 180 degrees. When the mold is filled with molten steel the axis of the filled mold substantially coincides with the axis of the trunnions and the center of gravity will be so located that the mold will tend to remain in either the upright or inverted position as may be desired. In carrying out the method comprising the present invention the teeming operation is regulated to permit the steel to form cupped zones and to crystallize sufliciently to provide a considerable thickness of metal adjacent the ends, sides, and bottom of the mold before the mold is filled sufliciently for the molten metal to contact with the chill top. It is to be noted that this portion.

I When the top 2 is reached throughout its entire length by molten metal the fountain 10 is removed and both the riser and the runner are chilled, then the mold is turned through 180 degrees. The clamps 6 must be securely set in order to permit of this turning movement. After the mold has set a sufficlent length of time for the ingot to be solidified, the clamps 6 may be knocked lOOSe and the chill cover will drop away, thereby permitting the ingot to fall from the mold. When the ingot and cover fall from the mold the center of gravity of the mold is above the axis of the trunnions because the mold now comprises an empty metal trough with the bottom up permost. This tends to cause the mold to right itself automatically for a new casting operation and at the same time causes the mold to move away from overthe ingot so that the latter can be easily removed.

As previously stated, the present process is particularly adapted to melted steel which carries a relatively large amount of gas and which is generally known in the art as blow hole steel, although it may be carried out with other types and kinds of metals. 1

Figure 6 indicates a mid-cross-section through an ingot according to the present invention and it will be noticed that a series of isocrystallization zones A are substantially cup shaped and terminate adjacent the upper side edges of the ingot while the isocrystallization zones B which form when the mold is inverted are substantially closed around the blow hole cavities C that are located in the middle portion of the ingot.

Having described my invention, I claim:

1. The method of casting steel ingots or the like, which comprises pouring molten steel into a horizontal chill mold and permitting the steel to partly solidify to form a long narrow cup having a thick solidified wall enclosing the molten steel, continuing the pouring until said mold is filled, chilling the long top surface of the molten steel in the mold to provide a solidified sheet enclosing the molten steel, and turning the mold upon its longitudinal axis to cause the gases from thecooling molten steel to collect against the thick solidified wall whereby cavities formed in the ingot are deep seated therein.

2. The method of casting steel ingots in a horizontal covered chill mold which comprises pouring molten steel slowly into said mold to permit crystallization of the steel against the long bottom and shallow sides of the mold, whereby the steel will cool sufficiently to form thick walls of solidified steel within which the molten steel is held. then filling the mold with molten steel and causing the same to contact'with the chill cover whereby the molten steel in the mold is enclosed in a crystallized shell which entraps gases expelled from the molten steel while crystalhzing and then rotating the mold through less than 360 degrees upon its longitudinal axis to cause the gases to collect against a thick side wall of the shell.

8. The method of casting steel ingots in a substantially horizontal covered chill mold which comprises slowly pouring the steel into the mold, causing the steel to contact with the chill cover whereby the molten steel isenclosed in a solidified shell, and then inverting the mold upon its longitudinal axis and permitting the ingot to completely solidify while in inverted position.

4. The method of casting steel ingots and and permitting the ingot to completely solidify while in inverted position.

5. The method of casting steel ingots and thelike from blow hole steel which comprises running the steel into a covered chill mold having a runner at one end and a riser at the other end and permitting the steel to solidify sufficiently to provide a solidified wall having a thickness which approximates one half of the transverse dimension of the ingot through a mid-section thereof, then filling the mold with molten steel and permitting the top surface thereof to chill to form a solidified skin enclosing the non-cry stallized steel, and then inverting the mold so that the thickened wall becomes the top thereof, and permitting the ingot to completely solidify while in inverted position.

6. In the art of molding steel ingots, a mold, a removable cover on said mold, a

' pair of tracks, means on said mold to cause same to traverse szid tracks from filling position to a dumping position,'the parts being arranged to cause the mold to tend to move away from-dumping position when the cover is removed.

7. In the art of molding steel ingots, a horizontal mold, a removable cover on saidv mold, removable locking means for the cover, a pair of tracks, means on said mold to cause same to traverse said tracks from filling position to a dumping position, the

parts being arranged to cause the mold to tend to move away from dumping position when the cover is removed.

