US2631836A

US2631836A - Refractory lining

Info

Publication number: US2631836A
Application number: US54730A
Authority: US
Inventors: Ralph F Willis
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1948-10-15
Filing date: 1948-10-15
Publication date: 1953-03-17
Anticipated expiration: 1970-03-17

Description

March 17, 1953 R. F. w|| s REFRACTORY LINING Filed 001;. 15, 1948 ATTO R N EY Patented Mar. 17, 1953 REFRACTORY LININ G Ralph F. Willis, McKeesport, Pa., assignor to United States Steel Corporation, a corporation .4 of New Jersey Application October 15, 1948, Serial No. 54,730

2 Claims.

This invention relates to refractory linings and is directed more particularly to a refractory lining for a gas port in a soaking pit having a centrally located gas port, such as shown in the patent to Morton No. 2,124,888. The gas port projects above the furnace floor level in order to prevent coke breeze, which forms the hearth, and other material from falling therein. During the charging and drawing of the ingots from the soaking pit, the crane operator often bumps or otherwise damages the projecting part of the gas port, thus causing premature failure and undue shutdown of the soaking pit. In order to strengthen the gas port, the operators resorted to the practice of baking in, which involves firing the furnace for some time prior to the charging thereof so that the refractory brick solidified into a mass. This practice has met with some success, but is objectionable in that it requires a considerable period of time so that the furnace has to be out of production for a longer period than is desirable. In a few instances, pre-cast refractory gas ports have been used, but these are expensive and very difficult to install.

It is therefore an object of my invention to provide a refractory lining which will have a long life.

Another object is to provide an improved type of gas port for a soaking pit.

These and other objects will be more apparent after referring to the following specification and attached drawing, in which the single figure is a cross sectional view of the gas port in a soaking pit.

Referring more particularly to the drawing, reference numeral 2 indicates the walls of a soaking pit having a bottom 4 made of fire brick. Extending upwardly through the center of the bottom 4 is a gas port 6 having a burner 8 at the lower end thereof. The upper part of gas port 5 is lined with chromite refractory brick l0. On each side of the gas port 6 is a trench l2 which is filled with coke breeze I4 upon which rests the ingots to be heated. I provide a frustoconical ferrous metal shield l6 around the refractory lining ID. This shield may be fabricated from low carbon steel plate or may be cast. A typical cast iron shield may contain 4.25% carbon, 0.50% manganese, 2.00% silicon, 080% phosphorus and .030% sulphur. A layer of chrome ore refractory I 8 is tamped into place between the lining in and shield Hi. This chrome ore refractory may be installed as a wet mixture of 50% chrome ore and 50% fire clay. The chrome ore refractory lining and the ferrous metal shield not only protect the lining l0 while the lining fuses and solidifies enough to withstand normal use, but also the shield itself becomes fused to the chrome ore lining and forms a very hard ferro-chromo-siliceous mass which is highly heat resistant and far superior in strength and wearing qualities to materials previously used in gas ports. This mass results when the furnace is heated up to its operating temperature which is approximately between 2300 F. and 2700 F. It has been found that the chemical analysis of this material varies somewhat as indicated below:

Percent Iron oxide, Fezoa 45 to Aluminum oxide, A1203 14 to 18 Chromium oxide, Cr2O3 14 to 18 silicon dioxide, S102 10 to 13 Magnesium oxide, MgO 7 to 9 821%.)???Siffiftfii;fi? iiiiiiiii} A particular analysis which has proven extremely satisfactory in use is as follows:

' Percent Iron oxide, F8203 47.56 Aluminum oxide, A1203 15.92 Chromium oxide, CrzOa 15.78 Silicon dioxide, S102 11.51 Magnesium oxide, MgO 8.13 Calcium oxide (lime), CaO 0.95 Carbon, 0 0.15

Total 100.00

This refractory material has a predominantly crystalline character at the temperatures indicated and has a comparatively small amount of glass phase which is highly viscous at the operating temperature and imparts ductility and toughness to the heated material. The average life of a soaking pit gas port has been increased from approximately two months to approximately nine months by the use of my invention. Apparently this increase in life is due to the ductility of the material. In other words, there is a certain amount of give to any impact so that chipping and cracking, which normally occur when hot ceramic materials are hit, are eliminated. Apparently the chrome ore refractory is saturated with the molten iron under slightly oxidizing conditions at operating temperatures. It will be seen that the shield protects the gas port from damage during the baking in period so that the soaking pit can be put into immediate operation, and then as the heat is applied the 3 shield will fuse and react chemically to form a very hard and heat resistant material. While the refractory was developed primarily for gas ports for soaking pits, it can also be used for gutters or runners in billet or slab heating furnaces as well as for other installations.

While one embodiment of my invention has been shown-and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. A gas port for a soaking pit or the like comprising a layer of refractory brick forming the inner lining of the port, an outer ferrous 15 metal shield entirely surrounding the periphery of the lining at the exit endof theport, and a 4 conical ferrous metal shield surrounding the periphery of the top part of the lining with its small diameter uppermost, and a layer of chrome ore refractory between the refractory and the shield, the ferrous shield being fused with the chrome ore refractory.

RALPH F. WILLIS.

REFERENCES CITED The following references are of record in file of this patent:

UNITED STATES PATENTS the

Claims

1. A GAS PORT FOR A SOAKING PIT OR THE LIKE COMPRISING A LAYER OF REFRACTORY BRICK FORMING THE INNER LINGING OF THE PORT, AN OUTER FERROUS METAL SHIELD ENTIRELY SURROUNDING THE PERIPHERY OF THE LINING AT THE EXIT END OF THE PORT, AND A LAYER OF CHROME ORE REFRACTORY BETWEEN THE REFRACTORY FORMING A SEPARATING LAYER AND THE SHIELD, THE FERROUS SHIELD BEING FUSED WITH THE CHROME ORE REFRACTORY.