Beta Titanium Alloys
Beta and near-beta titanium alloys carry 10–15 % or more of vanadium, molybdenum, chromium and iron — enough to retain the body-centred-cubic beta phase on cooling — so they can be solution-treated soft, cold-formed or machined, and then aged to 1,100–1,300 MPa yield through sections that Grade 5 cannot harden. Ti-10-2-3 and Ti-5553 are the landing-gear forging alloys, Ti-15-3 and Ti Grade 19 the strip and spring alloys, Ti-15Mo an implant alloy with a modulus about 30 % below Ti-6Al-4V. The trade-offs are 5–8 % more density than Grade 5, a lower stiffness, harder machining and a strict heat-treatment window.
Popular beta titanium grades
Compare in the explorer| Grade | Yield, MPa | Tensile, MPa | Density, g/cm³ | Machinability | Weldability | Best for |
|---|---|---|---|---|---|---|
| Ti-10-2-3 | 930 | 1,000 | 4.65 | Poor | Fair | Landing-gear forgings; 1,100 MPa through thick sections |
| Ti-5553 | 900 | 960 | 4.65 | Poor | Fair | Current landing-gear alloy; deeper hardenability |
| Ti-15-3 | 790 | 820 | 4.76 | Poor | Very good | Cold-formable strip and sheet, aged after forming |
| Ti Grade 19 | 860 | 930 | 4.82 | Poor | Good | Beta-C springs, fasteners and sour-gas hardware |
| Ti Grade 21 | 805 | 830 | 4.94 | Poor | Very good | Oxidation-resistant sheet to 600 °C; nacelles |
| Ti-15Mo | 570 | 760 | 4.96 | Poor | Very good | Low-modulus implant alloy, ASTM F2066 |
| SP-700 | 860 | 930 | 4.54 | Poor | Good | Superplastic forming of complex sheet parts |
Choose beta titanium for
Landing-gear and rotor forgings above 1,100 MPa yield, torsion and compression springs, high-strength fasteners, cold-formed sheet and strip that must be strong after aging, oilfield tubing and risers in sour brine, low-modulus orthopaedic implants, and any titanium part whose section is too thick for Grade 5 to harden through.
Look elsewhere when
Grade 5 annealed or STA already meets the load (it is lighter, stiffer, cheaper and easier to machine and weld), the part runs hot under sustained stress (beta alloys creep and over-age above about 300–400 °C — Ti-6242), the design is stiffness-limited (aged beta alloys run about 105 GPa against 114 for Grade 5, less still before aging), weight is not the driver (300M or 4340 steel at 1,900 MPa yield forges a smaller landing-gear part for far less), or the shop cannot control the aging cycle — an under-aged beta alloy is soft and an over-aged one is brittle.
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Beta titanium by application
- Landing gear and heavy forgings
- Ti-10-2-3 or Ti-5553 forged, solution-treated and aged to 1,100–1,250 MPa yield with 8 % elongation; both harden through sections Grade 5 cannot, and Ti-5553 tolerates a wider solution-treatment window in production.
- Springs and fasteners
- Ti Grade 19 (Beta-C) coiled or headed in the solution-treated condition and aged to about 1,200 MPa; its modulus of roughly 105 GPa and low density give a spring about 40 % lighter than the same steel spring. Ti-15-3 for flat clips and formed spring details.
- Formed sheet and ducting
- Ti-15-3 strip cold-forms, brakes and spins soft, then ages to full strength; Ti Grade 21 where the sheet also sees 500–600 °C or Skydrol exposure; SP-700 for deep superplastic-formed panels.
- Implants and oilfield tubing
- Ti-15Mo and Ti-12Mo-6Zr-2Fe for hip stems and spinal rods that need a modulus closer to bone; Ti Grade 19 and Ti Grade 20 (with palladium) for sour-gas production tubing, risers and drill-pipe hardware.
Working with beta titanium
- Machining
- The slowest titanium to cut: aged beta alloys sit at 38–42 HRC and solution-treated stock is soft but gummy, so run 20–30 % below Grade 5 speeds with sharp carbide, high feed, rigid fixturing and flood coolant. Machine in the solution-treated condition where the aging distortion allows, or rough soft, age, then finish — the age cycle itself causes little dimensional change, which is the beta alloys’ advantage over a water-quenched Grade 5 STA part.
- Heat treatment
- Solution-treat near the beta transus — just below it for Ti-10-2-3 (about 760–790 °C), above it for Ti-15-3 (790–815 °C) — air- or water-cool, then age 8 h at 480–540 °C for peak strength or 540–600 °C for toughness. The window is narrow: a 20 °C error in aging temperature moves yield by 50–100 MPa. Protective atmosphere throughout — beta alloys pick up hydrogen readily, and alpha case must be removed.
