Accession Number : AD0720762

Title :   Investigation of the Stability of Austenite Formed in Surface Layers During the Friction of High-Strength Cast Irons,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Markovskaya,L. I.

Report Date : 09 DEC 1970

Pagination or Media Count : 14

Abstract : To determine the stability of austenite formed during friction in surface layers of high strength cast irons the amount of gamma-phase was monitored over a span of 4 years during friction. The amount of gamma-phase was independent of the pressure and of the slip rate. Then, the specimens with max. contents of gamma-phase in the surface layers were tempered in vacuum at 200-600 degrees. With increased heating temperature, the amount of austenite decreased. The amount of gamma-phase on the friction surface decreased sharply during the initial 30 min. of tempering at all temps. Extension of holding time to 3 hr at 200, 300, and 400 degrees did not practically change the amount of gamma-phase in the surface layer. However at 500 degrees the gamma-phase completely decompd. in 10 min. The x-ray patterns of high strength cast iron specimens labeled with C indicate that during wear the C concn. in the surface layers increased and decreased in the deeper layers. During friction intense plastic deformation and increased temps. prevail as a result of which diffusional processes take place which lead to redistribution of alloy components. In most cases the appearance of austenite in the surface layers leads to increased wear resistance. (Author)

Descriptors :   (*IRON, FRICTION), CASTINGS, AUSTENITE, STABILITY, PHASE STUDIES, USSR

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE