US3034457A - Basic refractory brick - Google Patents

Description

May 15, 1962 R. P. HEUER 3,034,457

BASIC REFRACTORY BRICK Filed Nov. 1, 1960 United States Patent 3,034,457 BASIC REFRACTRY BRICK Russell Pearce Heuer, Villanova, Pa., assigner to Gener Refractories Company, a corporation of Pennsylvania Filed Nov. 1, 1960, Ser. No. 66,509 4 Claims. (Cl. 110-99) The present invention relates to basic refractory bricks and particularly to improved basic refractory bricks having metallic support structure molded on the bricks.

A purpose of the invention is to provide a composite basic refractory support structure, part of which is of plain carbon or low alloy steel and part of which is of corrosion resisting ferrous alloy, the corrosion resisting ferrous alloy being adapted to maintain the support when the plain carbon or low alloy steel portion erodes to the point where it no longer functions.

A further purpose is to provide a U-shaped support with the plain carbon or low alloy steel on the inside of the U and extending farther away along the refractory toward the hot end and with corrosion resisting ferrous alloy on the outside of the U and located primarily nearer to the cold end, the corrosion resisting ferrous alloy being adapted to maintain the integrity of the support after the plain carbon or low 4alloy steel is no longer capable of functioning.

A further purpose is to use layers of plain carbon or low alloy steel and also of corrosion resisting ferrous alloy for the support, the corrosion resisting ferrous alloy being desirably united to the plain carbon or low alloy steel as by welding, and being capable of maintaining the integrity of the structure after the plain carbon or low alloy steel has burned away.

Further purposes appear in the specication and in the claims.

In the drawings I have chosen to illustrate one only of the numerous embodiments in which the invention may appear, selecting the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIGURE 1 is a top plan view of a basic refractory brick of the invention.

FIGURE 2 is a front elevation of the brick of FIG- URE l.

FIGURE 3 is a side elevation in enlarged scale of the metallic clip of the brick of FIGURE l.

FIGURE 4 is a front elevation of the metallic clip of FIGURE 3.

FIGURE 5 is a fragmentary vertical section taken along the line 5-5 of FIGURE 2.

Describing in illustratiton but not in limitation and referring to the drawings:

In the prior art basic z refractory bricks have frequently been provided with hanger openings and ferrous metal clips molded on the brick which engage at the sides of the hanger opening and forni the effective cross element by which the hanger or hook supports the brick. In normal practice these clips have been of plain carbon steel which is subject to oxidation as the brick begins to erode and the hot end approaches closer to the clip.

Basic refractory roofs which would otherwise give good service have failed because the clip was destroyed by oxidation.

This problem is particularly acute where the basic refractory brick is employed below the slag line in a metallurgical furnace such as an open hearth steel making furnace, or where it is employed at a portion of the furnace structure which constitutes an angle such as a nose on a suspended open hearth downtake.

I have discovered that it is possible to improve the performance of the clip greatly by making it of two layers, one of which is of corrosion resisting ferrous alloy and f. ICC

the other of which is of plain carbon or low alloy steel.

I have also discovered that the layer of corrosion resisting ferrous alloy need not extend as far toward the hot end as the layer of plain carbon or low alloy steel since the failure of the plain carbon or 10W alloy steel will not occur until the brick has been in service for an extended period of time, by which time the brick will have eroded and lost weight, and also the layer of corrosion resisting ferrous alloy if in contact With the basic refractory will have sucient oxidized and reacted with the basic refractory to hold itself rmly in place even though the plain carbon or low alloy steel portion of the clip has been converted wholly into oxide.

Considering now the drawings in detail, I there illustrate a basic refractory brick having a basic refractory body 20 which will suitably be of chrome-magnesia or of magnesia-chrome or of magnesia with or without additions of alumina or chrornic oxide. In any case the basic refractory brick will contain at least 15% of magnesia by weight.

The brick has been shown as rectangular, although it may be of Wedge or key character or it may be a 'special shape as desired.

The brick body as shown has a hot end 21, a cold end 22, wide lateral faces 23 and narrow lateral faces 24.

Near the cold end the brick at the 'time it is molded has a hanger recess or support socket 25 of well known character, rwhich is suitably provided with a mouth 26 of outwardly tapering form, and an interior hanger or hook engaging recess portion 27 which is covered by the top or transverse portion 28 of a metallic clip 3i). The metallic clip according to the present invention is of U form, having side arms 31 which define the side of the hanger or hook engaging recess.

