US397478A - Robert j - Google Patents

Description

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ROBERT J. TILFORD AND HENRY M. REDEMANN, OF LOUISVILLE, KENTUCKY, ASSIGNORS TO THE REDEMANN TILFORD STEEL COMPANY, OF SAME PLACE.

MANUFACTURE or STEEL.

SPECIFICATION forming part of Letters Patent No. 397,478, dated February 5, 1889.

Original application filed July 25, 1888, Serial No. 281,018. Divided and this application filed November 13, 1888 Serial No.

I 290,738. (No specimens) To all whom it may concern:

Be itknown that we, ROBERT J .TILFORD and HENRY H. REDEMANN, citizens of the United States,residing at Louisville, Jefferson county,

Kentucky, have invented new and useful Improvements in the Manufacture of Steel, of which the following is a specification.

Our invention relates to certain new and useful improvements in the treatment of crude IO or low-grade steel to produce a refined or high-grade steel.

The most successful method of producing low-grade steel is that known as the .Sessemer process, described in his patentof 1855;

but this product, as is well known, is suitable chiefly for railways, axles, and like uses, and is totally unsuited for structures, machinery, and tool purposes unless puddled, hammered, and rolled, for the reason that in its normal state it is too soft, and when hardened it becomes too hard and brittle for the purposes stated. It was the recognition of these inherent defects in the Bessemer and low and medium grade steel which led us to the in- 2 5 vestigation of the subject which has developed our present invention, the object of which is the production at slight cost and a minimum degree of labor of a higher grade and more refined steel by treating the Bessemer and other low and medium grades steel in such manner as to produce a molecular change from a coarse grain to a line grain and silky fracture, to increase the tensile strength, elasticity, toughness, and ductility,

3 5 and to greatly increase the carbon. \Ve have found from experience that uniform results in all instances flow from the treatment of metals having like properties.

Vith these ends in view our invention 0 consists in heating the metal to be treated to a white heat, and then subinerging the same in a bath of glycerine and water having added thereto spirits of niter, aqua-ammonia, chloride of ammonium, sulphate of zinc, sulphate of alumina and ammonia, substantially as will hereinafter be more particularly set forth.

In some instances we employ simply glycerinc and water for the treatment of the metal;

but we desire to say that we lay no claim herein for such bodies alone, as they are covered by the first divisional application of our original application, Serial No. 281,018, filed July 25,1888, which divisional application is filed of even date herewith, this application constituting the second division of our original application referred to. Neither do we lay any claim to the broad or generic idea of heating lowgrade steel to a degree of heat represented by white heat, and then subjecting the metal so heated to a liquid bath, (in contradistinction to the dry or cementation process,) in which hydrocarbon or other similar gases are generated by contact with the heated metal and bath, as this last-named matter forms the subject of our said original application.

In the practice of this our present invention we employ the several chemical bodies in about the following proportions, to wit: 7o Spirits of niter, one and a half (15-) ounce; aqua-ammonia, one and a half (1 ounce; chloride of ammonium two (2) ounces; sulphate of zinc, one and a half (1.3) ounce; sulphate of alumina and annnonia, one and a half (1%) ounce; glycerine, three ounces; water, one-half (1;) gallon.

\Ve of course do not wish to confine ourselves to the exact proportions named, as they may be varied within reasonable limits and yet produce the same general results; but we have found from long experience and repeated tests and experiments that the proportions given produce the best results. In preparing the bath we preferably first powder or granulate the chemicals and mix the same thoroughly and intimately with the glycerine untill well dissolved, and we then add to the bodies so compounded the necessary quantity of water. It will also be understood that we do not wish to confine ourselves to the exact degree of heat imparted to the metal, as that may be varied slightly, so long as the results desired are obtained.

IVe have of course been unable to analyze the gases resulting from the contact of the hot-metal body with the bath, but are led to believe that they constitute a hydrocarbon gas which has a strong alfinity for the metal, and that the latter, being in aheated state, is in such a physical condition as to readily take up or absorb such gas; but as to the fact that the metal is highly improved we have no doubt whatever, as has been demonstrated by all the well-known scientific and mechanical tests.

It will be understood, of course, that when the treatment is applied adjacent to the furnaces where the low-grade steel is manufactured the ingots may be treated without reheating, and thus the expense of such reheating is avoided. After the metal has been subjected to the treatment in the bath described it is allowed to cool in the ordinary manner, and it may afterward be subjected to any ordinary hardening or tempering process, and the temper may, if necessary, be drawn and again restored without at all affecting the other properties acquired from the bath.

lVe are of course aware that the quality of Bessemer and other low and medium grade steel may be improved by what is known as the dry or cementation process,whieh requires a large expenditure of skilled labor and great length of time, and that, too, without always securing uniform and satisfactory results.

WVe desire it to be distinctly understood that we lay no claim to the broad idea of illcreasing the quality of steel. by subsequent treatment, as that has been heretofore done, especially bywhatis known as the cementation process, which may be termed a dry process, our invention differing from such process in the particular that it requires a period of time amounting to a small percentage of the time required in the cementation or dry process, and is in contradistinction to such process essentially a liquid or wet process, the former requiring many days, while the latter involves only a few minutes.

As before stated, we wish it to be understood that the chief feature of our process involves the employment of a bath having as its base glycerine and water, for in the use of these two bodies we accomplish desirable and improved results; but the addition to the glycerine and water of spirits of niter, aqua-ammonia, chloride of ammonium, sulphate of zinc, and sulphate of alumina and ammonia produce better and enhanced results; hence we Our invention or process is distinguished from processes for tempering steel in oil in that by our process the nature, the physical construction, and the molecular or granular construction of the metal are completely changed, whereas the tempering of steel in oil, as practiced by some processes, simply tempers the metal more slowly than is done by tempering in water and other properties, leaving the metal less hard but somewhat tougher than water-tempered material. The changes caused by the oil-tempering process are merely temporary, and do not change the physical or granular construction of the metal, and such changes as are caused thereby can be readily neutralized by reheating and allowing the metal to cool. The changes caused by treatment by our process are permanent, and cannot be removed by any known treatment or process without entirely destroying the steel properties of the metal by burning.

By our invention we greatly increase the tensile strength and elasticity, and yet do not destroy the per cent. of reduction of ductility, while with ordinary tempering the tensile strength and elasticity are greatly increased, but the per cent. of reduction and ductility is very much impaired.

Having thus described our invention, what we. claim as new, and desire to secure by Letters Patent, is-

The process herein described for converting steel, which consists in first heating the metal to be treated to a white heat, and then while so heated submerging the same in a liquid bath consisting of glycerine and water in the proportion of three ounces of the former and one-half gallon of the latter, combined with spirits of niter, one and a half ounce; aqua-ammonia, one and a half ounce; chloride of ammonium, two ounces; sulphate of zinc, one and a half ounce; sulphate of alumina and ammonia, one and ahalf ounce, substantially as hereinbefore set forth.

In testimony whereof we have hereunto set our hands in the presence of two subscribing witnesses.

ROBERT J. TILFORD. HENRY M. REDEMANN. Witnesses:

H. J. TILFORD, DAVID BARTLEY.