Original scientific paper

Dual Phase Ferrite-Martensitic Steel Micro-Alloyed with V-Nb

M. Džupon
Ľ. Parilák
M. Kollárová
I. Sinaiová

Abstract

For low-carbon V-Nb micro-alloyed steel, dual phase ferrite-martensitic microstructures were prepared with a variable martensite fraction, which ranged from Vm 20 to 88%. By measuring the temperature in the sample centre, the parameters of intercritical annealing and the relationship between Vm and the intercritical annealing temperature 720 °C <= t <= 850 °C were determined. By analysing the microstructure, the strength and plastic properties of this dual phase steel, the preparation method of dual phase ferrite-martensitic steels was tested. Dual phase ferrite-martensitic microstructures at Vm above 53% formed continuous martensite areas. A change of the microstructure type as compared with the state with Vm < 53% resulted in a change of the increase of RpO2 and Rm. With growing Vm the strength properties increased and the plastic properties decreased. Fractures after uniaxial loading had a ductile pit morphology. On extraction carbon replicas, changes of precipitation of fine disperse precipitates were studied on the normalized state and the intercritically annealed state.

Keywords

dual phase steel; intercritical annealing; mechanical properties; microstructure; heating; cooling

Hrčak ID:

6451

URI

https://hrcak.srce.hr/6451

Publication date:

12.12.2006.

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