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This metal and its alloys perform well in many severely corrosive environments. Besides corrosion resistance, key factors to consider in selection are fabrication methods, welding, and the choice of a fabricator.
Titanium offers excellent mechanical properties and corrosion resistance. These features, coupled with correct methods of fabrication, have led to the growth of this metal and its alloys in the chemical process industries (CPI). Titanium processing equipment often lowers operating costs by minimizing maintenance, limiting downtime, and maximizing life span. Also, the material permits zero corrosion allowance which results in a lower wall thickness.
Product purity, consistent quality, and uninterrupted production cycles are crucial to efficient operations in the CPI. The problems commonly associated with corrosion are product contamination, unscheduled shutdowns, excessive maintenance, and frequent costly component repair or replacement. That's why titanium has become the material of choice for many corrosion-resistant equipment applications.
Some other competitive materials have limitations which restrict their use. Plastic has thermal boundaries and lacks strength in high-pressure applications. Glass-lined steel is subject to thermal shock, which increases heat-up and cool-down cycle time, extending production cycles. Also, with glass-lined steel, maintenance is a concern.
In contrast, equipment fabricated with titanium or titanium alloys offers the following benefits:
Lower operating costs due to low maintenance;
Easier cleanability and improved cycle times;
Elimination of product contamination caused by flaking, scale formation, decomposition, or cross-contamination;
Extended equipment life;
Greater reliability of processes and reduced downtime; and
Increased process efficiency through the use of higher temperatures and pressures, when compared to glass or nonmetallics.
Physical and mechanical properties
Selection of the proper grade of titanium will normally be governed by a combination of mechanical properties (usually strength or formability) and corrosion resistance. Table 1 lists the nominal compositions for the most commonly used grades of titanium in the CPI. Titanium Grade 2, a medium-strength unalloyed titanium, is the most widely used grade. Its strength is similar to that of the common stainless steels and it has good cold formability. It is an easy grade to fabricate and weld, which allows users to replace stainless steel or nickel equipment without extensive redesigning in most applications.
The available grades of titanium comprise an almost continuous spectrum from low-strength, highly ductile commercially pure metal, to high-strength,...