US3206154A

US3206154A - Production of steel ingots

Info

Publication number: US3206154A
Application number: US248809A
Authority: US
Inventors: Raymond J Demaison
Original assignee: Quigley Co Inc
Current assignee: Quigley Co Inc
Priority date: 1962-12-31
Filing date: 1962-12-31
Publication date: 1965-09-14
Anticipated expiration: 1982-09-14

Description

Sept. 14, 1965 R. J. DEMAISON 3,206,1 i

PRODUCTION OF STEEL INGOTS Filed Dec. 31, 1962 4 Sheets-Sheet 1 Tlczi. [/6

p 1965 R. J. DEMAISON 3,206,154

PRODUCTION OF STEEL INGOTS Filed Dec. 31, 1962 4 Sheets-Sheet 2 INVENTOR fiwa/va JfiMA/Jd/V p 14, 1965 R. J. DEMAISON 3,206,154

PRODUCTION OF STEEL INGOTS Filed Dec. 31, 1962 4 Sheets-Sheet 3 Sept. 14, 1965 R. J. DEMAISON PRODUCTION OF STEEL INGOTS 4 Sheets-Sheet 4 Filed Dec. 31, 1962 M d 5w 3 M 5 m J M 0 2M W a w United States Patent 3,206,154 PRODUCTION OF STEEL INGOTS Raymond J. Demaison, Bronx, N.Y., assignor to Quigley Company, Inc., a corporation of New York Filed Dec. 31, 1962, Ser. No. 248,809 7 Claims. (Cl. 249-135) This application is a continuation-in-part of application Serial No. 27,408, filed May 6, 1960, which issued as US. Patent No. 3,163,898 on January 5, .1965.

This invention relates to the sealing of molds and stools used in the casting of steel ingots. The composition and methods described herein lend themselves very readily for use on worn stools and molds and provide a longer life for said molds and stools.

In the preparation of molds, stools and hot tops for teeming under the present state of the art, it is possible to do only a minor part of the repairs by the use of equipment, while the major part must be accomplished by hand. In the sealing of a mold and stool that has been badly eroded, the normal procedure is to seal the joint or space by means of a suitable refractory material placed around the outside of the mold, resulting in the [forming of ribs or tins in the space not completely caulked. Another problem which arises is that the caulking or scaling is not continuous, or the metal is teemed too fast into the mold, resulting in the metal in the tin not cooling rapidly enough to :prevent the pressure of the molten metal pushing out the caulking or sealing compound and thus causing the metal to run out, thereby necessitating the abandoning of the teeming of the mold and the loss of the metal already poured.

So it is easily seen how, under the existing practice, the formation of fins or ribs at the bottom of the ingot cannot be avoided once the mold and stool have become even slightly eroded. This condition does not exist on new stools as the surfaces are flat and therefore =fit tightly together, precluding the entrance of the molten metal. But conditions get worse after each pour, as the erosion is the result of teeming, and therefore sooner or later the molds and stools must be replaced with new ones.- With this situation in mind, the instant invention was conceived, first, to allow longer life of the molds and stools and, secondly, to prevent the formation of the ribs or tins on the ingots.

The removal of the ribs or tins is a necessity before further working of the ingot may be accomplished due to the danger of spoiling the complete ingot if worked on with the ribs or fins present. The common practice today is to burn or chip oif the ribs or tins and then grind the face to a clear even base of the parent metal. It is possible under certain conditions of cooling for the ribs or tins to bind in such a manner in the mold as to result in surface cracks in the ingot due to the forces developed in the ingot upon cooling or, in certain circumstances where the fins or ribs are of sufiicient thickness, to crack the complete ingot.

For the foregoing reasons, the existing method of caulking and sealing the molds and stools on the outside periphery has been very unsatisfactory due to the high costs that are involved and the loss of ingots due to leaks or cracks. The end result has been to greatly increase the costs which must be added to the ultimate steel production cost, necessitating a high product price.

