COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF TITANIUM GRADE 4 FASTENERS

Titanium Grade 4 (UNS R50700) is the absolute strongest classification of Commercially Pure (CP) Titanium. It serves as the ultimate bridge between the severe formability of the lower CP grades and the immense strength of alloyed titanium (like Grade 5). This exceptional strength is achieved by intentionally maximizing the allowable interstitial Oxygen and Iron content, which stiffens the alpha-phase crystal structure to yield mechanical properties that rival mild steel.

Because it contains no Aluminum or Vanadium, Grade 4 retains the phenomenal, uncompromised corrosion resistance of pure titanium. It is totally immune to chloride stress-corrosion cracking, pitting in marine environments, and degradation in oxidizing acids. UNS R50700 fasteners are the mandatory choice for applications demanding the absolute highest structural yield possible without sacrificing the biocompatibility or chemical inertness of unalloyed titanium, making them essential in aerospace airframes, severe chemical processing, and critical load-bearing medical implants.

In high-stress aerospace and biomedical applications, the precise management of Oxygen and Iron dictates the metal's performance limit. Exceeding the maximum allowed limits causes catastrophic embrittlement. Ananka ensures every Grade 4 fastener lot is backed by rigorous, aerospace-grade Vacuum Arc Remelting (VAR) certification.

• EN 10204 Type 3.1: Validates the critical 0.40% maximum Oxygen limit (driving the high strength), ensures Hydrogen remains strictly limited to prevent embrittlement, and confirms the annealed mechanical yield limits.
• EN 10204 Type 3.2: Available upon request for commercial aviation structures, naval submarine components, and critical surgical implant manufacturing requiring third-party testing oversight.

Grade 4 represents the physical limit of strengthening unalloyed titanium via interstitial elements. It allows the highest concentration of Oxygen (up to 0.40%) and Iron (up to 0.50%) of any CP grade. This deliberate inclusion creates a highly rigid, strong alpha-phase matrix without resorting to heavy alloying elements like Aluminum or Vanadium.

• Aerospace Structures: High-strength mounting brackets, engine firewall fasteners, and hydraulic system bolting where the strength-to-weight ratio of steel is unacceptable but Grade 5's lower ductility is a concern.
• Biomedical Engineering: Load-bearing spinal fixation screws, heavy orthopedic bone plates, and dental implants requiring maximum structural integrity and 100% biocompatibility.
• Aggressive Chemical Processing: Heavy flange bolts and pressure-vessel studs for reactors handling hot nitric acid, wet chlorine, and organic chlorides at elevated temperatures.

Due to its high structural rigidity, Grade 4 Titanium can withstand aggressive torque loads comparable to many carbon steels. However, because it remains an unalloyed titanium, the risk of severe thread galling (cold-welding) is extremely high under heavy friction. Generous application of premium dialectric anti-seize pastes or specialized Teflon dry-films is absolutely mandatory before applying torque.