Analysis of pickling process of titanium and titanium alloy processed materials

In the production process of titanium and titanium alloy processed materials, the removal of oxide is a crucial step, and pickling is the main means to achieve this goal. Before pickling, it is usually necessary to pretreat titanium materials, such as molten alkali washing, mechanical scaling or sandblasting, to remove most of the dirt and thick oxide layer on the surface, creating favorable conditions for subsequent pickling.

Pickling is a very effective removal method for slight titanium oxide films formed below 600 ° C. In the pickling process, titanium reacts with the acid to form metal ions, so as to remove the oxide. However, the pickling of titanium is not just a simple chemical reaction, it also involves an electrochemical phenomenon.

When pickling in mixed acid 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, and once it enters the metal, it may lead to hydrogen embrittleness of the metal, which seriously affects the performance and service life of titanium.

Therefore, when pickling titanium materials, the composition and proportion of the acid must be strictly controlled to prevent the occurrence of hydrogen absorption. In particular, the ratio of nitric acid to hydrofluoric acid must always be greater than 5. 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 too high nitric acid content will lead to a reduction in reaction speed and production efficiency, while also producing a large amount of smoke, which brings difficulties to the operation.

In addition, it is necessary to pay attention to the control of process parameters such as temperature and time during pickling. Too high temperature or too long time may lead to excessive corrosion of titanium, affecting the surface quality. Therefore, in actual operation, it is necessary to adjust the pickling process parameters reasonably according to the material, thickness and severity of the titanium oxide to ensure the optimal pickling effect.

In short, the pickling process of titanium and titanium alloy processed materials is a complex and fine work. Only by strictly controlling the composition, proportion and process parameters of the acid solution can we ensure the pickling effect and avoid unnecessary damage to the titanium material. Interested friends can continue to pay attention to our sharing and learn more about the knowledge and technology of titanium metal in production.