Still another one of the problems facing the industry has been the difiiculty of obtaining a suitable composition for the caulking and sealing which would not, under the 3,206,154 Patented Sept. 14, 1965 heat of the teemed metal, generate steam and cause gas pockets in the ingot or which, if mixed too wet, might actually cause an explosion as the water and molten steel come into intimate contact inside the molds.

One of the main features of the present invention is to provide a suitable composition for [a sealing and caulking compound which can be applied to hot molds, stools and hot tops, which will not explode or generate a gaseous vapor, .and which will possess the necessary refractoriness to withstand the heats encountered in use. The material developed and being presented in the present invention is a light weight high temperature porous plastic refractory composition that may be mixed with any suitable heat consumable compounds, such as hydrocarbons or carbohydrates, thereby eliminating the danger of gassing or exploding. For use at higher temperatures, the composition may be modified by adding high temperature refractory grains in suitable state, such as preferably chrome ore in a finely divided state. The opera-ting temperature of the insulating refractory composition is about 2400 F, and this may be increased to 2850 'F. by adding chrome ore in varying amounts.

Another feature of the present invent-ion is to provide an insulating refractory composition which may be extruded or sprayed by a gun in plastic form. The instant insulating refractory composition is' mixed with oil and may be applied to the molds, stools and hot tops while they are still hot and thus seal them for the next teem without necessitating their cooling, thereby saving time.

The sealing methods disclosed herein are for use in the normal setup used in a steel plant. It must be remembered that in each steel plant the method employed in mold handling may be different from that employed in some other plant, and therefore the application of the instant methods may have to be fitted in, or tailored to, the methods of a particular plant.

The worn or eroded space or joint between the mold and stool may be sealed in two ways by the use of the insulating refractory composition in plastic form disclosed herein. Firstly, it may be accomplished by placing a suitable amount of the insulating refractory material in extruded form from an extrusion gun on the top face containing the worn area of the stool in a continuous form and then lower the mold thereon, causing the insulating refractory material to be squashed out into and till the space or joint between the two parts and thus seal up the join-t. 'If the stool is badly eroded, it may be necessary to make a plurality of the extruded forms side by each to thus create a positive seal. 1n placing the extruded insulating refractory material on the stool, this should be done with reference to the inside face of the mold so as to fill in the joint to said face and thus eliminate the possibility of any rib or fin formation. Secondly, the mold may be placed on the eroded stool in its normal teeming position and then the space or the joint that exists between the mold and the stool filled in with the refractory material from the inside face of the mold by the use of a long nozzle extrusion gun with a suitable extrusion pattern.

The sealing insulating refractory composition that is used to seal up the molds and stools will be removed and cleaned off said molds and stools and discarded after the ingots are removed Still another feature of the invention is to provide a means for sealing the joint or space at the junction of the hot top (mold extension) and the mold. In this instance, the insulating refractory material may be applied in plastic form by the use of an extrusion or spray gun as occasion may demand. In some cases, it may be necessary to use a nozzle that will fit into the spaces desired in order to facilitate the sealing.

It will now be seen that a new concept has been advanced by the instant invention in the method of sealing molds, stools and hot tops. By the practice of the invention, it is possible to prolong mold and stool life, procure ingots without fins or ribs and also preclude blowouts or explosions. The natural result is to reduce costs and save time and still produce a much better product.

In the drawings:

FIG. 1 is a cross sectional view of a typical cast iron or steel mold and stool, not very badly eroded, with a single pass of the extruded plastic porous insulating refractory material in place on the stool ready for lowering the mold thereon;

FIG. 2 is a cross sectional view of a typical cast iron or steel mold and stool, very badly eroded, with a plurality of passes of the extruded plastic porous insulating refractory material in place on the stool ready for lowering the mold thereon;

. FIG. 3 is a cross sectional view of a typical cast iron or steel mold and stool, very badly eroded, with the mold in place on the stool, and shows the use of a long extension extrusion gun with a suitable flat pattern nozzle for extruding the plastic porous insulating refractory material into the space or crack between the mold and the stool on the inside face of said stool only; and

FIG. 4 is a cross sectional view of a typical mold of cast iron or steel with a cast iron or steel hot top in place thereon. The hot top is equipped with the usual refractory lining and preshaped sealing brick on its bottom face wired in place. The sectional view clearly shows the method of sealing the space between the preshaped refractory brick and the mold by the use of a plastic porous insulating refractory material sprayed or extruded into place.

