Base elements → Materials → Metallic materials

TITANIUM

Table of main properties of titanium

 

Property Grade 2 (Commercially Pure) Grade 5 (Ti-6Al-4V) Remarks
Density ~4.5 g/cm³ ~4.4 g/cm³ Both low
Young’s modulus (E) ~100–105 GPa ~110–120 GPa Higher for Grade 5
Tensile strength ~300–500 MPa ~900–1100 MPa Much higher for Grade 5
Hardness (HV) ~120–200 HV ~300–350 HV Grade 5 significantly harder
Thermal conductivity ~16–20 W/m·K ~6–7 W/m·K Lower for Grade 5
Electrical conductivity ~2–3 MS/m ~1–2 MS/m Low for both
Thermal expansion ~8.5–9 ×10⁻⁶ /K ~8–9 ×10⁻⁶ /K Similar
Melting point ~1660–1668 °C ~1600–1660 °C Slightly lower for Grade 5
Magnetism No No Non-magnetic
Corrosion resistance Excellent Excellent Outstanding for both
Machinability Moderate to difficult Difficult More difficult for Grade 5

Titanium is a transition metal used in watchmaking for its exceptional properties of lightness, mechanical strength, and corrosion resistance. Introduced relatively late in this field (late 20th century), it quickly established itself, particularly in technical and sports watches.

Its low density combined with high strength makes it especially suitable for applications where weight reduction and robustness are required. Titanium is also non-magnetic and biocompatible, further enhancing its relevance in contemporary watchmaking.

Main Properties

Titanium exhibits a set of remarkable properties:

  • Low density (~4.5 g/cm³)
  • Excellent mechanical strength
  • Very high corrosion resistance (formation of a protective oxide layer)
  • Non-magnetic material
  • Good fatigue resistance
  • Moderate Young’s modulus (~100–120 GPa)
  • Low thermal conductivity

These characteristics make titanium a material that is both lightweight, durable, and stable.

Titanium is classified into different grades, defined by its composition and mechanical properties. In watchmaking, two grades are particularly used:

1. Grade 2 Titanium (Commercially Pure Titanium)

Grade 2 titanium is an almost pure titanium (≈ 99%). It contains small amounts of iron (0.30%), oxygen (0.25%), carbon (0.08%), and nitrogen (0.03%).

Characteristics:

  • Very high corrosion resistance
  • Excellent ductility
  • Relatively easier machining (with risk of ignition)
  • Moderate mechanical strength

Applications in watchmaking:

👉 Appreciated for its comfort (lightweight) and corrosion resistance.

Grade 2 titanium does not allow for high-quality polished finishes and is therefore generally microblasted or satin-finished.

2. Grade 5 Titanium (Ti-6Al-4V)

Grade 5 is a titanium alloy containing:

Characteristics:

  • Very high mechanical strength
  • Excellent fatigue resistance
  • High corrosion resistance
  • More difficult machining (risk of ignition)

Applications in watchmaking:

👉 It is the most widely used grade in high-end watchmaking and technical applications.

Unlike Grade 2, Grade 5 allows for high-quality polished finishes.

3. Other Grades

Although rare or virtually unused in watchmaking:

  • Grade 1 → very pure, highly ductile
  • Grades 3–4 → intermediate properties
  • Specific alloys → proprietary developments

Titanium is often treated to enhance its properties:

Titanium is used for:

Advantages

  • Very lightweight
  • Corrosion-resistant
  • Non-magnetic
  • Biocompatible
  • Good mechanical strength (Grade 5)
  • Comfort on the wrist

Limitations

  • Difficult machining
  • Susceptibility to scratching (Grade 2)
  • Low thermal conductivity
  • More complex polished finishing