Overview
Titanium is a lightweight, high-strength metal known for its exceptional resistance to
corrosion, heat, and fatigue. It has a silver-gray color and is as strong as steel but
only about 60% of the weight. Titanium's unique properties make it ideal for various
applications across multiple industries, including aerospace, automotive, medical, and
marine.
Grades and Specifications
Titanium is available in several grades, each with specific compositions and properties.
The most commonly used grades include:
- Grade 1: Commercially pure titanium with excellent corrosion
resistance and formability.
- Grade 2: The most widely used titanium grade, offering a good
balance of strength, ductility, and corrosion resistance.
- Grade 5 (Ti-6Al-4V): An alloy containing 90% titanium, 6% aluminum,
and 4% vanadium, known for its high strength and heat resistance.
- Grade 9 (Ti-3Al-2.5V): A titanium-aluminum-vanadium alloy with good
weldability and moderate strength.
Specifications:
- ASTM: B348, B265, B381
- ASME: SB348, SB265, SB381
Chemical Composition
Titanium's chemical composition varies depending on the grade. Here is a general
breakdown of the composition for Grade 5 (Ti-6Al-4V):
| Element |
Composition (%) |
| Titanium (Ti) |
90.0 min |
| Aluminum (Al) |
5.5 – 6.75 |
| Vanadium (V) |
3.5 – 4.5 |
| Iron (Fe) |
0.40 max |
| Oxygen (O) |
0.20 max |
| Carbon (C) |
0.10 max |
| Nitrogen (N) |
0.05 max |
Mechanical Properties
Titanium exhibits remarkable mechanical properties, which can vary depending on the grade
and processing. Typical mechanical properties for Grade 5 titanium are:
- Tensile Strength: 880 MPa (minimum)
- Yield Strength: 790 MPa (minimum)
- Elongation: 10% (minimum)
- Hardness: 300 HB (Brinell hardness)
Applications
Titanium is used in a wide range of industries due to its unique properties:
- Aerospace: Components such as aircraft frames, landing gear, and
engine parts due to its strength-to-weight ratio and resistance to extreme
temperatures.
- Medical: Surgical implants, dental implants, and prosthetics due to
its biocompatibility and corrosion resistance.
- Marine: Shipbuilding, offshore structures, and components exposed
to seawater because of its excellent resistance to saltwater corrosion.
- Automotive: High-performance engines, exhaust systems, and
suspension components for lightweight and strength advantages.
- Chemical Processing: Heat exchangers, reactors, and piping systems
in corrosive environments.
Corrosion Resistance
Titanium is highly resistant to corrosion in many aggressive environments, including
acids, chlorides, and seawater. This resistance is primarily due to the formation of a
passive oxide layer that protects the metal from further degradation. It is particularly
effective in:
- Seawater applications: Ideal for marine environments and offshore
equipment.
- Chemical processing: Resistant to corrosion in a variety of
chemical environments.
Heat Treatment and Workability
Titanium can be challenging to work with due to its low thermal conductivity and high
strength. However, it can be processed through methods such as:
- Forging: Used to create complex shapes and enhance mechanical
properties.
- Welding: Typically requires careful control of heat to prevent
contamination.
- Machining: Often requires specialized tools due to its hardness and
tendency to gall.