The production process and welding quality of titanium plate determine its quality
Titanium plate is a striking feature of corrosion resistance is strong, this is due to its affinity for oxygen especially big, can generate on the surface and the oxide film layer, can protect the titanium from medium corrosion, in acid, alkali, neutral salt aqueous solution and oxidizing medium has a good stability, stainless steel and other than the existing common non-ferrous metal corrosion resistance are all well.
The quality of titanium plate is largely determined by the smelting process of titanium plate manufacturers, including the chemical composition of titanium, titanium water cleanliness (gas, harmful elements, inclusions) and casting billet quality (composition segregation, decarbonization and surface condition), which are the key control points of smelting operation.
In addition, the industrial titanium plate also requires enough hardenability to ensure that the entire spring section to obtain uniform microstructure and mechanical properties. The main reason of fatigue crack is the oxide inclusion in titanium, and the damage of D inclusions to fatigue life is greater than that of B inclusions. Therefore, foreign titanium factories and automobile factories put forward higher requirements for oxide inclusions in industrial titanium plates, such as the Swedish SKF standard requires that the oxygen content in titanium is lower than 15×10-6, and the D type inclusions are lower than the B type inclusions. In particular, Al2O3 and TiN inclusions do great harm to the fatigue life of titanium spring. In order to produce high quality industrial titanium plates, special smelting methods such as electroslag remelting or vacuum arc remelting are usually used in the past.
Because titanium plate has special physical and chemical characteristics, so its welding process is very different from other metals. Titanium welding is a TiG welding process in which the welding area is effectively protected by inert argon. Before using argon, check the factory certificate on the cylinder body to verify the purity index of argon, and then check whether there is leakage or failure of the cylinder valve.
Titanium plate welding must ensure that:
The metal in the welding area is not polluted by active gas N0H and harmful impurity element CFeMn above 250℃. Purity shall not be less than 99.98% water content less than 50Mg/m32 Argon: industrial grade pure argon.
No coarse crystalline structure can be formed. Welding process must be in accordance with the predetermined construction sequence, can not produce large welding residual stress and residual deformation. Therefore, strictly according to the process quality management standards, the implementation of the whole process of quality control. The factors of human, machine, material and method are in a good state of control, so as to ensure its quality within a reasonable period.