Ti6Al4V [Grade 5 Titanium]

Ti-6Al-4V (Grade 5), classed as an alpha-beta alloy, is the most widely used of the high strength titanium alloys. The alloy combines its good mechanical strength and low density (4.42 kg/dm³) with excellent corrosion resistance in many media.

Overview

Grade 5 titanium is fully heat treatable (solution heat treatment plus aging) in sections up to 25mm and can be employed up to around 400°C. Ti-6Al-4V ELI (Grade 23) has a reduced oxygen content (0.13% max.) compared with Grade 5. This confers improved ductility and fracture toughness with some reduction in mechanical strength. Uses include fracture critical airframe structures and for offshore tubulars.

Corrosion Resistance

Grade 5 titanium offers excellent resistance to many marine and offshore oil & gas environments. Titanium and its alloys resist a wide range of acid conditions being highly resistant to oxidising acids, possessing useful resistance to reducing acids and offering good resistance to most organic acids at lower concentrations and temperatures. Titanium should not be used with red fuming nitric acid and is rapidly attacked by hydrofluoric acid.

The addition of 0.05% palladium (grade 24), 0.1% ruthenium (grade 29) or 0.05% palladium and 0.5% nickel (grade 25) significantly increases corrosion resistance in reducing acid chloride and sour environments, raising the threshold temperature to well over 200°C.

Typical Applications

Commercial applications for this engineering material include: