US1018366A - Production of machined shapes of manganese steel. - Google Patents

Description

finish in their machined portions.

n' r appear, the'blank from 3 NITE STATES.

,wmrmnn s. v.ror'rnn, or new YORK, '11.

PATENT oFnroE. I

Y., ASSIGNOB. TO m szrnnnrommo 'com'rm, or' wrmmq ron, DELAWARE, aconrona'rron onDELAw'AnEf others skilled in the art .to which it apper tains to make and-use the same Myinvention relates to the manufacture of cut gears o'r 1ike shapes of manganese 16 steel which-require machining, such as pin- :ions, bevel gears, spurgears, :worms, threaded bars and other machinery parts requiring'aecurate machining in additlon to such 4 forining as may readily be done' by, forging 20- or other hot shaping.

- Ithas for'its ob'ect the production'of such manganese steel shapes in a condition of suitable hardness and strength, and of the requisite-smoothnessandaccuracy of which the cut gear or the like is to be made.

may be produced by rolling, forging, "or pressing a suitably cast ingot of manganese steel and cutting the same into individualblanks; or the blank may be cast to form, or east; early to form and subsequently wrong t. In any-case the gears or the'like,

.are.broug ht into fina -form an condition 85 operation which consists or hree main stages, to -wit: a preliminary' rought cutting oi the teet of the gear, at temperatures 40 Itero' lilglifs eed steel; second, heat treat- "',"ing".. lthe. roughly cut sha e and :It so a'sto give it'- the des red toug 'n'ess an strength; and completing the cutting at a temperature' of about'300ff- O. to 420 C. for

.'t he portions finallyto'be removed, thecomplet on of the. cutting-being effected with Ia finetoothegl wheel, milling cutuenehin i PRODUCTION OF MACHlINEDBHAPES 0F MANGANESE STEEL. v

, Specification Letters Patent. P t nt d FQIL 20, 19 12, Application filed December 18, ran.

Serial No. 686,500.

'ter, reamer, or other tool shape suitable for finishing the surfaces which require machiningt o In the production ofwrought manganese steel gear blanks or the like from aningot, it is preferable to .first cast the man anese steel ingot; then beat it until in a con ition suitable-for rolling' then roll it to "a bloom or billet, and out I sired weight. The blanks are bred h t into 5 gear blanks of'thedethe desired form with an interine aate 'reheating, if necessary, which may be at anytemperature affording the requlsite lductiL 1ty and which will usually-range iromabout 800 C. to 1250 C. The blank should, how ever,'in the final stage, at thefworkin operation. be worked at temperatures et-we'en'- 65 preferred condition of the steel, The

880 C. and about 1075?, C., so as to obtain t e blan should then be heated to a red heat, say to between500? C. and-1075? -C. preferably to about 900. C. to 1000" for rough'eutting to form, if such rou h cutting is necessary. The rough cut; ape is then quenched, or first bro'ughtlto" an equalized temperature throughout of about 1000?. 4

C. and quenched; the equalizing reheat be'-* ing gof such a character as to again'bring into solution in the blank any carbide that.

mayhave separated 'out in the course of the operation. more accurate machining,- it "should; be heated, in' the parts to be thus further If the blank requires .further-.'

chined, 'to"about 300 0-. to420 C., .and"-i s' then machined to finish, with suitable high= speed steel? tools. If extreme accuracy of the finishedflsha e is required the blank is 7 preferably "even y. reheateqb this time to a temperature and420,-.C.-, and is then .very rapidly out throughout. ht. etween 300 CL to finished form, whereupon it is permitted I to evenly; cool to atmospherie temperature.

In this manner, a distortionof the finish ed shape unequal shrinkageirreoolinggafter" the fina maehiningl accuracy in smogt is avoided, Additional, ness. and finish may; obtainedQin some cases, by grinding'cemi s parts of the piece to produce the desired surface. 1

Wherethe gear blank is to be cast as such, the manganese steel, of the desireda composition, is cast'into molds in such manner that porosity. and shrinkage cavltles are (avoided in the cast blank. The blankisthen separated from the gate and head metal, and'is then heat treated either im- 1'0 mediately from the heat of casting, or later,

