Evaluation of Fracture Tearing Resistance of Dissimilar Metal Welds in Laser Welded Thin Steel Sheets

摘要

This paper focused on the stable crack growth in laser welds of thin automotive steel sheets. The stable crack growth was monitored using the contactless measurement—the videoextensometry technique on compact tension (CT) specimens with parallel and perpendicular notch orientation to the longitudinal weld axis. Specimens with electro-spark notches were loaded by eccentric tension at two loading rates (0.0217 and 2.17 mm·s~(-1)). From the obtained data, δ_R-curve and J_R-curve were established. From R-curves, the resistance of the stable crack growth for both, base materials, and their laser welds, was determined. Crack growth resistance determined for a CT weld specimen was higher than for the base materials.