US2210357A - Composite wear-resisting body - Google Patents

Description

Aug. 6, 1940. 1'. G. BEAMENT COMPOSITE WEAR-RESISTING BODY original Filed Feb. 17, 195e offmserfi www@ MWMWMMWWWWWWZJ wmu SSN Patented Aug'. 6, 1940 UN'ITED STATES PATENT OFFICE azionato ,25x-sagem 0..., 0....., A

original appunti February 11, 193s, serial No.

, 64,238. Divided 'and this application Septem- `1 bei' 27, 1937, Serial No. 165,797

sired number of preformed, highly wear-resistant and suitably spaced inserts.

The invention resides in al new article of manu facture characterized by the selection for the body member and inserts, respectively, of metals, alloys or classes of metal having physical properties which cause them; 'when assembled` -in accordance with the invention, to enter into a new cooperative relationship productive of service, eiilciency and lasting qualitiessuperior to those ofl previously known composite wear-resisting objects.

Another object of the present invention is to -provide a n'ovel article of manufacture also char acterized by a novel distribution of areas besultant capacity of heat transfer between thesel tween the inserts and the body in which they are embedded, or a novel selection of the shapes and proportioning of the masses of the individual inserts to the mass of thebody metal surrounding and spacing them apart so that-with the remembers of' the composite object in the original' casting of the body about the inserts, the physical properties of said object'are superior to those of known structure.

Still a further object of the present invention is to provide a novel article of manufacture embodying the principles of proper Aproportioning of the masses of the individual inserts to the mass of the body metal surrounding and spacing the same apart to provide for theproper transfer of heat between these members o'f the composite 'object in the originalcasting'A of the body about the inserts to secure the superior` physical properties hereinbefore mentioned, and which may be further characterized ,by an. additional heat treatment consisting "of subjecting both of vthe metals, alloys or classes of metal, respectively', constituent ofi the inserts and the body, aftertheir assembly -and therefore simultaneously; which affects them differently and brings out in them those physical yproperties which enable them to enter into the novel cooperative relation aforesaid.

application is a divisionof mycopending application Serial No. 64.238, filed February 17,

1 )Other objects, features, capabilities and advantages are compreheded by the invention, as

will later appear and as are thereby.

Referring to the drawing:

Figure 1 is a plan view of an abrasion-resistant body produced in accordance with the pres- 5 ent invention;

Figure 2 is a section on the line 2-2 of Figure 1;

Figure 3 is a section on the line 3-3 of Figvurei; and

Figure 4 is a chrono-thermographic -chart of temperatures developed in the herein-described alloy inserts when submerged in molten mangainheretly DOS-S8554. A

vnese steel poured into a mold in accordance with the present invention. 16 I represents a composite body designed to serve as a crushing member and rendered highly resistant to abrasion and of great structural integrity. by application of theA principles` oi the present invention. In said body, 2, 3, represent no inserts made of the herein-described alloy having a high coeiliciency of resistance to abrasion.

' 'Ihese inserts are of two different designs, namely,

of circular and quadrilaterai section, respectively, alternated in positions in a manner to render z5 substantially symmetrical the intervening embracing walls l of the body metal, which condition is enhanced by concaving thesides of the quadrilateral inserts.

As shown in Figures crease inA traverse dimension inwardly in order that they may be countersunk in the body i, and with the result that the intervening walls 4 increase in thickness outwardly, thereby materially strengtheningthe sustention of the ends of 35 the inserts where they merge with the working surface of the body and at the Sametime, by the highcontractile force, the separating walls 4 are given a large inward moment which, 'exverted upon the pyramidal vsides of the inserts,

