The Study On Chemical Etching Process Of Depth And Its Effects On Properties For TA12 Titanium Alloy

Chemical etching is a machining method in which metal part to be processed is exposed to chemical medium, while the predetermined position of part is corroded by chemical solution, and then obtain the required shape, processing size and dimensional accuracy. Due to no cutting stress, chemical etching can be used to machine the parts with complex shape, easier deformation and large area. Therefore, chemical etching process for titanium alloy is an important and indispensable key technology of the aircraft and weapons equipment manufacturing.Chosen TA12 titanium alloy plate as the research object, through the titanium alloy milling to protect the choice of adhesive, laser carving technology research and too structure design, AC850 for milling protection rubber is determined, while the type of laser carving laser energy and relationship between film thickness and laser energy were confirmed. Moreover, to determine the tooling structure with rotating device was also determined in order to ensure the uniformity of parts milling.In this study, the influences of nitric acid, hydrofluoric acid, and titanium ion concentration on etching speed were mainly studied, while surface topography, surface roughness, surface residual stress before and after milling of titanium alloy were investigated. In addition, tensile properties, fatigue performance and material hydrogen content before and after milling of titanium alloy were also analyzed. The results show that with the increase of hydrofluoric acid concentration, the etching rate presents rise tendency. The etching rate decreases with the increase of titanium ion content. When the nitrate concentration, hydrofluoric acid concentration and the temperature range were respectively 80 g/L, 120 g/L and 24-28℃, the corrosion processing of titanium alloy was optimum. Moreover, etching titanium ion concentration in liquid has great influence on etching speed, roughness on the surface of the titanium alloy and stability of the etching liquid.Compared with mechanical processing, tensile properties and low circumferential stress fatigue properties at room temperature and high temperature of TA12 titanium alloy after chemical corrosion processing are better than those of specimens by mechanical processing, which conform the requirements of the process specification.Therefore, the deep chemical etching process can realize the application on Engine external culvert box(“shape of well in Chinese” in the rib) and booster cylindert(“shape of well in Chinese”, “shape of rice in Chinese” and irregular shape in the ribs).