,as desired, the purpose of-this heat treat anentbeing to brin into solution and even:

distribution throughout, the mass, the car- ;bids that have separated out during the freezing and cooling of the metal.,

w The cast gear blank may be brought into a wroughtcondition, attemperatures be,- tween 950 0( and 1250'0. by pressing or otherwise, and, in such case, should be finally .20 ;-,worked at temperatures below 1075 and preferably at a temperature of about.1000-x 0. and should not thereafter'be heated above 1025 C. for any considerable time of; hea t.

m'g. ;For rough cutting'theblank, it may then be brought to any temperature between 500 0. and l075 0.and rough out, and should then be quenched from a temperature substantially equalized throughout of from- 800 0.'to;1075 0. After quenching, it'- may then. be'reheatedtd-between 300 0. and 420 0., for-. accurate machining, when .such further. machining is rerulired.

In those-instances injvhich the cast mangane'se steel blank isfsubjected to the preliminary cutting operation,,j without 'first pressing or otherwise working the blank, the preliminary cutting or machining operationis conducted, as above, at a temperature ranging from 500- 0. to 1075 0. and when 40 the preliminary cutting or machining,

quired is so deep as to involve a heating to these temperatures (or to an .remperature above 420 0.), a'subsequent heat treatment will be necessary, consisting in bringing themetal to a temperature. of about 1025* 0; after the cutting operation, and for a time sufiicientto restore the metal to a conditionsuitable :Eor quenching. The cast blank may, in some instances, be heat-' treated so as to bring into solution the carbids that have separated out during freezing and cooling; it may then be cooled, re-

heated to S9. 500 0. to-1075? 0., and rough cut or mac ined at that temperature. It

may then be heated toan equal temperature throughoutwithin the range of'say 975 0. to 1025 C. and immediately quenched. For final accurate machining, it may then be heated to between 300 0. and 420 0,, ma-

chined to finishedform, and finally cooled.

The method of making out gears" and other machined shapes in accordance with my invention, is characterized by the .c'ircumstance that after the blank has been brought into a wrought condition, by suit- ;able pressin rolling or otherwise working it, before su jecting it to the cutting operation,, the reliininary cutting is conducted under, such conditions as not to destroy the wrought condition; furthermore, after the preliminarily -cut blank has been quenched, the final accurate cutting ,is efi'ected, in .ac-

cord'ance .with 'my invention, within a'temperature ran e which will not destroy the toughness a hardness incident to quench-- ing. These characteristic features are capable of utilization, either separately or in combination, as fully appears from the typi- "cal instancesof the practice of the invention hcreinbefore described. Having thus described my invention what Ilclaim' is: 1

1. The .method of producing machined 'shapes of manganese steel, which comprises wvorking the metal at temperatures beginning at between 950 0. and 1250 0., continuing the working of the metal at temperatures between 800 0. and 1075 0. thereby obtaining a fine-grained wrought condition of the metal, preliminarily machining-attemperatures between 500 ,0. and 1075 0., heating at temperatures between. 800;0. and 107 5 0., rapidly cooling to below 420 0. and completing the machin- 'ing at temperatures between 300 0. and

420 0.; substantially asdescribed.

V 2. The method of producing machined shapes of manganesesteehwhic'h comprises workin the metal at temperatures which in the nal forming are below. 1075 C. and

preserving the wrought condition incident to-such working by machining at temperatures which are between500 0. and 1075 v0.; substantially as described.-

3. The method of producing machined shapes of manganese steel, which comprises workin the metal at temperatures which in the nal forming are below 107 5 0. and

preserving the wrought condition incident to such working by machining at temperatures which are between 500 0. and 1075 0., and toughening the metal by heating at- .temperatures between 800 0. and 1075 C. and ra idly cooling to a temperature below 420 substantiall as described 4. The method 0 producin machined .shapes of manganese steel, whic j comprises fworkin the metal at temperatures which .111 the nal forming are below 1075? 0. and- 300 'C. and 420 C.; substantially as detween 300 G. and 420 (3.; substantially as 10- scribed. v described. 5. The method of producin machined In testimony whereof I afiix my slg'nashapes of manganese steel, whic consists in ture, in presence-of two witnesses.

' heat-treatingand working the blank until it is in a fine-grained toughened wrought WINEIELD POTTER condition, and avoiding loss of the toughened Witnesses state during the final machining by efl'ect- Jo n- C. PENNIE, ing such final machining at temperatures be 7 MINERVA LoBnL.

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' Washington, D. G.