Titanium bar stock is specified by grade family, governing ASTM/AMS/EN standard, and cross-section geometry; ASTM B348 covers wrought titanium bar and billet for general use, while ASTM B265 governs the flat-rolled sister form used when converting bar to plate [S2][S3].
Distributors such as Supra Alloys and ISO 9001:2015-certified service centers stock CP Grades 1-4/7/11, Ti-6Al-4V (Grade 5), Ti-6Al-4V ELI (Grade 23), and Grade 12 in rod, bar, hex, square and flat geometries, with the titanium alloy family dominating aerospace and chemical-processing demand [S3][S8].
Grade Family and UNS Number Mapping
Supra Alloys lists Commercially Pure Titanium in Grades 1, 2, 3, 4, 7, and 11 [S3]. Ti-6Al-4V (Grade 5, UNS R56400) is the dominant aerospace alloy, and Grade 23 (UNS R56401) is the ELI extra-low-interstitial version for fracture-critical medical and aerospace structures [S3]. Grade 12 (UNS R53400) carries 0.3 % Mo and 0.8 % Ni for improved crevice-corrosion resistance versus CP titanium in hot chloride media [S3].
Avoid pairing Grade 2 with hot HCl or hot concentrated chloride brines — specify Grade 7 or Grade 12 instead; equally, do not substitute Grade 5 for CP titanium in cathodic-protection anodes or electrolyzer cell components, where the alloying elements shift the electrochemical potential [S3].
Governing Standards and What They Lock Down
ASTM B348 is the default specification for wrought titanium and titanium-alloy bars and billets, covering chemical composition, tensile / yield / elongation minimums, and dimensional tolerances across the CP and alloy families [S2]. BS EN 2858-3 (Titanium and titanium alloys — Forging stock and forgings — Technical specifications — Pre-production and production) governs European aerospace forging stock when the bar is intended to be re-forged into rotating components, and is paired with a separate EN 2000-series material standard for the specific grade [S5].
AMS 4928 (Ti-6Al-4V bar, annealed) and AMS 4911 (sheet/plate) are the customary aerospace material specs in North America; EN 3.7164 / EN 3.7165 cover the same Ti-6Al-4V composition under the European designation system.
Form Geometry and Tolerance Stack-Up
Round bar is the default machining feedstock; hex bar (typically AF 8-65 mm) is specified for headed-bolt preforms; square and flat bar are common for orthopaedic implant blanks and chemical-process frames. ISO 9001:2015-certified mills such as those listed by North Steel and ABLTi Corporation supply CP and alloy titanium in all four geometries, plus custom comps, with diameter tolerances usually held to ASTM B348 h7-h9 depending on the cut [S8][S9].
For bar feeding into a multi-spindle Swiss screw machine, h6-h7 round bar with < 0.05 mm/mm straightness is typical; for hydraulic / valve stem service on a pressure transmitter or industrial valve body, specify turned-and-polished finish (Ra ≤ 0.8 µm) and ultrasonic-tested (UT) per ASTM E213 to reject inclusions [S3][S8].
Selection Criteria Compared Side by Side
Four grade options cover the majority of industrial demand: CP Grade 2 (formable, weldable, cost baseline), CP Grade 4 (higher strength CP for fasteners), Grade 5 / Ti-6Al-4V (workhorse alloy, 895 MPa min UTS), and Grade 7 / Ti-0.15Pd (reducing-acid corrosion). The pressure sensor diaphragm and instrument-body use case is served by CP Grade 2 or 4; rotating aerospace components by Grade 5 or 23; hot chloride / HCl / H2SO4 service by Grade 7, 11 or 12 [S3][S8].
Lead time from Chinese mill hubs in Baoji, Shaanxi (XI GONG Ti, Baoji Xilitong, Baoji Huaxi Metal, Rongyuan Ti) is typically 4-6 weeks for standard round bar; aerospace-grade lots with full heat-by-heat traceability run 8-12 weeks [S4][S6][S7][S10].
Who Should NOT Pick the Default Grade 2
CP Grade 2 is the wrong choice when the service exceeds 315 °C continuous (creep becomes a concern above this threshold for CP grades), when the chemistry is reducing acid or hot chloride, or when strength-to-weight drives the design. Substitute Grade 5 / Ti-6Al-4V for any rotating or fatigue-loaded part above 200 MPa allowable stress, and Grade 23 / Ti-6Al-4V ELI for medical implants and fracture-critical aerospace fittings where interstitial Fe/O/N must be controlled to < 0.13 % O [S3].
CP Grade 2 is also the wrong choice for sour-service NACE MR0175 environments — when H2S partial pressure exceeds 0.0003 MPa (0.05 psi) in oilfield downhole or refinery service, an alloyed grade is mandatory, not optional. The same principle applies to the stem and seat ring of an industrial valve in hot chloride brine, where Grade 12 or Grade 7 is the engineering baseline [S3].
Mill Cert, Traceability, and What to Demand
Every quoted lot should carry an EN 10204 3.1 (or 3.2 for aerospace) mill test certificate stating heat number, chemical analysis, mechanical properties, and standard-conformance statement. AWS A5.16 welding-rod traceability matters when the bar will be welded into a pipe spool or pressure-vessel nozzle; pairing bar and weld-wire to the same heat is cheap insurance against galvanic drift between flow-meter body and pipe [S3][S7].
Service centers such as Supra Alloys and North Steel publish full stock lists with grade, form, and condition, while Chinese manufacturers (Baoji cluster) typically respond to detailed RFQ with heat-lot-level chemical analysis and dimensional inspection reports [S3][S4][S6][S7][S8][S10]. Specifying the governing standard, the UNS number, and the condition (mill-annealed vs solution-treated-and-aged) up front cuts both the RFQ cycle and the post-shipment rejection risk.
Practical Buyer Shortlist Logic
Step 1 — write the service environment: max temperature, media chemistry, applied stress, fatigue cycle count. Step 2 — pick grade family: CP for formability and corrosion; Ti-6Al-4V for strength; Pd-bearing Grade 7/11 for reducing acid; Grade 12 for hot chloride [S3]. Step 3 — pin the standard (ASTM B348 for general industrial, AMS 4928 for aerospace, BS EN 2858-3 for European forging stock) and UNS number (R50400 Gr2, R56400 Gr5, R52400 Gr7, R53400 Gr12) [S2][S3][S5]. Step 4 — request EN 10204 3.1 MTR, condition (annealed / STA), dimensional tolerance class, and UT report before placing the order [S3][S8].
Trackable signals over the next 60-90 days: ASTM B348 revision activity through Subcommittee B10.01, Pd spot price movement (direct impact on Grade 7 / 11 quotes), and Baoji-mill capacity announcements from the titanium alloy cluster that will move standard mill-product lead times by ±2 weeks [S4][S6][S10].
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