US1018364A - Making wrought manganese-steel car-wheels. - Google Patents

Description

UNITED STATES PATENT OFFICE.

.WTNFIELD S. POTTEE OF NEW YORK, N. Y.

MAKING WROUGHT MANGANESE-STEEL GAE-WHEELS No Drawing.

To all whom it may concern:

Be it known that I, WINFIELD S. Power, a citizen of the United States, residing in the borough of Manhattan, city, county, and

State of New York, have invented certain hard and dense structure, particularly in the flange and tread portions of the wheel, the manufacture being so conducted as to avoid in thapreliminary and in the final forming operations, various laminations and other irre larities of structure in the steel which Wou d tend to cause irregular wearing or breakage of the wheel in service.

My improved wheel when brought to its final form and dimensions is substantially devoid of laminations and weak cleava e surfaces, and in a condition of great strengt the tread and flange portions particularly being in a state of maximum hardness consistent with the necessary toughness and shock-resistance.

In carrying out my invention, the manganese steel, while still molten, is suitably cleansed by reducing agents and by means of fluxes, and is held in the ladle prior to casting until the impurities have floated out of the metal.

Thein ot is then cast of a size to produce several w eel blanks and may be of.the usual tapered form. The casting is so conducted as to avoid shrinkage cavities and porosity in the main body portion of the ingot, that is to say, in that portion which is to be cut up into wheel blanks. To this end, the metal is preferably poured into molds having tops which retain the steel longer molten.

in the upper than in the lower ortion of the mold, so that the impurities o the steel accumulate in that portion or part of the upper portion of the ingot which is to be rejected y cropping after the first stage of the forming operation. To this end, a mold having a suitable refractory top portion may be employed. Or the ingot may e produced Specification of Letters Patent.

Application filed December 18, 1911. Serial No. 668,288.

Patented Feb. 20, 1912;

in accordance with my U. S. Patent No. 967 830,dated Au st 16, 1910.

when the in ct we been cast, as aboveor an other suita le manner to 'avoid porosity it is permitted to freeze, and is then stripped from the mold, while still hot, and is placed in the heating furnace or soaking pit. At the time of stri ping the in 0t, and when it is introduced into the soa ing pit, it has frozen and cooled to a temperature in the average of from about 1000 C. to about 1100 C. In the soaking pit the ingot is equalized at a. temperature between about 1150 CL and 1200 C. to eliminate irregularities of composition and structure occurring during freezing and cooling. Great care is to be exercised at this juncture to avoid an coarse re-graining of the steel, and, to t is end, after the ingot has been soaked within the temperature range referred to and has been equalized throughout, it is withdrawn from the soaking pit, for the reason that to retain it therein after the irregularities of composition and structure have been removed tends to brin about the coarse re-graining referred to. 0 also, the retaining of the ingot within the soaking pit after the irregularities of com osition and structure have been removed as the further tendency to bring about, to a greater or less extent, an evolutlon of gases within the mass which correspondingl forces apartthe crystals of the steel an thereby decreases their cohesion.

When the ingot has been brought, in the soaking pit, to the desired condition and has been removed therefrom, it is reduced to a bloom of substantially uniform cross-section throughout, and is then cut into wheel blanks of the required weight, at temperatures between 1125 C. and 1200 (3., and preferably Without heating it above about 1175 C. For example, the bloom ma be cut by one or more rotating cutting isks into suitable wheel blanks. Instead of cut-' ting these blanks of a length and diameter approximating the ultimate diameter of the finished wheel, I prefer, inthe first instance, to roll or otherwise work the ingot when bringing it to parallel form down to a considerably lesser cross-section, so that in cutting ofl a blank of the requisite weight therefrom, the blank will be correspondin 1 longer than the ultimate average the ess of the wheel. By this expedient,