The side portions 31 at their ends remote from the cold end of the brick have lanced outward projections 32 which extend out into and are embedded in the refractory by inserting the metal parts in the mold during molding of the refractory.

In accordance with the invention the U-shaped clip comprises an inner layer or portion 33 which is of plain carbon steel or low alloy steel, which may for the purposes ofthe present invention be defined as steel having an alloy content of less than 5%. 'I'he U-shaped clip has an outer layer 34 which is composed of corrosion resisting ferrous alloy Which will preferably be of the type containing about 18% of chromium and 8% of nickel, but may also be of the straight chromium type containing in the preferred embodiment 14 to 16% of chromium, balance iron. Typical corrosion resisting ferrous alloys may for example be any of the 300 series or any of the 400 series corrosion or heat resisting steels as for example listed in Metals Handbook, 1954 Supplement, page 34.

The corrosion resisting ferrous alloy outer layer is united to the plain carbon or low alloy steel inner layer by welding, suitably spot welds 35, on the sides.

It will be noted that the corrosion resisting ferrous alloy outer layer is relatively shorter or does not extend as far toward the hot end, because at the time lit primarily functions when the plain carbon or low alloy steel inner layer 31 has been destroyed, the weight of the brick will be greatly reduced and the corrosion resisting ferrous alloy outer layer at thetemperature of service in the metallurgical or other industrial furnace'will have oxidized and reacted with the basic refractory along the outside of the side arms of the corrosion resisting layer 34 to form compounds such as magnesium ferrite, so as to integrate the corrosion resisting ferrous alloy to the basic refractory body.

In operation, after the refractory structure is installed and the hanger or hook is inserted into the recess of the brick beneath or toward the hot end with respect to the bridging portion 28 of the clip, the hot end will progressively erode or spall away, until the brick has shortened to an extent that the plain carbon steel portion of the clip reaches a temperature and is exposed at thatV teinperature for a4 sucient Vtime so that it will begin toY oxidize and react with therefractory and eventually be completely destroyed. Before ythe plain carbon or low alloy steel portion of the clip can be destroyed, the corrosion resisting ferrous alloy portion which is in contact with the refractory on the side Walls of the U becomes heated and notwithstanding V(its corrosion resistance bet cornes oxidized suliciently to react with the refractory and firmly integrate itself to the refractory.

By the time the plain carbon or low alloy steel portion of the clip has been destroyed to the extent that it cannot function, the corrosion resisting ferrous alloy portion is thoroughly anchored and able to function and hold t the hanger or hook. Itis notrnecessary, however, that the corrosion resistable spirit andscope of my claims.

Having thus described my invention whaty I claim as new and desire to secure by Letters Patent is:

1, In a basic refractory brick, a body of basic refractory, and a ferrous metal support embedded in the body, comprising a duplex strip having two layers, one of which layers is of steel having analloy content of less than 5% by Weight and another of which layers is of corrosion resisting ferrous alloy.

2. A basic refractory brick of claim 1, in which the support is U-shaped, having an opening within the U.

3 A basic refractory brick of claim 1, in which the support is U-shaped, the layer of'steel having` an alloy content of less than 5% being embedded in the basic refractory and the layer which is Vof corrosion resisting ferrous alloy being around the outside of theU.

4. A-basic refractory brick of claim 1, in which the support is of U shape, the layer of steel having an alloy content of less than y5% being on the interior of the U and having projectionswhich extend into and are molded in the basic refractory body, and the' layer of corrosion resisting ferrous alloy being relatively shorter and extending around the outside of the U with arms Vwhich are molded in the refractory, there Vbeing an' opening on the inside of the U.

References Citedv inthe file of this patent UNlTED STATES PATENTS

Claims (1)

1. IN A BASIC REFRACTORY BRICK, A BODY OF BASIC REFRACTORY, AND A FERROUS METAL SUPPORTED EMBEDDED IN THE BODY, COMPRISING A DUPLEX STRIP HAVING TWO LAYERS, ONE OF WHICH LAYERS IS OF STEEL HAVING AN ALLOY CONTENT OF LESS THAN 5% BY WEIGHT AND ANOTHER OF WHICH LAYERS IS OF CORROSION RESISTING FERROUS ALLOY.

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