突扩管条件下材料的冲刷腐蚀机理研究Ⅰ碳钢

利用新近研制的双相流冲刷腐蚀激光多普勒实验装置，通过失重测试、表面形貌观察、局部流速流态测试和曲型部位的电化学测试，研究了突扩管条件下碳钢ＡＩＳＩ１０２０在单相及含砂人工海水介质中的冲刷腐蚀机理。结果表明：冲刷腐蚀峰值发生在距突扩位置约２．５Ｄ的部位（Ｄ为粗管直径），与重附着点的位置相同，不同部位的冲刷腐蚀形貌有着明显差异，并与局部流速流态是相互对应的。冲刷对腐蚀的影响主要表现在流动对氧传质过程的

EROSION-CORROSION MECHANISM UNDER SUDDEN PIPE EXPANSION I. CARBON STEEL

The erosion-corrosion mechanism of AISI1020 in artificial sea water with or without1000 × 10-6 silica sand under sudden pipe expansion condition was investigated through weight loss test,surface morphology observation, local flow regime measurements (LDA) and electrochemicalmeasurements at specific position. The results showed that the maximum of erosion-corrosion was locatedat about 2.5D (large pipe diameter) downstream the sudden pipe expansion which was the same as thereattachment point. The erosion-corrosion morphologies at different positions were significanly different,which was just responding the local flow regime. The effects of erosion on corrosion were mainly due tothe enhanced mass transfer of the oxygen. The effect of flow on anodic process of carbon steel wasrelatively small.