Chrome face versus iron side wear — an analysis of some radioactive piston-ring wear studies

360

LITERATURE

ANU

CURRENT

I’VEKI-S

\.OI..

1

(I)j7/

58)

combinations, speed of sliding, and load From a linntetl number of tests where particles forme(I by rubbing were purposely trapped between the contact surfaces, it appears that the wear rate is definitely increased by accumulation of wear particles. This work was done under subcontract to Rettrs Atomic l’ower l)ivrsion, whmh is operated f
Iron

Side Wear

-

An

Analysis

of Some

Radioactive

Piston-Ring

K. G. hROWD, Jr. (Ethyl Corporatmn, l>etroit, Michigan) ~- I’resentetl October 7th, I<>,<;. at Toronto, Canada. T’reprmt No. 57T2c-3, Am. Sot. Lubrication Engrs. (i\Sl,E) After outlining the effects a field problem may present in the near future, ant1 tlescr~bing somr laboratory equipment selected and installed especially to study factors contributing to the problem of heavy duty scuffing of chromium-plated top compression rings, results of controlled tests have shown the mrsleading conclusion which was indicated when unplatetl cast-iron rings were nseti The assumption that cast-iron wear and chromium plate wear are influenced in the same dircctron by given variables under operating conditions conducive to ring scuffing 1s not true so far as ori formulation is concerned. Frictional

Heating

and Its Influence

on the Wear

of Steel

N. c. Il:wsrr (Associated Electrical Industries, T,td., \ltlcrrnaston, licrks., England) ~- ,I, Ipp/_ f’hys., 28 (1957) 960-968; (16 fig., 24 ref.). High frictional temperatures during the dry or imperfectly lubricated rubbing of steel produc
of Atmospheric

Oxidation

in High-Speed

Sliding

Phenomena.

I

M. (‘OCKS (Scientific Laboratory, Ford Motor Company, I)earborn, Michigan) - ,/. ,ilppf. Phy>., 28 (1957) 83j-843; (13 fig., 29 ref.). An experlmental study of the role of oxidation in inhibiting metallic interactron between metal surfaces sliding at high speeds (up to 66 mjsec) is descrrbcd. Metallic interaction was detected b\ microscopm examination of the surface clamage after sliding. 13y using hardened steel, information concerning surface temperatures was deduced from subsequent hardness measurements. :lt light loads the metal surfaces were severely torn, but at higher loads the tearing became less severe. .\bove a certain load, which depended on the speed, tearing was almost ehmimatcd from at lcast one of the surfaces. Other expertments supported the conclusmn that thus was clue to the mcrease due to a process of oxide disintegration. LTntler these conditions the wear rate increased rapidI!with rncrease rn load or- speed, whereas the wear associatctl wrth metallic tearing at light loads showctl little increase with load, and decreased with increasing speed. The friction coefficient ~lecrcasetl wrth Increasing load ant1 with increasing speed The shapes of the underlying botlir~ influenced the average surface temperatures and therefore the wear and surface (lamage and creatcci (lifferences even for a pair of mating surfaces. Role of Atmospheric

Oxidation

in High-Speed

Sliding

Phenomena.

II

XI. C‘OCICS (Ford YIotor C‘ompany, ljearborn. Michrgan) - I’resentctl October 7th. I,,~J, at Toronto, Canada. l’reprint No. 57l.C‘.4, .\m. SW. Tubrrcation Engrs. (<\SIX). An experimental study of the role of trxltlation due to frictlonal heating in unlubr-rcatetl high speetl (r3ooo ft./nun) shtling of metals is discussed. I)etarlctl results for steel r,n steel have been described in another paper. ‘Thus paper discusses a general picture corrclatrng the results for sex~ral metal combrnations ant1 also a bondctl metal carbrtlr. Thr results mtlicatc that the oxidation gives consirleral)lc protection agamst surface damage. \\‘ith copper on copper (previously run-in), copper on steel, and bonded tungsten carbide on bonded rarbitlc relatively little tearing of thaw metal (or carlnde) is obscr\-e(l at light loads. The oxidation shonltl increase wrth mcreasrng loa(l. and these combinations behave like steel in that on at least one of the surfaces there is, if anythmg even less metallic tearing at high load It low loads wear is mild, in harmcmy with the oxide protection, but at higher loads se\‘erc wear is attributctl to tlisintcgration within the oxide itsell With nickel on mckel the oxidation fails to prevent laxly severe metnllrc tearing even at higlr loads. Some consequences of these phenomena in the variation of friction, wear, and surface damage, with load, speed, and sample geometry are described.