Fretting of Hardened Steel in Oil

Abstract

To determine the effect of hardness onfretting wear, tests of AfSf 4340 steel were made in an oil bath using a new machine designed to make fretting corrosion tests with a wide range of parameters. Hardness values from 258 to 743 Vickers were tested, the hardest specimen having a nitrided surface. The fretting action used, 0.005 in. reciprocating motion at pressuresfrom 430 psi to 5840 psi, produced much lessfretting than similar tests in air, with little or no.oxide products resulting. The galled areas were measuredfor depth of pit and height of deposit with the results indicating some small effects due to hardness up to 460 Vickers. The nitrided specimens, however, produced smaller fretted areas and the roughening of their surfaces was shallow.

Detection of Excess Ammonia Emissions from In-Use Vehicles and the Implications for Fine Particle Control

“…Ammonia emissions to the atmosphere arise from a great many sources including decay of livestock waste (1)(2)(3)(4)(5), use of chemical fertilizers (6)(7)(8)(9)(10), emissions from sewage treatment plants, and biological processes in soils (11)(12)(13)(14)(15). Ammonia also is emitted in small amounts from most combustion processes.…”

The roles of contact conformity, temperature and displacement amplitude on the lubricated fretting wear of a steel-on-steel contact

“…They also observed a higher wear rate for lubricated tests at elevated temperatures, but attributed this to thermal softening of the tin coating. Other studies by McDowell [14], Neyman [15], Neyman & Sikora [11] have also concluded that the wear of a lubricated fretting contact is primarily influenced by the ability of the lubricant to exclude oxygen from the contact, and hence the reduced tendency to create brittle oxidized wear particles which thus results in a reduction in wear rate. The same conclusion, namely that oxygen exclusion would reduce fretting wear, was also reached by Shima et al .…”

Leaching Loss of Nitrogen in Submerged Rice Cultivation

“…The physico-chemical conditions like cation exchange capacity, clay content, soil reaction, moisture holding capacity and organic matter content of the soil influence the retentivity and availability of N (Nommik, 1:957;Goring and Martin, 1959), while NH + 4 ions of ammonium fertilizers, applied in the reduced zone, may remain almost stationary at the site of application due to adsorption by the negatively charged clay particles of the soil (Haque and Ibrahim, 1965). However, McDowell and Smith (1958) also noted the movement of ammoniacal nitrogen, most in sand and silt loam soil and least in clay. Migration of NH+ 4 -N is closely related to the movement of water, and the magnitude of migration depends on concentration of the fertilizer (Ray et al, 1957), which is influenced by whether it is applied in one dose or in split applications.…”