Corrosion Properties of Welded Ferritic-Martensitic Steels in Liquid Lead-Bismuth at 600C

<jats:p>A static corrosion test for ferritic-martensitic steel HCM12A with three types of welding in lead-bismuth eutectic (LBE) was conducted at 600°C for 500 h. The specifications of TIG welding, YAG laser welding and electron beam welding were 40A/12V of electrical conductance, 278W/14.3J of heat input and 5.0 mA of beam electric current, respectively. Oxygen concentration was controlled to be about 4.7×10−6wt% by injecting Ar-H2-H2O gas mixture into LBE. After corrosion test, cross sections of the specimens were analyzed by using optical microscope and SEM/EDX. Toughness profiles of fusion zone and base metal were determined by using Vickers hardness tool. The results show coarse grain structure in fusion zone (FZ) and typical ferritic-martensitic grain structure in base metal (BM). It was found that those Cr-rich spinel oxide layer and diffusion zone were formed on the surface. The total thickness of oxide layer and diffusion zone on and in the fusion zone was about 18–30μm. It was much thicker than 10–15μm on BM. The hardness was higher in the fusion zone than in the BM.</jats:p>