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研究了燃气旧管道Q235管线钢焊接接头各个微观区域在土壤模拟溶液中的电化学行为.测量了各个微区的极化曲线,测定了相关的电化学参数.结果表明,各区域的Ecorr由低至高和icorr由大至小的顺序依次为:熔合线,不完全正火区,过热区,正火区,回火区,母材,焊缝区.同一个焊接接头的七个不同热经历区域暴露于同一电解质时,也将构成一个多电极体系.其中,熔合线和不完全正火区将成为复杂多电极体系形成的原电池中的阳极,最可能遭受到优先的腐蚀溶解;焊缝区和母材区则是原电池中的阴极,腐蚀敏感性低且在一定程度上受到阴极保护.
The electrochemical behavior of each microscopic area of Q235 pipeline steel welded joint in gas simulation solution was studied.The polarization curve of each micro-area was measured and the relevant electrochemical parameters were measured.The results showed that the Ecorr of each area was changed from low The order of the highest and the highest icorr are as follows: fusion line, incomplete normalizing zone, overheating zone, normalizing zone, tempering zone, base metal and weld zone. Seven different thermal experience zones of the same welded joint When exposed to the same electrolyte, it will also form a multi-electrode system in which the fusion line and the incomplete normalizing zone will become the anodes in a galvanic cell formed by a complex multi-electrode system, most likely to be subject to preferential corrosion dissolution; And the base metal area is the cathode in the primary cell, corrosion sensitivity is low and to some extent by the cathodic protection.