I am enabled to more accurately cut the ingot into blanks of the desired weight. The blank is then worked in its outer portions, having at this time a temperature 5 within the range of 1125 C. to 1200 C. For example, it is placed in a suitable die, closelly fitting its margin and is then subjects to heavy pressure and is thoroughly worked in its outer portions particularly, the die bein of such a character as to prevent any su stantial amount of stretching in this tread'portion. The purpose of this preliminary working of this outer or tread portion of the blank, while at the same time preventing elongation or stretching of said tread portion is to avoidany such lamination in the finished roduct as would be due to internal flaws in the blank. That is to sa the thorough working of the outer or tree portion of the blank at this stage of the operation has the eifect of consolidating the metal in the tread portion and eiiminating any possible internal flaws or cleavage surfaces therein. The blank is then removed from the die and reheated for further forming. By a suitable rolling or ressing operation the central part or the innermost portions of the blank are suitably worked to bring them into the desired wrought condition in so far as this can be accomplished in one heating, or during one or more re-heatings, and the blank as a whole is finally brought to the desired form throughout, either in a single operation or 85 a plurality of pressing or rolling operations. During any of the reheating operations, the re-heating is to be so conducted as to avoid any coarse re-graining of the steel after its initial working; moreover the re- 40 heating operations should be of but moderate duration, so that neither the temperature of the re-heatin nor its duration shall have the effect 0 bringing about a feeble cohesion between the grams of the steel particularly in the tread and flange portions of the blank. The standard practice, therefore, as just indicated, should preferably exclude a re-heating of the tread portions of the blank at any time above 1175 C. or thereabout. If, however, the exigencies of the case require that the steel should be hotter than 117 5. (3., in order to suitably form the hub and web of the wheel, the entire blank may be reheated for a short time above 1175" C. (say 1200 0.).

The handling of the metal from the heat of casting through the various re-heating operations should'be so conducted that after each forming operation the blank is taken quickly from the preceding operation and with as little less of its eat as may be to a reheating furnace having the desired maximum temperature to be employed for the next forming operation. For example, the blank after having been severed from the parallel bloom should be delivered to the next heating furnace with an average temperature of 1000 C. if possible, or with any higher temperature less than the'temperature suitable for the reheating furnace at this time, which will be about 1175 C. The blankwill then be brought to the desired maximum term erature for thenext forming step prefera ly with a steadily rising temperature until the maximum tem perature is reached and the piece is then only held in the furnace for a time suificient to obtain a substantial e uality of temperature throughout the blaiik. The same recaution should be observed with regar to each succeeding handling and reheatin of the blank; as, if the blank is permitte to cool, or is placed in a furnace havin a temperature much less than the inten ed maximum the rise of temperature in the blank. to the working heat will on account of the peculiar properties of the metal be so slow asto produce a considerable crystal building and a coarse and feebly coherent re-graining of the metal.

If on account of the lack of suitablenfacilities the blank at any stage of its formation must be cooled to a low temperature, as for example to below a black heat before the followin reheating and forming o ration can be e ected, the cooling and su sequent reheating should be then conducted with the followin precautions:

The b ank having been partially worked and having at the end of this portion of the operation a temperature of say 1050 C. or above, will be rapidly cooled (as by means of a water spray) until at a temperature of about 400 to 600 C. and may then be cooled in the air or as desired to ordinary temperatures. If the blank is worked until at a temperature ranging from say 700 to 1000 C. it may be air cooled if desired. In

the subsequent reheating the blank is preferably reheated of 420 C. or thereabout; for example, it is gradually heated to between 400 to 650 C. whereupon it is chargedinto a furnace and the blank is then heated as rapidly as possible and preferably with a steadily rising 1 heat to the desired temperature for the next forming operation.

The wheel isfinally worked throughout at temperatures below 1075 C. and is ot thereafter reheated to above 1025 G. except for very short periods of reheating.

The final. working of the tread portion for the production of the greatest density and strength of metal should begin at aminitial. temperature throughout below 1125 C. and is preferably completed at a temperature throughout of about 900 to 1025 C. Thereafter, the tread and fiangeportions should not again be re-heated 'to a temperature above 1025 for any considerable time a1 gradually to a temperature 110 the finished wheel may tion to temperatures above 420 0. or

though good results could be obtained by reheating up to temperatures as high as 1075 C. for a very short time.

At the termination of the final working, be immediately cooled, as hereinafter described, or it may be placed in a furnace having a temperature range, for exam le from 900 to 1075 C. but preferabl a out 1000 0., for a short time sufiicient y to substantially e ualize the temperature throughout the whee, and the wheel is then taken from the furnace and subjected to a ra 'd cooling operation.

