US3341092A

US3341092A - Nozzle construction with thermally expanding refractory insert

Info

Publication number: US3341092A
Application number: US393523A
Authority: US
Inventors: Alfred E Finn
Original assignee: Harbison Walker Refractories Co
Current assignee: Harbison Walker Refractories Co
Priority date: 1964-09-01
Filing date: 1964-09-01
Publication date: 1967-09-12
Anticipated expiration: 1984-09-12

Description

Sept. 12, 1967 A. E. FINN 3,341,092

NOZZLE CONSTRUCTION WITH THERMALLY EXPANDING. REFRACTORY INSERT Filed Sept. 1, 1964 INVENTOR. ALFRED E. FINN United States Patent Ofiice 3,341,092 Patented Sept. 12, 1967 3,341,092 NOZZLE CONSTRUCTION WITH THERMALLY EXPANDING REFRACTORY INSERT Alfred E. Finn, Pittsburgh, Pa., assignor to Harbison- Walker Refractories Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Sept. 1, 1964, Ser. No. 393,523 3 Claims. (Cl. 222-566) The present invention relates to improved bottom pour ladle nozzle construction, and more particularly to improved bottom pour ladle nozzle and refractory liner insert construction.

Particularly in the manufacture of steel and steel alloys, it is conventional to tap molten metal from a furnace into a ladle in a pouring pit. The pouring pit is usually at a lower elevation than the floor on which the metal lur-gical furnaces reside, so that the molten metal may flow by gravity from the furnace to the ladle. Spaced from the furnace are a plurality of ingot molds, and the ladle of molten metal is moved through the pouring pit to a position above these ingot molds. Molten metal is poured from the ladle into the ingot molds to form ingots. Usually, the metal is poured from the ladle through a nozzle, which opens through the bottom thereof. These nozzles have been the source of many difficulties. The refractories, which are employed in such pouring nozzles, have Worn at excessive rates or have had pieces crack and spall away, by reason of heat shock and contact with molten metal and slags. One of the primary problems is that these pieces of refractory find their way into the castings and form foreign inclusions'and flaws, which harm the quality of a final product made from that casting.

Heretofore and presently, the trade almost exclusively uses fireclay refractories for these nozzles. Fire clays have been used because they are somewhat plastic at elevated temperatures and are, therefore, expected to promote better sealing with a stopper to prevent further flow of the metal. However, mineralogically, fireclay refractories are not best suited for contact with molten metal and slag. Such refractories are of relatively low refractoriness and have tended to be rather rapidly consumed during pouring, with the eroded material lodgingwithin the ingots. This has caused variation in nozzle orifice diameter as the pouring proceeds, thereby varying pouring rate.

Accordingly, it is an-object of the present invention to provide an improved refractory pouring nozzle construction.

Another object of the invention is to provide a refractory liner insert for use with existing refractory pouring nozzles.

A further object of the invention is to eliminate many of the problems heretofore encountered in pouring molten metal.

Other objects of the invention will be apparent hereinafter.

In order to more fully understand the nature and objects of the invention, reference should be had to the following detailed description and drawings in which:

FIG. 1 is an elevation view partly in cross section of a bottom pour ladle and nozzle assembly;

FIG. 2 is an elevation view partially in cross section of the lower portion of a bottom pour ladle illustrating a particular embodiment of this invention; and

FIGS. 3a and 3b are elevation views in cross section of the bottom section of a pouring nozzle illustrating other embodiments of the instant invention.

Briefly, according to an embodiment of the present invention, there is provided an improved bottom pour ladle nozzle construction. The improvement comprises an open ended, hollow cylindrical refractory nozzle liner insert disposed within the surface areas of the nozzle, which define the outlet of the nozzle. The refractory insert is expandable at operating temperatures, to which the nozzle is subjected to a degree sufiicient to provide a contiguous seat, substantially conforming to adjacent surface areas of the nozzle which define said outlet. There is also provided means cooperating with the insert disposed exterior to, but adjacent, the outlet of the nozzle, to hold the nozzle insert in place prior to the maintenance of said operating temperatures.

