換熱器用無縫鈦管失效分析

摘" 要：該文通過采用宏觀檢測、顯微組織分析、掃描電鏡分析、能譜分析等方法對流動介質為氯化物溶液的換熱器用無縫鈦管進行失效分析，發現流動介質為氯化物溶液的換熱器中無縫鈦管主要是通過以下2種方式發生腐蝕失效的，一種是Fe+離子存在于鈦管材表面會在鈦管材表面形成點腐蝕，通過點腐蝕的方式使鈦管發生腐蝕失效；另一種是當換熱器的管板和管材形成一定縫隙時會發生間隙腐蝕，間隙腐蝕發生時鈦管會伴隨有吸氫反應和自催化作用，最終導致管材產生腐蝕孔洞而失效。同時筆者建議在制作內部流動氯化物溶液的換熱器時不易將不銹鋼管板和鈦管組合使用，并且管板與管材之間的間隙大于0.5 mm以免在使用過程中發生點腐蝕和間隙腐蝕導致換熱器泄漏。

關鍵詞：換熱器；無縫鈦管；失效分析；腐蝕；宏觀檢測

中圖分類號：R735.1" " " 文獻標志碼：A" " " " " 文章編號：2095-2945（2024）25-0084-05

Abstract： In this paper， through the use of macro detection， microstructure analysis， scanning electron microscope analysis， energy spectrum analysis and other methods to the flow medium for chloride solution of the heat exchanger seamless titanium tube failure analysis， found that the flow medium for chloride solution in the heat exchanger seamless titanium tube corrosion failure mainly through the following two ways： one is Fe+ ions on the surface of titanium pipe will occur Titanium pipe surface form point corrosion， through the point corrosion of titanium tube corrosion failure; The other is that when the tube plate of the heat exchanger and the pipe form a certain gap， the gap corrosion will occur. When the gap corrosion occurs， the titanium pipe will be accompanied by hydrogen absorption reaction and self-catalysis， and eventually lead to corrosion holes and failure of the pipe. At the same time， we suggest that it is not easy to use stainless steel tube plate and titanium tube in combination when making heat exchangers with internal flow chloride solution， and the gap between the tube plate and the pipe is greater than 0.5mm to avoid point corrosion and gap corrosion resulting in heat exchanger leakage during use.

Keywords： heat exchanger; seamless titanium tube; failure analysis; corrosion; macroscopic detection

鈦管作為鈦基型材的一種，具有生物相容性好、比強度高、耐腐蝕好等優點，被廣泛用于醫療、海水淡化、石油化工、航天航空和海洋船舶等領域。尤其近年在化工領域的應用非常普遍，主要用做冷凝器的換熱管，不光解決了耐腐蝕、比強度高的問題，同時換熱效率也是非常高；但換熱器在使用過程中，仍發現有部分鈦管材發生腐蝕穿孔，造成泄漏，給企業帶來不小的經濟損失，一直困擾著整個行業。本文就換熱器用無縫鈦管發生腐蝕失效的機理及原因進行探索。……