The re id coo ing operation may be carried out y immersing the entire wheel in water or in molten lead having a temperature butslightly above its melting point; or in any other suitable manner appropriate to rapidly extractingthe greater part of the heat of the wheel. Or, the rapid cooling of the wheel after it has been equalized at a temperature of about 1000 C. may be executed by supporting the wheel from its central openin on a shaft by which it is rotated, and uring this rotation, subjecting it to a suitable number of high ressure water jets until its temperature is re need throughout to below 420 0.; whereupon it may be gradually or rapidly cooled to atmospheric tem rature.

Tli: machining of the running surface of the wheel and also the borin of the hub of the wheels of man anese stee ma be conducted either by grinding or by ringing the parts to be machined to a temperature slightly below 420 0., say 300 0. to 420 0.

and thereupon turning or boring as may be necessary. However, no portion of the mass is re-heated after the rapid cooling eraereabout.

Having thus described my invention what I claim is:

1. The method of producing wrought manganese steel car wheels, which consists in casting a manganese ingot so as to avoid porosit and of a size to produce several,

wheel lanks; permitting the ingot, after freezlng, to cool to between 1000 0. and

1100 0.; reheating to between 1125 0. and 1200 0.; reducing the ingot to substantially uniform cross-section throughout its length and cutting it into blanks; immediately reheating the blanks to not above1200 0.; working the outer portion of the blanks and forming the hub and web portions, the final working of the hub and web portions takin place at temperatures below 1075 0. an the final working of the tread portion takin place at temperatures below 1025 0.; equa wing at between 975 0. and l025 0.; and rapidly coolin to below 420 0.; substantially as descri ed..

2. The method of producin wrou htpreliminarily working, a manganese steel wheel blank at temperatures between 1125" 0. and 1200 0.; finally working said blank throughout at temperatures between 900 0. and 1075 0.; ualizin at about 1000 0.; and re idly co dlin to below 420 0.; substantia ly as descri ed.

3. The method of producing wrought manganese steel car wheels, which comprises preliminarily working amanganese steel wheel blank at temperatures between 1125 C. and 1200 0.; finally working said blank throughout at tem eratures between 900 0. and 1075 0.; rapidly cooling to below 420 0., and machming to form at a surface tem erature for the portions to be machined 0 between 300 0. and 420 0.; substantially as described.

'1. The method of producing wrought manganese steel car wheels, which comprises reducing the ingot to. snbstantiall uniform cross-section throughout its len and cuttin it into blanks at an initial temerature 0 about 1175 0. thereafter worklng the blank into wheel form in a number of forming operations with intermediate reheating; the re-heatin for each forming operation being ra id y conducted up to a out 1175 0. and or a period of moderate duration; finishing the working at temperatures below 1075 0.; and finally cooling,

rapidly to below 420 0.; substantially as described.

5. The method of producin wrought manganese steel car wheels, w ichcomprises reducing the ingot to substantiall uniform cross-section throughout its lengt and cuttin it into blanks at an initial temperature 0 about 117 5 0. thereafter workmg the blank into wheel forms in a number of forming operations with intermediate rerises reliminaril workin a man anese. P r Y g g steel w eel blank at temperatures between 1125 and-1200 0.; com letin the working of all parts of the b ank t er'eafter at temperatures below 1075 0.; and finally cooling rapidly to below 420 0.; substantially as described.

7. The method of producing wrought manganese steel oar wheels, which comprises rimarily working a manganese steel wheel lank at temperatures between 1125. 0. and 1200 0.; completing the working of all parts of the blank thereafter at temperaprises consolidating the outer portions of a tures below 1075" C.- equalizing at between manganese steel wheel blank by compressing 900. C. and 1075 and fi nally cooling at between 1125 C. and 1200" 0.; working rapid iy; substantially as described. the blank to wheel form; then working the 8. he method of producing wrought blank throughout at temperatures below mang'anese steel car wheels, which come 1075 0.; and cooling rapldl from about prises Ereliminarily working *a manganese 1000 C. to ,below 420 0.; substantially as steel w eel blank at temperatures between described. 1125 O. and 1200 (1.; completing the work- In testimony whereof I afix my signawing of all parts of the blank thereafter at ture, in presence of two witnesses,-

tem eratures below 1075 C.- and finall cooling ra idly from about 1(i00 to be WINFIELD POTTER low 420 substantially as described. Witnesses:

9, The method of producing wrought M. A. BILL,

16 manganese steel car wheels, which oom- Joan G. Pmmm.