Document mNOvEqBpK26MK8E2DpJKqjnd

\ 1 jected refined base stock shipments for off-spec color. Nowadays, re finers may not be able to maintain previous crude sources, and for- mulators have to accept whatever refined stocks they can get--ifother specifications are met--and adjust their formulations to make the best of available stocks. As a result, lu bricant colors are not necessarily the same, even though lubricating quality is identical. Another factor that may affect the familiar color of a lubricant is a change in additives. For example, lead naphlhenate has been used to help gear oils resist extreme pres sure and impact loads. Recently, OSHA has urged that toxic or po tentially toxic substances such as lead naphthenate be removed from Many lubricant manufacturers use dynamometer stands such as this to test industrial workplaces. gear oils. Changing additives is not an easy process. Laboratory data on poten tial replacements are only sugges tive; performance is proven only after expensive and tedious field trials. Nevertheless, some synthetic extreme pressure agents, after field testing, are being phased in as re placements for the lead naphthe nate. Since their color is not .the same as the amber lead soap, they too can contribute to changes in tra ditional colors. The net result is that color has even less value than it ever did as a guide to lubricant quality. Shop per sonnel must be more alert than ever to the requirements of the ma chinery they service and qualities of the oils they pour. an additional incentive to develop asbestos-free compositions. The application for solid lubri cants is as afriction modifier. Con ventional friction materials have up to 15 components. Asbestos is by far the major component, compris ing some 60 to 80% of friction mate rials. Phenolic resin is typically used as a binder. Various additives are incorporated--more on the basis of art than scientific knowl edge. Other commonly used additives include ground rubber, for elasticity; coal, as a cheap source of graphite; gilsonite, as a friction modifier; and zinc oxide, as a corro sion inhibitor. Asbestos is very difficult to re An appreciable increase in the coefficient of friction at higher tem peratures. (Pads frequently get to 200+F, and reach 400 to 500F with prolonged downhill braking. Under severe braking, pads reach 10003F, red heat.) High pad wear. Unacceptable noise. Dow Coming Corporation, Mid land, Michigan, has developed a new product, "Lubolid", to help solve these problems. Now in use, Lubolid is a mixture of molybdenupi displfide-and other materials for use as a friction modifier in clutch and brake friction materials. According to George V. Kubczak, Development Engineer at place, especially as a major compo Dow Coming, its benefits are: nent. because it uniquely combines A more constant coefficient of a high, stable coefficient of friction friction. (Changes in industrial and au with an almost ideal balance of Reduced disc wear. tomotive friction materials are abrasiveness and lubricity. Reduced noise. enlarging applications for solid lu Semimetallic compositions, first The principal competitive mate bricants such as molybdenum disul used in Europe and Japan, are now rial for this application is graphite. fide. This surprising application of coming into use here. In these com Graphite has useful properties to lubricants in friction materials positions, also called ``resin-mets'", 2000QF: its cost depends on the spe comes as a result of environmental wool or shavings from steel or brass cific grade used. However, graphite pressures. replace asbestos as the fibrous requires moisture for good Asbestos is now a major compo component. The resin-mets, how lubricity--which may lead to corro nent of friction materials, but indus ever. have problems: sion problems. Also, any moisture try anticipates an EPA ban on its "Morning sickness" -- inade initially present is lost when pad use. Pos'.oie Itabiliu suits mav be quate braking with cold starts. temperatures reach 2l2Forhigncr. pro. 11 so i'. jl I I SCI 02166