Document kmJBzoG5LeLzqVM7Exgdm93yy

,t x \;;y #** . * *, \ i .* * '".***. -.;y * -vt.;* * ** * . ** * . t * * V '; * . '* y V> t I .* #*, *,* 4/ .w< i^f `fiifi*. Si, ii-mV-"*. - . - 'r''' -'* ' .v-S :. t- e : f.r <r*. +*!+* |-** -- --. .s'"-.<? v"}.V'-i -v'*'TC Simulation and Characterization of Used Brake Friction Materials and Rotors M. G. Jacko and R. T. DuCharm# Research Laboratories, The Bcndlx Corp. International Automotive Engineering Congress Detroit, Mich. January 8-12,1973 730191 v.o'l ,"'..V; . .y t MAR 000615 730191 Simulation and Characterization of Used Brake Friction Materials and Rotors M. 6. Jacko and R. T. DuCharma Research Laboratories, The Sendlx Corp. FRICTION MATEKIAI-S FOR automotive brakes ire complex compmtlci containing thire gciKtal daises of matettali: chrysotlle asbestos fiber, the foundation and reinfotefng agent; modifiers that adjust or maintain the friction level and wear rate or conltul the noise ptopet ties; and an organic resin binder. Drums or discs (which ate almost universally made of cast peatistlc stay lion) and the friction material-form the rotor-status fitetion palt which is the heart of the automotive brake. The brake converts the kinetic energy of Iht moving vehicle Into heat, absorbs the heal, and eventually dissipates It to the atmosphere. As a result of the energy conversion at the staloc.iotor Interface, tlie compositions and mkroslnicluies of the brake lining and rotor tutfaces arc altered. At low service temperatures, the phenolic resin and organic friction modifiers In the friction material undergo ploughing and mechanical damage before they convert on the surface to compositions with slightly higher catbon/nxygcn ratios. At somewhat higher use temperatures, the resin and organic filelion modifiers council to carbon mure readily, and tills in turn oxidizes lo ciifion dioxide. At the same time, the asbestos wcatt away mote rapidly because of the seduced binder strength and volume at the surface. At still higher tempera tures, the ssbestot converts from its fibrous form lo an olivine puwdri with blile nt no reinforcing value. When heal Is gen erated at tire sliding Interface between stator and totor much faster than II can be dissipated, the temperature rises and may teach a point wbett the lining or pad components decompose, oxfdlre, ot melt. The sliding sutfice of the lining cunlalnlng these reacted components h called Ihc frictional heal affected layer (F1IAI.). Al low aervice temperatures, the surface aaperitlei of the rotor ire mechanically worked and Ihc surface becomes eHos tility free of graphite. Also, the cementlte plates In the sur face layer are broken up and distributed as fine particles In a ABSTRACT A method has been developed lo simulate wotn-in-ierrice brake friction materials and rotors. The simulated thin tlnlnp and worn rotors were prepared by grinding (he materials to a predetermined level and then subjecting the prethlnned fric tion couple lo a moderate locitlal-dynamnnseter conditioning set{ttence. The friction materials were characterized by opllcal microscopy and iheimogravimetilc analysis. The rolota were characterised by surface roughness metwremenla and scanning electron microscopy. Tlie simulated components were shown In hivt (he same nticroMiucture and chemical compositions as worn-ln-senriet components. The extent or ihettnal and mechanical damage was found lo be proportional lo the duly cycles experienced. By the method described, live frictkm-afTcctcd layers of the simulated friction couple were found to be Intermediate be tween those of a simitar csrupte with 40000 mllea flight use and those of a couple with JMQ miles of medium-duty dura bility vie. These ifcnulifed components were then used In e study of the effects of worn brake components on braking system performance. MAR 000616 ferrite matria. When the surface b subjected to very high ternpenturii, muleuslte fuinu it tin rubbing surface with in ac companying Inctease in surfaca hatdneu(l, 2).