In the drawings, similar numbers are applied and used to identify similar parts in order to simplify the description.

Referring to FIG. 1, the mold may be tapered in any manner and the sides may be straight or fluted as deemed necessary for the proper teeming and cooling of the steel therein. On the stool 11, there has been placed an extruded section 12 of a plastic porous insulating refractory material in proper position with relation to the inside face of the mold and of sufficient cross sectional area to completely seal up the space or crack or joint which occurs when the mold 10 is lowered thereon. The extruded section 12 may be made in various forms, such as circular, square, rectangular, etc. It can readily be seen, therefore, that, by sealing said crack with the instant plastic porous insulating refractory material, the formation of any fins or ribs will entirely be eliminated notwithstanding the eroded condition of the contacting faces of both the mold and stool.

In FIG. 2, a plurality of extruded sections 12 of proper .cross section and placement are located on the stool 11 and the mold 10 then lowered into position. As the mold is lowered onto the stool, it will squash out the extrusions 12 and thus fill the space between the mold and the stool from the inside face of the mold outwardly toward the outside rim. The innermost section 12 is so located that, upon squashing, it will completely fill the space to the inside face of the mold, resulting in no fins or ribs when the mold is teemed.

FIG. 3 shows the mold 10 in place for teeming on a very badly eroded stool 11 with a wide crack or space therebetween. In this instance, the crack or space is sealed by the injection of plastic porous insulating refractory material 15 from an extrusion gun 30 which is equipped with a nozzle producing a flatter type extrusion. ,In order to allow the insertion of the sealing material in hot molds, the extrusion gun is equipped with a long stem or handle which allows the operator to keep above and off to one side away from the heated mold. It is not necessary to completely fill up said crack, as the heat from the mold and stool will immediately harden the composition. However, care should be taken to leave the composition flush with the inside face of the mold to preclude the possibility of forming fins or ribs.

FIG. 4 is a cross sectional view of the upper half of a cast iron or steel mold 10 with a standard commercial cast iron or steel refractory lined hot top 20 in place thereon. The hot top 20 has a precast refractory lining 21 and is supported on the mold at the proper height by means of spacer blocks 23. The cast iron or steel mold may be either straight sided or fluted as desired, and the usual metal wiper strip 24 as well as the usual preshaped refractory brick 25 are supported on the hot top 20 by means of wires 26 and 27 hooked into

holes

28 and 29 contained therein. The wiper strip and preshaped refractory brick are so formed and contoured as to allow clearance space over the entire periphery in order to place the hot top into the tapered mold, and it is this space which must be completely sealed in order to preclude the formation of ribs or fins on the top of the ingot. According to the present invention, the sealing of this space is accomplished by the use of a spray gun 31 which discharges the plastic porous insulating refractory material into the area 33 on top of said wiper strip and, in addition, by the use of a spray or extrusion gun 32 which discharges or extrudes the plastic porous insulating refractory material up into the area 34 between the refractory brick 25 and the mold side. In this manner, the entire periphery of the hot top may be sealed both top and bottom without any diificulty.

In the practice of this invention, cleanliness is an important factor. The molds should be thoroughly cleaned on their bottom sides and the stools must also be thoroughly cleaned and all scale and skelp removed as well as dirt and dust. The sealing material will pose no problem as it hardens on heating and can therefore be readily removed when the ingot is taken from the mold during the stripping and cleaning process. The same thing is true in stripping the hot top from the ingot. Also, where molds and stools are very badly eroded, it may be necessary to use an extremely large size nozzle in order to extrude the plastic porous insulating refractory composition in suflicient volume; hence it is important to have on hand a variety of extrusion tips in order to properly seal any space that may develop.

