Titanium & Titanium Alloys

Titanium alloys were developed in the early 1950s for defense and aeronautical applications because of their high strength-to-weight ratio. Through innovation in very diverse markets, production of titanium significantly increased making the material much more readily available. This increase in production has lowered costs allowing even more industries to utilize its unique combination of strength, weight, and corrosion resistance. 

Commercially Pure (CP) Titanium, Ti 6Al-4V and Ti 6Al-4V ELI, Ti-Pd, and Titanium Grade 12 are the most common titanium alloys used in industry. There are additional grades with more limited availability for more specialized circumstances.

Titanium alloys bridge the gap between the properties of steel and aluminum and are used in such varied applications as satellites, plating racks, cryogenic storage vessels, saline water conversion units, wet chlorine gas piping, seawater pumps, pulp and paper production, airplanes, yachts, jewelry, eyeglass frames, golf clubs, high current superconductors, off-shore drilling equipment, dental implants, and hip and knee replacements.

  • Ti - Pd

    Ti-Pd (Grade 7) is mechanically and physically equivalent to CP-Ti (Grade 2), except with the addition of the interstitial element palladium. Ti-Pd (Grade 7) possesses excellent weldability and fabricality, and is the most corrosion resistant of all titanium alloys. In fact, it is most resistant to corrosion in reducing acids. Ti-Pd applications include chemical processing, pulp and paper, petrochemical, pollution control, metal finishing and the marine industries.

  • CP Titanium Grades 1 - 4

    Commercially Pure (CP) Titanium is used primarily for its corrosion resistance. It resists pitting, crevice and cavitation corrosion, erosion and stress corrosion cracking in salt water, marine atmospheres and a broad range of acids, alkalis and industrial chemicals. The corrosion resistance results from a very thin (~10nm), stable, continuous oxide layer that regenerates instantaneously if any oxygen or moisture is present. Titanium is mostly corrosive resistant when placed in oxidizing or mildly reducing media.

  • Ti 6Al-4V and Ti 6Al-4V ELI

    Ti 6Al-4V and Ti 6Al-4V ELI are the most widely used titanium alloys and account for more than half of all the titanium sponge used worldwide. Aerospace applications account for 80% of that usage. The remainder is found in defense, marine, medical, chemical, and other industries.

    Neither grade of Ti 6Al-4V has corrosion properties quite as good as CP titanium, but both are corrosion resistant in seawater, oxidizing acids, aqueous chlorides, wet chlorine gas and sodium hypochlorite.

    Altering the interstitial levels tends to enhance certain properties; Ti 6Al-4V ELI (Extra Low Interstitials) is a popular alloy where medium strength and good toughness are required. The strength and ductility are similar, but the fracture toughness of the ELI grade is about 25% higher than the standard grade. The ELI grade is usually specified for seawater applications (MIL-T-9047) and for medical use (ASTM F136). A medical grade of Ti 6Al-4V (ASTM F1472) also exists.

  • Titanium Grade 12

    Grade 12 titanium is also very near pure with some molybdenum and nickel added. This alloy offers slightly improved strength and optimum ASME Code design. Ti Grade 12 is readily weldable and has superior crevice corrosion resistance.

Specifications

Mechanical Properties

Alloy Specifications UTS (psi) YS (psi) EI (%) RA (%)
     min.  min.  min.  min.
 CP-1  ASTM B265 / B348 Grade 1  35,000  25,000  24   30
 CP-2  ASTM B265 / B348 Grade 2  50,000  40,000  20  30
 CP-3  ASTM B265 / B348 Grade 3  65,000  55,000  18  30
 CP-4  ASTM B265 / B348 Grade 4  80,000  70,000  15  25
 Ti 6AI-4V  ASTM B265 / B348 Grade 5  130,000  120,000  10  25
 Ti 6AI-4v ELI  ASTM B265 / B348 Grade 23  120,000  110,000  10  25
 Ti-Pd  ASTM B265 / B348 Grade 7  50,000  40,000  20  30
 TiCode 12  ASTM B265 / B348 Grade 12  70,000  50,000  18  25

Other Properties

Coefficient of Thermal Expansion (in/in/°C) 8.64 x 10-6
Thermal Conductivity (BTU/hr/ft2/°F/ft) 9.0
Electrical Resistivity (micro-ohm-cm) 47.8
Magnetic Susceptibility 1.25 x 10-6
Young's Modulus ( lbf / in2 ) 16.8
Poisson's Ratio 0.41
Density ( lb/in3 ) 0.163