Application Of TA10 Titanium Alloy in Ammonium Chloride Evaporator

　　Industrial pure titanium has strong corrosion resistance in room temperature ammonium chloride solution, but it has crevice corrosion tendency in high temperature and high concentration ammonium chloride solution. There is a pure titanium ammonium chloride evaporator in a chemical plant in China. 8Mo was severely corroded and had to be scrapped.

　　analysis test

　　Baoji Nonferrous Metals Processing Factory Qiu Honglin and others conducted metallographic and scanning electron microscopy analysis on the corrosion. The metallographic analysis of the corrosion site did not reveal abnormal changes in the structure, nor did they find the existence of hydrides associated with crevice corrosion, and the structure was still equiaxed.

　　The corrosion part was analyzed by PSEM-500X scanning electron microscope. They found that the surface was honeycomb-like, but there was no crack. The element energy spectrum analysis found that the corrosion area contained a large amount of Cl, and its composition was: 58.207%Ti, 34.205%Cl, 4.631%Fe , 2.441%Ca, 1.259%Si, 0.254%K.

　　Repair and application of TA10 titanium alloy

　　Qiu Honglin and others first removed the deposits. To this end, a titanium spray pipe was installed under the lower tube plate to spray on time to reduce scaling.

　　The biggest improvement is to use TA10 titanium alloy to make NH4Cl evaporator, it is a Ti-0.3Mo-0.8Ni alloy, its composition (mass %): Mo0.2-0.4, Ni0.6-0.9, Fe-0.30, C -0.08, N0.03, H0.015, O0.25, other impurities are single 0.1, total 0.4, the rest Ti, it is a low-strength titanium alloy, the operation shows that there is no crevice corrosion, it can be seen that high temperature and high concentration NH4Cl The use of TA10 titanium alloy in solution is completely safe and reliable.