High Temperature Straining Behaviour Of High FeSi Electrical Steel By Torsion Tests

Journal Article · Sat Apr 07 00:00:00 EDT 2007 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2729554· OSTI ID:21057049

Calvillo, P R; Houbaert, Y ^[1]; Garcia, N Lasa ^[2]

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1. Department of Metallurgy and Materials Science, Ghent University, Technologiepark 903, B-9052 Gent-Zwijnaarde (Belgium)
2. Escuela Superior de Ingeniero, Campus Tecnologico de la Universidad de Navarra, Paseo de Manuel Lardizabal 13, 20.018 San Sebastian (Spain)

Steel with an increased Si-content has better magnetic properties in electrical applications in terms of high electrical resistivity, reduced energy losses and low magnetostriction. Nevertheless, the oxygen affinity of this element at high working temperatures and the poor ductility observed at room temperature caused by order structures make the thermomechanical processing of these alloys rather difficult. Since these materials do not present a phase transformations from ferrite to austenite, a fundamental study of their workability using torsion tests will help to understand and to optimise their production process. Important critical temperatures in these materials are Tord (the temperature above which the material is disordered), Tnr (the temperature below which static recrystallisation is not taking place any more) and other restoration temperatures appearing during processing.Fe-Si electrical steels, with silicon concentrations of 2, 3 and 4 wt.-%, were tested according to a multi-deformation torsion schedule under continuous of cooling conditions in 18 passes, with temperature ranges from 1150 to 810 deg. C, at a strain rate of 1 s-1, the interpass time and the amount of plastic deformation were varied from 20 to 5 sec and from 0.1 to 0.3, respectively. Different critical temperatures, important for the processing of these alloys, were calculated from the dependence of the mean flow stress (MFS) on inverse temperature, based on their changes of slope. The temperatures at which the restorations mechanism, the recrystallization and the recovery stops, Tnr were determined and can be described using the relation developed here, based on their dependence on composition, deformation parameters and cooling rate. The metallographic analysis of quenched samples is in good agreement with the critical temperatures obtained through the measurement of the MFS.

• OSTI ID: 21057049
• Journal Information: AIP Conference Proceedings, Vol. 907, Issue 1; Conference: 10. ESAFORM conference on material forming, Zaragoza (Spain), 18-20 Apr 2007; Other Information: DOI: 10.1063/1.2729554; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITE
CRITICAL TEMPERATURE
DEFORMATION
DUCTILITY
ELECTRIC CONDUCTIVITY
FERRITE
FLOW STRESS
IRON SILICIDES
MAGNETOSTRICTION
PHASE TRANSFORMATIONS
PLASTICITY
RECRYSTALLIZATION
STEELS
STRAIN RATE
STRESS ANALYSIS
TEMPERATURE DEPENDENCE
THERMAL STRESSES
THERMOMECHANICAL TREATMENTS
TORSION