US1541746A - Manufacture of steel - Google Patents

Description

Patented June 9, 1925.

ALBERT H. ACKERMAN, OF CHICAGO, ILLINOIS, ASSIG-NUR TO COMMERCIAL STEEL CUMPANY, it. CURPORATION 0T ILLINOIS.

MANUFACTURE OF STEEL.

1t 0 Drawing.

To all whom, it may concern:

Be it known that l, ALBERT H. AOKERMAN,

a citizen of the United States, and resident of Chicago, county of Cook, and State of lllinois, have invented certain new and useful Improvements 1n the Manufacture of Steel; of which the following is a specifica-.

steel.

, A further object of the invention is the provision of a method of so applying the treatment described in the said application of Charles Cumings to baths of molten metal as to secure the most beneficial results with increased safety.

The materials used in the carrying out of the method of the invention may be the same as those described in said application, the improvements provided by the invention being in the method of applying the substances to themetal.

. llt is at present preferred, as described in the application to which reference has been made, to bring the bath of molten metal to be treated to the chemical analysis desired in the finished product before carrying out the method of the invention and to then add the non-ferrous ores to the bath,

The ores referred to may comprise for each ton of metal to be treated about forty pounds of a mirture'of equal parts of tungsten and chrome concentrates. The tungsten ore should. contain about of tungstic acid and the chrome ore about an equal proportion of chrome oxide. Equivalentmaterials may be substituted for those named which are now believed to have the edect of preventing undue changes in the chical analysis of the bath, especially as to its application filed December 23, 191a. Serial No. 346,976.

carbon content, which might be caused by the subsequent treatment.

Vlfhen the process of the invention is car-' ried' out after bringing the bath to its desired chemical analysis and after the non ferrous ores have been added, the bath is preferably poled and a space of time allowed in which ebullition may subside. lln

till

the case of a bath of substantially five tons this will occur in about fifteen minutes.

The bath is then subjected to the action of violent agitation in the nature of a series of sudden shocks and which may be accompanied by coincident rise in temperature. The action may be secured by adding to the bath an intimate mixture of a fuel and an oxidizing agent. Suitable materials and quantities per ton of metal are found to be from two to four pounds of charcoal in finely divided condition, about four ounces of potassium chlorate and about. eight.

ounces of barium dioxide, intimately mined. In the process of the present invention the continued action of the mixture of materialsnamed, or their equivalents, is secured-by introducing it into the bath by successive increments. The

may be in the form of a steady stream as by pouring or as by feeding into'a blast of air or other gas, which gas may be the fuel of-the mixture, or it may be by a stream interrupted at intervals or by successive charges of'selected sizes and at determined intervals. When introduced in streams the supply of the materials must be sufficiently rapid to produce gas with sullicient rapiait' I? to produce the results desnred. The term 1 successive increments is used as a generic term to designate any of the named or equivalent methods of introduction of the material or any other method in which the application of the last of the mixture of en plosive material to the bath is separated from the application of the first thereof by an apprecia le interval of time, as distinguished from projecting the whole qpantity thereot into the bath at one time. is at present preferred to add the miirture in suceessive eh'arges'of considerable size. Tf the latter course is followed when treating metal in the open hearth or electric furnace, the successive charges may be separately tenclosed in nilammable envelopes, as for ta introduction lltltl stance paper bags and may be thrown into I the furnace at the desired intervals.

The size of the separate charges, when the process is carried out in this manner, will depend largely upon the. size of the receptacle in which the bath is held and the space available for expansion of the resulting gases. The mixture described being an explosive, the use of too large a charge would be disastrous, yet it is at present believed to be desirable to approach the limit of safety in size of charge.

When separate charges are employed, the proper interval between charges may be determined by watching the action of each, subsequent charges being introduced when the agitation caused by the action of each preceding one has somewhat subsided. After the last charge has been introduced the bath should be allowed to stand until the agitation has subsided and ebullition has ceased. In the instance of a heat of from five to ten tons, in an open hearth furnace ofordin'ary dimensions, the explosive material may be suitably separated into five or six charges, in which case the treatment carried out as indicated would consume approximately. ten minutes or, including the time for action of the non-ferrous ores, a period of from twenty to twenty-five minutes tor the entire process.

It may be desirable for some purposes to introduce the explosive materials into the body of the mass of molten metal either gradually or in successive charges. In the case of the electric or open hearth furnace this may be accomplis ed by enclosing separate charges in containers more resistant to heat than the paper bags above mentioned and forcing the containers below the surface by means of rods, or by projecting a tube of heat resistant material, as fire clay, into the mass and passing the container into the bath through the tube.

In the use of the Bessemer converter the material may be blown into the bath with the air blast and thus be readily introduced either gradually or by successive charges.

By the addition of the explosive mixture to the bath by my invention the molten metal is subjected to a succession of shocks through a substantial period of time and hence the agitation may be more thorough in its action than if acting as a single impulse.

