Experimental study on impact toughness of structural steel and its butt-welded joint at low temperature and corrosion

The safe and life extension utilization of steel structures in cold offshore regions demand studies on the toughness of structural steel at low temperature and corrosion. In present work, the effects of low temperature and corrosion on impact toughness of the typical structural steel of Q235 and its butt-welded joint are studied. Constant current acceleration associated with salt spray acceleration corrosion experiment are performed to corrode specimens. The Charpy impact tests for Q235 steel and its butt-welded joint at different temperatures and corrosion times are carried out. The micro-morphologies of impact fracture surface are also studied by scanning electron microscopy (SEM). It can be found that the impact energies of Q235 steel and its butt-welded joint are degraded as temperature decreases and corrosion rate increases. The effect of corrosion on impact energy is aggravated by low temperature. The impact toughness of Q235 steel and its butt-welded joint are influenced by the coupling effect of low temperature and corrosion. This study can provide information for the fracture resistant design of steel structures in low temperature and corrosion environment.