* Coniaquently, Hit thermal and mtehtnieal futeti which act it llw friction couplt lnlirfict ptoduc* i complin cltemkally tnd physically iltncd inkfirtliuetuia whkh ciiimtl h accu rately deacrlbed fur an average wurn-lfl-iettrke fiktbxi couple. For (hi brain degradation ptug/jm described In Kf. 3. it wai rwenury to ilmulal* thin worn Ilnlnp. Th* objective of thi< piprr li to describe a itudy whrri tin objrcllvet wen in: I. Develop i nietluxj to lunulate worntn-iervke llninp and roton. 2- Select suitable methods to characterize tin thermally ind mechimcilly dima|id rubbmi tuifacn of uted ind simulated worn ltt nrvki lininp. 3. Demonitrate that the level of braking duty cm be corn* Uted with the extent of thermal and mechanical damage at the rubbing lurfacea. la the brake degradation program, the brake ayitemt of two vehicle! were Mudied-a custom-size vehicle equipped with dbc fronli/drum reari and an intermediate-lire vehicle with drum fromi/dium rears. Simulated uied lininp and rolou were pie* pared to match all lha wlteel comtiinailom uied tn (lie pro* ' gram. Tin data reported hen were for the front drum brake! of the intermediate-size vehicle and the corresponding simu lated worn-in-service lininp and drums. EXPERIMENTAL PROCEDURES FRICTION MATERIALS Fig. I U a block diagram which showa tha Interrelailoniltips of the experimental sequences performed for (he friction materials. Threa combinations of used llningi were used in this psopani. Tiny ere described as fulluwa. Combination A 40,000 Miles light Use Aiet of tear drum linings from a 10 X 2 In drum brake was obtained from in tm* ployee driving a 1969 InlcrmedUie-ilu vthlcle on flat (errata In lha Detroit area. fiMuhinallon H 18,700 Mile* Hut Durability A act uf rear drum Imlnp ftmn an 11 X 2.S In drum brake wai obtained from a 1971 custom-ilze teal vehicle at the Bettdla Automo tive Development Crnter. The total mileage wta 18,700 mllet. Tin final 3300 nnlci were durability-test miles. In Ihb dura* bility test, the duly nl llte >li>in varied .700 ittph at 7 ft/s* de* ccleratitHi cafe to as Ingli at 70 0 niph at IS ft/l^ deccleutiun rate. Several snubs such as 50-30 inph at moderate devc-lenlion rates were atm included, llte average lining temperature! were 300 F tut the fronts and ISO !' on the tears. Tim duty wuuld be typical til a I n* Angelrs subuibanite ctimiiiuliug to hit downtown cniphiyinc-iit. Combination t` Smmlaled Wntiiln-Servkc linn Unhipx- A set of drum llnlngt Horn a 10 X 2.S In drum brake wat nmu* Numbers In parenlltctei tlcilgtiate Reference! al end of piper. Uted aa thin Ilnlnp and then dynamometer (cited, llte lining had a Ihkkneu of 0.03S In al (lie middle uf the shoe bcfuie the dynamumeter test sequence. fropoud SlmuUtkm Method The Initial confideradon for the simulation of i thin lining coinUnadun was the deflnlllon of the Anal thlckncu desired In the burnished con dition. Tlte mlnlmiim Ihkkneu teemumended by llte vcliktc menufectuiei IsO.U.UIIn. Contequcnlly.llii followingptocedute wes proposed to rtmulelc tliln worn Ilnlnp. A set of OEM (original equipment msnufactutei) primary tnd Kcondiiy linings wat obtained fiom the manufactursr. After bonding In the shoes, the Ilnlnp were groond to e pre determined llncknesv uf O.OJS In end e tadiua 0.013 In leu than (Jut uf lire simulated wurn drum to be used wttlt the lininp. Hie tinlnp were then installed on a full-wheel inertial dyna mometer at Iktidlx Automotive Cunltol Systems Croup, South Iknd, Ind. Tlu- brake wes tun through the following condlltonutg ici|uen>.c: 1. JOOSlup Iluimdi: 40-Omphat 10 ftfa* dcccletulon operating at 230 F. 2. 