Pure titanium undergoes an allotropic transformation from the hexagonal close-packed alpha phase to the body-centered cubic beta phase at a temperature of 882.5°C (1620.5°F).

Commercially pure, or CP, titanium is unalloyed. At service temperatures it consists of 100% hcp alpha phase. As a single-phase material, its properties are controlled by chemistry (iron and interstitial impurity elements) and grain size. CP Titanium is classified into Grades 1 through 4 depending on strength and allowable levels of the elements iron, carbon, nitrogen, and oxygen. CP Ti Grade 4 is the strongest of these grades, with a minimum yield strength of 480 MPa (70 ksi), and has the highest allowable oxygen and iron content of the grades.

Grade 4 combines the excellent resistance to corrosion and corrosion fatigue of titanium with high strength that makes it a candidate to compete with steels and nickel alloys for many chemical and marine applications.

Applications:
CP Titanium Grade 4 could be considered in any application where strength and corrosion resistance are important. Grade 4 also has good ductility, is moderately formable, and has superior corrosion fatigue resistance in seawater. Applicable service temperatures for CP Ti Grade 4 are up to 204°C (400°F).

Some applications have included airframe and aircraft engine components, marine and chemical processing machinery, heat exchangers, reaction vessels for chemical processing and desalinization plants, corrosive waste disposal wells, and pulp and paper production.