US1954280A - Apparatus for the production of steel - Google Patents

Description

April 10, 1934. H. A, BRASSERT APPARATUS FOR THE PRODUCTION OF STEEL Filed July 24, 1931 3 Sheets-Sheet 1 eri,

April 1934- H. A. BRASSERT 1,954,280

APPARATUS FOR .THE PRODUCTION OF STEEL Filed July 24, 1931 3 Sheets-Sheet 2 Herman 55705667;

A ril 10, 1934. H. A. BRASSERT 0 APPARATUS FOR THE PRODUCTION OF STEEL Filed July 24, 1931 :5 Sheets-Sheet 3 iiliiiiiiiiiiiifiiiiiiiiiiliiii? Patented Apr. 10, 1934 PATENT osslcr.

1,954,280 APPARATUS FOR THE PRODUCTION OF STEEL Herman A. Brassert, Chicago, Ill., assignor to r H. A. Brassert & Company, Chi

poration of Illinois cago, 111., a cor Application July 24, 1931, s i-m1 No. 552,814

. 2 Claims.

My invention relates to apparatus for the production of steel and has for its primary object the provision of apparatus for the production of steel in a shorter time with a smaller consumption ofheat and greater efiiciency of operation than what is possible with the present processes.

' Another and further object of my invention is the provision of an apparatus for the production a of steel which combines in one operation the open hearth and Bessemer processes and in addition enables thesteel to be further refined after being blown or its character changed by charging other metalsinto the bath,

It is well known that the Bessemer process is the quickest and most economical method of mak= ing steel from pig iron, as it requires only from ten to twenty minutes time to remove the carbon. and other metalloids to produce steel without adding external heat. There are, however, many objections to the Bessemer process, particularly in that it requires an iron of special quality, one kind for the acid Bessemer and another kind for the basic Bessemer process. The former requires an iron low in phosphorus and relativelyv high in silicon, and the other an iron high in phosphorus and very low in silicon; Inmany cases, iron ores which are available for steel production are of such a nature that suitable iron for eithenthe acid or basic Bessemer process cannot be produced. f

Another disadvantage of the Bessemer process is that themetal becomes surcharged with gases and over-oxidized in the blow, and on account of the lack of means for employing external heat there is no opportunity for subjecting the bath to a reducing and de-gasifying process. The oxidation of metal in the blow increases the losses, and in'conjunction with .the presence of gases held in sdlution, deteriorates the quality of 1 steel. Furthermore, the present Bessemer converter requires a relatively high pressure of the 'blast which is expensive to produce and aggravates the condition of over-oxidizing certain portions of the metal, and also leads to heavy losses through spitting.

My invention overcomes all of these difficulties, as it provides an apparatus for carrying out the method which combines the advantage of the Bessemer and open hearth methods, and accomplishes the conversion of ironinto steel and the subsequent refinement into a high grade metal in has been the practice in the so-called duplex method of refining steel- Another and further object of my invention is the provision of an apparatus for making steel, in which the bath which is blown is comparatively shallow and therefore requires only a fraction of the blast pressure required in the Bessemer process and yet the total content of the bath may be several times as"; great as is now used in the present Bessemer converter. For instance, in a furnace having a capacity of sixty tons, the depth of the bath will be approximately twelve inches and the length approximately twenty-one feet. It is, of course, evident that the furnace, by being made proportionately longer, the depth of the bath can be still further decreased. This is important because a twenty-four inch bath requires a blast of at least thirty pounds pressure, which not only requires a considerable amount of power, but also results in violent action between the blast and the metal. The ideal application of air is to pass it through a shallow bath at low pressure and in as finely divided streams as possible. This results in a perfect distribution between blast and metal and also causes uniform reaction between the oxygen of the blast and the metalloids in the iron. y

In carrying out this process in my improved apparatus I avoid a condition whereby in the lower part of the blast metal particles may become oxidized and the carbon in this area is entirely consumed, whereas in the upper layers of the bath carbonmay still be present, necessitating the continuance of the blow, although oxidation of the metal will continue in the parts of the bath which are unprotected by carbon. This causes the Bessemer bath to become surcharged with ironoxides, resulting in a higher loss of iron than that incurred with the open hearth or electric furnace process. By applying the blastbnly, the contact of oxygen and metal is over a much larger surface, and is more gently and uniformly applied, with the result that a better quality of steel is produced with a lower'iron loss.

Another and further object of my invention is the provision of an apparatus for making steel in which after the carbon is sufflciently removed by being blown, the furnace can be tilted back and a furnace refining, deoxidizing or de-gasifying process carried on, with additional charges of metal to be made through the charging doors in order to fulfill chemical specifications, as in the manufacture of alloy steels.

Another and further object or my invention is the provision of an apparatuswhich is economi-v cal in operation with respect to heat consumption,-in that the gases emanating from the blow .are taken down into the regenerator or recuperator located below or adjacent to the furnace, and the heat there absorbed fromthese gases 'is transferred to the incoming air and thereby Another and further object of the invention is the preservation of the high temperature of the bath during and after the blow. It is possible to stop the blow before all the carbon is removed'and reduce the carbon percentage in the bath by adding ore to bring the carbon down to the desired limits and making use of the excess heat instead of allowing the gases produced in the blow to pass out into the atmosphere,- as is now common with the usual type of Besseme converter.

These and other objects of my invention will be more fully and better understood by reference to the accompanying sheets of drawings, and in which- Figure 1 is a fragmentary sectional view of one end of a tilting furnace embodying my invention, showing the furnace in reducing position;

Figure 2 is a cross sectional view of a furnace embodying my invention on line 22 of Figure 1;

and Figure 3 is a plan section of the view shown in Figure 1 on line 3-3.

Referring now specifically to the-drawings and in which generally an open hearth furnace of the tilting type is shown and described, to which certain additions have been added, as will be hereinafter described, a foundation 10 is shown, upon which is mounted a plurality of blocks 11, 11 having rollers 12, 12 mounted thereon in any suitable manner and adapted to engage a track 13 on the outer periphery of a semi-circular frame 14, which includes a plurality of longitudinally extending beams 15, 15, and upon which transversely extending members 16, 16 are mountedwhich in turn support the furnace proper. A motor 17 is provided'which, through suitable reduction gearing in a gear housing 18, engages with a gear wheel,19, which in turn engages upon a semi-circular rack 20 on the frame 14 and forms 6 usual refractory material, and has a tap opening 22 therein with a spout 23 adjacent the tap opening by means of which 'the molten metal is tapped out of the furnace. A side wall 24 is provided with the usual roof construction 25 which is supported by the side wall 24 at one 'side and at-thev opposite side by a frame 26 which extends along one side of the furnace and which has a frame member 27 therearound within which a grid 28 is mounted, with a metallic windbox 29 being mounted at the back of the grid 28, to the back of which a blast pipe 30 isconnected having an upper connection 31 and a lower connection 32.

- The pipe-30 extends upward and acrossthe top of the furnace where it is joined to a header 33 which in turn is connected to a blast supply pipe 34 by. means of aconnection 35, the center of the connection 35 being coincident with the center of the furnace so that as the furnace is tilted or rotated, .the header 33, turning in connection 35, will rotate with the furnace. ,An air blast is' supplied through the pipe 34 to the header 33 and through the pipes 30, and delivered into the windbox 29 through the grid 28 and into tuyeres 29 mounted in the refractory wall adjacent the grid 28, and forms a means by which the bath is subjected to the blast when the furnace is turned or tilted to one side.

The end construction of the furnace is stationary and is of the usual form and comprises a fuel passage 36 by means of which gas, oil or other fuel is forced into the open hearth furnace, with an air passage 37 in the usual form which connects with another air passage 38 leading to the regenerators, all of which is common in furnace constructions of this type.

In operation of the device, the furnace is held in vertical position in which shown and the reduction ofimpurities inthe bath carried on to the point desired, whereupon an air blast is conducted through the header 33 and pipe 30 to the windbox. Thereafter the furnace is tilted so that the bath of metal flows .to one side of the furnace over the tuyeres and. is there subjected to the action of the blast coming through the tuyeres and blown to the desired extent. As will be understood, the bath in this case is quite shallow as compared with the bath in the usual Bessemer converter, and in order to blow the bath sufliciently it is necessary to have a low air pressure. The bath is thereupon blown to a suflicient degree and the gases developed therefrom withdrawn from the furnace into the regenerative chambers at the end of the furnace where their heat is absorbed in the usual manner. Thus the heat developed from the gas is utilized in the regenerative chambers for heating the incoming air and the blast passing upward in the furnace maintains the roof and walls of the furnace in a heated condition without the use of fuel during the-blowing operation. If desired the bath can be heated by continuing the supply of fuel to the furnace during the blowing operation, or the fuel may be shut off during this operation.

After the bath has been sufliciently blown, the furnace is tilted back and if it is desiredto add any other material to the bath it can be done at this time through the usual charging doors of the furnace, such as special alloys and the like, and the bath further reduced'or refined as may be desired. If this is not desired, the furnace may be tapped and the bath removed by pouring the molten metal out over the spout 23.

It will thus be understood that not only is the refining operation carried on in the furnace under open hearth conditions, but that the blowing of the metal and ,the removing of the metalloids and carbon therefrom is carried on within the same furnace without the necessity of removing the metal from the furnace'into the converter and thereafter blowing the charge. In addition, it will beunderstood that the metal bath bein extremely shallow, the blowing operation is pe formed more quickly by less air pressure, and because of the use of the comparatively thin bath, smaller streams of air can be used in performing the blowing operation, thus bringing the bath into intimate contact with the air easily and more quickly than with the usual Bessemei' converter, and with the additional preservation and use of the hot gases resulting from the blowing operation,

It will be understood that the drawings illustrate only one end of a furnace adapted to carry out my invention, and that the supporting elements, motors, etc., may be duplicated as often as maybe desired, depending upon the size and length of the furnace, and that the opposite end of the furnace is a duplicate of the end shown in the drawings. g

While I have described more or less precisely the details of construction, I do not wish to be understood as limiting myself thereto, as I contemplate changes in form and the proportion of parts and the substitution of equivalents as cir-.

cumstances may suggest or render expedient without departing from the spirit or scope of my invention.

I claim:

1. In combination, a furnace having an elongated wide shallow hearth portion, means for directing a flame over said hearth-portion, a windbox extending along one side of the hearth structure, a plurality of small tuyeres extending through said side of the hearth, said tuyeres being located above the normal metal line in the hearth, the tuyeres extending through a wide. substantially flat wall surface, the surface beingv at substantially right angles ,tothe heartln-and means for tilting the furnace to bring the surface having tuyer'es therein to substantially a horizontal plane whereby the tuvre surface will support a wide shallow bath.

2. In. combination, a furnace having an elongated wide shallow hearth portion, means for directing a flame over said hearth portion, a windbox extending along one side of the hearth structure, a plurality of small tuyeres extending through said side of the hearth, said tuyeres being located above the normal metal line in the hearth, the tuyeres extending through a wide, substantially flat wall surface, the surface bein at substantially-right angles to the hearth, and means for tilting the furnace to bring the surface having tuyeres therein to substantially a horizontal plane whereby the tuyere surface will support a wide shallow bath, said bath having approximately the area of the bath in adjacent hearth portion and the tuyeres being located over the major portion of said bath area.

HERMAN A. BRASSERT.

its

Images