" portion of the metal will vgenerally limit the the inserts to a range containing presses the latter firmly to a seating upon that body which underlies the In producing objects under the present invention, the material of the wear-resistant in- 5 serts, 2, 3, is ofnsuch nature that the inserts can be best formed by casting. The' high degree of wear-resistance Arequired of themand their essentially lower coeillcient of thermal contraction alloy or compositionpf atleast 1V2% v and preferably 3% carbon; at least-1.50% and not greater than 10% 01 a metal of the chromium group, preferably 2% chromium: .with or withl outnickeh the nickel, if used, being in a proporu 2 and 3, inserts 2, :,mgo tion of at least 1% and not greaterthan 7%, and preferably 4%; and the remainder being es` sentially iron. Other constituents such as manganese, silicon, sulphur, phosphorus and the like, ordinarily found in castings, may be present in minor percentages without adding to or detracting substantially from the quality ofthe a1-` loy employed for the inserts; and these constituents when present may be regarded as' non-es,- sentials. The body memberi lwhich must not y only be tough and shock resistant but have a g'reatercoeiiicient of thermal contraction than theinserts, is preferably made of iron with about 11i/2% carbon and about 13% manganese, a1- though low carbon steel may be' used with a measurableproportionof the advantages herein set forth. v

` An alloy falling within the ranges above outlined for the inserts does not possess its maximum potential resistance against wear if left in the condition in which it is cast,.but requiresv a heat treatment comprising a secondary heating ofthe said alloy to a temperature above its critical point from which it may be cooled fairly rapidly. Surprisingly, treatment of the formed inserts, such, for instance, as-heating them to 1850F. followed by quenching in water, somewhat softens the high carbon alloy i'romv which they are formed but renders it somewhat tougher than it was in the condition as cast, and 'at the same time very materially increases its' resist-y ance to wear. It has also been found that if. the inserts made of an alloysuch as above indicated be subjected to what is commonly termed drawing, that is to say, reheatedto a relativelylower temperature varying from 400 to 1200 F., or at least a temperature under the critical tempera'- ture of the alloy.v for a period of from one to threehours depending on the.drawing temperature, the hardnessis increased materially andthe lresistance to wear is sometimes more than dou-- bled and even tripled, When an alloy of the above-described composi-p tion, obviously too fragile to permit of its use-in producing the body of an object subjected to shock or impact in use, is to be subdivided into the relatively small inserts or units such as indi'cated at 2, l, of Figures 1, 2 and 3` of the accompanying drawing, and these units. are-.to be nounted in a body member I made of the hereinidentified tough, ductile manganese steel, the hard, brittle, wear-resistant alloy is first cast-in the form of inserts; these inserts are then placed in a mold spaced one-from` another in a manner to insure between` them masses of body material. bearing a `desired relationship to the mass ofthe inserts; the molten body material is then poured 'under conditions that will insure its flowing around and lling the spaces between the inserts and therebyE developing heat'transfer of a capacity determined by the volumeof molten` metal in saidv spaces, and which said volume', by predetermination of said spaces, -is that -which will 'raise the temperatureof the inserts to a degree appropriate to the quenching in the heat treatment of the present invention before'the poured metal hasY cooled below the temperature appropriateV toits ownquenching. Hence, when both components are subjected. to one andy'the ,same quench, this quench will ail'ect the two-different alloys differently and'cause them'to enter into a new physical relationship which will lend superior qualities to thennished object. The quench will Y -preferably be that conventionallyused in the 'l5 production of'o'bjects 'of manganesesteel. It will high compression, might render vcomposite object. v

be from an appropriate degree of heat remaining after the cast, for instance, about 1850 F., which temperature will have been imparted to the inserts by the poured enveloping steel and will also be approximately the temperature to which the s poured metal has cooled after a few minutes of standing s The advantageous effect of this simultaneous quenching from anappropriate heat of two dif- 'ferent materials herein identified as entering 10 into thel composite structure, is that it bestows upon the respective materials physical properties that are quite distinct one from the other. It renders the body-forming material tough and ductile at the same time 4that it renders the inll serts hard and brittle; the brittleness, however,

' being counterbalanced by the embrace of the in- .serts'by the tough ductile material, which embrace is of 'a higher order than in'previously known cast composite objects. This heat treat- I ment lwill be still more effective if the lcomposite object receives -the further heat Vtreatment of drawing from a temperature of 400i to 1200- say, V600-througli a period of from one to three hours. The quenching is economical because it u is from 'the casting heat and serves as well to produce the quenching --indispensable to cast l manganese steel. More than this, quenching from the heatvsupplied by the casting operation conditions the enveloping body metal for contracting upon the inserts and firmly gripping them without developing checks'or cracks in the cooled casting; the high coefficient of thermal cdntraction in the embracing body metal, in cooling from its pouring heat and the high stresses of compression which vit imposes upon` the inserts renders impossible the loosening o! the inserts in the enveloping body, greatly en" hances the sustention of ,the inserts against g spallingunder forces encountered in use, all 40 makes it possible to use for the inserts an alloy the brittlenesfs of whichfin the a'bnce of such l their use imy practicable.

