Accession Number : AD0482893

Title :   STRUCTURAL STUDIES OF BEARING STEEL UNDERGOING CYCLIC STRESSING.

Descriptive Note : Summary rept. no. 2,

Corporate Author : SKF INDUSTRIES INC KING OF PRUSSIA PA RESEARCH LAB

Personal Author(s) : Martin, J. A. ; Borgese, S. F. ; Eberhardt, A. D. ; Berlinghof, W.

Report Date : 29 APR 1966

Pagination or Media Count : 63

Abstract : Accumulations of plastic strain, visible in the light microscope as white etching deformation bands, are shown to develop in bearing steels undergoing cyclic stressing. Under the electron transmission microscope the deformation bands appear as cell like structures circled by tangled dislocation loops and devoid of temper carbides. Two conditions are found to initiate the growth of deformation bands: (1) localized plastic yielding around imperfections; (2) plastic yielding of some volumes of the bulk material under the influence of the maximum shear stress when it exceeds a critical threshold level, estimated to be 120,000 psi. Deformation bands are shown to be involved in the propagation of fatigue cracks and are associated with the early stages of fatigue cracking initiated by two types of imperfections: surface furrows and non-metallic inclusions. (Author)

Descriptors :   *STEEL), (*STEEL, BEARINGS), (*DEFORMATION, STRESSES, FATIGUE(MECHANICS), STRAIN(MECHANICS), SHEAR STRESSES, PLASTIC PROPERTIES, MICROSTRUCTURE, ELECTRON MICROSCOPY.

Subject Categories : Properties of Metals and Alloys
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE