US1211826A - Iron alloy. - Google Patents

Description

UNITED STATES PATENT OFFICE.

- FRED c. 'r DANIELS, or NATICK, massAcHUsETTs.

IRON ALLOY.

No Drawing.

To all whom it may concern:

Be it known that I, FRED C. T. DANIELS, a

citizen of the United States of America, residing at Natick, in the county of Middlesex and State of Massachusetts, United States of America, have invented certain new and useful Improvements in Iron Alloys; and I do hereby declare the following to be a full, clear, and exact description of the invention,

such as will enableothers skilled in. the art- 'to which it appertains to make and use the same.-

My invention relates to a casting alloy of iron for casting sand rolls and-like machinery parts for shaping hot or cold metal. It

is especially adapted for rolls that take the place of chilled rolls for rolling mills, especiallyjwhere on account of gthe width of the fianges of the shapes to be rolled, a deeply chilled roll is necessary. Such a chilled roll is very diflicult to make in'the foundry, and is equally unsatisfactory to use in the rolling mill. For these reasons rolls of special iron alloys have recently been substituted for the chilled rolls.

My alloy is used for the manufacture of rolls for rolling hot and cold iron and steel,

forging and bending dies, rolling mill guides, pipe balls, shear knife edges and cut ting tools, and for other high duty devices "and machines in which hardness combined with toughness and ability to resist wear and shocks to a high degree are most desirable and advantageous.

The object of my invention is to produce a metal or alloy that is superior to other iron alloys and casting metals.

My newalloy. is distinguished from known casting metals by a hardness, exceeding chilled iron rolls and also exceeding that of rolls of. special alloys; by a decided tou h-' "ness'when-heat treated, whichalmostc in- .cides with that of manganese steel, and my -,metal differs therefrom not only in composi- Ition and in the treatmentthereof, but also in i the uses to Which'it may be put, 'in that it may be cast into pieces'of very large section,

' due to thefact that it does not require the same strenuous and sudden quenching and annealing heattre'atmentthat is required by manganese steel toproduce its properties,

Thavenever before encountered, that when.

, My alloy hasithe. peculiar property, which Specification of Letters Patent.

heated-to 750 C., more or less, and maintained at that temperature" for a length of.

time, depending upon the thickness of' the casting, of from one to sixty hours, andallowed to slowly cool, its hardness increases.

In addition to iron my alloy contains carbon, silicon, nickel and manganese,also other elements usually present in iron alloys and kept 'within the usual limits of foundry pracor silicon, or both manganese and siliconcustomary in foundry practice.

The nickel content ranges from about 1.00 per cent. to about 3.50 per cent. Such an alloy containing also silicon, phosphorus, sulfur and manganese (or any combination of these last elements within the usual foundry practice ranges) gives a new and, valuable Patented Jan. 9, 1917. Application filed April 3, 1916. Serial No. 88,718.

alloy. of'iron. It is a white iron entirely i it throughout the casting, andis improved by Castings of this alloy are heat treatment. I subjected to a prolonged heating by placing them in a furnace and heating them from 700 to 850 C. for from oneto sixty hours.

The length of time that the heating is continued is entirelydependent upon the thick.

ness of the casting, it being. my object to heat the casting through and through to the. temperatures above mentioned and then allow itto slowly cool. This can be done by closing the fiues of the furnace and allowing the casting to remain therein until the tem-' .perature has dropped to' about 125 C. to

250 0., when the'casting may be taken out strains, but also greatly increases the. tough- "ness of the alloy, which is a very valuable property of this alloy.

and allowed to cool in the open. This heat treatment not I only removes the 'castlng My invention also embraces the use of manganese in quantities inexcess of the usual foundry practice, that is to say when presentin a high nickel high carbon iron quantities above one per cent., and suitably My experience with casting irons shows that the presence of manganese in the iron up to about .30 per cent. has a softening effect, that if the manganese content be increased from about- .30 per cent. to about 1.00 per cent. known foundry practice, it will have no noticeable efl'ect on the high carbon iron, and that when the manganese content is increased over 1.00 per cent. and up to 2.75 per cent., it will have a strong hardening effect on the iron, have a tendency to hold the carbon in the combined state, and will produce a better wearing surface in rolls well cooled by water:

My invention also consists in adding silicon in excess of the quantities used in general foundry practice tothe high nickel highcarbon iron, either-with or without manganese, but always in such quantities that the, resulting compound shall be a I white 1ron.

My experience shows that when silicon is added to the mixture, whether manganese is present or not, the higher-carbon limit above given cannot be used, and that the carbon content must be nearer the lower carbon limit above given, and specifically the carbon content of a' high silicon iron cannot'be much above 1.80 per cent. carbon in the absence of a high per cent.-of manganese. When a high per cent, of manganese is present, however, a high percentage of silicon may be used with a much higher carbon content, namely 2.20 per cent. carbon and thereabout.

To the best of my knowledge silicon has not been used in sand casting white irons in quantities over one per cent. and where the carbon range is over 1.25 per cent.

In my alloy the silicon may vary from 1.50 per cent. to 5.00 per cent. and imparts t0 the alloy extreme hardness, especially in the presence of a high percentage of manganese and the upper permissible limits of carbon. Silicon is prone to convert the carbon .into its graphitic state thereby producing a gray or black iron useless for the hi h duty purposes for which my alloy is ma e, and therefore care should be taken to control-the proportion of the ingredients so as to produce a white iron.

