The quality of titanium plates largely depends on the smelting process of the titanium plate manufacturer, including the chemical composition of titanium, the cleanliness of the titanium melt (gases, harmful elements, inclusions), and the quality of the billet (composition segregation, decarburization, and surface condition). These aspects are the key control points in the smelting operation.
Additionally, industrial titanium plates require sufficient hardenability to ensure uniform microstructure and mechanical properties throughout the spring cross-section. The primary cause of fatigue cracks is the presence of oxides in titanium, with Class D inclusions posing a greater risk to fatigue life than Class B inclusions. Consequently, foreign titanium factories and automakers have set higher requirements for oxide inclusions in industrial titanium plates, such as the Swedish SKF standard, which demands oxygen content in titanium below 15×10-6 and Class D inclusions below Class B inclusions. Especially, Al2O3 and TiN inclusions are more harmful to the fatigue life of titanium springs. To produce high-quality industrial titanium plates, special metallurgical methods such as electric furnace - electroslag remelting or vacuum arc remelting were commonly used in the past.
Due to the unique physical and chemical properties of titanium plates and bars, their welding processes differ significantly from those of other metals. Titanium material welding is a TiG welding process that effectively protects the welding area with inert argon gas. Before use, the purity of the argon gas is verified by checking the factory certification label on the cylinder, followed by inspecting for any leakage or malfunction in the cylinder valve.
Welding of titanium plates and bars must ensure:
Metal in the welding area remains unpolluted by active gases such as NOH and harmful impurities like CFeMn above 250°C. Purity must not be less than 99.98%, moisture content less than 50 Mg/m³, and argon: industrial grade pure argon.
The formation of coarse crystal structures is not permissible. The welding process must adhere to the predetermined construction sequence, and should not generate significant welding residual stresses or deformation. Therefore, it is essential to strictly follow the quality management standards for each process, implement comprehensive quality control throughout the process, ensuring that all factors such as personnel, machinery, materials, and methods are in a well-controlled state. This guarantees the welding quality of the titanium tubes within a reasonable timeframe.
