Grade 2 titanium is an unalloyed (commercially pure) titanium grade, and it is widely recognized for its excellent ductility and superior formability among titanium alloys. This combination of properties makes it highly suitable for a broad range of manufacturing processes.
1. Ductility
Ductility refers to a material's ability to deform plastically before fracturing.
Elongation (A50mm): Typically 20% minimum and often ranges from 20% to 25% in the annealed condition. This is significantly higher than many high-strength titanium alloys (e.g., Grade 5 Ti-6Al-4V typically has 10-15% elongation).
Reduction in Area (RA): Typically 30% minimum.
Toughness: It exhibits good low-temperature toughness, maintaining ductility even at cryogenic temperatures without a ductile-brittle transition.
2. Formability
Grade 2 titanium is the most formable among the commercially pure titanium grades (Grade 1, 2, 3, 4).
Cold Forming: It is readily formable by conventional cold working processes such as deep drawing, bending, stamping, roll forming, and spinning. It can be formed into complex shapes with relative ease.
Springback: Like all titanium alloys, it exhibits higher springback compared to steel or aluminum after bending. Tooling design must account for this.
Warm Forming: For very complex geometries or to reduce springback and forming loads, warm forming at temperatures between 150°C to 300°C (300°F to 570°F) is often employed, which further improves its formability.
Annealing: The material work-hardens during cold forming. Intermediate annealing (typically at 700°C to 800°C) is required to restore ductility between forming operations for severe cold working.
Summary
In summary, Grade 2 titanium offers excellent ductility with high elongation values and superior formability, especially in the annealed condition. It is the preferred choice for applications requiring complex shaping via cold or warm forming processes, such as heat exchangers, chemical processing equipment, and architectural components.