10 Slop Fade: 600 mph at 13 fl/a* tlecclctallon wills 33 i Intervals. 3. 12 Stop Recuvety: 30-Omphal 10 fl/a* deceleration rm*ozt-!T,, jwni aii.mmi) ! MAR 000617 starling 2 nnn iflcs the hit lad* Hop and it 2 min lutetvali thereafter. Owrtctcrtution Methihlt laboratory procedures fix rliaiactrilrini fttctltm materials were optical mtcrmcnpy ml Ihriinugiivlmetric analysis IVialls of thne technlqiiet nr given below. Optical Microscopy Sections of material for optical micro*copy comiited of at lean a 1.0 X 0.5 in area oflinini friction uirfxe removed from the center of each linln|. The material wai mounted in bakelite or plcaiglaa tuch that the linln| fric tion unfair layer wai perpendicular to the surface to he poltilied ami inch that the unfair to hr pnllilird would iliow mtciualiucture beneath the llnhi| friction autfKe. Hie umple wai then rough ground and pollihed. Eaaminilton with ob lique reflected light at SOX uiing a Reichert Zelopan Microaeope took place pilot to photographing repreicnlilirre aectlona. Themtogratdmftrie Analyiii (TCA) After the removal of Ihc aectlom for mlctotcopy, umplet were removed for chemi cal analyiii by lltetmogravimeliy. The liyeri were removed by aurface icraping with a (harp scalpel onto a tint-free paper. The correct amount waa removed for layer I by adding Ihc actaplngs to a weighed vial until 12 t I mg waa obtained. (A temple of 10 mg wit uietl In Ihe tubiequcnl inalytli.) In moil cisci, four layen were removed; In aome caiet, only three wen removed. The characteristic! of llteie layer! were then deter mined and a chemical cumpoaltlun ntlmaled. Ftp. 2 la arhematte diagram allowing lire thk-kneaxa ami depth* of material analyzed. Ilecatnc each major component or group of componenll hu III own chiracleriillc TCA thcimugrain, this analytical tech nique wu aelecied lo give i compositional anilyala of the vertoua componenll un the ftlcllonal heat-affected layer and the undctlying layetl. In Ihe TCA technique, a unit] lample (uwally 10.0 mg) wit placed un a mlcrobalinec In a controlled almotphete (usually flowing air at 40 em^/mln). The sample wai then heated at 20C/mln from 20-1000 C (Fig. 3). In tome Inriancea, lire umple wit healed to I200C if no liable residue value was obtained at 1000 C. The weight, reeoaded at i function of tempeialuie, gives the TCA thermogram. The TCA Instrument used in this work was a DuFont Model 9S0 thermogravimetric analyzer. ROTORS Fig. 4 (a t Mock diagram which draws the fasterrelationships of the npcrlmcnial sequences performed for the rotor malrrials. I'acd Rtriurs Two drumt which had been used for 40,000 miles wlih comblnailun A used linings (prtvtuusiy described) wete obtained from an employee vehicle driven on flat lettain In the Delroll area. Sinitililed lbed Kitluri Tire simulated used drums wetc produced with the litmtlalcd thm used linings described In the previous teclluti. Tlrey were produced from standard OEM drums. Fruputtd Slmulttlon Method Two OEM drums wete -- ground to a turfite ruugjineu of 20-30 pin (AA) which was choicn to simulate