- Forming
- Ti-15-3 in the solution-treated condition bends to about 2 t, draws and roll-forms like annealed stainless with low springback, then is aged in a fixture; Ti Grade 19 wire is cold-drawn and coiled into springs before aging. Ti-10-2-3 and Ti-5553 are forged hot at 750–800 °C, just below the beta transus, and are not cold-formed.
- Welding
- Weldable in the solution-treated condition by TIG, laser or electron-beam under full argon, then aged so the weld reaches base-metal strength; Ti-15-3 and Ti Grade 21 weld well, Ti-10-2-3 and Ti-5553 are usually machined from forgings rather than welded. Welding an aged part over-ages the heat-affected zone and must be followed by a full re-treatment.
Other titanium series
Beta Titanium Alloys — frequently asked
What is beta titanium?
Beta and near-beta titanium alloys carry 10–15 % or more of vanadium, molybdenum, chromium and iron — enough to retain the body-centred-cubic beta phase on cooling — so they can be solution-treated soft, cold-formed or machined, and then aged to 1,100–1,300 MPa yield through sections that Grade 5 cannot harden. Ti-10-2-3 and Ti-5553 are the landing-gear forging alloys, Ti-15-3 and Ti Grade 19 the strip and spring alloys, Ti-15Mo an implant alloy with a modulus about 30 % below Ti-6Al-4V. The trade-offs are 5–8 % more density than Grade 5, a lower stiffness, harder machining and a strict heat-treatment window.
Which grade of beta titanium should I use?
Ti-10-2-3 (Ti-10V-2Fe-3Al) for large forgings that must hold 1,100–1,200 MPa yield through 100 mm sections — landing-gear trucks, beams and helicopter rotor hubs — with fatigue and toughness that Grade 5 STA cannot match at that strength. Ti-5553 (Ti-5Al-5V-5Mo-3Cr) is the newer landing-gear alloy with better hardenability and a wider forging window, specified on current airliner gear. Ti-15-3 (Ti-15V-3Cr-3Sn-3Al) when the part is sheet, strip or tube: it cold-forms in the solution-treated condition about like annealed stainless, then ages to 1,000–1,100 MPa — ducts, brackets, clips and formed airframe details. Ti Grade 19 (Beta-C, Ti-3Al-8V-6Cr-4Mo-4Zr) for springs, fasteners and sour-gas oilfield hardware where corrosion resistance rides with 1,200 MPa. Ti Grade 21 (Beta-21S) resists oxidation and hydraulic fluid to 600 °C for nacelle and exhaust sheet. Ti-15Mo (ASTM F2066) and Ti-12Mo-6Zr-2Fe (ASTM F1813) are the low-modulus, vanadium-free implant alloys; SP-700 is the superplastic-forming grade for complex sheet parts at 775 °C.
Which grade of beta titanium is the strongest?
Ti-8Mo-8V-2Fe-3Al has the highest yield strength in the series at 1,240 MPa; Ti-6-22-22 follows at 1,160 MPa. Values are for each grade's default condition.
Which grade of beta titanium is easiest to machine?
Ti-15Mo (machinability poor, 24/100), then Ti Grade 20 (22/100).
Is beta titanium heat-treatable?
Yes. These grades gain their strength from heat treatment; the conditions and their properties are listed on each grade page.
Ti-10-2-3 or Ti-5553?
Both are landing-gear alloys aged to 1,100–1,250 MPa yield. Ti-10-2-3 is the older one with more supplier and property data, but its iron content segregates in large ingots and its solution-treatment window is only about 30 °C. Ti-5553 replaces the iron with molybdenum and chromium, hardens through thicker sections, forges over a wider window and gives more consistent properties in 200 mm billets, which is why newer airliner gear specifies it. For a redesign of an existing Ti-10-2-3 part stay with Ti-10-2-3; for a new heavy forging Ti-5553 is the safer production choice.
Is Ti-15-3 really cold-formable?
Yes — in the solution-treated condition it is about 750–800 MPa yield with 20 % elongation and bends to roughly 2 t, close to annealed 304 stainless, where Grade 5 sheet needs 4.5 t or hot forming. The formed part is then aged 8–16 h at about 510–540 °C to 1,000–1,100 MPa yield with little distortion. That sequence is why it was developed: strip-producible, formed soft, strong in service. The costs are about 7 % higher density than Grade 5, lower stiffness and a longer heat-treatment cycle.