The refractory nozzle liner may be composed of any high quality refractory material, such as zircon, high alumina refractory (i.e. at least about A1 0 by weight, is preferred), and high mangesia refractory (i.e. at least about 90% MgO, by weight). Accordingly, such a liner insert may be employed, in combination with a pouring nozzle composed of a relatively low quality refractory material, such as fire clay, in order to greatly reduce erosion of the composite pouring nozzle when it is subjected to molten metal, as previously was experienced with an all fireclay refractory nozzle not having a liner insert.

Another advantage of the nozzle liner is that it is versatile, i.e. can be fabricated and stocked in various wall thicknesses and orifice diameters regardless of the dimensions of the ladle. The nozzle must fit the ladle. The size of the liner is related to the nozzle and, as long as the outer diameter of the liner closely approximates the inner diameter of the nozzle, the thickness and orifice of the liner can vary. In the processing of molten metals, quite often heat orders (one which specifies a certain pouring rate) are changed before and during tapping. A nozzle without a liner is inflexible, since it has a set orifice diameter. Accordingly, when the above contingency arises, a liner having an orifice diameter, suitable to accommodate a specific pouring rate, may be slid into the nozzle orifice without much delay. This, of course, improves the economy of the operation.

Referring to FIG. 1, there is shown a bottom pour ladle having a nozzle and liner assembly according to this invention. Such a ladle normally includes an outer metal shell 10 lined with a suitable refractory composition. The sidewalls 11 of the ladle are commonly lined with alumina-silica ladle brick,-since they are inexpensive yet satisfactory in most instances. The bottom of the ladle includes an outer metal shell '12, also lined with a refractory composition 13, usually similar to that which is used to line the sides. A slag lip 14 opens through a portion of the upper periphery of the sidewall and is usually fabricated of a refractory monolith. Opening through the bottom, adjacent the sidewall, is a noZZle 15. The nozzle is lined at the outlet portion with a refractory insert 16. A downwardly extending stopper rod 17, terminating in a stopper head 18, is axially aligned with the nozzle inlet.

According to one aspect of the invention, the outer diameter of the liner insert closely conforms to the inner surface areas of the nozzle which define the outlet. The nozzle 16 may be temporarily seated within said outlet, by use of a mortar, until the hot metal is released through the nozzle. Upon pouring of the metal, the heat generated will cause the insert to sufiiciently expand and firmly seat it in place during the remainder of the pouring operation.

In FIG. 2 there is shown the bottom of the ladle of FIG. 1, illustrating another aspect of the instant invention. After inserting the refractory nozzle liner 16, into the outlet portion of the nozzle 15, a ring-shaped metal member 20 is disposed closely adjacent the surface areas of the nozzle, exterior of the nozzle proper, which is held in place by a cantilever support. The aperture 21, in the ring member 20, is of slightly larger diameter than the inner diameter of the liner insert and is aligned with the hollow in the insert, so that the leading edges of the aperture, in the ring, extend about /2 the distance of the wall thickness of the liner insert toward the hollow thereof. This is to allow the ring member to retain the insert 16, in place, until operating temperatures have been reached, to allow the insert to expand for permanent seating without permitting the ring member to be exposed to the fiow of molten metal. The ring member may be welded or otherwise joined to a bracket 22, which is attached to a shaft 24. The shaft 24 has a bent portion 25 which is seated in a hook 26, or other means, to provide the cantilever support. The hook 26 may be secured to the ladle at the tangential joint-ure of metal shells and 12. Thu when desired, the retaining ring member may be removed from the nozzle by lifting the handle 27 of the shaft 24 operably connected to the ring.

With reference to FIGS. 3a and 3b, there are shown other specific embodiments of the present invention. Here, the open ended, hollow refractory nozzle liner insert 16 contains an outer peripheral flange 28 at the lower end thereof. Thus, only a portion of the insert is disposed within the surface areas of the nozzle 15 which define said outlet. The peripheral flange is exterior to the outlet but is contiguous to the lower end of the outlet.

