Titanium And Titanium Base Alloys
Titanium Alloys are generally divided into three groups (Alpha, Alpha-Beta and Beta). The Alpha group contain most importantly aluminum and tin. They can also contain molybdenum, zirconium, nitrogen, vanadium, columbium, tantalum, and silicon. Alpha alloys are not suitable for heat treatment. Alpha alloys are used for aircraft parts and cryogenic equipment.
The Alpha-Beta group can be strengthened by heat treatment. The alloys are used in aircraft and aircraft turbine parts, chemical processing equipment, marine hardware.
The Beta Alloys have good hardenability. Beta alloys are slightly more dense than other titanium alloys, having densities ranging from 4800 to 5050 kg/m3. They are the least creep resistant alloys, they are weldable, and can have yield strength up to 1345 x 106 Pa.(Solution annealing and age hardened) Beta alloys are the smallest group. They are used for heavier duty purposes on aircraft.
Titanium is a light metal having a density of about 4540 kg/m3. This compares to steel at 7900 kg/m3 and Aluminium at 2710kg/m3. Titanium has a melting point of about 1668oC which is higher than iron at1560oC. Titanium has a Modulus of Elasticity of 110 x 109 Pa. compared to steel at 210 x 109 Pa. Therefore Titanium has a significantly high deflection under the same load than steel. Pure Titanium can be cold rolled to 90% reduction in thickness at room temperatures without cracking.
There are a number of grades of commercially pure (unalloyed) titanium as identified in ASTM B265 (Gr,1,2,3,4,7,11,and 12) (see table below for Gr 1 to 4)). Each grade has a different amount of impurity content (Grade 1 have lowest impurities). Grade 1 to 4 are classified as pure even though grade 4 is much stronger and less ductile than grade 1. Grade 4 contains higher levels of oxygen which is classified ( for pure titanium ) as an alloying element. Oxygen and Nitrogen and Carbon are all interstitial alloys (they insert themselves in the crystal intertices of the crystals and prevent relative sliding). They therefore increase the hardness and reduce the ductility. Oxygen is the main element controlling the strength of unalloyed titanium.
| Designation |
Applications |
Specifications |
| UNS R50250 3.7025 |
Industrial, aerospace components; heat exchangers, wire, CPI equipment, medical and dental devices, tubing, pickling baskets. |
MIL-T-81556. ASTM B 265, B861, 337, 338, 348; ASTM F 67 |
| UNS R50400 / 3.7035 |
Industrial, aerospace components; heat exchangers, wire, CPI equipment, medical and dental devices, tubing, pickling baskets. |
AMS 4902, 4921, 4942; MIL-T-9046, -81556. ASTM F 67; B 337, 338, 348, ISO 5832-2. |
| UNS R50550 |
Airframe, heat exchangers, cryogenic vessels, industrial components, CPI equipment, tubing, exhaust pipe shrouds. |
AMS 4900; MIL-T-9046, -81556. ASTM F 67; ASTM B 265, 337, 338, 348. |
| UNS R50700 |
Industrial, aerospace components; heat exchangers, cryogenic vessels, wire, CPI equipment, medical and dental devices, tubing. |
AMS 4901, 4921; MIL-T-9046, -9047. ASTM F 67; ASTM B 265, ASTM B861, 337, 338, 348, 381 |
| UNS R52400 / 3.7235 |
Industrial components, CPI equipment, heat exchangers, pressure vessels, fittings, tubing. |
ASTM B 265, B 337, B 338, B 348,B 381. ASTM F 467, F 468. |
| UNS R53400 |
Industrial components, CPI equipment, heat exchangers, pressure vessels, fittings, tubing. |
ASTM B 265, B 337, B 338, B 348,B 381. |
| UNS R54620 & R54621 |
High-temp jet engines. Blades, discs, spacers, seals. High performance automotive valves. Rotor and premium grades. |
AMS 4919, 4975, 4976. MIL-T-9046, -9047, -81556. |
| UNS R54620 modified |
High-temp jet engines. Blades, discs, spacers, seals. High performance automotive valves. Rotor and premium grades. |
MIL-T-9047 modified. |
| UNS R54810 |
Fan & compressor blades, discs, spacers, seals, rings. Excellent creep resistance. Rotor and premium grades. |
AMS 4915, 4933, 4972. MIL-T-81556, -83142. |
| UNS R56260 |
Intermediate-temperature jet engine applications. Blades, discs, spacers, seals. Rotor and premium grades. |
AMS 4981. MIL-T-9047, -83142. |
| UNS R56320 |
Excellent cold formability, 20-50% higher tensile properties than CP grades. Extruded hydraulic tubing, intermedullary nails. |
AMS 4943, 4944; MIL-T-9046, -9047. ASTM B 265, 337, 338, 348, 381. |
| UNS R56320 |
Excellent hot and cold formability with high strength. Aerospace structural components, fasteners. |
AMS 6946; ASTM B 265, 338, 348, 381, 861. |
| UNS R56400 |
Blades, wheels, discs, rings, fasteners, cases, hubs, vessels, forgings, wire, CPI equipment, medical and dental devices |
AMS 4906, 4920, 4928, 4965, 4967; MIL-T-9047, -81556; ASTM B 348, B 381, F 1472. |
| UNS R56401 |
Applications requiring excellent fracture toughness and fatigue strength; aircraft, structural components, biomedical, automotive. |
AMS 4907, 4930, 4931. MIL-T-9046, -9047, -81556; ASTM F 136. |
| UNS R56700 |
Biomedical implants. Femoral hip stems, fracture fixation plates, spinal components, fasteners, nails, rods, screws, wire. |
ASTM F 1295, ISO 5832-11. |
| UNS R56620 |
Airframes, jet engines, rocket engine cases, nuclear reactor components, ordnance components. |
AMS 4918, 4936, 4971, 4978, 4979. MIL-T-9047, -81556. |
| UNS R58150 |
Biomedical implant components and fasteners. Hip stems, fracture fixation devices, spinal rods and clips, rods, screws, wires, cables. |
ASTM F2066 |
| UNS R58120 |
Patented beta titanium alloy. Contact Stryker Orthopaedics for more information. Medical and surgical devices. |
ASTM F 1813, HMS 5163. |
| UNS R58153 |
Metastable beta titanium alloy. Industrial and aerospace components, pressure vessels, fittings, tubing, fasteners. |
AMS 4914. |
| UNS R58350 |
Patented beta titanium alloy. Contact Stryker Orthopaedics for more information. Medical and surgical devices. |
(See US Patent 8,323,453) |
| UNS R58640 |
High-strength, metastable beta alloy. Spring wire, fasteners, torsion bar for aerospace and automotive applications. |
AMS 4957, 4958. MIL-T-9046, 9047. MIL-F-83142. |
| UNS R58650 |
Compressor disks, heavy section forgings for gas turbine engine components. Hightensile strength and good fracture toughness. |
AMS 4995. |
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