the roughness of the used drums. The drums were so prepared since work (I) it Bendlx Research Fig 2 Schematic mowing Merlon mater1*1 Uyara intfani UHSMXIS' IMMtAtIDUUOMnil Pig. 4 * Used 41k and drum aimuiallon ptocadrm Laboratories has shown a correlation ofboth weir and coeffi cient of friction with ratface roughnesa. Thta work has alio drawn that a particular lining camblnaUo* tends lo produce * certain turface roughnesa on the dims when Heady-stata coo- MAR 000618 4 r J. Typktl TCA Ihaimogismi far common friction ibimiU cam- ^ *' Tpph'al TCA thesmogram tm wini I filciion nalnUI dllloni wt fetched. Thus the drams were finished u eloee la (hit study-state point u found for uied drams. These polished drums were then run thrau|h (he ilmuUltaa method previously described. Ourteiertinlaii Method Each of the used drums wee checked for surface finish at four locations. One sample wu then cut out of the wear track of each used diura. These samples were then polished and etched foe cross-sectional ex amination by scanning electron microscopy to determine the surface structure. EXPERIMENTAL RESULTS FRICTION MATERIAL The following paragraphs de scribe the experimental results uf this study as they pertain to the friction materials used. Interpretation of TCA Thermograms Fig. S shows TCA thermograms for typical brake lining componenls. FI|. 4 shows s typical thermogram for a friction mateiial that has not been used; Fig. 7 shows a typical thermogram for a frictional heat-affected portion oi layer of a friction material after ua. In almost all cases, 10.0 * 0.1 mg of the friction material layer was analyzed. Tire thermogram weight changes were then normalized to 100%. Table 1 shows the TCA tempera ture ranges that could be related to known mechanisms of friction materials. -In several cases, especially fur the top layer, the asbestos dehydioxylalion weight lots did not have good definition. Tim was due in part to thetmal reaction of the polymers to carbonaceous-type miterials which lust weight in the TCA over the range 500-900 C. However, this was not s serious pmlilcm at Site method of data pieumtstion lu show clieinlcaF iniitpoviiion (tends enabled a good compaiison of lining degra dation among the three sets of linings. Fin each tilling the following coives sie plotted for tlie vari* out lining layers: volatile cuutciii. potymci content, inorganic cunieiil (includes final TCA residue plus carbonaceous con tent), asbestos dcliydruxylaiiuii, and asbestos estimate (plotted as I OX asbestos dehydroxylatimi weight loss as 100% asbestos loses approximately 10% (weight) in the same temperature range I. Fig. 7 - Typical TCA Ibeimogiam tm (itetkanal hcil-effeited layer <t used friction materiel Table 1 TCA Temperature Ranges end Known Friction Materiel MeckealuM TCA Temperature Range CW Mtriuiihm 2V7SO 250-571 57*SOO <00-1000 1000* 75-410 410-1170 II70-I47S 1475-1152 1112* Late of moislui* pfeis low moteenier eigkt pyioiyii* product! (called nlalilet) tow doe W drgiadellon ef Cashew, rub ber, and inin polymers Alb*stul debydiosytotbw Carbon naidaeinn Inmgsac tesWus-ae furlber *Hpll change Thin Lininp (Simulated) Tlie TCA thermograms of four sample layers taken from the primary lining have been plotted in Fig. I to show the ptogressive changes in the curve with changes in duty occurring at the dtffeient layer depths or toe* Irons. The OEM material thermogram shows the best defini tion, while tlie layer I shows a "washed-out" cuivv. Table I summarizes the TCA thcnmigiani data for the piimary lining of combination