US3508615A

US3508615A - Composite pouring tube

Info

Publication number: US3508615A
Application number: US681804A
Authority: US
Inventors: Walter C Troy
Original assignee: Amsted Industries Inc
Current assignee: Amsted Industries Inc
Priority date: 1967-11-09
Filing date: 1967-11-09
Publication date: 1970-04-28
Anticipated expiration: 1987-04-28

Description

A ril 28, 1970 w. c. TROY 3,508,

COMPOSITE POURING TUBE Filed Nov. 9, 1967 2 Sheets-Sheet l FIG.|

INVENTOR. V i/ A LT ER C. TROY ATT'YS April 28, 1970 w. c. TROY COMPOSITE POURING TUBE 2 Sheets-Sheet 3 Filed Nov. 9, 1967 was I INVENTOR. WALTER CTROY FIG.2

ATT'YS United States Patent 3,508,615 COMPOSITE POURIN G TUBE Walter C. Troy, Evanston, Ill., assiglor to Amsted Industries Incorporated, Chicago, Ill., a corporation of New Jersey Filed Nov. 9, 1967, Ser. No. 681,804 Int. Cl. B22d 37/00, 41/00 US. 'Cl. 164-433 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a method and article for transferring molten metal from one vessel to another and more particularly to a pouring tube that is immersed in the molten metal to be cast.

Pouring tubes used for transferring molten iron or steel from a ladle or other vessel into a mold are normally composed of a refractory material that resists high temperature attack by the melt. A primary disadvantage found in the use of such pouring tubes resides in the porosity of the refractory material, which may result in the undesirable penetration of air or other gasses through the pouring tube and into the molten metal passing therethrough. Especially in pressure pouring operations wherein the melt is forced upwardly from a ladle through the pouring tube and into a mold, gasses entrained in the molten stream may cause serious defects in the resultant casting.

Several proposals to prevent gas penetration have involved the provision of an impermeable sleeve, usually composed of steel, around the pouring tube, such as de scribed in Patent 3,279,003 to Yates. However, since the lower portion of the pouring tube is immersed in the molten metal, difiiculties may arise in preventing disintegration of the protective sleeve.

Accordingly, an object of this invention is to provide a composite pouring tube that will be effective to prevent gas penetration therethrough, notwithstanding the immersion of the tube in molten metal.

Other objects will appear from the following description taken in connection with the accompanying drawings, wherein:

FIGURE 1 is a small scale sectional view showing the use of a pouring tube in conjunction with a ladle and mold in a pressure pouring arrangement;

FIGURE 2 is a large scale longitudinal sectional viewof a pouring tube embodying the features of the present invention; and

FIGURES 3 and 4 are more detailed views of the bracketed portion of FIGURE 2, which illustrate the function of the present invention.

With reference now more particularly to FIGURE 1, the pressure pouring arrangement shown comprises, a ladle open at the top thereof and disposed in a substantially sealed tank 12 having a removable cover 14. A A pouring tube 16 is disposed through an opening in tank cover 14 and extends from a lower portion of ladle to a mold, shown schematically at 18, which is positioned above the cover. In order to initiate the ouring operation, molten metal is introduced into the ladle 10 to a line indicated approximately at 20, and the ladle is placed in the tank 12. Cover 14 is then applied, and the pouring tube is immersed in the melt. A mold 18 is then placed in communication with the top of the pouring tube 16.

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Pouring is then commenced by introducing pressurized pneumatic fluid, such as air, into the tank 12 through a tank inlet 22.

It may thus be seen that the pouring tube 16 must be capable of immersion in liquid steel for extended periods. Moreover, that portion of the tube 16 above the molten metal line 20 must be capable of resisting penetration by air in the tank 12, especially because of the pressure differential between the pressurized tank interior and the molten metal in the pouring tube.

The pouring tube shown in FIGURE 2 provides a solution to the above problems by providing a gas impermeable sleeve around only that portion of the tube above the line of the molten metal or slag. As shown, the pouring tube comprises an upper head assembly 24, which supports the pouring tube in the opening 26 of the cover 28. The head assembly 24 includes an inner ferrule 30 surrounding the refractory tube 32 and having an inwardly extending flange 34 at the lower end thereof. The upper portion of ferrule 30' has an outwardly extending flange 36, which rests on the inner periphery of a ring member 38 that rests on cover 28. A retaining ring 40 is secured around inner ferrule 30 and to ring member 38 by cap screws 42 or the like, with an asbestos gasket 44 therebetween. A collar 46 having a downwardly extending flange 48 is fitted over an engaging shoulder 50 of the inner ferrule 30.

Ferrule 30 is provided with a bore 52 between its internal and external surfaces, said bore communicating with an aperture 53 in the retaining ring 40, thereby providing a vent between the refractory tube 32 and the atmosphere. In assembling the head assembly 24 to the upper portion of the refractory tube 32, steel wool 54 or the like is inserted above the interior outlet 56 of the ferrule bore 52, and ceramic grout 58 is rammed between the ferrule and the refractory tube 32. The collar 46 is then placed on the assembly.

An impermeable and temperature resistant sleeve 60, such as a bare steel tube of about one-eighth inch thickness is provided around an intermediate portion of the refractory tube 32 below the interior outlet 56 of the ferrule bore 52, with the ferrule 30 overlapping the sleeve. The impermeable sleeve 60 is held in positionby means of ceramic grout 62 rammed between the ferrule 30 and said sleeve. The diameter of the sleeve 60 is greater than the diameter of the refractory tube 32, such that an annular space 66 is provided therebetween communicating with the ferrule bore 52 and thus with the atmosphere. In addition, a temperature resistant or refractory wrapping 64 may be provided around the lower exposed portion of the sleeve 60, although this is not essential to the proper functioning of the pouring tube.

