Titanium Tube Gr9 (Ti-3Al-2.5V) Seamless CWST ERTi-9 up to 2.5m length

Grade 9 titanium is the structural fabricator's dream for lightweight, corrosion resistant components of any size. ERTi-9 Titanium has matching properties to ASTM base metal Grade 9 titanium and also known as the half version of Grade 5 titanium. Used for applications where better ductility, formability and weldability are needed but a lower tensile are acceptable. Often used in oil production, aircraft honeycomb foil, piping and pressure vessels frames and hydraulic system tubing, as well as sports equipment, including tennis rackets, bicycles and golf clubs.

Seamless, CWST tubing in stock, or made-to-order.

Pipe stock is 2.5 meters (98.4 inches) long. Additional shipping charges may apply for oversize/over dimension lengths.

All tubes are Cold-Worked Stress-Relieved condition – typical for high-performance bicycle frames, aerospace hydraulics, and structural applications.

Material Properties – CWSR Condition:

Property	Value (Metric)	Value (US)	Notes
Ultimate Tensile Strength (UTS)	900 – 965 MPa	130 – 140 ksi	Min 860 MPa / 125 ksi
0.2% Yield Strength	760 – 860 MPa	110 – 125 ksi	Min 725 MPa / 105 ksi
Elongation (in 50 mm / 2 in)	10 – 15 %	10 – 15 %
Modulus of Elasticity	110 GPa	16.0 × 10⁶ psi
Shear Modulus	~42 GPa	~6.1 × 10⁶ psi
Poisson’s Ratio	0.32	0.32
Density	4.48 g/cm³	0.162 lb/in³

Tube Dimensions and Calculated Section Properties (CWSR):

Size (US)	Size (Metric)	OD	ID	Wall (t)	Metal Area	Weight	Moment of Inertia I	Section Modulus Z	Polar Moment J (≈2I)
0.5" × 0.035"	12.7 mm × 0.89 mm	12.70 mm	10.92 mm	0.89 mm	34.4 mm²	0.238 kg/m	1.54 × 10⁶ mm⁴	0.121 × 10⁶ mm³	3.08 × 10⁶ mm⁴
		0.500 in	0.430 in	0.035 in	0.0533 in²	0.160 lb/ft	0.00370 in⁴	0.00740 in³	0.00740 in⁴
0.75" × 0.052"	19.05 mm × 1.32 mm	19.05 mm	16.41 mm	1.32 mm	76.8 mm²	0.531 kg/m	5.16 × 10⁶ mm⁴	0.406 × 10⁶ mm³	10.3 × 10⁶ mm⁴
		0.750 in	0.646 in	0.052 in	0.119 in²	0.357 lb/ft	0.0124 in⁴	0.0248 in³	0.0248 in⁴
1.0" × 0.065"	25.4 mm × 1.65 mm	25.40 mm	22.10 mm	1.65 mm	127 mm²	0.879 kg/m	11.9 × 10⁶ mm⁴	0.939 × 10⁶ mm³	23.8 × 10⁶ mm⁴
		1.000 in	0.870 in	0.065 in	0.197 in²	0.591 lb/ft	0.0286 in⁴	0.0573 in³	0.0572 in⁴
1.5" × 0.087"	38.1 mm × 2.21 mm	38.10 mm	33.68 mm	2.21 mm	257 mm²	1.78 kg/m	53.7 × 10⁶ mm⁴	2.82 × 10⁶ mm³	107 × 10⁶ mm⁴
		1.500 in	1.326 in	0.087 in	0.398 in²	1.194 lb/ft	0.129 in⁴	0.172 in³	0.258 in⁴

Recommended Mandrel Bend Radii (Centerline Radius – CLR) for CWSR Grade 9 Titanium

(Cold bending with proper mandrel and wiper die; boost recommended on larger sizes)

