Titanium 6Al-2Sn-4Zr-2Mo grade (also known as Ti 6-2-4-2) is a near alpha alloy known for its exceptional creep resistance, strength, and sturdiness, and is often used in a duplex annealed state. Due to its heat resistant nature and durability, 6-2-4-2 titanium materials are most commonly used in the engineering of aircraft and turbine engines (discs, blades, and impellers), airframe components, and high performance automotive valves. Ti 6-2-4-2 comes in a variety of standard specifications including AMS 4919, AMS 4975 and more.
At Rickard Specialty Metals, we have 30 years of supplying 6-2-4-2 titanium forgings, plate, sheet and more to your custom measurements. Our forging process includes open die forgings, ring rolling and more. See below for a list of common forged shapes we supply, including round bar, flat bar, and more.
NOMINAL COMPOSITION
- Al 5.5 – 6.5
- Sn 1.8 – 2.2
- Zr 3.6 – 4.4
- Mo 1.8 – 2.2
- Fe .25 max
- O .12 max
- Si .06 – .1
- C .05 max
- N .05 max
- H .015 max
- Y .005 max
- Remainder Each .1 max
- Remainder Total .3 max
STANDARD SPECIFICATIONS
- UNS R54620
- AMS 4919
- AMS 4975
- AMS 4976
- AMS 4979
- AMS T 9047
- MIL-T 9046
- MIL-T 9047
- MIL-F-81556
- MIL-F-82142
- Werkstoff 3.7145
- EN 3.71450
- DIN: 3.7164
- GE C50TF7
- GE B50TF21
- GE B50TF22
- PWA 1220
TI 6-2-4-2 FORGINGS
- Ti 6-2-4-2 Round Bar
- Ti 6-2-4-2 Flat Bar
- Ti 6-2-4-2 Rectangular Bar
- Ti 6-2-4-2 Rolled Rings
- Ti 6-2-4-2 Forged Rings
- Ti 6-2-4-2 Disc
OTHER PRODUCT FORMS
- Ti 6-2-4-2 Sheet
- Ti 6-2-4-2 Plate
- Ti 6-2-4-2 Extrusion
- Ti 6-2-4-2 Extrusion angles
- Ti 6-2-4-2 Billet
- Ti 6-2-4-2 Ingot
- Ti 6-2-4-2 Machined Parts
Ti-6Al-2Sn-4Zr-2Mo Additional Information:
Physical Properties
Hardness: HRC 39 max, typical HRC 34-36.
Density: 0.164 lbs/cubic inch
Modulus of Elasticity: 16 msi
Coefficient of Expansion: 5.2 microinch/inch/degree F from RT to 600F
Welding
Weldability for Ti 6Al-2Sn-4Zr-2Mo is moderate. It is recommended to use post weld thermal processing. Processing technique should be chosen carefully to minimize residual stresses, but not reduce properties significantly. It is recommended to use a weld filler for fusion welding. Additionally, complete inert gas shielding is required.
Forming
Formability is difficult for 6-2-4-2 titanium. For severe forming conditions it is recommended to perform forming at elevated temperatures.
Corrosion Resistance
Corrosion resistance for Ti-6Al-2Sn-4Zr-2Mo is generally excellent, although, the alloy is sometimes susceptible to hot salt stress corrosion cracking. With proper processing this risk can be minimized.
Heat Treatment
6-2-4-2 titanium heat treatment will differ depending on the alloy form:
- Bar and forgings are typically alpha beta solution annealed at 25F-50F below the beta transus (~1770F – 1790F) for 1 hour. Then air cool with precipitation heat treat at 1100 F for 8 hours. Then repeat air cool.
- Sheet and strip is typically duplex annealed at 1650F for 30 minutes. Then air cool and reheat to 1450F and hold for 15 minutes. Then repeat air cool.
- Plate is typically duplex annealed at 1650F for 60 minutes. Then air cool and reheat to 1100F and hold for 8 hours. Then repeat air cool.
Forging
Typically forging for ti 6-2-4-2 is done in the alpha-beta region (1650F-1800F) to impart a mixed mode microstructure (primary alpha and transformed beta phases). Finished forgings should have all alpha cases (hard, brittle, oxygen enriched layer) removed prior to usage. Forgings will be heat treated via one of the methods mentioned in the heat treatment section prior to usage.
Mechanical Properties (Based on AMS 4975)
MINIMUM TENSILE PROPERTIES
Tensile Strength: 130 ksi (896 MPa)
Yield Strength at 0.2% Offset: 120 ksi (827 MPa)
Elongation in 4D: 10%
Reduction of Area: 25%