X100钢级螺旋缝埋弧焊管抗H2S腐蚀性能研究

    Study on H2S Corrosion Resistance of X100 SSAW Pipe

    • 摘要: 对X100钢级螺旋缝埋弧焊管进行了氢致开裂(HIC)和硫化物应力腐蚀开裂(SSCC)试验研究,结果表明:X100钢级螺旋缝埋弧焊管焊接接头比管体的抗H2S腐蚀性能差。分析认为:带状组织和硬度高是导致管体和焊接接头氢致裂纹超标的主要原因,氢致裂纹主要是穿晶型和沿晶型开裂;而焊缝中存在夹杂物,以及焊缝中晶内针状铁素体组织和热影响区中粒状贝氏体组织引起的硬度波动和偏高,是导致焊缝处发生应力腐蚀断裂的主要原因。电化学试验和残余应力测试,也进一步证实了X100钢级螺旋缝埋弧焊管焊接接头比管体更易于腐蚀。

       

      Abstract: Conducted for the study purpose are the hydrogen induced cracking(HIC)test and the sulfide stress corrosion cracking(SSCC)test to the X100 spiral submerged arc welded(SSAW)pipe. The test results show that H2S resistance of the pipe's weld joint is lower than that of the pipe body. And the analysis reveals the facts as follows. At the first,it is the banded structure and high hardness that act as the main role in causing excessive development of hydrogen induced cracking of both the welded joint and the pipe body,and the hydrogen induced cracks are mainly of transgranular fracture and intergranular fracture. And the SSCC occurring in the weld seam area is mainly due to the presence of inclusions in the weld seam proper,and the on-the-high-side and fluctuated hardness caused by the existence of the intergranular acicular ferrite structure in the weld seam and the granular bainite structure in the heat affected zone. Finally, the results from electrochemical polarization test and the residual stress test also further confirm that in case of the X100 SSAW pipe,its weld joint is more apt to be corroded than the pipe body proper.

       

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