The insulating refractory material disclosed herein is such that when the heat is applied or when it is applied to a heated surface, the hydrocarbons or carbohydrates used for the mix are heat consumable and are immediately vaporized and fumed off and the composition allowed to solidify, thus avoiding the emission of any water vapor or steam under pressure such as would normally be the case with water mixed refractory compositions. The material can be supplied ready mixed in drums (52 gal.) which can be handled by suitable pressure guns such as the Alemite Versetal Gun or other pressure type tank guns in which it may be extruded or sprayed as desired. It may also be supplied in dry mix form in bags and mixed with light fuel oil, kerosene or other suitable hydrocarbon compounds and used as stated above. Some of the compounds that may also be used for mixing the composition are carbohydrates, such as molasses, linseed oil, cottonseed oil, mineral oil, etc.

The composition of the plastic porous insulating refractory material to be mixed with hydrocarbons or carbohydrates herein described is as follows:

( 1) Mineral fibers 5 to 15% (2) Insulating Porous Dust 25 to 40% (3) Hydraulic Setting Cement 25 to 40% (4) Fireclay 20 to 35% The insulating porous dust is a standard product made by taking plastic fireclay and mixing it with fiberized paper,

Sawdust and water and formed into bricks which are then fired at 2500 F. to burn out the carbonaceous material mixed therein to result in a highly porous refractory weighing from 40 to 50#/ cubic foot depending on the fineness and quantity of the fiberized paper. The bricks are then ground to such fineness as to pass through a 20 mesh screen.

In the above composition the mineral fibers that may be used are as follows:

(A) Basalt wool (melting temperature 2400 F.) (B) Asbestos (melting temperature 2350 F.)

One of the reasons why the above material is capable of being used immediately and safe to put on hot surfaces is the fact that it is porous and thus precludes blowing or creating internal pressure which may cause blowing. The gases are released internally and bled out through the pores of the composition to result in no problems even under extreme temperatures.

When the basalt wool fibers are used in the composition, the melting temperature is in the neighborhood of 2400 F. while if the asbestos fibers are used the melting temperature is only 220 F. The weight per cubic foot with either of the two fibers is approximately 604%.

The melting temperature of the insulating refractory material may be varied upward for use with metals of higher temperatures by adding any one of a number of suitable solid high temperature refractories in fine grain form in varying ratios. A typical example obtained by the use of chrome ore is as follows:

SampleNo u #1 The use of chrome ore in very fine grain form is preferred as it will intimately mix with the insulating refractory material and, as can be seen from the above table, increases the melting temperature of the composition. The weights of the resulting compositions will also increase in proportion to the amount mixed into said composition. Some of the other high temperature refractory grains that may be used are Bauxite, Aluminas, Silicas, Magnesites, etc.

From the above facts and disclosures, it will be appreciated that the composition disclosed herein can readily be modified in varying ratios to increase the melting temperatures as deemed necessary for any application.

The use of the basalt wool fiber is of extreme interest as the form of the fiber is long and amorphous and is non-hydroscopic, with the result that it is entirely free of water pickup such as can occur on damp days when the humidity is high. This is also inherently true of asbestos fibers.

The composition will be mixed with light fuel oil,

kerosene or other suitable heat consumable compounds to a proper plastic consistency suitable for spraying or extruding under pressure in a suitable gun. It may therefore be used on hot molds for sealing with no danger of steaming or explosions.

The same composition with slight modifications may be used with water if desired to seal the molds and stools at lower temperatures and allow them to stand for a short period of time to dry out before using. It is not necessary that the insulating refractory composition dry hard as it may be remembered that the composition is porous and in itself allows the vapors released in drying out and setting to be relieved through the pores.

6 The composition of the plastic porous insulating refractory material to be mixed with water is as follows:

Percent (1) Mineral fibers 5 to 15 (2) Insulating porous dust 25 to 40 (3) Hydraulic setting cement 25 to 40 (4) Fireclay 20 to 35 (5) Aluminum powder 0.1 to 0.5

Such a composition is well known and is being presently made and sold under the trademark Insulag.