By way oi' illustration of the advantage ofcon` 45 trolling heat transfer through the relative of the insert alloy and the,enveloplng body alloy of the composite article, ,to-wit, by selecting theY spacing of properly shaped inserts inthe mold,

assume the introduction into a mold of one hun- I0 dredpounds of alloy inserts so spaced as to admit 'between and around them two hundred pounds ci molten steel at 3000 F., and that the mold be poured and permitted to stand until the heat has become equanzed between the body 'and vthe 1nsa serts, the meantemperature 4of the composite lmass will be found -to stand at a point between '1800 and 1900 F. which may be just-right-for` the -quenching *incident to the ilrst heat treatment which the body and the inserts, jointly, are to l0 receive;A 'I'he proportion of body metal to insert H metal shouldbe such as, on the one hand, to prevent Aexcessive 'heating of the inserts-and, on

the other-hand, to insure sufficient heatingl as a preliminary to the quenching Btepin the heat A `treatment. In other words, the heat transfer from the molten metaljto the inserts should be s uch as to leave Aa final temperature above the critical for the' insert but below -the fusion temper'ature thereof. Subject to'these conditions, 70

the percentageof'insertmassmaybevariedbeltween 25% and 75% of the entire mass of the 'By way of further explanation. reference may y be had-to the chartawearinscn the :company-f u' 'l impart to the insert alloy ing drawing and consisting o f a time-temperature curve secured by inserting a thermo-couple in an insert while in position in the mold and then taking the temperature readings at' periods commencing steel had been poured into the mold. This chart shows that the temperature was rapidly raised to around 1700", then more slowly to 1850;v that it remained above 1700* for a period of around fteen minutes; and that this proved ample t'o the qualities required before quenching in the rst heat treatment of the inserts.- y f o From the foregoing, it will be seen that the present invention also contemplates the determining of themasses'of the insert and body metals entering into the composite structure so that the ratio of the one mass to the other is such as will permit utlizing the heat of the poured body such a unit will be substantially superior to thatv apparatus subjected in use 1 ance withthe present invention,

' l solid body,

metal for bringing the, initially cold inserts to a temperature appropriate for quenching purposes andwithout cooling the poured metal to a temperature Vbelow ,that appropriate quenching; also, as corollary to this, the .increasingor decreasing of the'percentageof body metal to insert metal until the final temperature obtained in the mold is increased or."decreased to the degree desired.

A simple and relatively inexpensive procedure within the broadest aspect of the invenll'fion,

. would be to make the inserts of a high-carbon,-

high chromium alloy which ls'not substantially Asoftened by heat treatment, then cast around these inserts a body mass of plain low carbon steel, then place the composite unit inservice withoutheatv treatment. The performance' of of known structuresa plain mass of manganese steel, for instance'.

Among the particular fields of application to which the invention is highly appropriate and which will serve to illustrate its. uses,v are ore and other mineral grinding and crushing members, wearing plates for; ja'w crushers, wearing portions of crushing rolls, skid plates, chiites and other to abrasive action of non-metallic materials. 1

In addition `to the very superior perfomance .characteristics'of an object produced in accordfor instance, a rock'crushing member, the invention also affords a number of production advantages. production of cast manganese steel liner plates, for instance, the casting -yield is usually notover of -the nolten metal, due to the high shrlnk age of heavy sections which must' be fed as a whereas with this insert` method of l casting, especially when, as is preferred, thev sec'- vcls ,.When the cost of melting ing and cutting" of the. mold 1o-invention becomes. quite evident.

tional areas of the inserts and of the interven-A ing body metal are about equal, the chilling effect of'the'inserts and the `xliigfioding up of the body metal into thin'walls unding the inserts produces the equivalent of relatively thin chilled-cast plates or ceptable metalv bodies enveloping the new wear- 'resisting members'will usually be as high as 90%. e wastage and the like is considered, the saving afforded by the present Due to the cooling eiect of the inserts also, there is no fusmaterial as always occurs when these'units are cast in one piece; hence, cleaning costs aresubstantially re- I duced.

