To study the tensile properties of dual phase (DP) steels after blanking, specimens were prepared by blanking and wire-electrode cutting, and static tensile tests of specimens made of DP590, DP780 and DP980 were performed by utilizing non-contact video gauge at MTS793 material testing machine.
The influence of gauge length on tensile behaviors and properties, and the necking phase and fracture appearance of specimens with different blanking clearances through tensile curves were analyzed. The result shows that with the decrease of gauge length, the 0.2% proof strength Rp0.2, the tensile strength Rm, and the percentage elongation at maximum force Agt remain unchanged but the percentage total elongation at fracture At increases notably. There is a clear difference between blanking and wire-electrode cutting specimen in tensile fracture curves. The At of blanking specimens is lower than that of the wire-electrode cutting specimen and decreases with the rise of blanking clearance. Blanking specimens of DP590 and DP780 were fractured in polygonal line after nonuniform necking and transverse cracks, while DP980 is similar to the shear shape of wire-electrode cutting specimens with apparent shear bands during necking.