In the above composition the mineral fibers that may be used are as follows:

When the basalt wool is used in the composition described above as the mineral fibers the melting temperature is in the neighborhood of 2400 F. while if the asbestos fibers are used the melting is only about 2200 F. The weight per cubic foot with either of the two fibers is approximately 38 to 40#.

In this instance the melting temperatures of the com position may again be varied upward as in the first composition by the addition of suitable solid high temperature refractories in fine grain form in varying ratios.

While the invention has been described in connection with the steel industry, it is not limited thereto, but is intended to cover such variations as are equivalent in composition structure and function.

What is claimed is:

1. A steel ingot mold and end closure member having a seal located in the space between them to prevent the escape of molten steel from the mold cavity into said space, said seal consisting of a composition which com prises light weight fibrous porous plastic insulating re" fractory material consisting essentially of from 5 to 15% of mineral fibers, 25 to 40% of insulating porous dust, 25 to 40% of hydraulic setting cement, and 20 to 35% of fireclay.

2. A steel ingot mold and end closure member according to claim 1, wherein the light weight fibrous porous plastic insulating refractory material is mixed with a suitable heat consumable compound.

3. A steel ingot mold and end closure member according to claim 1, wherein the sealing composition also comprises solid high temperature refractory grains in finely divided form mixed with the light weight fibrous porous plastic insulating material and having a substantially higher melting point.

4. A steel ingot mold and end closure member according to claim 1, wherein the sealing composition also comprises solid high temperature refractory grains in finely divided form mixed with the light weight fibrous porous plastic insulating material in ratios of from 3 to 1 to 7 to 1.

5. A steel ingot mold and end closure member according to claim 1, wherein the weight of the sealing composition after setting is approximately 60# per cubic foot.

6. A steel ingot mold and end closure member having a seal located in the space between them to prevent the escape of molten steel from the mold cavity into said space, said seal consisting of a composition which comprises light weight fibrous porous plastic insulating re fractory material consisting essentially of from 5 to 15 of mineral fibers, 25 to 40% of insulating porous dust, 25 to 40% of hydraulic setting cement, 20 to 35% of fireclay, and 0.1 to 0.5% of finely divided aluminum powder.

7. A steel ingot mold and end closure member according to claim 6, wherein the weight of the sealing composition after setting is approximately 38 to 40# per cubic foot.

(References on following page) References Cited by the Examiner UNITED STATES PATENTS Kelly 106-204 Thackray 22-139 Adams 22-139 Seigle 106-286 Lindemuth 22-139 Lindernuth 22-139 Daussan 106-55 Sterick 22-139 Yerrick 22-147 Marie et a1 22-147 s 8 FOREIGN PATENTS 3/26 Great Britain.

WILLIAM J. STEPHENSON, Primary Examiner.

MARCUS U. LYONS, MICHAEL v, BRINDISI,

Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N00 3,206,154 September 14, 1965 Raymond J. Demaison It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line line 25, for "220 F." read 2200 F.

Signed and sealed this 5th day of April 1966.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner of Patents

Claims

1. A STEEL INGOT MOLD AND END CLOSURE MEMBER HAVING A SEAL LOCATED IN THE SPACE BETWEEN THEM TO PREVENT THE ESCAPE OF MOLTEN STEEL FROM THE MOLD CAVITY INTO SAID SPACE, SAID SEAL CONSISTING OF A COMPOSITION WHICH COMPRISES LIGHT WEIGHT FIBROUS POROUS PLASTIC INSULATING REFRACTORY MATERIAL CONSISTING ESSENTIALLY OF FROM 5 TO 15% OF MINERAL FIBERS, 25 TO 40% OF INSULATING POROUS DUST, 25 TO 40% OF HYDRAULIC SETTING CEMENT, AND 20 TO 35% OF FIRECLAY.