The A106 Gr B low carbon steel, which was used in the electric power plants and heavy chemical plants, was welded by multi-pass arc welding. The heat affected zone (HAZ) formed by welding was corroded in acid chloride solution, or in saturated H₂S c...
The A106 Gr B low carbon steel, which was used in the electric power plants and heavy chemical plants, was welded by multi-pass arc welding. The heat affected zone (HAZ) formed by welding was corroded in acid chloride solution, or in saturated H₂S containing acid chloride solution, or in saturated H₂S containing acid chloride solution under applied current. In this order of corrosion solution, the rate of corrosion increased, because H₂S accelerated the iron dissolution, hydrogen evolution, and the formation of nonprotective FeS, whereas the applied current accelerated the electrochemical reaction. The scales formed in acid chloride solution consisted primarily of Fe₃O₄, while those formed in H2S containing acid chloride solution consisted primarily of Fe₃O₄ and FeS.