几种金属材料在高炉煤气管道冷凝液中的电化学腐蚀行为

Corrosion Behavior of Several Metal Materials in Blast Furnace Gas Condensates

某电厂干法除尘高炉煤气管道中的316L不锈钢膨胀节发生严重腐蚀,取高炉煤气管道中3个不同部位的冷凝液,利用电化学阻抗谱和极化曲线研究了904L和254SMo超级奥氏体不锈钢、2507和2205双相不锈钢及纯钛在3种冷凝液中的耐蚀性能。结果显示:高炉煤气管道冷凝液中含有高浓度氯离子,具有较低的p H值,冷凝液中904L和2205不锈钢的电荷转移电阻Rct值最小,254SMo和2507不锈钢次之,纯钛的Rct值最大;5种材料在冷凝液中的腐蚀电流密度从大到小依次为904L>2205>254SMo>2507>Ti;在稀释后的冷凝液中254SMo不锈钢的Rct值显著增大,在稀释5倍的冷凝液中254SMo不锈钢的Rct值与纯钛接近。

Severe corrosion happened in 316 L expansion joints of blast furnace gas pipeline where dry dedusting was used. The anti-corrosion performance of 904 L and 254 SMo super austenitic stainless steel( SS),2507 and 2205 duplex stainless steel,and titanium was studied using electrochemical impedance spectroscopy and polarization curve. Results showed that the condensate from blast furnace gas pipeline contained high concentration of chloride and had low pH value. 904 L SS and 2205 SS had the minimum charge transfer resistances Rct,followed by 254 SMo SS and 2507 SS,and titanium had the maximum Rctin condensate. The corrosion current density of these five materials in condensate from the maximum to minimum was as follows: 904 L > 2205 > 254 SMo > 2507 > Ti. The Rctvalue of 254 SMo SS was increased distinctly in the diluted condensate and it was close to the Rctvalue of titanium in 5-fold diluted condensate.