immediately after molten manganese to its own such as liners for ball mills or rod mills,

bars, and the yield of .ac-

heavy Another advantage of using inserts in manganese steel in accordance with the presentinvention relates to their eect upon overall pattern shrinkage. Inthe production of some articles-.- rod millv liners, straight manganese steel is about lgthsl of an inch per foot, whereas in the insert construction the overall shrinkage is only about ths of an inch perfoot.

In the making of heavy liner plates, jaw crushver parts, and the like, it is standard practice to employ dry sand molds, that is, molds of vrelatively expensive composition, an additional cost in ovens until they are thoroughly dry and hard. With this insert practice, ordinary-green sand molds can be used with additional s'aving in time and money. Furtherfor instance-shrinkage o f' which are baked at more, when any metal or alloy is made into castings'of large cross section and heavy .massive areas, there is quite a series and harmful segregation ofconstituents, with large grain size and ,general interior metallographic orientation of the metal which militat' against the highest service. By filling the mold partly full of cold metal bodies and then casting the body metal into thin chilled layers approximating in thickv ness that of the inserts, the metal of the support- Sing body becomes very fine grained; tough in condition, and generally superior to the same metal poured with heavy cross section.

Ixf these several applications of the invention, the inserts should be practically surrounded on might presentY almost' any mosaic arrangementv of the insertl andl body metal, vitis desirable to stagger kthe confines of the inserts, 'for' instance, by selecting designs such as illustrated on the drawing, toprevent continuity of planes of weakness. In this connection, it will be noted that the. designs of inserts are such that their masses are symmetrcally dstributed about their` centers rather than forming elongated polygons or vthe like.

The use of corrosion resistant alloy for the in? 'I have foundthat e t. serts has special advantages.

a large. portion of theI loss on wearing surfaces nordinarily ascribed towear is dueto corrosion. Ordinary steels, for instance,- rust very rapidly, and particularly when the surface film is in very unstable. condition due to' severe cold working of the surface itself, by the ore being ground, or by grinding elements-balls, for instance. i-,During the actual operation of wet crushing, for example, the surfaces of wear-resisting members l'rapidly rusted and progressively and repeatedly wipedof! by the abrasives, may, vbecause of their continued bright appearance, seem not to corrode, but the fact is that the losses through corrosion are large; Therefore, of twov metals havingthe same degree of hardness or wearing resistance,` the one possessing the greatest resistance to corrosion will`lbestow longer operating life. The vcomposite body of the present invention anords'. the advantage that the high 'carbon chromium `containing alloy has greater resistance to ycorrosion than low carbon steeel or manganese steel, and for this reason gives longer 4 life under conditions where progressive rust or' corrosion is a factor. r

vWhile I have herein described 'and upon the drawing shown an illustrative embodiment of the invention, it is to be understood that the invention is not limited 'thereto but may comprehend other constructions, arrangements of parts. details and features without departing from the spirit of the invention. `I claim: f-

1. A new article of manufacture, consisting of a composlte highly wear-resistant metal object comprising lnsertcomponents and a body coinponent in which the insert components are embedded, the body component being formed of an iron alloy containing about 1%% carbon and -/13% manganese, and the balance substantially all iron, and the insert componentsL comprising an alloy consisting of iron together with about 3% carbon, 2% chromium and 4% nickel, and

said metal of said body component having a materially greater thermal contraction than the metal of the' insert components.

2. A new article of manufacture, consisting of a composite, highly wear-resistant metaly object -con'iprising insert componentsiand a body coniponent.- in which the insert components are embedded,.the body component being formed of an iron alloy containing about'1%% carbon and 13% manganese, ,and the balance substantially all iron, and the insert components comprising an alloy consisting of iron, a metal of the chron iium group in a proportion of from 5% to 10%, nickel in a proportion of from 1% to 7%, and carbon in a proportionv of from 1% to 3%, and iaid metal oi'r said body component having a magreater thermal contraction thanthe metal4 of the insert components.

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