X65管线钢焊接接头耐腐蚀性能研究

针对长输管线钢在输油过程中焊接接头腐蚀严重的情况,分别采用PAW焊打底+MAG焊填充、盖面以及TIG焊打底+MAG焊填充、盖面的方法对国产X65管线钢进行焊接,并将所得到的焊接接头与X65管线钢上的SAW焊接接头进行比较。对比3种焊接方法所得到的接头在显微组织、硬度上的差别,并通过三电极电化学研究方法和SSCC试验,评价了不同焊接接头的耐腐蚀性能。结果表明,采用PAW焊打底的焊接接头组织均匀细小,SSCC敏感性最低,耐蚀性能最好;TIG焊打底的焊接接头显微组织与母材相近,耐蚀性能稍差于PAW焊打底的焊接接头;而SAW焊的焊接接头晶粒较粗大,裂纹敏感性稍高,耐蚀性能最差。

Research on the corrosion-resistant performance of the X65 pipeline steel welded sub

Considering the fact that the welded sub of the long-distance transmission pipeline steel will be seriously corroded in the process of oil transportation,the domestically made X65 pipeline steel is welded by means of PAW weld priming plus MAG weld packing,capping and TIG weld priming plus MAG weld packing and capping,and then the obtained welded sub is compared with the SAW welded sub of the X65 pipeline steel. The distinctions of the subs obtained by the three welding methods are identified in terms of microstructure and hardness,and the corrosion-resistant performance of the different welded subs is evaluated according to the tri-electrode electrochemical research method and the SSCC test. The results show that the welded sub adopting PAW weld grounding is even and fine in structure,with the lowest SSCC sensitivity and best corrosion-resistant performance. The welded sub adopting TIG weld grounding is similar to the base material in microstructure,with its corrosion-resistant performance slightly weaker than that of the PAW welded sub. The crystalline grain of the SAW welded sub is relatively bigger,with higher crack sensitivity and lowest corrosion-resistant performance.