Corrosion Resistance of New Standard 09CrCuSb Acid Resistant Steel to 50%H₂SO₄

The corrosion behavior of the new standard 09CrCuSb acid resistant steel under different temperature conditions (25, 50, 60, 70 ℃) in a 50% H₂SO₄solution was studied through electrochemical testing and full immersion corrosion test. The results show that as the temperature increased from 25 ℃ to 70 ℃, the corrosion rate of the new standard 09CrCuSb steel showed an overall increasing trend. At 70 ℃, the corrosion rate was the highest, as 2.70 g/(m²·h). This was related to the decrease in protective Fe₃O₄content in the corrosion products, the increase in unprotected FeSO₄·H₂O content, and the change in micropores in the rust layer as the temperature increased. In addition, due to the adjustment of the content of elements such as Cu, Mo, Sn, Sb and W in 09CrCuSb steel in the new standard, compared with the old standard 09CrCuSb steel, the anodic passivation current density was reduced. Under the same temperature condition, the corrosion resistance of the new standard 09CrCuSb steel was greatly improved.