C. Fig. 9 Is a plot of Ihc estimated composi tion ss l function of location for (be primary lining of (he TT wwsett Wf* BP *r MAR 000619 T(!A Ttmetraltitr Rastr.C 25-230 230-371 375-100 100-1000 1000* Tiki* 2 T(IA Vttimutnm DtU f*t Thmttf Unlnf CmkMmiImC ftneewd XtriiMhA lav MlKslar *rtl(M pvrelrrhpreescu plMiMlatst* folyrnff 4cfr4t<bA Asbestos grhyeresylatlMi CiiboucitMi cont*t KmUim PM Use. 44 154 14 M N4 TCA WckM l--. % l*c**4 Ssstf. Tkhd me. Pestth $tm ti 24 14 15.0 113 173 74 74 4 . - -- -n 74.0 724 7)4 s OFM UarriU U 74.0 4 -- *4.0 Ftg. I hcptahi chant* l> TCA Ihmnoiriim fee AlITtital wiflN (tom 4muUI* wom-M urvk* frfctWs sutatal Fig, t Ecllmalrd compotlltmi * fsncllon *f tacarioa fa* tbrtUt*4 wsrsin-wtrirt prtmaiy Bnlng simulated worn-lnservlee thin lining*. These did were takea from Tibi* 2. Tibi* 3 summarizes the TCA Ihcrmogrim did for the secondary lining of the simulated worn-in-service thin linlnp combination. Ft*. 10 it a plot of the estimated composition M function of Incalton. Fiji. 11 and 12 in SOX pholomlcrog/iphi fot the primary secondary llnlnp showing th ciou lection of the Me- Uonal hcal-iffcclcd layer and id undtilyinj atiuctut*. Used (ininji For both tell of used llnlnp, dblri were pro- patrd fin racli lining summarising litr 1CA weight losses. Corresponding curves wera obtained for the etiinuied eompodtiotTaii function rtf tocaBon for each ItntngfFIjf. Tand Wf. Thcie curves are pieaenled In the fnltnwinj teclion. Cumpiiium of Had for Died and Simulated Wom ln Servk* Thin Friction Malcriah A companion of Fig. 11 and lire other phntunikinpapht for lire eiota sections of the primary llnlnp pvt no concrete Indication of the chanpi In lining chemistry which had taken place. Fig. 11 did thaw a dukencd rt|kKi below the tubbing surface while ih other photomtcr> papht did not. A similar comparison of Fig. 12 and the other photomicrographs for the secondary Uninp waa leu revealing. No real coociuifoni could be drawn from comparisons based on color difference*. A better comparison could be obtained from the physical site and structure of the organic friction modifiers at the sur face. In severe thermal damage. Ihcse materials shrink in size end become nonexistent it the rubbing surface, when com pared to the same materials hi the deep underlying regions. The llnlnp of combination A (40,000 mites light use) showed no such change. The organic friction modified for the linings of combinations B and C did show similar, slight sire tediaeHorn which indicated a slightly heavier duty than that under gone hy irnnhiiijlian A. For tlie primary linings ofcombinations A. B. and C.Flgs. 13 and 14 ire plots of the data In Table 2 plus (lie data for the other (wo primaries This Is the most convenient method of comparing tlie slate of tlie l-'IIALa nf cnmhlnathmi A, B, and l\ Fig. 13 showi the variations of polymtr content and volalltcs content while Fig. 14 show* the Inorganic content end asbestos dchydroxylaifon content at a function of Ihtimrf history (tocailoti In material). In ait cases, the polymer con test decreases at the rubbing surface while the low moteeuler MAR 000620 < T(IA Temmilait Rmie.C JS-MO 250-STS 575-100 00-1000 lOOtK TlM* )' TUA TkeimoflM DiU foe lKu4ur Lwln* CamMaallM C Ptupueed UwluaMI Lev auiacuUt ve%kl frtttflk pioiticM ptwawUtma Poiyawt A|iWitlN Aikcuol ivhr4rairkrta* CiUuiumw mimm KatUiM KiAVeleJMUw.