Metal ring members

30 and 32, having a configuration as shown in FIGS. 3a and 3b, respectively, are joined to the nozzle insert 16 at the outer surfaces of flange 28 by methods well known in the art. Metal band members 34 and 36, as shown in respective FIGURES 3a and 3b and of a design particularly suited to each application, are welded or otherwise joined at one end to the metal ring members. The other end of the metal band member contains a lip 38 that is inserted in a peripheral groove or slot 40, at the lower end of the nozzle 15. Accordingly, the nozzle liner insert 16 is fitted .into the outlet of the nozzle 15; and the lipped band is adjusted so that the lip portion of each band falls securely in place in the peripheral groove of the nozzle, to insure that the liner insert remains in place, prior to the maintenance of temperatures sufficient to expand the liner into a tight fitting relationship with the inner surfaces of the nozzle.

While the invention has been described with reference to a particular embodiment, it will be understood, of course, that modifications, substitutions, and the like may be made therein without departing from its scope.

Having thus described the invention in detail and with sufficient particularity as to enable those skilled in the art to practice it, what is desired to have protected by Letters Patent is set forth in the following claims.

I claim:

1. In combination with bottom pour ladle refractory nozzle construction, said nozzle having an inlet and an outlet, an open ended, hollow cylindrical refractory nozzle liner insert disposed within the surface areas of the nozzle which define said outlet, said refractory insert being expandable at operating temperatures to a degree suflicient to provide a contiguous frictionally engaging seat substantially conforming .to adjacent surface areas of the nozzle which define said outlet and means cooperating with said insert disposed exterior to but adjacent the outlet of the nozzle to temporarily hold said nozzle insert in situ prior to maintenance of operating temperatures.

2. The combination with a refractory pouring nozzle having an inlet and an outlet, of an open ended, tubular refractory nozzle insert disposed within the surface areas of the nozzle which define said outlet, means cooperating with the nozzle and insert arranged for temporarily holding the insert in place until the combination is subjected to operating temperature, said insert arranged to expand upon subjection to said operating temperature to frictionally engage adjacent surface areas of the nozzle and provide a positive seal against penetration of molten metal.

3. The combination with a refractory pouring nozzle of the fireclay type having an inlet and an outlet, of an open ended, tubular refractory nozzle insert disposed within the surface areas of the nozzle which define said outlet, the insert fabricated of a refractory material different from the nozzle and which has a greater thermal expansion at operating temperatures whereby to expand within said nozzle and trictionally engage adjacent portions of said nozzle and provide a positive seal against flow of molten metal therebetween, and means cooperating with said nozzle and insert arranged to temporarily hold them in relative position until said insert expands at operating temperatures.

References Cited UNITED STATES PATENTS 1,832,873 11/1931 Milner 137-801 2,424,878 7/1947 Crook 29-493 2,799,067 7/ 1957 Peterson 249202 FOREIGN PATENTS 919 11/1915 Great Britain. 948,358 1/ 1964 Great Britain.

OTHER REFERENCES Mantell, C. L, Industrial Carbon, 1946, pp. 367, 369.

I. SPENCER OVERHOLSER, Primary Examiner.

R. D. BALDWIN, Assistant Examiner,

Claims

1. IN COMBINATION WITH BOTTOM POUR LADLE REFRACTORY NOZZLE CONSTRUCTION, SAID NOZZLE HAVING AN INLET AND AN OUTLET, AN OPENING ENDED, HOLLOW CYLINDRICAL REFRACTORY NOZZLE LINER INSERT DISPOSED WITHIN THE SURFACE AREAS OF THE NOZZLE WHICH DEFINE SAID OUTLET, SAID REFRACTORY INSERTED BEING EXPANDABLE AT OPERATING TEMPERATURES TO A DEGREE SUFFICIENT TO PROVIDE A CONTIGUOUS FRICTIONALLY ENGAGING SEAT SUBSTANTIALLY CONFORMING TO ADJACENT SURFACES AREAS OF THE NOZZLE WHICH DEFINE SAID OUTLET AND MEANS COOPERATING WITH SAID INSERT DISPOSED EXTERIOR TO BUT ADJACENT THE OUTLET OF THE NOZZLE TO TEMPORARILY HOLD SAID NOZZLE INSERT IN SITU PRIOR TO MAINTENANCE OF OPERATING TEMPERATURES.