1. Minimum Service Temperature
Tensile strength ≥ 240 MPa
Yield strength ≥ 170 MPa
Elongation ≥ 24%
even at -253°C, making it suitable for cryogenic equipment such as liquid oxygen/nitrogen storage tanks, rocket propellant systems, and superconducting magnets.
2. Brittleness at Ultra-Low Temperatures
Absence of ductile-brittle transition (DBT) down to its minimum service temperature (-253°C). Its HCP structure remains stable without phase transformations that cause brittleness.
High purity (typically 99.5% titanium content, with low interstitial impurities like oxygen, nitrogen, and carbon ≤ 0.2%, 0.03%, and 0.08% respectively per ASTM B265). Impurity control prevents the formation of brittle intermetallic phases or grain boundary segregation.
Practical validation: Gr.1 is widely used in cryogenic engineering (e.g., LNG transportation, aerospace cryogenic systems) due to its consistent toughness (Charpy impact energy ≥ 34 J at -253°C) and resistance to fracture under low-temperature loading.
3. Maximum Service Temperature
Oxidation resistance degrades: Titanium forms a protective TiO₂ film at temperatures ≤ 315°C, but above this, the film thickens, cracks, and loses protectiveness, leading to rapid oxidation and embrittlement (due to oxygen absorption into the metal matrix).
Mechanical properties decline: Tensile strength and fatigue resistance decrease significantly at temperatures > 315°C, as thermal softening becomes prominent.
Short-term (intermittent) use: Gr.1 can withstand temperatures up to 427°C (800°F) for brief periods (e.g., emergency operations), but prolonged exposure at this temperature will cause permanent material damage.
