TITLE:
The Effect of Microstructural and Geometric Inhomogeneities Induced by Laser for Forming Strain Analysis on Sheet Metal Formability
AUTHORS:
Sergey Guk, Daria Plotnikova, Rudolf Kawalla
KEYWORDS:
Laser Grid Marking, Deformation Analysis, Inhomogeneity, Sheet Metal, Formability
JOURNAL NAME:
Materials Sciences and Applications,
Vol.7 No.5,
May
20,
2016
ABSTRACT:
A
commercially available laser marking system based on diode-pumped Nd:YVO4 laser
was used for creating grid patterns for forming strain analysis of a dual-phase
steel. The aim was to determine and analyze the influence of laser working
parameters on the formability of sheet material by means of an in-depth
characterization of this induced microstructural and geometric inhomogeneity.
The electrochemical etching served as the reference method without the negative
effect of generating inhomogeneity. The formability was evaluated using the
cupping test according to Erichsen. While the quantification of geometric
inhomogeneity was based on the determination of the notch factor, light
microscopy and microhardness measurement were used for the evaluation of
microstructural inhomogeneity. Furthermore, on the basis of the results an
empirical regression model was established which described in terms of quantity
the relationship between the examined factors such as laser power, pulse
frequency and scanning speed as well as the command variable and the mark
depth. The results showed that microstructural inhomogeneity in the used
marking parameters due to their locally very limited formation did not have an
appreciable influence on the mechanical properties. In contrast to this, the
induced geometric inhomogeneity had a marked influence on the material
formability.