DBPapers
DOI: 10.5593/sgem2017H/63/S24.011

THE INFLUENCE OF ULTRASOUNDS ON THE STRUCTURE OF SOME LOW CARBON AND MANGANESE DUAL-PHASE STEELS

C. Dulucheanu, T. Severin
Thursday 23 November 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgemviennagreen.org, SGEM2017 Vienna GREEN Conference Proceedings, ISBN 978-619-7408-29-4 / ISSN 1314-2704, 27 - 29 November, 2017, Vol. 17, Issue 63, 85-92 pp; DOI: 10.5593/sgem2017H/63/S24.011

ABSTRACT

This article presents results of the studies conducted by authors for determining the influence of ultrasounds, used in the intercritical quenching, on the structure of some low carbon and manganese dual-phase steels (0.087% C and 0.511% Mn, respectively 0.101% C and 0.529% Mn). The samples of these steels were heated to temperatures between 760 and 820 C (temperatures between the critical points Ac1 and Ac3), for 30 minutes and then quenched in water, water in ultrasonic field with frequency of 40 kHz and water in ultrasonic field with frequency of 59 kHz; after quenching were determined the volume fraction of martensite (VM) and the ferrite microhardness from the structures obtained. Both the cooling in ultrasonic field, and growing the quenching temperature in the range intercritical ( + ) led to increase the volume fraction of martensite and the ferrite microhardness, the influence of ultrasounds on them being more noticeable at the samples quenched from 760 and 780 C. The intercritical quenching from temperatures between 760 and 800 C ensured structures that had amounts of martensite (VM) which were within the ranges of values (VM = 10 to 35 %) provided by the standards that define dual phase steels.

Keywords: dual-phase steel, intercritical quenching, ultrasonic field, volume fraction of martensite, ferrite microhardness