Tests of steel produced by the improved process described, as compared with steel of substantially the same chemical analysis produced by former methods, the condition as to heat treatment being the same, have shown much improved physical properties.

The invention in its broader aspects is not restricted to the composition oi. 'the steel, but comprehends a treatment of steel of any character in such manner as to produce in the bath a sudden shock of considerable violence, and the agitation is prolonged either by a continuous or intermittent application of the agitating agent and is accompanied by a sudden and substantial rise in temperature.

The more specific details of the method as described have been found of value in maintaining, notwithstanding the use of the particular means for securing the agitation, the desired chemical analysis of the product. The use of other agents than those named for producing the prolonged violent agitation would come within the scope of the invention, and might render the use of nonferrous ores, as described, unnecessary, or might involve the use of other materials or steps for securing the desired character of the product.

I claim as my invention:

1. The process of preparing metal which comprises subjecting a molten bath of the metal to a series of agitations in the nature of sudden shocks, said shocks being of sufiicient intensity so that their combined effect may produce a substantial improvement in the tensile strength and other physical prop erties of the finished product.

2. The process of preparing metal which comprises subjecting a molten bath of the metal to a series of agitations in the nature of sudden shocks accompanied by a substantial rise of temperature, said shocks being of suflicient intensity so that their combined efi'ect may produce a substantial improvement in the tensile strength and other physical properties of the finished product.

3. The process of making steel which comprises subjecting a molten ferrous bath to a series of agitations in the nature of sudden shocks, said shocks being of sufficient intensity so that their combined eiiect may produce a substantial improvement in the tensile strength and other physical properties oi the finished product.

4. The process of making steel which comprises preparing a molten bathof metal of substantially the chemical composition desired in the finished product, adding to said bath a quantity of material adapted to prevent substantial change in carbon content during subsequent treatment and subjecting the bath to an agitation in the nature of a series of sudden shocks, said shocks being of sufficient intensity so that their combined effect may produce a substantial improvement in the tensile strength and other physical properties of the finished product.

5. lhe process of making steel which comprises preparing a molten bath of metal of substantially the chemical composition desired in the finished product, adding to said bath a quantity of material adapted to prevent substantial change in carbon content during subsequent treatment and subjecting ill) the bath to a series of the bath to an agitation in the nature of a series of sudden shocks accompanied by a substantial increase of temperature, said shocks being of sufficient intensity so that their combined effect may. produce a substantial improvement in the tensile strength and other physical properties of the finished product.

6. In the preparation of steel, the process which comprises preparing a bath of molten metal and adding to saidbath a succession of single integral masses of material of such.

a nature and each mass of such a quantity as to generate large volumes of gas substantially instantaneously, whereby to subject shocks of suflieient intensity so that their combined efi'ect may produce a substantial improvement in the tensile strength and other physical properties of the finished product.

7. In the preparation of steel, the process which comprises preparing a bath of molten metal of substantially the chemical analysis desired in the finished product, adding to said bath a quantity of material adapted to prevent substantial change in chemical composition during subsequent treatment, and adding to said bath a succession of single integral masses of material of such a nature and each mass of such a quantity as to generate large volumes of gas substantially instantaneously, whereby to subject the bath to a series of shocks of suflicient intensity so that their combined efi'ect may produce a substantial improvement in the, tensile strength and other physical properties. of the finished product.

8. The process of making steelwhich comprises preparing a molten ferrous bath and adding to said bath successive single integral masses of an intimate mixture of fuel and an oxidizing agent each mass being of such a size as to substantially instantaneously generate large volumes of gas.

9. The process of making steel which comprises preparing a molten ferrous bath and adding to said bath successive single integral masses of an intimate mixture of finely divided fuel .in solid form and an oxidizing agent each mass being of such a size as to substantially instantaneously. generate large volumes of gas.

10. The process of making steel which comprises adding to a molten ferrous bath of metal of substantially the analysis de-- sired in the finished product a quantity of material adapted to prevent substantial change in chemical composition during further treatment and subsequently adding a succession of single integral masses of an intimate mixture of fuel and an oxidizing agent.

11. The process of making. steel which comprises adding to a bath of molten metal, of substantially the analysis desired in the finished product, a uantity of tungsten concentrates, poling t e mass, allowing the ebullition to subside, and adding to the bath a quantity of an intimate mixture of fuel and an oxidizing agent, the act of adding the mixture being protracted.

12. The process of making steel which comprises adding to a bath of molten metal, of substantially the analysis desired in the finished product, a quantity of a'mixture of equal parts of tungsten and chromium ores, poling the mass, allowin the ebullition to subside, and adding toit e bath during a protracted period of time a quantity of an intimate mixtureIof fuel and an oxidizing agent.

13. The process of making steel which comprises adding to a bath of molten metal,

of substantially the analysis desired in the finished product, a .quantity of material adapted to preventsubstantial change in carbon content of the bath during subsequent treatment, and adding a quantity of an intimate mixture of finely divided fuel and potassium chlorate divided into separate charges. I

ALBERT H. ACKERMAN.