蒸发器管束用钢管的耐蚀性研究

    Study on Corrosion Resistance of Steel Tube for Evaporator Pipe Bundle

    • 摘要: 碳钢在拜耳法氧化铝工艺中耐蚀性不足,通过添加Cr、Cu等元素研发低合金耐蚀钢。基于显微组织、机械性能、耐蚀性能等的综合评估和分析表明,有别于A179碳钢的球化态改善耐硫酸腐蚀性,BGNDMA和BGAABC低合金钢合金化实现耐蚀性,热轧态耐蚀性等效热处理态,其组织仍均为碳钢常规的铁素体+珠光体。相比于20G和A179碳钢,在60℃6%和10.3% H2SO4溶液中,BGNDMA和BGAABC低合金钢耐蚀性至少提高4倍以上。在125℃,20% NaOH溶液中总体腐蚀率∧1.0 mm/a,BGAABC则∧0.1 mm/a,均未发生碱脆。

       

      Abstract: Since the corrosion resistance of carbon steel is insufficient in Bayer alumina process,the low alloy steel for corrosion resistance is developed by adding Cr,Cu and other elements.The comprehensive evaluation and analysis of micro-structure,mechanical property and corrosion resistance are carried out.The results show as follows:for improving corrosion resistance in dilute sulfuric acid,BGNDMA and BGAABC are low alloy steel,which corrosion resistance of hot rolled state is equivalent to that of heat treatment state,unlike spheroidized A179 carbon steel.The micro-structures of BGNDMA and BGAABC are still ferrite & pearlite like carbon steel.The corrosion resistance of BGNDMA and BGAABC in dilute sulfuric acid is at least four times higher than that of carbon steels such as 20G and A179 in 6% & 10.3% H2SO4 solution at 60℃.BGNDMA and BGAABC can completely replace 20G and A179 carbon steels in dilute sulfuric acid corrosion environment such as alumina industry.Corrosion rates of evaluated low alloy steels are lower than 1.0 mm/a in 20% NaOH solution at 125℃,while BGAABC is lower than 0.1 mm/a,and no alkali fragile occurs.

       

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