熱交換器之海軍黃銅管板腐蝕原因分析

Corrosion Damage of Naval Brass Tubesheet in Sea Water

濱海工業區內的熱交換器經常使用海水作為冷卻水源，因而黃銅合金成為熱交換器重要的耐蝕性結構材料之一。在本文探討的腐蝕案例中，熱交換器管板發生嚴重的壁厚減薄甚至貫穿現象，而且使用年限僅約五年，因此針對此件破損管板進行目視檢查、金相組織檢查、電子顯微鏡分析、以及模擬腐蝕試驗等。試圖釐清其主要的腐蝕與劣化機構，並分析電解海水產生次氯酸離子對於腐蝕速率的影響程度。

Seawater is a frequently used cooling media for seaside plants. Hence copper and copper alloys with excellent corrosion resistance to seawater are one of the major construction materials for heat exchangers and condensers for such applications. This paper investigated several possible failure mechanisms and intended to determine the dominating cause for Naval brass condenser tubesheet to suffer from a severe wall thinning and even perforation. And its service life was as short as 5 years or so. The influence of hypochlorous ions, which was introduced by electrolysis of seawater, on corrosion rate was also studied.