造纸蒸球焊缝与热影响区耐蚀性研究

Corrosion Behavior of the Welded Seam and Heat-affected Zone of the Rotary Digester in Ammonium Sulfite Solution

针对亚铵法制浆造纸设备严重腐蚀的问题,采用三电极电化学研究法、金相组织分析法及失量法研究了造纸蒸球焊缝与热影响区在亚硫酸铵介质中的腐蚀行为。结果表明,温度升高和亚硫酸铵溶液浓度增大均促使焊缝与热影响区的腐蚀速率增大。随着亚硫酸铵介质pH值由酸性向碱性转变,极化体系中阳极区均出现钝化,其腐蚀速率减小。Q235钢经J420焊条焊接后,组织特点决定了焊缝的腐蚀速率大于热影响区。

The corrosion behavior of the welded seam and heat-affected zone of the rotary digester in ammonium sulfite solution was studied by using three anodes electrochemical method and metallurgical structure analysis. The results showed that the corrosion rates of the welded seam and heat-affected zone are accelerated by increasing the temperature and concentration of ammonium sulfite solution. The passivation appeared in the two anodes in the polarization system, the corrosion rate reduced when the solution pH changed from acid to alkali. The welded seam＇s corrosion rate was faster than the heat-affected zone＇s, which was determined by their structures after the Q235 steel was jointed by J420 electrode.