8. In the art of molding steelingots, a mold, a removable cover on said mold, a

pair of tracks, means on said mold to cause move away from dumping position when the cover is removed.

9. In the molding art, a horizontal ingot mold,-a pair of tracks on which said mold is adapted to be rolled from filling position to dumping position, the parts being constructed and arranged to cause said mold to tend to automatically return to filling position when the ingot is removed at the dumping position.

10. In the molding art, an ingot mold, a pair of tracks on which said mold is adapted to be rolled from filling position to dumping position, the parts being constructed and arranged to cause said mold to tend to automatically move away from dumping position when the ingot is removed at the dumping position, whereby the ingot is clear of vertical obstructions sothat the ingot may be easily removed.

11. In the molding art, a horizontal mold, trunnions on the ends of the mold, tracks on which the trunnions are adapted to roll, the center of mass of said mold being adjacent the axis of said trunnions, and a removable part attached to said mold in such manner that said center of mass is raised above said axis when said part is removed to cause the mold to tend to roll on said tracks when said part is removed.

12. In the art of molding steel ingots, a

'mold, a cover for said mold, a pair of tracks,

trunnions on said mold and adapted to roll on said tracks to invert said mold for dumping the ingot and to cause a transitory movement of said mold along said tracks from a filling position to a dumping position.

13. As an article of manufacture, a substantially horizontal ingot mold comprising a body portion, a chill cover for said body portion, means to lock said cover in position on said body portion, and supporting trunnions for facilitating inverting said mold.

14. As an article of manufacture, a sub-- stantially horizontal ingot mold comprising a body portion, a chill cover for said body portion, means to lock said cover in position on said body portion, supporting trunnions for facilitating inverting said mold,

and a track upon which said trunnions ;are

adapted to roll. I

15. As an article of manufacture, a substantially horizontal ingot mold comprising a body portion, a chill cover for said body portion, means to lock said cover in position on said body portion, supporting trunnions for facilitating inverting said mold,

and a track upon which said trunnions-are adapted to roll, with the center of gravity being adjacent the axis of the trunnions when the mold is filled with steel and being "between the axis of the trunnions and the bottom of the mold when the cover is removed and the mold is empty.

16. As an article of manufacture, a horizontal chill mold for casting steel ingots comprising a body portion, a chill cover for said body portion, means to lock said chill cover in position,andtrunnion's mounted on the ends of said body portion with the axis of the trunnions substantially passing through the center of gravity of said mold when the mold is filled with molten steel.

17. In the art of molding steel ingots, a mold, a cover for said mold, a support, trunnions on said mold and adapted to roll on said support to invert said mold for dumping the ingot and to cause a translatory movement of said mold along said support from a filling position to a dumping position.

18. As an article of manufacture, an ingot cast from blow hole steel and comprising cupped isocrystallization zones on one side of said ingot and enclosed isocyrstallization I zones on the other side of said ingot with gas formed cavities adjacent the minimum cupped zone.

19. As an article of manufacture, an ingot cast from blow hole steel and comprising cupped insocrystallization zones on one side of said ingot and enclosed isocrystallization zones on the other side of said ingot with all surfaces of the ingot chilled and with gas formed cavities adjacent the minimum cupped zone.

20. As an article of manufacture, ah ingot of steel or the like having cupped zones of isocrystallization on one side thereof and closed zones of isocrystallization within the cupped zones and gas formed cavities within the minimum closed zone.

21. As an article of manufacture, an ingot of steel or the like having cupped zones of isocrystallization on one side thereof and closed zones of isocrystallization within the cupped zones.

22. The method of casting steel ingots or the like which consists in pouring the molten metal into a horizontally disposed chill mold, allowing the metal to partly solidify, continuing the pouring until the mold is filled, then chilling the top surface to form a shell over the molten metal, and finally inverting the mold upon its longitudinal axis and allowing the ingot to solidify in its inverted position. i

23.- In a horizontal ingot mold apparatus, a body portion, a chill cover for said body portion, a support, and trunnions on said body portion to roll on said support to invert said body portion, said trunnions being arranged on the body portion to move same along said sup ort from a dumping to a fill-- ing position w 1811' the cover is removed and the mold is empty. RAY G. COATES.

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