% - fm Wmm I*A4 (up*' nu4 Scrap* Kwh ill as. U 4.J u 14 IU IU *14 MS .u U VO 14 M 0.5 a. 70.0 HA 4.0 MJ OKM ' Meleilei 14 12.0 14 04 [ i * H- - 0 AUIITOC ESTIMATE INOROANIC CONTENT A POLYMER CONTENT AUEITOO DENVOHOXUATTON VOLATILE! CON TENT 30 I! li* II- Cum wiiaw of dmaUlcd VIMa in Kivke ikla pfltnwjr bniaf 10 OEM MATERIAL "fTvN--F sa1 LAVER NUMOER { SURFACE FI*. 10 Eillauteii twnpotitlaa M faxctio* af IwalkM he ilwnliled wtaa-Li <aitfc wroadwy Mala* i f" L weight volattlei content Incteitei. In ill cavi, Iht Inorganic content of III* iubbln| lutfiee l> hl^ict while Ihe ubcitui content It lower. The extent of Indicated icaetinn Tim ill of tltew licntlt gradual from Ihe tut face llayer !) Into III* depth til iht KIIAl. (Iiyir 4). In ill caect, except fur ilie u> Ikiuii tlchydroxyleihm, Ihe eomblnjiliHi (' lining li bracketed by the A ind H nuferlilt. l-'ur (tie levnnJity llninp, III* data fiuni Tibi* 3 and llul 1 fiM llw ullwr two inalerlali weie phillcd on Figa. 1$ end li. I w- li ( i.mmlmuf lunulalcd In vnkt Ihia wiunJoy Tlitv ligutea ihuw tlw variation of volatile^ content. pulyinet kata* L- MAR 000621 m fig IS-CempafteecfFHAt. cfcatactarMcatpotrnwf e*tt4 nbtlhi cmunl) fa frinwr talw FtB. U Cotnptriio* oflllAL cKatacItTftffca (tnorpnfc ronlfat tW fcKo <ih|i4nirtilln CMltull f tcmmimy lalap MWIWI I MntwiulM MIIMM --r*~i--i IMIMM { TMt 4 - Surface Flat* DM Im Xmm* Rmfhaaa (aeuaac* ton Tuilnf lalm--etata VaHkta thad Diana m t.tt (OhM Ij-trifkittarw Hlla| f*taim4bte Vahlcta SlawlaUd Vetwie-Satviae Dtataa tr 2-50wtef<4Af Aflat Ttnlni fail 1 fait: fill J fail 4 A.aa 11-72 12-22 20-21 10-22 15-24 II22 12-17 14-17 11-77 15-21 12-17 12-17 14-10 14-20 12-1* fig U-Cmptritan af FHAL thifK-trriitict 0ar|il< content aa4 abate 4thr4rir1aitai eoaUaf) (a priMrr Mnlnp -^t -+-V+"*aJ-t Fig IS'CM'Hitaaod'IIALrfcuKlatktfciCpotr'nat ctwtinltni vatetOai twMinl) r Kcondtif lainga content, Inorganic content, and iibeiloi dehydtoxylailon con tent at function of theimal liittoiy (location In mateiiil). In tit catci, the polymer content drcteavri it the tubbing wtfKf while the low molecular weight aotalilct content Incicatei. In 11 caiei, the Inoiganic content of the tubbing tutface Inctciica while the atbcitot content b lowered. The extent of the Indi cated ttKtlnn It mote abrupt ftom the tutfKe layer (l*y*r I) Into the depth of live F1IAI. (layet 4) lhan fot the eorretpondlog pthnatlet. In all cawt, live combination C lining It buck eted by the A anal B tnalrilala, KOTOKS Table 4 thwt the retullt of the wiftce flnlvh teadlnga fur live tned rninr and for the tltitulaled wotn-lnetvkc Inteimedlale vehicle dtuini along with the OHM tpectflctlhint. Compiling (tie wimilaled dtumt with the worn-lntecvlce dtumt. It can be teen that the limitation ptoeedute tned produced a surface roughneta very dote to that of dtumt tned for 40400 mllet. Thlt wti to be expected If the dium ilirti at t turfact tooglmeit cloie to the tteadyetafe point earned by the llnlngt. The wom-ln-atrrict drum! wet* run with the tame llnlnga at the Intermediate vehicle, tnd thui the Keidy-ttiie point wn the tame. it aa. ' ujajmh>;hs 4! MAR 000622 . I Fi*. 17' Tinl (nr cut-lna micioiliucturv (iOOOX SKU nted 7J* fat KFtediKlisii) FI*. 