Titanium grades

CP Titanium Grade 11 — Ti-0.12-0.25% Pd. Same mechanical properties as Grade 1 (lowest strength CP) but with dramatically improved crevice corrosion resistance in reducing acid environments due to Pd addition. Used for chemical process equipment, heat exchangers, and vessels handling HCl, H2SO4, and other reducing acids where unalloyed CP-Ti would corrode.

Titanium alloy with 0.3% Mo + 0.8% Ni — improved crevice and reducing-acid corrosion resistance over CP grades. Strength similar to Grade 2 but much better in chemical environments containing hot brines and reducing acids. More cost-effective than Grade 7 (Pd). Used for heat exchangers, pressure vessels, and chemical processing equipment in corrosive service.

Ti-6Al-4V ELI (Extra Low Interstitials) — the medical-grade version of the most common titanium alloy. Lower O, N, C, Fe limits than Grade 5 for improved fracture toughness, ductility, and biocompatibility. ASTM F136 specifies it for surgical implants. Slightly lower strength than Grade 5 but better fatigue crack growth resistance. Used for orthopedic implants (hip/knee), spinal fixation, dental implants, and cryogenic aerospace applications.

Commercially pure titanium Grade 3 — highest oxygen (0.35% max) of the CP grades = highest strength (UTS 450-550 MPa). Between Grade 2 (general purpose) and Grade 4 (maximum CP strength). Used for chemical process equipment, marine hardware, and structural components where higher strength than Grade 2 is needed but alloy cost (Ti-6Al-4V) is not justified.

Palladium-enhanced commercially pure titanium — the most corrosion-resistant Ti grade. Same mechanical properties as Grade 2, but with 0.12-0.25% Pd for dramatically improved resistance to reducing acids (HCl, H2SO4) and crevice corrosion. Premium price justified only where extreme chemical resistance is needed. Used for chemical processing equipment, desalination plants, and chlor-alkali cells.

Medium-strength alpha-beta titanium alloy — the standard for seamless tubing. 50% stronger than CP Grade 2 with better cold formability than Ti-6Al-4V. The go-to alloy for hydraulic tubing in aerospace and bicycle frames. Used for aircraft hydraulic lines, offshore risers, and sporting goods.

Near-alpha high-temperature titanium alloy. Better creep resistance than Ti-6Al-4V at temperatures above 400°C — usable to 550°C continuous. Sn and Zr are alpha-stabilizers providing solid-solution strengthening without eutectoid decomposition. THE jet engine compressor disc alloy (stages 2-7 typically). Also used for afterburner structures, blisks, and gas turbine components. Si addition (0.06-0.10%) further improves creep.

Beta-rich alpha-beta titanium alloy — higher Mo (6%) than Ti-6242 for significantly higher strength (UTS 1100+ STA). Forged beta then STA (Solution Treat + Age) for peak properties. Used for high-compressor discs and blades in jet engines where strength at 300-450°C is critical. More Beta phase than 6242 = higher strength but lower creep resistance. AMS 4981.

The most widely used titanium alloy — accounts for ~50% of all titanium production. Alpha-beta alloy with exceptional strength-to-weight ratio. Used for jet engine components, airframe structures, medical implants (hip/knee), fasteners, and racing components. Biocompatible.

Extra Low Interstitial version of Ti-6Al-4V — the standard titanium for surgical implants. Reduced O, N, C, Fe for improved ductility, fracture toughness, and biocompatibility. Used for hip and knee implants, bone screws, dental implants, spinal fusion devices, and cardiovascular stents. Also called Grade 23.

Alpha-beta titanium alloy with Nb replacing V — developed specifically to eliminate vanadium cytotoxicity concerns. Similar mechanical properties to Ti-6Al-4V but with superior biocompatibility and corrosion resistance in body fluids. ISO 5832-11 / ASTM F1295 for surgical implants. Trade name: IMI 367 (originally). Used for hip prostheses, knee replacements, fracture fixation plates, spinal devices, screws, and dental implants.

The softest and most ductile commercially pure titanium grade. Lowest O content (0.18% max) for maximum formability. Used for plate heat exchangers, chemical plant vessels, explosive cladding, deep-drawn parts, and anodizing applications. Lower strength than Grade 2 but superior formability.

The workhorse commercially pure titanium grade. Best balance of strength, ductility, and corrosion resistance among CP grades. Excellent resistance to seawater, chlorides, and oxidizing acids. Used for heat exchangers, chemical processing, marine hardware, desalination, and medical implants.

The strongest commercially pure titanium grade. Highest oxygen content (0.40% max) for maximum strength among CP grades. UTS min 550 MPa — approaches some Ti alloys. Used for airframe skins, marine hardware, surgical implants, and chemical plant components requiring higher strength than Grade 2.