Analysis Of The Pickling Process Of Titanium And Titanium Alloy Processing Materials

In the production process of titanium and titanium alloy processing materials, removing the oxide skin is a vital step, and pickling is the main means to achieve this goal. Before pickling, the titanium material usually needs to be pretreated, such as molten alkali washing, mechanical scalding or sandblasting, to remove most of the dirt and thicker oxide layer on the surface, creating favorable conditions for subsequent pickling.

For the slight titanium oxide film formed below 600℃, pickling is a very effective removal method. During the pickling process, titanium reacts chemically with the acid solution to form metal ions, thereby achieving the removal of oxide skin. However, titanium pickling is not just a simple chemical reaction, it also involves electrochemical phenomena.

When pickling in a mixed acid solution containing hydrofluoric acid or fluoride, special attention needs to be paid to the reduction reaction of hydrogen ions. These hydrogen ions may be reduced to atomic or molecular hydrogen.

Among them, molecular hydrogen has a tendency to diffuse into the metal. Once it enters the metal, it may cause hydrogen embrittlement of the metal, which seriously affects the performance and service life of titanium. Therefore, when performing titanium pickling, the composition and proportion of the acid solution must be strictly controlled to prevent the occurrence of hydrogen absorption.

In particular, it is necessary to always keep the ratio of nitric acid to hydrofluoric acid greater than 5. The control of this ratio is essential to prevent hydrogen embrittlement. However, it is also necessary to pay attention to the nitric acid content should not be too large, because the nitric acid content is too high, the reaction speed will be reduced, the production efficiency will be reduced, and a large amount of flue gas will be generated, which will bring difficulties to the operation.

In addition, attention needs to be paid to the control of process parameters such as temperature and time during the pickling process. Too high temperature or too long time may cause excessive corrosion of titanium and affect surface quality.

Therefore, in actual operation, the parameters of the pickling process need to be rationally adjusted according to factors such as the material, thickness and severity of the oxide skin of the titanium material to ensure the optimization of the pickling effect.

In short, the pickling process of titanium and titanium alloy processing materials is a complex and delicate work. Only by strictly controlling the composition, proportion and process parameters of the acid solution can the pickling effect be ensured while avoiding unnecessary damage to the titanium material. Interested friends can continue to follow our sharing to learn more about the knowledge and technology of titanium in production.