Estimation of Strength Properties from Microhardness Results in Dual Phase Steels with Different Martensite Volume Fraction

  • Gábor Béres Department of Materials Technology, Faculty of GAMF Engineering and IT, John von Neumann University, H-6000 Kecskemét, Izsáki út 10., Hungary
  • Zoltán Weltsch Department of Automotive Technologies, Faculty of Transportation and Vehicle Engineering, Budapest University of Technology and Economics, H-1111 Budapest, Stoczek u. 6., Hungary

Abstract

This study is about the effect of the martensite volume fraction and indentation load on microhardness profiles of dissimilar types Dual Phase steels and DC04 mild steel. Experimental investigations were performed by mickrovickers method with using of eight different indentation loads from 0.01 kp up to 1 kp. Besides, microscope and tensile tests were carried out to complete the estimation.
The hardness profiles show similar characteristics in case of all examined steels independent from the microstructure. In the lowest load ranges at 0.01 and 0.025 kp (HV0.01 and HV0.025), there are no appropriate approximations with the martensite volume fraction, due to the high deviation of the hardness results which caused by the little indentation geometry. In higher ranges, above 0.05 kp (HV0.05), linear evaluations could be applicable. With the utilization of the fitted parameters, a definite relationship is reported in the hardness values and even in the strength and elongation properties with the martensite content. Based on these correlations such contexts are added which make contact between microhardness and strength values for the practice. The discrepancy between the measured and calculated results stay under 10 HV which is less than 5%.

Keywords: indentation load, martensite volume fraction, dual phase steels
Published online
2018-05-09
How to Cite
Béres, G. and Weltsch, Z. “Estimation of Strength Properties from Microhardness Results in Dual Phase Steels with Different Martensite Volume Fraction”, Periodica Polytechnica Transportation Engineering. doi: https://doi.org/10.3311/PPtr.12113.
Section
Articles