Titanium alloy has high corrosion resistance, high specific strength and excellent high temperature resistance. It has been widely used in the aerospace industry, but it is difficult to process, difficult to form, and requires high temperature treatment. In sheet metal processing, the processing temperature is as high as 800 ° C, and the temperature is kept for 20 to 30 minutes, which needs to be protected with paint. Due to the relatively high processing temperatures, the coating cannot be removed at all by conventional methods. To this end, after repeated tests to determine the high-temperature concentrated alkali soaking and removing the coating, there are two kinds of processes, and the removal effect is very satisfactory.
(1) NaOH 125～175g/L ZLA 375～425g/L temperature Boiling time 1h or more.
(2) NaOH 450～650g/L NaNO3 3100～150g/L NaNO2 275～125g/L Temperature Boiling time 1.5h or more.
The above two formula removal effects are very satisfactory. In actual production, in order to further improve the cleaning quality and improve the production efficiency, ultrasonic technology can be used. The process specifications are as follows:
Process: ultrasonic alkali washing→hot water washing→cold water washing→acid washing The alkali washed workpiece is pickled 2～ 4min, its surface is evenly bright, revealing the true color of silver-white metal, the surface is free of oxide scale, can be welded, the hydrogen content is ≤0.01%, meeting the requirements of GB3620.