19 -Cnm-seeltoiul msnotuisctwe of Umulslre wacwhs servlet lnUfMc4UU vehicle 4iiun(l0,000X SIX ie4m<4 (1% fat lepeeCuetoss) i FI*. II CraM-wctloasI mkrustructurv of Simulalr4 wutrs-hMeniee ImiimIIiu vehicle ilnini (IO.OOOX JIM tt4ue*4 IM fat afidiia FI*. >0-CioutectloesJ nlcrostructure of titcd dium fion ui inter Bniitte vehicle tflci 40,000 miles (SOOUX St.ll itdutnl m tm Mftodaciiua) Thui, to simulate th* worn drum surface finith, a roughnett of 20-30 (tin (AA) should be produced oa the intermediate re hide drums before the worn component simulation procedure (200 slop burniih 4 10 stop fade 12 stop tecuvcry) la run oa the dynamometer in order to simulate used drum surface finish. Recent work (2) at Bcndix Research Laboratories has shown that the micrustructuse of the cast iron friction surface (drum or disc) varies with usage. Therefore, crust-sectional etamina tions were made tin selected samples with the scamiin* elec tron mlcioscwpc in ruder to compare simulated wutn parts with parti wum ns setvic*. Fig. 17 shows a typical gray cast Iron inlcrosciucture. The microsltuctuie iitmisls uf giaplilte Slid peaillle. I hr black dikes are graphite and tlie pcarhtc cuuihlt of alternate layers of ferrite (u lion tlic giay phase) and nun cailude (cctnemlle, FtjC- the white phase). Figs. 18 and It show two cross-secUunal photomicrographs of the used Intel mediate vehicle drums. Ilic ruhbing surface of tlie ilium was approximately In the middle uf both picture*. Two plieiiumciia can be observed In these pictures. First, the graphite flakes do nut continue all tire way to the sutfac* of FI*. 21 Crow lei-tiunal mk-ioslnsc-tute of w4 Jiums fi.-m Imetier (late vsturlc afki 4ti.n(IU mites (1000X SI U rntu.nl a 11 fur rept* ClKUim) lit* drum. Tlie graphite near (lie surface was irimnred and tlie void formed fillcJ by pearlllc. Second, tlie prailulc structure was disturbed at the surface, tlie cemcntite platelets being broken up and dispersed In the ferrite matrix. Figs. 20 and 21 sluiw (wo cron-sectional pholnmlcrogripht of simulated wum in-service Intermediate vehicle drums. The lower photograpli shows tlie pinch out of tlie graphite (lake p^wi mew nyne ii i-i inpyj,!i ift t m" IRIA ,up,M L- r?* r Lf MAR 000623 * nen Ihe tmfsce iliniUi In tlie uwd Intermediate vehicle drama. Until photi'to show lit* dlsluihame nf the pejil Ilk: ilruclute neai Ihe tuhlilng luiftct il exhibited by llte used drumi. CONCLUSIONS 2. Pullsli lire ilimn surface lo 20.10pin surface finish and the dlw unfit e In III .'ll pin surface finish. J. Kim 20U slop burnish, 10 slop fade, end 12 Pop revovviy with linings lhal eic lo he used with Use drain* or dtaci in fur ther (eating. l-'tif (he brake tlrgiJtlJlinn program, II wn nerevvury In utmi- ACKNOWIJ-IXiMUNTS Ute e ae! of thin uwd linings. A method wu developed for prodiiclni imi cluiaclcn/ing simulated thin linings and their Tire authors wish to acknowledge the Department of Trans- enmpotllloni it then frictional hcit-tffecled layers to those of porttflon, National tliglrway Traffic Safety Adminlatritlun, linings from customer usage. The combination C linings were who luppurted this wink through ConttKl No. DOT-IJS-090- cumpatrd to two ulliri sets of linings: cimthlnallon A hntngs, 124. The pmjrrt monitor witC. I. Parker, which had umlei|ooe 40.0UU miles uf light duly (teptcaenti- Tire authura wisli lo (hank llie fodowing for their variant live of (lit terrain driving In northern climates); and combine- contrlbutloni: K. 13. Stapleton fur running Ihe thermograri- tlon B lining!, which had undergone 3300 miles of durability metric inalyiet, D. G. Jonei for prcperallnn of Ihe mlcraicopjr testing (lepreientatlve of hilly tertians or southern, warmer eft- qreelmeni, P. A. Thesier of Rendlx Automotive Conlrol Syv rrutet with much city ficeway driving). By the TGA method, temr Croup (Troy, N. Y.) fra providing tire thin linlnga, J. L. the surfaces of combination C linings were found to be kitcr- Turak of Bendlx Automotive Control Syilemi Group (South mediate In composition lo those of the other two combina Bend, tnd.) frit supervising the dynamometer simulations, and tions and the method of conditioning them did Indeed produce W. A. Stout of Bendix Automotive Development Center for linings similar lo those of normal consumer-type driving. providing the dutabiUty temples. The recommended procedure for simulating worn friction malarial was as frtQowt: 1. Grind tire linings or pads to nominal dimension iexulted RUFF.RF.NChS for thin friction material ttsling. 