US397477A - Egbert j - Google Patents

Description

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

MANUFACTURE OF STEEL.

SPECIFICATION forming part of Letters Patent No. 397,477, dated February 5, 1889.

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

, 290,737. (No specimens.)

To all whom it may concern.-

Be it known that we, ROBERT J. TILFORD and HENRY M. REDEMANN, citizens of the United States, residing atLouisville, Jeffer- 5 son 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 usefulimprovements in the treatment of crude or low-grade steel to produce a refined or highgrade steel.

The most successful method of producing low-grade steel is that known as the Bessemer process, described in his patent of 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, 2e 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 in herent defects in the Bessemer and low and medium grade steel which led us to the illvestigation 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 grade steel in such manner as to produce a molecular change from a coarse grain to a fine grain and silky fracture, to increase the tensile strength 5 and elasticity, toughness, and ductility, 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.

With these ends in viewour invention 0011- sists in heating the metal to be treated to a white heat, and then submerging the same in a bath of glycerine and water in the proportion of three (3) ounces of glyeerine to one,-

half gallon water and allowing it to remain submerged until the change is effected, which should be until the metal is substantially cool, or until such reduction of heat in the metal is made that it will no longer take up the gases generated by contact with the bath. Te have found in some instances that better results and effects are obtained by the addition to the bath of glycerine and water of spirits of niter, aqua-ammonia, chloride of ammonium, sulphate of zinc, sulphate of alumina, and ammonia; but to this last-named addition we lay no claim herein, as the same forms the subject-matter of a second divisional application of our application, Serial No. 281,018, filed July 25, 1888, of which this application is the first division. Neither do we lay herein. any claim to the broad idea of first heating low-grade 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 similar gases are generated by contact with the heated metal and bath, as this last-named matter forms the subject of our original application referred to.

' WVe of course do not wish to confine our-- selves 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 propertions given produce the best results.

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 maybe varied slightly, so long as the results desired are obtained.

o have of course been unable to analyze the gases resulting from the contact of the hotmetal body with the bath, but are led to be lieve that they constitute a hydrocarbon gas which has a strong ailinity for the metal, and that the latter, being in a heated state, is in such a physical condition as to readily take 0 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 adj aeent to the f urnaces where the low-grade steel is manufaotured 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 of glycerine and water 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.

WVe 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, which 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 increasing the quality of steel by subsequent treatment, as that has been heretofore done, especially by what is 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 of 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 bet ter and enhanced results; hence we do not wish to confine ourselves to the use of abath embodying all the bodies named.

Our invention or process is distinguished from processes for tempering steel in oil in that by our process the nature and the physical 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 allow ing the metal to cool. The ch nges 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 percent. of reduction or 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.

NVhat we claim as new, and desire to secure by Letters Patent, is

The process herein described for converting lower-grade steel into refined or highergrade steel, which consists in heating the metal to be treated to a white heat, and then submerging the heated metal in a liquid bath .of glycerine and water in the proportion of three ounces of the former to one-half gallon of the latter, 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.

WVitnesses:

HENRY J. TILFORD, DAVID BARKLEY.