The high percentage of silicon in the presence of the high percentage of 'man- I ganese will produce a much harder and a f; much longer-wearing surface than when the manganese is not resent, with the accomj panying necessary ower carbon content.

per sq. in.

cast; magnetic after heat treatment as above Rolls 'ofmy new composition show a much longer wear, or, n other words, will rolls or rolls of other special iron alloys.

With the carbon over 2.20 per. cent. the silicon should be kept under .75 per cent;

and while such a ratio of silicon to carbon.

hasbeen known in other casting irons, they have not had the high nickel contentof my alloy, and consequently have not had the hardness, nor have they had the toughness, imparted to them by heat treatment.

produce more tonnage of rolled material for an equal amount of dressing than chilled The alloys of the compositions embraced in my invention are all white metal, and have exceptional properties; they have a tensile strength when not heat treated from 50,000 lbs. to 60,000 lbs. per square inch; I

when annealed as described, the tensile strength is increased from 75,000 lbs. per square inch to 100,000 lbs. per sq. in., and this tensile strength is still further increased when forged hot. V

The. forgeability of the alloy after being heattreated when brought up to forging heat is an unexpected property, and is greater when the carbon content is low and when the silicbn is present in the smaller quantities. For example, a high nickel low carbon iron with the silicon and other customary elements present within the ranges of ordinary foundry practice gave the following tests; cast material 60,000 lbs., -annealed 100,000 lbs. forged hot, 140,000 lbs. The tensile strength of other forged compositions made in accordance with my invention with and. without either or both silicon and manganese varied between this high limit of;140,000 lbs. per sq.

in., to 100,000 lbs. per sq. in. The raw, that is the unheat-treated metal, the heat-treated metal and the forged metal, when cold show no noticeable elongation in the testing ma chine.

Their hardness as tested by the scleroscope or sclerometer is shown to be above that of any iron alloys with which I am acquainted. The hardness of my raw material as so measured ranges from 55 to 70; of the toughened heat-treated material from 60 to and the forged material for the various compositions, V

Manganese is preferably present in all the compositions in quantity-suflicient to impart fluidity and soundness to the material. Another peculiarity is that the presence of' small quantities of vanadium, tungsten,

copper, molybdenum, aluminum, chromium, cobalt, and titanium and similar elements, havegiven no noticeable alteration in the i n I propert es of my alloy, whether-present 1n the original ore, pig or scrap, or added as elements, alloys or ferro-alloys. Specimens of alloys made in'accordance with my invention were found to be non-magnetic when described, and when quenched loses its magnetic properties.

Examples ofwhite irons which I have .made are represented by the following 5 analyses:

A few specific analyses of individual heats are given by way of example, as follows:

The color of the raw alloy is-like that of cast steel, and the color when heat-treated is like that of annealed steel. The fracture of the raw product (un-heat-treated) is bright crystalline, the fracture of the heat-treated product is dull. The dressed surface of the raw product is bright and shiny, that of the heat-treated product is dull and silky.

It is, of course, well understood that it is diflicult to obtain different large molten masses of iron alloy having exactly the same composition, and slight; variations in the proportions of the ingredients comprising my alloy shall be deemed within the terms of my invention.

, The alloy should be run into the molds at 40 a casting temperature between 1200 C. and

1350 0., and preferably between 1225 C. and 1235 C.

My alloy is hard, long-wearing, tough, and shock-resisting, exhibiting all of these properties to a greater extent than any other iron alloy with which I .am acquainted.

I claim I 1. An iron alloy containing silicon, sulfur, phosphorus, manganese, combined carbon from 1.25% to 3.50%, and nickel from 1.00% to 3.50%, the relative proportions of the said elements being maintained to produce a white iron under all conditions.

2. An iron alloy containing silicon, sulfur, phosphorus, combined carbon from 1.25% to 3.50%, nickel from 1.00% to3.50%,

and a manganese content above the percentage used in foundry irons, the relative proportions of said elements being maintained to produce a white iron. 3. An iron alloy containing silicon, sulfur, phosphorus, combined carbon from 1.25% to 3.50%, nickel from 1.00% to 3.50%, manganese from 1.00% to 2.75%, the relative proportions of said elements being maintained to produce a white iron.

4. A white casting metal, an alloy of iron containing sulfur, phosphorus and manganese, and also containing carbon from 1.25% to 2.20% in the presence of a nickel content from 1.00% to 3.50% and silicon from 1.00% to 5.00%.

5. A white casting metal, an iron alloy containing sulfur and phosphorus, and also containing carbon from 1.25% to 2.20%, nickel from 1.00% to 3.50%, manganese from 1.00% .to 2.75%, and silicon from 1.00% to 5.00%.

6. A white casting metal, an alloyof iron containing sulfur and phosphorus, and also containing carbon from 1.25% to 2.20% in the presence of nickel from 1.00% to 3.50%

and a high manganese and a high silicon content.

7. A white casting metal, an alloy of iron containing sulfur and phosphorus and also containing carbon from 1.25% to 2.20% in the presence of a nickel content of 1.00% to 3.50% and a high silicon content commensurate with respect to the carbon content.

8. A white casting metal, an alloy of iron, containing manganese about .7 3% sillcon, about .028% sulfur, about 033% phosphorus, about 1.76% carbon and about 3.14% nickel.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribing witnesses.

FRED C. T. DANIELS.

'Witnesses H. J. SGHURFLEB, A. E. SGHUBART.