The impermeable sleeve 60 extends downwardly for only a portion of the refractory tube 32 and preferably is of such a length that only a relatively short length of the sleeve, on the order of about two inches or more, will extend below the slag and molten metal line when the pouring tube is inserted into the ladle. That portion of the sleeve and any covering thereon which are submerged in the molten metal rapidly melt and are separated from the assembly.

The function of the pouring tube during the pouring operation is best understood by reference to FIGURES 3 and 4. FIGURE 3 illustrates the position of the composite pouring tube relative to the molten metal 70 and any slag 72 that may be floating at the top of the melt prior to the raising of the molten metal in the refractory tube 32 by the application of superatmospheric pressure thereto. As shown by dotted lines at 74, that portion of the sleeve 60 immersed in the molten metal 70 disintegrates, and the annular space 66 is blocked at the molten metal line by partially solidified slag and metal. Thus, a relatively impermeable shield is provided around that portion of the refractory tube which would otherwise be exposed to the superatrnospheric pressure. Any volume or pressure increase in the gas within the annular space 66 will be vented through the ferrule bore 52 (FIG. 2).

As the pouring operation is commenced and the molten metal 70 is raised in the refractory tube 32, the molten metal line around the tube is successively lowered, exposing corresponding successive portions of the tube that are not surrounded by the sleeve 60 as shown in FIGURE 4. Such exposure, however, has not been found to be detrimental, since a thin protective layer of molten metal and possibly slag, such as that layer indicated at 76, is retained on the outer surface of the refractory tube 32.

It should be understood that the above explanation of the function of the present invention is necessarily based on observations made of the composite pouring tube after completion of the pouring operation and on the basis of other indirect observations, since it is virtually impossible to visually inspect the tube during the actual pouring operation because of the extreme temperature and pressure. The impermeable sleeve 32, of course, must be replaced with each pouring operation, while the refractory tube 32 may be reusable.

It should also be understood that various modifications may be made to the structure of the composite pouring tube described herein without departing from the scope of the appended claims.

Having thus described the invention, what is claimed 1. In a pressure pouring operation employing a refractory pouring tube that is partially immersed in molten metal during said operation, a process for preventing penetration of gasses through the pouring tube comprising disposing a bare impermeable sleeve around a portion of said refractory pouring tube, and immersing said refractory pouring tube in the molten metal such that a portion of said impermeable sleeve is brought into direct contact with the molten metal and melted.

2. The process of claim 1 comprising the additional step of venting the space betweensaid refractory pouring tube and said impermeable sleeve to the atmosphere prox imate the upper end of said sleeve.

3. Composite pouring tube for partial immersion in molten metal comprising a refractory tube, a bare impermeable sleeve disposed around an intermediate portion of said tube and composed of a material that melts upon contact with said molten metal, said impermeable sleeve being of larger diameter than said tube and being so positioned such that a portion thereof is brought into direct contact with the molten metal with the immersion of said refractory tube.

4. The invention according to claim 3 wherein means are provided proximate the upper portion of said sleeve for venting the space between said sleeve and said tube to the atmosphere.

5. Composite pouring tube for use in connection with pressure pouring wherein a ladle containing molten metal is disposed in a tank and said pouring tube extends from a lower portion of said ladle through an opening in the top of the tank and communicates with a mold, and wherein that portion of the pouring tube between the molten metal line in said ladle and the top of the tank is exposed to superatmospheric gas pressure during the pouring operation, said composite pouring tube comprising a refractory tube extending from said lower portion of the ladle to said mold, means for supporting said refractory tube in said opening in the top of the tank, a bare metal sleeve around an intermediate porton of said tube and supported by said last-mentioned means, said metal sleeve being of suflicient length to extend slightly below the molten metal line in said ladle when said refractory tube is in position near the bottom of the ladle, an annular space between said refractory tube and said metal sleeve along the entire length of said metal sleeve, and vent means communicating with an upper portion of said annular space for venting said annular space to the atmosphere.

'6. The invention according to claim 5 wherein a temperature resistant wrapping is provided around said metal sleeve.

7. In conjunction with a pressure pouring operation wherein a ladle containing molten metal is disposed in a substantially sealed tank, a refractory pouring tube is inserted through an opening in the top of the tank to a position near the bottom of the ladle, and a mold is positioned above said tank in communication with said refractory pouring tube, and wherein superatmospheric .gas pressure is applied in said tank to force the molten metal upwardly through the refractory pouring tube and into the mold, that portion of the refractory pouring tube between the molten metal line and the top of the tank being initially exposed to superatmospheric gas pressure, the process of preventing penetration of gasses through said pouring tube and into the molten metal passing therethrough, said process comprising disposing a bare relatively impermeable metal sleeve around said exposed portion of the refractory tube prior to its insertion into the molten metal, said metal sleeve being of sufficient length to extend slightly below the molten metal when said refractory tube is placed in pouring position, placing the thus formed pouring tube assembly in pouring position such that the lower portion of said metal sleeve comes into direct contact with said molten metal and is melted, and applying superatmo'spheric pressure in said tank.

References Cited UNITED STATES PATENTS 1,184,523 5/1916 Field 164-133 XR 2,379,401 6/ 1945 Poulter 16463 3,279,003 10/1966 Yates 138-l49 XR THERON E. CONDON, Primary Examiner H. A. KILBY, JR., Assistant Examiner US. Cl. X.R. 164337