Titanium Grade 23

Ti-6-4, ASTM Grade 23 titanium, UNS R56401 (ELI), Ti-6Al-4V ELI, Ti64

Titanium alloys are divided into three main groups: alpha-phase, beta-phase, and alpha-beta-phase. Grade 23 Ti 6Al 4V ELI alloy is an alpha-beta wrought alloy. The ELI stands for extra-low interstitial. For an alloy to be branded as an ELI product, it should be produced as such at the mill. Excellent, especially when direct contact with tissue or bone is required. Ti-6Al-4V's poor shear strength makes it undesirable for bone screws or plates. It also has poor surface wear properties and tends to seize when in sliding contact with itself and other metals. Surface treatments such as nitriding and oxidizing can improve surface wear properties.

The following sections will discuss in detail about grade 23 Ti-6Al-4V ELI alloy.

Chemical Composition

The chemical composition of grade 23 Ti-6Al-4V ELI alloy is outlined in the following table.

Physical Properties

The physical properties of grade 23 Ti-6Al-4V ELI alloy are tabulated below.

Mechanical Properties

The following table shows the mechanical properties of grade 23 Ti-6Al-4V ELI alloy.

Thermal Properties

The thermal properties of grade 23 Ti-6Al-4V ELI alloy are tabulated below.

Other Designations

Equivalent materials to grade 23 Ti-6Al-4V ELI alloy are as follows:

AMS 4907, AMS 4931, ASTM F136, ASTM F467 (TI-5), ASTM F468 (5), ASTM F468 (S), MIL F-83142

MIL T-9046, MIL T-9047, SPS M618, AMS 4930, AMS 4956

Machinability

Grade 23 Ti-6Al-4V ELI alloy can be machined using slow speeds, the right quantity of coolant flow and high feed rates. High-speed tools should be used for tooling this alloy and the recommended tool types are tungsten carbide designations C1-C4 or cobalt-based.

Forming

Grade 23 Ti-6Al-4V ELI alloy can be hot or cold formed. Forming techniques include hydro press, stretch or drop-hammer.

Welding

Weldability of Grade 23 Ti-6Al-4V ELI alloy is rated as fair.

Heat Treatment

The material can be solution treated at 904-954 °C (1660-1750°F) for 2 h, and then water quenched.

Annealing

For annealing Grade 23 Ti-6Al-4V ELI alloy, the material has to be held at 732°C (1350°F) for about 1/4 and 4h. It should then be furnace cooled to 566°C (1050°F) then air-cooled.

Forging

Rough forging can be performed at 982°C (1800°F), and completed at 968°C (1750°F).

Hot Working

Hot-working enhances the overall ductility of the material.

Cold Working

Cold working features of this material is the same as that of austenitic stainless steel. Post-work annealing is recommended to re-attain favorable performance properties.

Aging

Aging of Grade 23 Ti-6Al-4V ELI alloy can be performed at 538°C (1000°F) for 4 h and air-cooled.

Applications

Grade 23 Ti-6Al-4V ELI alloy is used in the following areas:

• Surgical implants

• Aircraft components

• Structural components

• In a variety of saltwater applications

• In high-pressure cryogenic vessels down to -320°C

• In applications requiring excellent fracture toughness and fatigue strength.

Forms:

Sheet, Strip, Foil, and Tubing

Standards:

ASTM B265 Gr.23 - Sheet, plate

ASTM B338 Gr.23 - Heat exchange tube

ASTM B861 Gr.23 - Titanium and Titanium Alloy Seamless Pipe

ASTM B862 Gr.23 - Titanium and Titanium Alloy Welded Pipe

ASTM B348 Gr.23 - Bar

ASTM B381 Gr.F23 - Forgings