Commercially pure, or CP titanium is unalloyed titanium with a purity range of 99.0% to 99.4%. The term commercially pure (CP) titanium is applied to unalloyed titanium and designates several grades containing minor amounts of impurity elements, such as carbon, iron, and oxygen. CP Ti Gr. 1 has the highest corrosion resistance, formability, and lowest strength, whereas CP Ti Gr. 4 offers the highest strength with moderate formability. The most used grade is CP Ti Grade 2. The chemical compositions and physical properties of the four grades of CP titanium are listed below.