Titanium Grade 1 (UNS R50250) represents the highest purity, softest, and most ductile classification of Commercially Pure (CP) Titanium. Because it contains the absolute lowest levels of interstitial elements—specifically Oxygen and Iron—it provides the ultimate combination of severe deep-drawing formability and extraordinary chemical resistance. While it does not boast the extreme tensile strength of alloyed titanium (like Grade 5 / Ti-6Al-4V), Grade 1 serves a highly specific and critical engineering purpose.
Weighing nearly 45% less than steel while maintaining complete immunity to chloride-induced stress corrosion cracking and localized pitting, Grade 1 Titanium is practically indestructible in flowing seawater, hypochlorite solutions, and wet chlorine gas. This makes UNS R50250 fasteners the apex metallurgical choice for highly corrosive chlor-alkali chemical processing, critical desalination heat exchangers, marine architecture, and biomedical implants requiring flawless biocompatibility.
| Material Classification | Commercially Pure (CP) Titanium - Highest Ductility |
|---|---|
| UNS Designation | R50250 |
| Microstructure | Single-Phase Alpha Matrix |
| Magnetic State | Completely Non-Magnetic |
| Density | 4.51 g/cm³ (0.163 lb/in³) — Exceptionally Lightweight |
| Size Range | Metric: M2 to M36 | Imperial: #2 to 1-1/2" |
| Primary Attribute | Maximum Cold Formability & Ultimate Chloride Immunity |
Contains detailed isocorrosion charts for wet chlorine gas exposures, strict PTFE/Fluoropolymer anti-galling lubrication guidelines, and custom cold-heading upset ratios for solid rivets.
⬇ DOWNLOAD DATASHEETIn high-purity titanium, the microscopic absorption of interstitial gases (Oxygen, Nitrogen, Hydrogen) during the melting process will violently embrittle the metal. Ananka provides absolute transparency, ensuring all Grade 1 fasteners are traced back to strictly controlled Vacuum Arc Remelting (VAR) processes.
The defining characteristic of Grade 1 Titanium is its stringent limitation on Oxygen and Iron. While higher grades intentionally allow more Oxygen to increase structural strength, Grade 1 restricts it heavily to maximize the metal's ductility. This ensures the material can be heavily deformed (cold-headed or drawn) without micro-fracturing.
| Titanium (Ti) | Oxygen (O) | Iron (Fe) | Carbon (C) | Nitrogen (N) | Hydrogen (H) |
|---|---|---|---|---|---|
| Balance (~99.5) | 0.18 Max | 0.20 Max | 0.08 Max | 0.03 Max | 0.015 Max |
| Mechanical Property | Typical Limits (Annealed Temper) |
|---|---|
| Tensile Strength | 35,000 psi (240 MPa) Minimum |
| Yield Strength (0.2% Offset) | 25,000 - 45,000 psi (170 - 310 MPa) |
| Elongation (in 2 inches) | 24% Minimum |
| Hardness (Brinell) | ~ 120 HB (approx. 70 HRB) |
| Standard / System | Designation |
|---|---|
| ASTM Specifications | ASTM B348 (Rod/Bar), ASTM F467 / F468 (Fasteners) |
| Common Trade Names | CP Titanium Grade 1, Unalloyed Titanium |
| Medical Specifications | ASTM F67 (Unalloyed Titanium for Surgical Implant) |
| European Equivalent | Titanium 3.7025 (Ti1) |
| Mating Bolts/Screws/Rivets | Internal Threads (Nuts) | Washers / Gaskets |
|---|---|---|
| Grade 1 CP Titanium Bolts & Solid Rivets | Grade 1 CP Titanium Hex Nuts | Grade 1 Flat Washers or PTFE |
CRITICAL WARNING: Titanium alloys possess an inherent, severe tendency to gall (cold-weld) when threaded under friction. If a raw titanium nut is threaded onto a raw titanium bolt without lubrication, they will seize and fuse together almost instantly. Premium dialectric anti-seize pastes (such as Moly or specialized fluoropolymers) are absolutely mandatory prior to installation. Grade 1 is also a soft metal; over-torquing must be avoided.
| Nominal Diameter | Threads Per Inch (UNC) | Max Target Torque (in-lbs) — Lubricated | Max Target Torque (ft-lbs) — Lubricated |
|---|---|---|---|
| 1/4" | 20 | 45 - 55 | ~ 4.0 |
| 5/16" | 18 | 90 - 110 | ~ 8.0 |
| 3/8" | 16 | 160 - 180 | ~ 14.0 |
| 1/2" | 13 | 350 - 390 | ~ 31.0 |
While both are Commercially Pure (CP) titanium, the primary difference is the Oxygen content. Grade 2 allows slightly more oxygen (up to 0.25%), which acts as a mild hardener, making Grade 2 stronger but less ductile. Grade 1 restricts oxygen to 0.18% maximum, making it the softest and most highly formable titanium grade. If you need to heavily cold-head a rivet or severely bend a fastener without cracking, Grade 1 is the superior choice.
It is exceptionally resistant to wet chlorine gas and chloride solutions (like seawater or bleach). The moisture in "wet" chlorine continuously repairs titanium's protective oxide layer. However, in strictly dry chlorine gas, the protective film cannot regenerate, and the titanium will rapidly corrode and can even violently ignite. Proper moisture content in the chemical stream is critical.
Titanium Grade 1 is highly biocompatible and virtually non-toxic. When implanted, the human body's tissues and bone actually osseointegrate (bond directly) with the titanium's natural surface oxide layer. Because it is totally inert to bodily fluids and completely non-magnetic (safe for MRI machines), it is the global standard for surgical repair hardware.
