ASTM B338 Titanium alloy grade 12 Tubes for Condensers and Heat Exchangers

Gr12 Titanium Bar

Titanium Plate Gr12

Gr12 Titanium Piping

Titanium Foil Roll Gr12

Gr12 Titanium Coiled Wire

Titanium alloy grade 12 is a high corrosion resistant alloy containing small additions of nickel and molybdenum, which enhance corrosion resistance and increase the strength of the alloy to give better mechanical properties than the commercially pure grades. It is used in mildly reducing or fluctuating conditions. In particular, it is used instead of the commercial purity grades (e.g.grade 2) for better resistance to crevice corrosion in hot brines, and where the extra strength allows the use of lighter sections.

At room temperature, it is an alpha alloy and may contain minor amounts of beta phase. It transforms to beta phase at 890°C ± 15°C

Titanium is reactive, and has a very high affinity for oxygen, which forms a skin of very stable and highly adherent oxide. The skin gives excellent corrosion resistance, despite the reactivity of the metal. The oxide layer forms spontaneously and on exposure to the atmosphere. However, when new parent metal is exposed to anhydrous conditions or in the absence of air, rapid corrosion may occur. Care should also be taken if titanium is to operate in contact with hydrogen, as hydrogen embrittlement from hydride formation can increase strength, with loss of ductility.

GNEE can supply titanium alloy 12 as plate, sheet and strip, rod and bar, seamless and welded pipe, weld fittings, seamless and welded tube, forging billet and forgings.

Titanium alloys are widely used due to their excellent corrosion resistance, particularly in chloride solutions. The addition of small amounts of nickel and molybdenum to grade 12 titanium gives it superior corrosion resistance compared to commercially pure grade 2 titanium alloys, while also significantly increasing its strength. While this grade's overall corrosion resistance is inferior to palladium-alloyed grade 7 low-alloy titanium, it exhibits resistance to crevice corrosion in hot chloride solutions. Titanium alloys also offer excellent resistance to general corrosion, with corrosion loss rates typically below 0.04 mm/year.

Titanium alloy grade 12 is forged conventionally, within the narrow temperature range 815 – 900°C. Titanium and titanium alloys are generally more difficult to forge than both aluminium and alloy steels, due to their high strain rate sensitivity and rapid increase of strength with falling temperature. Hot forging leaves a thick, hard outer layer of titanium oxide on the surface. This layer is called "Alpha Case" and is usually removed by pickling in a mixture of nitric and hydrofluoric acids. As supplied, titanium alloys are usually annealed and pickled, and can be readily cold formed in conventional machines using standard methods. In cold forming the "alpha case" does not form and further pickling is not needed, except to remove any carbon steel embedded in the surface, which can cause pitting corrosion.

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