US3352530A

US3352530A - Bottom ring for a hot top

Info

Publication number: US3352530A
Application number: US324565A
Authority: US
Inventors: Darold W Thiem
Original assignee: Individual
Current assignee: Universal Refractories Corp
Priority date: 1963-11-18
Filing date: 1963-11-18
Publication date: 1967-11-14
Anticipated expiration: 1984-11-14

Description

Nov. 14, 1967 D. w. THIEM BOTTOM RING FOR A HOT TOP Filed Nov. 18, 1963 INVENTOR. DAROLO w. THIE M LAZO 8 BARRY ATTORNEYS United States Patent 3,352,530 BOTTOM RING FOR A HOT TOP Darold W. Thiem, 650 N. Sunnyslope Road, Elm Grove, Wis. 53122 Filed Nov. 18, 1963, Ser. No. 324,565 2 Claims. (Cl. 249202) This invention relates to an improved hot top bottom ring and more particularly to a novel Wiper strip for a bottom ring and the method of mounting such a strip on a single-use refractory ring.

This application constitutes an improvement on hot top bottom ring structures set forth and claimed in co-pending application, Ser. No. 108,203, filed May 5, 1961, now Patent No. 3,110,942, assigned to the same assignee.

The bottom ring structure disclosed in the co-pending application utilized a single-use refractory ring either of unitary of sectionalized construction on which a wiper strip had been mounted. The wiper strip included an integral wiper blade which projected outward angularly from .the refractory ring to yieldably engage the wall of the associated ingot mold. This blade acted as a seal, in that the molten metal as it rises in the hot top will fill the gap between the hot top and the ingot mold until it comes into contact with the wiper blade. It had been found that the molten metal will chill or set when it engages the wiper blade, setting up a seal in the gap around the bottom ring. The wiper blade was made of relatively thin metal and at times the molten metal burned through the blade without chilling, resulting in an overflow of the ingot molt in the gap between the hot top and the ingot mold more generally known as a leaker.

One of the principal objects of the present invention is .to provide an improved Wiper strip for a hot top bottom ring that'reduces the possibility of overflowing the ingot mold during pouring.

Another object of the present invention is to provide an improved wiper strip that is readily adaptable to a continuous' method of manufacture.

A- further object is to provide an improved wiper strip 'for a bottom ring that will produce a secondary chilling the outer periphery of a refractory ring in a single operation.

A still further object is to provide a hot top bottom ring that can be quickly and easily aligned on the periphery of a refractory ring.

These objects are accomplished by forming a wiper strip from a single strip of thin metallic material with a base leg and a side leg which intersect at an angle corresponding to the angle between the base and side of a refractory ring. The side leg is formed with an integral section having a crescent or semi-cylindrical shaped or a V or U shaped cross section which extends longitudinally of the side leg intermediate its edges. Groups of slots are provided in the integral section at spaced intervals with a group of notches provided in the base leg opposite each group of slots to allow for bending of the wiper strip around the corners of the refractory ring. The wiper strip is mounted on the refractory ring by wrapping it around the periphery of the refractory ring until its ends overlap. To aid in locating the wiper strip on the refractory ring a notch may be provided on one side of the ring with a corresponding indentation in the wiper strip. When the wiper strip is aligned with the side and base of the refrac- "ice tory ring, the indentation will seat in the notch preventing any further movement of the wiper strip on the surface of the refractory ring.

The sides of the wiper strip are generally heated and the ends overlapped and welded together. As the heated sides cool, they will shrink, pulling the wiper strip tightly into position on the refractory ring with the base leg and side leg of the wiper strip matingly engaging the base and side of the refractory ring, placing the entire ring in compression. When the bottom ring is clipped into position on the bottom of a hot top casing and the hot top placed in an ingot mold, the integral section will substantially bridge the gap between the bottom ring and the surface of the inside wall of the ingot mold. As molten metal rises in the gap between the refractory ring and the mold, it will first engage the lower portion or wall of the integral section. A chilling effect will be produced in the molten metal which will normally cause it to set, forming a seal. In the event that the molten metal is not chilled sufiiciently to set, it will burn through the lower portion of the integral section and rise up into engagement with the upper portion or wall of the integral section. A second chilling effect will then occur which will set the molten metal that has burned through the lower portion or wall. This second chilling eiiect gives additional assurance that the molten metal will not overflow during the pouring operation.

Other objects and advantages will become more readily apparent from the following detailed description when read in connection with the accompanying drawings, in which:

FIG. 1 is a view in perspective of a typical hot top showing the bottom ring in partially broken sectional form clipped to a hot top casing.

FIG. 2 is an enlarged sectional view taken on line 2 2 of FIG. 3 showing the wiper strip offset from a refractory rmg.

FIG. 3 is a view of the bottom ring inverted to show the wiper strip mounted on the refractory ring and aportion of the wiper strip broken away to show the locator.

FIG. 4 is a view in perspective of a wiper strip with the integral section having a crescent-shaped cross section.

FIG. 5 is a view in cross section of a wiper strip' having a V-shaped integral section.

FIG. 6 is a partial view in cross section showing the .integral section of a wiper strip bridging the gap between a hot top is shown having a bottom ring lfl mounted on the bottom of a hot top casing 12. Any conventional means may be used to hold the bottom ring in position on the hot top casing such as clips 15. The hot top casing shown is of standard design having a metal case 14 and a pair of trunnious 16 (only one shown) for transporting the hot top in the mill. The inner wall of the case is lined with a number of refractory bricks 18 which are held in position by mortar or cement. This type of hot top casing is shown for illustrative purposes only since the bottom ring of the present invention can be used with any of the known types of casings.

The bottom ring includes a refractory ring 20 which is formed from a refractory material held together with a binder and either baked or bonded together at the manufacturing point. The ring shown is of unitary construction, but may be made from two U-shaped sections or four L- shaped sections depending on the size of the ring. A locating notch 48 may be provided in one side of the refractory ring if desired.

A wiper strip 22 is Wrapped around the refractory ring by hand and its ends 24 overlapped slightly so that they can be welded together. The strip is formed with a base leg 25 and a side leg 26 with the acute angle a between these two legs substantially the same as the acute angle 11 between the base 27 and side 29 of the refractory ring. An integral section 28 having a crescent or semi-cylindrical shape (FIG. 2) is provided on the side leg and projects outward beyond the lower corner 30 of the refractory ring.

The wiper strip can be formed by many different methods, but a two-step operation is preferred. In the first step, the strip is cutto the desired length and slotted. The length of the strip will be slightly longer than the circumference of the refractory ring so that the ends can be overlapped for Welding.

Slots

40 and 42 are provided in the integral section and notches 44 are stamped in the base leg. Slots 40 and notches 44 are located at intervals corresponding to the ditsance between corners of the refractory ring. Slots 42 are located at the points where clips 15 are to be used to hold the bottom ring on the hot top. An indentation or dimple 48 can be pressed into the side leg below the integral section in the forming operation at a point equidistant from the ends of the strip. In the second step, the wiper strip is placed in a forming die in order to form the angle betweenthe base leg and side leg and the shape of the integral section. With this process of manufacturing the wiper strips, they can be stored and shipped in straight or flat sections and mounted on the refractory ring in a single operation.

The wiper strip can be mounted on the refractory ring by a single individual in one operation by holding the ends of the wiper strip with the wiper bent in a loop. The wiper strip is then positioned around the outer periphery of the refractory ring with the base leg and side-leg in abutting relation to the base and side of the refractory ring. The ends of the wiper strip are pulled tight until they overlap. The slotted and notched sections of-the wiper strip are extremely flexible and will bend freely around the corners of the refractory ring in close engagement therewith. If the indentation is provided in the wiper strip, it will be aligned with the notch in the refractory ring, positively locating the strip so that the ends are overlapped at the midpoint on the opposite side of the refractory ring. This is importhe wiper strip arepulled tightly, overlapped and welded.

As the heated sections of the strip cool, they will shrink, drawing the strip into tight engagement with the refractory ring. This prestresses the'ring, increasing its strength considerably as more completely described in the co-pending application.

Referring to FIGS. 6 and 7 a broken sectional view of 4 the bottom ring and wall of an ingot mold is shown. The integral section 28 will engage the wall of the ingot mold or be spaced slightly away from the wall, leaving a small gap. If the wiper ring is squeezed between the ingot mold and the bottom, it is sufiiciently flexible so that it will not break off. In FIG. 6, the molten metal is shown in engagement with the lower wall 32 of the formed section. The molten metal will melt the wiper strip, but the metal in the strip will normally produce a chill effect in the molten metal that causes the outer skin 50 of the molten metal to set, sealing the gap. If the heat of the molten metal burns through the outer skin of set steel, it will rise up into engagement with the second wall 34 (FIG; 7) where a secondary chill-effect occurs. Since the exposed surface of the rising molten metal has already undergone a primary chilling effect at the lower wall, the upper wall will cause a second chill effect that guarantees that the metal will set. 1

The same effect will be produced'by a V-shaped integral section 36 as shown in FIG. 5. The lower wall 38 of the V-shaped section will be engaged by the molten metal pro-'- ducing the initial chill effect. If the molten metal'burns through the lower portion, it will engage the 'upper'wall 39 which produces the secondary chill effect. Any wiper strip cross section such as a V or U which places two walls in the path of the molten metal in sequence will provide the desired effect.

Although only a few embodiments of the present invention have been shown and described, it should be apparent that various changes and modifications can be made without departing from the scope of the appended claims.

I claim:

1. A wiper strip for a refractory ring, the combination thereof forming a bottom ring for a hot top used in pouring molten metal in an ingot mold, comprising a strip of metal having a base leg and an edge leg, said'edge leg having a multi-walled section integral therewith and'forming a continuation along the full length of the wiper strip for producing a first chill effect when engaged by-molten metal rising in the ingot mold and a second chill effect in the event that the molten metal burns through the'first wall.

2. A wiper strip according to claim 1 wherein said multiwalled section has a first metal wall and a second metal wall positioned in the gap between the bottom ring and ingot mold, whereby molten metal rising in the gap will engage said walls sequentially.

References Cited UNITED STATES PATENTS 3,058,182 10/1962 Urmetz et a1. 249-.202 3,110,942 10/1963 Thiem et al. 164-6 I. SPENCER OVERHOLSER, Primary Examiner. R. D. BALDWIN, Assistant Examiner,

Claims

1. WIPER STRIP FOR A REFRACTORY RING, THE COMBINATION THEREOF FORMING A BOTTOM RING FOR A HOT TOP USED IN POURING MOLTEN METAL IN AN INGOT MOLD, COMPRISING A STRIP OF METAL HAVING A BASE LEG AND AN EDGE LEG, SAID EDGE LEG HAVING A MULTI-WALLED SECTION INTEGRAL THEREWITH AND FORMING A CONTINUATION ALONG THE FULL LENGTH OF THE WIPER STRIP FOR PRODUCING A FIRST CHILL EFFECT WHEN ENGAGED BY MOLTEN METAL RISING IN THE INGOT MOLD AND A SECOND CHILL EFFECT IN THE EVENT THAT THE MOLTEN METAL BURNS THROUGH THE FIRST WALL.