Performance Titanium Ti: 4.507 g / cm3, Tm: 1688 ℃. Having allotrope change, ≤882.5 ℃ hcp structure of α phase, ≥882.5 ℃ body-centered cubic structure of β phase. Low strength of pure titanium, but high strength, good plasticity, low titanium tube stock temperature toughness, high corrosion resistance. Titanium has good pressure processing performance, cutting poor. Titanium heating in nitrogen combustion can occur, and therefore should be heated and welded titanium using argon. Titanium is titanium tubing classified according to the impurities, titanium into highly pure titanium (purity 99.9%) and commercially pure titanium (purity 99.5%). There are three grades of commercially pure titanium, respectively TA + sequence number 1,2,3 digital representation, the larger the number, the lower the purity.