Strain aging sensitivity of multi-phase pipeline steel

Transversal pre-strain experiments were carried out to investigate the effect of transversal hole enlargement on the tensile strain behavior of multi-phase pipeline steel. Experimental results indicate that the work hardening behavior after pre-strain treatment has directional characterization. When the pre-strain direction parallels to the final tensile strain direction, the work hardening rate is very high. Only when the pre-strain rate is lower than 2%, the yield ratio can keep below 0.95. When the tensile strain direction is perpendicular to the pre-strain direction, the strain-stress curves can maintain a continuous yield character, which has low yield ratio (below 0.75) and high uniform elongation rate. In addition, strain aging treatment was carried out to investigate the effect of anti-corrosion thermal coating treatment on the tensile strain behavior of multi-phase pipeline steel. It is shown that the multi-phase pipeline steel has excellent anti-aging stability.