Leakage reason of heat exchange tube of oil cooler

Corrosion leakage occurred in the heat exchange tube of oil cooler produced by a company after it was put into use for 9－12 months. The causes of pipeline corrosion and leakage were analyzed by means of macroscopic observation, chemical composition analysis, metallographic examination, scanning electron microscopy and energy spectrum analysis, and atomic absorption spectrometry. The results show that the chloride ions and sulfur ions in the heat exchange tube medium of the oil cooler were deposited in the fouling of the inner wall of the tube and enriched in the front of the tube wall matrix, resulting in a large number of pitting corrosion on the inner wall. The pitting corrosion position and the uncorroded position formed a large cathode and small anode corrosion cell, which accelerated the corrosion rate, and the pitting corrosion pit was further expanded under the erosion of the medium in the tube, which eventually led to the leakage of the pipeline.