2. Run 200 stop burnish, 10 slop fade, and 12 stop recovery 1. S.K.RhcA.MInfluence odBatoeMcnUmgy aa-theWeac with drums and/or discs that arc to be used In (he test se quence. Tire comparison! of rotor surface finish end the crose- of Friction Materials In Automotive Brakes.** SAETuoucikini, Vol. 80 (1971), paper 710247. 2. S. K. Klree, X. T. DuCharme, and W. M. Spurgeon, "Chw- sectfonal mlcruilructure of parla used in service with lima- Kterlzitlon nf Ceil Iron I'rkllon Sutftcca." Piper 720056 Iiled worn peril Indicated that a valid simulation proetdurs presented,it SAE Automotive Engineering Corgieta, Delioil, haa been also derived for drumi and rotor*. January 1972. The recommended procedure for almulatlng worn drama and 3. T. W. Kcrtncn, M. H. Cetdon, end G. L. Parker, "Deter disci la as fullowa: mining the EfTecti of Brake Degradation." Paper 730190 pee- I. Machine drum or dlae to nomlnd dimension required If Muted it SAE Automotive Engineering Congress, DelroM, dram la lo be oversized or the disc ta to be thin. January 1973. Tfcrt p*f*t h trireri m ta W IfftiiR. StMPke(k *n4 m OvtttM ail (N Ml'% sM m m tfc Mhut. * iut Society of Automotive Engineir,lnt *wm *.** - a In- UM Vy SAE ( ,-Vma crt-l *-4 fvnaaC. BvuPM*4Sf pMd wl flu tfrt r faW.JKt la IAS. TuamU-a fasyanpenaa lyWtW A* jap* la fa* at W part, aaaiacl *a 1X1 NSScalSaat BiUot wl He |2p|iSt4M. Mafetf toUJA. MAR 000624 N , eAB -751S PRODUCT SPECIFICATIONS Hi-avy duty. 2 H P. motor. U/L approved. 110 volt 10 amp;,. 110" max auction, IIS CFM. *10' x iv." I D. flexible plastic hose, with connector, crevice tool and duster brush accessories. Sled platform chassis with two 8" rubber wheels and Irom caster (or mobility in service areas. *Durable chrome end epoxy finish. *Oimensions 35" h x 20" w x 24" deep. *Shippmg Weight -- 58 lbs. F.O.B. Cleveland. Ohio i FK-7S1S Filter Pack FILTERS MUST BE CHANGED MONTHLY TO MAINTAIN THE REQUIRED HIGH EFFICIENCY Filtnr Pnr.k contains four complcio Replacement Filter Kit*,, providing four months of service. Etich includes: Asbostos dust filtrstion elements. O.S.H.A specified respirator and impermeable dis posal bag. Shipping Weight: 7 lbs. F.O.B. Cleveland, Ohio TEMPO TANKtK arooet FM.jooe J# e*itan Capacity 'St teiMief fika|pvfstfiiteairtIheWftmtieM<f MV * M hsMW i* him* n iy*` *-/* m> "n iff.ei'*) PnsigBi# kgs e**f a*--p* | w> Hte*ens* !#*<* U 'ssi r* TCMfrO TOOt/STOJMOC OX rr*i *WertH(*(mmeseei rM<Mr snpett *PPSei**<MreSisISn(T1*'|.ete* a*e#fM* ItfW ! *svmih tarsoM P*H(MI liRMf New tw8 mu*fPfieewni*ir*rMln'f 'IN* HHl TtMSO AUXILianV ftCFUELINO TANK MOOCL AT-ae (l.Awy>e'rfa*ii*.MSO8 CwetilSl*ea* iiCemi |hueWn*f iw* *&HM M -*** >P> < Ptl^f UM I IH" MM Ihstl M *CaH flMtsP 14 f*uf> P.1*4 UNI (8*iMe(l4 *tt*eell***ai*t* lelewMwatfdkg|Ma| TEMPO PRODUCTS COMPANY QP ART Altl f I 4r|l4Ai COAPUAAlf PAA Milt im C*c** ' C*e4**A 0** 44l*t MU . TEMFO airuct.ExoEFUti.cn TANKCM mooel nee (100 OaXoa CiwrW 1**IP*--<| A* *i*--*.kf t*s*d* n ByfrAf (*a.*tfit *HA Q M A isge H""44 Mm AM * 7 *t MiimipSf wp,m*ee^ttAk* 4*4M %4 UP8*ppr>eMt*epwrMP4 Ms All# |N| NMUU I A l PBS MAR 000625