US1568822A - Rail steel - Google Patents

Description

Patented Jan. 5, 1926.

UNITED STATES HOWARD J. FORCE, OI SCRANTON, PENNSYLVANIA.

I RAIL STEEL.

No Drawing.

To all whom it may concern:

Be it known that I, HOWARD J. Foncn,a citizen of the United States, residing at Scranton, in the county of Lackawanna and State of Pennsylvania, have invented certain new and useful Improvements in Rail Steels; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to the manu facture of steel for railroad rails and the like. It has for its primary object the provision of a rail steel which is not only su perior in physical properties whereby breakage and rapidity of wear and disintegration are reduced as well as transverse fissures very materially eliminated, but which also avoids certain difliculties and losses ordinarily encountered in the manufacture of steel rails under present processes.

A further object of the invention is to secure a steel of superior quality which makes it possible to reduce the size of rails if de-' sired. The steel which I have evolvedwill increase the length of the life of the rail, not only in regard,to the wear but also very materially reduces disintegration and piping creased, and in order to meet these increased;

or seamyrails. A rail made of this steel will also stand under the standard drop testing machine greater deflection ornumber of blows, and will show a higher average hardness and stifl'er section than the present steel rail.

In the last few years in railroad transportation the average speed and weight of cars have been materially increased; also the use of steel wheels has increased, which very materially increases the wear on rails, wit the result that impact and shock on the rail have proportionately materially inrequirements and burdens, the weight per yard of rail has been necessarily greatly increased, until at the present time it is at least double the quantity of which it was made up a few years ago. Many attempts have been made in various sections of the 7 manganese percentages, making the rail Application filed July 17, 1925. 'Serial No. 44,871.

brittle, which brittleness is due to the segregation, and causing many pipes in the steel at the same time. This hasresulted in rails being exceedingly brittle and has caused heavy failures, especially under low temperatures. Difliculty has also been encountered in rolling the heavier sections, especially with the high carbon content. Furthermore, the allowable range within which the rolling temperatures must be confined is narrow and itis well known that it is diflicult to maintain such uniform temperature conditions, and should rails be rolled outside of such temperatures, crystallization of the steel or defects which later possibly develop into transverse fissures are produced. This ,is due to the low elongation of the steel brought about position.

It is the purpose of my invention to provide a steel having greater superior physical properties and especially adapted to meet possibly by its chemical comthe increased service requirements and to overcome the other difficulties herembefore' weight per yard, are as follows:

Vary from .30' to .4798 carbon in the lighter weights. per yard, up to .62 to .85); carbon for the heavier weights. The man ganese varies from .60 to .90% in some cases, and .80 to 1.10% in others, but no effort has ever beenmade to vary the manganese in proportion to the carbon. The phosphorus varies up to .10 with a maximum silicon of 2.5%. I have found that the variation of the carbon contents and the manganese in certain proportions give excellent results. viz:

With carbon from .50 to .60%, manganese should be about 1.50%. Where vthe carbon runs down to the lower range, that is, at 30%, the manganese may be run up to as high as 1.90%. It is, of course, well understood that in the manufacture of steel rails that considerable limit must be given to the various elements in order to make the process commercial, but these limits must not be so reduced as to affect the wearing qualities of the rail. With the proper carbon content and the proper manganese content, a steel of a high tensile strength and elastic limit with a goodeiongation and reduction of area is produced, and one which contains little or no crystallization. Neither is it necessary in a steel of this kind to do any heat treating, which very materially adds to the cost of steel. i

It has also been discovered that the large percentage of manganese has a very neutralizing effect upon the sulphur and tends to keep the sulphur and phosphorus in combination lends itse f most readily to heat treatment.

' If the manganese and carbon constituents are employed in the range of tirgportions noted, I find it unnecessary to utl e molybdenum, chromium, nickel, tungsten, titanium and vanadium and to this extent the product and process are rendered simpler and less expensive. A greater degree of uniformity may also be preserved in the manufacture and in the article. In short, a more homogeneous-and reliable steel is produced.

In carrying out the process, it. appears to be exceedlngly important in the production of this steel for rails that the manganese all be added to the furnace before the steel is teamed into the ladle. It has been the ractice to add a very large proportion o the manganese in the ladle but this has only been done as a rule when steel .of a very much lower manganese content is being manufactured, and with the result that the steel in many cases is unsatisfactory.

It has been heretofore thought necessary to employ molybdenum where high reentages of manganese were used to 0 set socalled undesirable effects of the manganese, especially where the steel was subjected to heat treatment; and it has also been a common 'misapprehension that, although the manganese increased considerably the tensile strength of the steel, it did so at a loss of reduction of area and elongation; and that the manganese segregates, which condition was popularly supposed to be corrccted by the use of molybdenum.

After making several thousand tons of steel according to the present method, I find these conclusions in error and am enabled to dispense with the use of molybdenum, thus saving considerable expense and annoyance and accomplishing the manufacture by simpler and more direct methods. Possibly if the percentage of manganese is raised the molybdenum ma be necessary but so long as this element is ept within the range referred to only uniformly excellent results in the product are found.

It will be readily apparent to those skilled in the art, that the foregoing steel will show a very great increase in wear and safety over the standard steel rails as now produced, my steel having a' marked increase in resistance to impact and shock and to alternating stresses without crystallization.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is 1. A railway rail made of steel containing carbon, from .30 to .85%; manganese, from 1.15 to 1.90%; phosphorus, not to exceed .05%; and silicon, not to exceed 30%.

2. A railway r'ail made of steel containing carbon from .30 to 85%; manganese from 1.15 to 1.90%; phosphorus not to exceed .0573; silicon not to exceed 30%; and other elements not to exceed 25% each.

HOWARD J. FORCE.