Editorial Feature

Titanium - Architectural Suitability

Titanium is absolutely immune to environmental attack, regardless of pollutants. Where other architectural metals exhibit limited lifespan, titanium endures. It withstands urban pollution, marine environments, the sulphur compounds of industrial areas and is failure-proof in even more aggressive environments. Because it is the most noble metal, the coupling of titanium with dissimilar metals does not accelerate galvanic corrosion of the titanium.

These properties make titanium perfect for use in architectural applications.

Physical Attributes

Immunity to Environmental Attack

Architectural titanium's unsurpassed corrosion resistance results from its stable, highly-adherent, protective surface oxide film. Because the metal is highly reactive and has a strong affinity for oxygen, the beneficial oxide film forms spontaneously when exposed to moisture or air. In fact, a damaged oxide film can generally restore itself instantaneously.

Lowest Thermal Expansion

Titanium's coefficient of thermal expansion is half that of stainless steel and copper and one-third that of aluminium. It is virtually equal to that of glass and concrete, making titanium highly compatible with these materials. Consequently, thermal stress on titanium is very low.

Light Weight

The specific gravity of titanium is 4.51 g/cm3 - about 60% that of steel, half that of copper and 1.7 times that of aluminium. Being such a lightweight metal, titanium imposes less burden on structure. It is easily fabricated and permits ease of installation.

Environmentally Safe

Due this its relative inertness in most atmospheres, titanium is considered environmentally friendly. It is 100% recyclable and the product of a renewable resource.

Greatest Strength

In addition to having excellent mechanical strength (comparable to mild steel), titanium is durable and shock resistant. Its modulus of elasticity (a measure of strain rate) is half that of stainless steel. This means titanium is more flexible than other architectural metals during earthquakes and other periods of violent movement.

Best Energy Efficiency

For a metal, titanium is an excellent insulator. Its thermal conductivity of 10 Btu/hr.-ºF/ft. is very low (one-tenth that of aluminium) increasing a building's energy efficiency.

Products and Processes

Forms, Sizes and Grades to Meet Your Specifications

Architectural titanium can be supplied as coil, sheet, composite panel and tube. Sheet is the most commonly used form, with typical thicknesses from .4mm to 1mm, available in widths up to 48". Commercially pure Grade 1 (ASTM B265) is most commonly specified for architectural applications.

Fabrication

Conventional installation and fabrication procedures, similar to those used for other architectural metals, apply to architectural titanium. Its workability is comparable to stainless steel.

Standard metal forming tools, processing and techniques are used to shear, form, machine and join titanium. Regular TIG welding procedures can be employed and titanium's self-restoring oxide film prevents welds from deteriorating. In addition, titanium's appearance can be customized through a variety of secondary metal processing techniques, including etching, embossing, spinning, abrasive blasting, plating and perforating.

A Cost Effective Building Material

Titanium has come of age as a competitive building material. New, more effective production techniques, combined with an abundance of raw and refined ore, have improved availability. Titanium's corrosion immunity, strength and physical properties combine to allow reduced wall thickness, lowering its installed unit cost. Well-researched designs that capitalize on its unique attributes and long-term savings from durability and low maintenance make titanium one of today's most cost effective building materials on a lifecycle basis.

Aesthetic Qualities

As a building material titanium is available in its natural finish or it can be anodised to a spectacular range of colours. And due to its outstanding corrosion resistance, titanium requires no corrosion preventive coating.

Natural Surface Finish

The basic appearance of natural titanium is pleasing due to its soft reflectivity and subtle silver-grey colour. The process of annealing and pickling the titanium induces the reflective metallic surface finish.

A Spectrum of Striking, Saturated Colours

Colour specifications can be met by anodising the metal and by modifying the natural surface finish prior to anodising to vary the hue of a colour.

Architectural titanium can be processed to achieve a variety of surface textures, from a soft matte to a near gleaming reflectivity. The colour and finish are inherent to the film and the metal as a result of the anodising process. When titanium's natural clear oxide film is increased through anodic oxidation, colour is created by the phenomenon of light interference - the rainbow principle.

As light rays travel through the film, they are partially reflected, refracted and absorbed. The reflected rays differ in phase, creating interference that gives the titanium colour. As the film thickness increases, the colour changes - from bronze, to green, to red-violet, through the full range of spectral colours.

Source: Timet

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