RESEARCHES CONCERNING BALL-BEARING STEELS WIRES DRAWING IN ULTRASONIC FIELD SECOND PART: INFLUENCE OF ULTRASONIC ON THE FORCOPER DRAWING SERIES AND CHANGES OF MECHANICAL CHARACTERISTICS

摘要

The second part of the paper emphasizes the irreversible action of ultrasonics in ball-bearing steel (RULIV/STAS 11250-89) wire drawing in ultrasonic field with changes of mechanical characteristics, technologically materialized by force reduction per drawing series especially caused by the "surface effect of ultrasonies", based on the "mechanism of friction reversion", providing V sq root V v < 1.By means of this new ultrasonic drawing procedure, (especially recommended for hardly cold-workable metalic materials where relatively low drawing rates are used ), products with much more uniform mechanical characteristics are obtained, with the possibility to increase plastic deformation degree per pass while obtaining much higher values for safety coefficients at drawing as compared to classical cold working where are no external influences.