Titanium Gr4

Titanium Grade 4 is the strongest of the commercially pure titanium alloys, while maintaining excellent corrosion resistance, weldability and biocompatibility. It is a popular choice in applications where high strength is required together with low weight and exceptional corrosion resistance, such as medical technology, offshore and pressurized systems.

Recommended filler material for welding: Titanium Grade 4 or equivalent titanium alloy with inert gas protection.

General material description:
Type: Commercially pure titanium (minimum 98% Ti), highest content of interstitial elements (e.g. oxygen)
Structure: HCP structure (hexagonal close-packed)
Developed for: Applications requiring higher strength but still low weight and extremely good corrosion resistance
Alternative names: Titanium Grade 4, CP Titanium Grade 4, UNS R50700, Werkstoffnr 3.7065, ASTM B265

Key benefits:
Highest strength among commercially pure titanium grades
Excellent corrosion resistance in aggressive fluids and seawater
Good weldability and biocompatibility – often used in implants
Low weight (~4.51 g/cm³) – perfect for light but strong components
Good resistance to stress corrosion cracking and hydrogen induced cracking

Disadvantages / Limitations:
Less formable than Grade 1–3 – requires more force when cold working
Not heat-hardenable – mechanical properties are determined by chemical composition
Not optimal for high temperature applications (>450°C)

Applications by industry and value:
Medical technology: Dental implants, hip prostheses, surgical instruments – strength + biocompatibility
Offshore / Marine: Heat exchangers, valves, fasteners – strength + seawater protection
Chemical industry: Pressure vessels, tanks, flanges – acid resistance + mechanical load-bearing capacity
Aviation: Structural parts, pressurized components – lightness + strength
Energy / Nuclear power: Equipment in aggressive environments – stability

General corrosion description:
Stable passive oxide film provides very high resistance to general corrosion
Resists seawater, chlorides and oxidizing acids very well
Resistant to hydrogen-induced cracking (HE)

Corrosion environments where the material works well:
Seawater (static and flowing)
Acids: nitric acid, phosphoric acid, organic acids
Chloride-rich environments (NaCl, CaCl₂)
Oxidizing chemicals and bleaching liquids

Corrosion environments where the material should be avoided:
Hydrofluoric acid (HF) – attacks the oxide film
Reducing acids (hydrochloric acid, sulfuric acid at high temp)
Stagnant acidic solutions at high temperatures

Technical material properties (annealed condition):
Property (Typical value)
Yield strength (0.2%): ~480–550 MPa
Tensile strength: ~550–680 MPa
Elongation at break: ~15–20%
Density: ~4.51 g/cm³
Elastic modulus: ~105 GPa
Thermal conductivity: ~16–18 W/m·K
Application temperature: Rec. ≤ 400°C (temporarily up to 500°C)
Weldability: Very good – inert gas required when welding
Machinability: Moderate – more force than for Grade 2 required