The experimental investigation of formability and springback in laser welded DP600 sheets


Aydin K., KARAAĞAÇ İ.

MATERIALS RESEARCH EXPRESS, vol.6, no.12, 2019 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 6 Issue: 12
  • Publication Date: 2019
  • Doi Number: 10.1088/2053-1591/ab5f26
  • Title of Journal : MATERIALS RESEARCH EXPRESS

Abstract

Formability and springback behaviours of dual-phase 600 (DP600) sheet material bonded with laser welded in different power parameters were investigated experimentally. In the first stage of the study, springback behaviours of non-welded DP600 sheet material were investigated. In the next stage of the study, springback behaviours of DP600-DP600 samples, which were bonded with three different power parameters (1400 watts, 1500 watts, 1600 watts) by welding, were investigated by bending in V bending dies. Die angle (15, 30, 45, 60 and 75 degree) and holding time (0, 10 and 20 s.) were determined as process parameters in the study. In higher welding powers, it was observed that both the melting zone and the heat-affected zone were expanded. Then ferrite phases in these expanding zones have been transformed into martensite phase. This case provided to increase the stiffness and thereby improved the spring-capability. Because of increase hardness due to the increase in laser welding power, average springback angle of welded sheet increased by 5.72%. In addition die angle is one of the parameters that strongly change the springback angle. Negative springback was observed at the die angle of 15 degrees. It was found that the springback angle increased on an average of 57.2% as the die angle was increased from 30-degree to 45-degree. On the other hand, the springback angle decreased on an average of 18.7% as the die angle was increased from 45-degree to 75-degree. This case is due to the conglomerating of the stresses in a narrow space after a 45-degree die angle. Depending on the increase in holding time, the springback angle decreased by 10.05% because of an increase of residual stresses.