换热器用无缝钛管失效分析

该文通过采用宏观检测、显微组织分析、扫描电镜分析、能谱分析等方法对流动介质为氯化物溶液的换热器用无缝钛管进行失效分析,发现流动介质为氯化物溶液的换热器中无缝钛管主要是通过以下2种方式发生腐蚀失效的,一种是Fe+离子存在于钛管材表面会在钛管材表面形成点腐蚀,通过点腐蚀的方式使钛管发生腐蚀失效;另一种是当换热器的管板和管材形成一定缝隙时会发生间隙腐蚀,间隙腐蚀发生时钛管会伴随有吸氢反应和自催化作用,最终导致管材产生腐蚀孔洞而失效。同时笔者建议在制作内部流动氯化物溶液的换热器时不易将不锈钢管板和钛管组合使用,并且管板与管材之间的间隙大于0.5 mm以免在使用过程中发生点腐蚀和间隙腐蚀导致换热器泄漏。

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.