CNC Machining of Titanium Alloys:

Titanium alloys’ material parameters determine CNC machining difficulty and efficiency. Below are core parameters:

Chemical Composition (Key Alloys)

1.Ti-6Al-4V (Grade 5): Ti≥88%, Al 5.5–6.75%, V 3.5–4.5% (most used, balances strength and machinability).
2.Ti-6Al-2Sn-4Zr-2Mo (Grade 12): Ti≥85%, 含 Al、Sn、Zr、Mo (high-temperature resistant, for high-heat precision parts).
3.CP Ti (Grade 2): Ti≥99.2%, trace impurities (good ductility, low strength, for low-load parts).

Mechanical Properties (For Parameter Setting)

Tensile Strength: Ti-6Al-4V (annealed: 860–930MPa; heat-treated: 1100–1200MPa); CP Ti (345–550MPa).
Hardness: Ti-6Al-4V (HB 300–350, tool-wearing); CP Ti (HB 120–180, prone to tool built-up edge).
Ductility: Ti-6Al-4V (elongation ≥10%, control feed rate); CP Ti (elongation ≥20%, need chip removal).

Thermal Properties (For Heat Management)

Thermal Conductivity: 1/5 steel, 1/10 aluminum (Ti-6Al-4V: 7.6 W/m·K, heat concentrates at cutting zone).
Thermal Expansion: Low (Ti-6Al-4V: 8.6×10⁻⁶/°C, 1/2 steel, small part deformation, precision ±0.005mm).
Phase Transition Temp: Ti-6Al-4V: 995–1010°C (avoid exceeding, prevent structure change).


Machinability Parameters (For Process Optimization)

Machinability Index: Ti-6Al-4V: 30–40 (1018 steel=100, difficult to machine, need low speed, high rigidity).
Chip: Brittle but sticky at high temp (need 80–150bar high-pressure flushing).
Work Hardening: Strong (surface hardness +50–100%, avoid repeated cutting, use sharp tools).
Tools: Cemented carbide/CBN (TiAlN/AlCrN coating extends life 2–3x).