Effect of Weld Thermal Cycle on the Electrochemical Corrosion of Q315NS Steel in Acidic Solution

摘要

The effect of welding thermal process on the electrochemical corrosion of Q315NS in H_2SO_4 and HC1 solution were investigated. Different weld thermal cycles with different peak temperatures were used in a Gleeble thermal-force simulation testing machine to simulate weld HAZ, and electrochemical measurements were carried out. The results demonstrate that a microstructure of granular bainite was generated in CGHAZ while others consisted of ferrite and pearlite. The electrochemical corrosion of different HAZ was different in H_2SO_4 and HCI, due to different micro structure. The BM and HAZs in 50 wt. % H_2SO_4 solution has a certain passivation behavior, while there was no passivation behavior in 3.5 wt. % HC1 solution. The corrosion resistances in HAZs are inferior to that in BM. In addition, the corrosion resistance in the CGHAZ is the weakest.