Tube OD	Tightest Practical CLR (experienced shop, low ovality <5%)	Recommended Production CLR (safe, <3% ovality, <1% thinning)	Absolute Minimum CLR (risk of wrinkling/cracking)
12.7 mm (0.5")	25 mm (1.0") → ~2.0 × OD	38 mm (1.5")	19 mm (not advised in CWSR)
19.05 mm (0.75")	44 mm (1.75") → ~2.3 × OD	57 – 64 mm (2.25 – 2.5")	38 mm
25.4 mm (1.0")	63 mm (2.5") → ~2.5 × OD	76 – 89 mm (3.0 – 3.5")	51 mm
38.1 mm (1.5")	114 mm (4.5") → ~3.0 × OD	152 mm (6.0")	95 mm

Rule of thumb for CWSR Grade 9:

Minimum CLR ≈ 2.5 – 3.0 × OD for reliable production bends
3–4 × OD is very safe and common in high-end bicycle frames
Tighter than 2× OD in CWSR usually requires hot bending or annealed material

Maximum Allowable Bending Stress (approximate, no safety factor)

Using typical CWSR yield 800 MPa / 116 ksi: M_max = Z × σ_y → allowable bending moment before yielding

Tube Size	Allowable Moment (yield)
0.5" × 0.035"	~97 N·m (860 lb·in)
0.75" × 0.052"	~325 N·m (2,880 lb·in)
1.0" × 0.065"	~751 N·m (6,650 lb·in)
1.5" × 0.087"	~2,260 N·m (20,000 lb·in)

This data package is what most high-end frame builders and aerospace shops use when working with these exact Grade 9 CWSR tube sets.

Key Differences Between Annealed and CWSR Ti-3Al-2.5V (Grade 9) Tubing:

Property / Characteristic	Annealed (fully recrystallized)	CWSR (Cold-Worked Stress-Relieved)	Practical Impact for Frame Building / Fabrication
Ultimate Tensile Strength (UTS)	620–800 MPa (90–116 ksi)	860–965 MPa (125–140 ksi)	CWSR is ~30–40 % stronger
0.2 % Yield Strength	480–650 MPa (70–94 ksi)	725–860 MPa (105–125 ksi)	CWSR has ~50–70 % higher yield → stiffer, dent-resistant frames
Elongation (ductility)	15–20 %	10–15 %	Annealed is noticeably more forgiving when bending
Minimum bend radius (typical safe)	1.5–2.0 × OD (very tight bends possible)	2.5–3.5 × OD (3–4 × OD recommended for production)	Annealed allows much tighter bends without cracking or excessive ovality
Spring-back during bending	Moderate	High (10–20 % more than annealed)	CWSR requires more over-bend compensation on the bender
Ovality & wall thinning tolerance	Can tolerate 8–10 % ovality and more thinning	Must keep <3–5 % ovality and <8 % thinning or risk cracking	CWSR needs better tooling (mandrel, wiper, boost)
Fatigue strength	Good (~350–450 MPa)	Excellent (~450–550 MPa)	CWSR is preferred for high-stress bicycle and aerospace applications
Weldability	Excellent	Very good, but slightly narrower parameter window	Both weld well; CWSR just needs a touch more care
Post-bend heat treatment possible?	Usually not needed	Can be locally annealed after very tight bends if required	Rarely done, but possible on CWSR to recover ductility in bent areas
Typical applications	Custom one-off frames, very complex geometries	Vast majority of high-end production Ti frames (Seven, Moots, Litespeed, Firefly, etc.)	CWSR is the “standard” for modern Ti frames because the strength advantage outweighs the slightly harder bending
Cost	Usually same tube price, but more labor to bend	Same tube price	Fabricating CWSR takes longer → higher shop labor cost

Quick Decision Guide for a Fabricator:

Want →	Choose
Absolute tightest bends, complex shapes, one-off art bikes	Annealed
Maximum strength & stiffness, best fatigue life, production-friendly geometries	CWSR (this is what 95 % of high-end Ti frames use today)
Somewhere in between	Some builders buy CWSR and locally anneal only the tight bends (advanced technique)

CWSR is the go-to for almost all modern titanium bicycle frames because the strength and fatigue benefits far outweigh the slightly larger bend radii required. Annealed is reserved for builders who need to hit extremely tight radii that CWSR simply won’t allow without cracking.