ASTM B348 Titanium Bar: Round, Square, Hex & Billet Specification Guide

Published by Engineering Team, Shaanxi Qianyi Tuoda Technology Co., Ltd on 2026-10-21

ASTM B348 Titanium Bar, Round Bar, Square Bar, Hex Bar & Billet: Machining & Forging Guide

Table of Contents

• 1. What Is ASTM B348?
• 2. Round, Square, Hex, Flat & Billet
• 3. Common B348 Grades for Bar & Billet
• 4. Hot-Rolled, Forged, Turned, Ground: Pick the Right Condition
• 5. Diameter Tolerances & Straightness
• 6. UT, ET, Tensile & Mill Certificates
• 7. How to Write an ASTM B348 RFQ
• 8. Bar Procurement Mistakes That Ruin CNC Jobs
• 9. Our Bar → CNC → Finished Part Service
• 10. FAQs
• 11. Related Standards

1. What Is ASTM B348?

ASTM B348 is the standard specification for titanium and titanium alloy bars and billets. It covers annealed commercial pure titanium and titanium alloy long products used for machining, fasteners, shafts, valve parts, and forge stock.

The ASME version is SB-348. For pressure-vessel and ASME-code projects, drawings often call out SB-348; for general engineering and export orders, ASTM B348 is enough. Most mills hold dual certification on the same heat.[1,2](@ref)

B348 is not “one product”. It covers round bar, square bar, hex bar, flat bar, and billet — the starting material for everything from a medical screw to a 200 kg flange forging.

2. Round, Square, Hex, Flat & Billet

3. Common B348 Grades for Bar & Billet

Medical parts usually need ASTM F67 / F136, not just B348. Aerospace bar may also be called out to AMS 4928 / AMS 4921. Always confirm on the PO.[3,8,9](@ref)

4. Hot-Rolled, Forged, Turned, Ground: Pick the Right Condition

• As-rolled / black: oxide scale, loose tolerance, cheapest; rough machining stock.
• Forged: refined grain flow; used for billets, flanges, rings.
• Pickled: scale removed, matte silver; general industrial use.
• Rough turned: skin removed, safer for CNC starting stock.
• Centerless ground: tight diameter, h9 / h7 / h6; Swiss-turn and medical use.
• Polished: Ra ≤0.8 µm or Ra ≤0.4 µm for medical / food / pharma.

Buying black hot-rolled bar for precision CNC is the fastest way to waste 30% of every bar in setup cuts.

5. Diameter Tolerances & Straightness

ISO 286 h-class shaft tolerances are common in export orders: h9 general, h7 stock, h6 on request.[3,6](@ref)

6. UT, ET, Tensile & Mill Certificates

• Chemical analysis: per heat, Fe/O/N/C/H + alloying elements
• Tensile: UTS, 0.2% YS, elongation
• UT: ASTM E2375 / ASTM A388-style for billets and large dia bar
• ET: surface crack detection for ground bar
• Alpha-case check: metallographic review for aggressive chloride service
• Certificate: EN 10204 3.1 standard, 3.2 with TPI

SB-348 code work may require Charpy impact for low-temperature service and stricter receiving inspection — B348 alone does not add those by default.[2](@ref)

7. How to Write an ASTM B348 RFQ

Weak: "Titanium bar Gr5 20 mm"

Strong: ASTM B348 Gr.5 Ti-6Al-4V round bar, φ20.0 h9, annealed, centerless ground Ra 1.6, 3000 mm stock length, UT per order, EN 10204 3.1, heat no. on tag

Must specify:

1. Standard: ASTM B348 or ASME SB-348
2. Grade: Gr.2 / Gr.5 / Gr.23 / Gr.7 / Gr.12
3. Shape: round / square / hex / flat / billet
4. Size & tolerance: φ20 h9, 25×25 h11, hex 17 mm A/F
5. Condition: annealed / forged / turned / ground / polished
6. Length: random, fixed, or cut blanks
7. NDE: UT / ET / none
8. Certificate: 3.1 / 3.2

8. Bar Procurement Mistakes That Ruin CNC Jobs

9. Our Bar → CNC → Finished Part Service

• ASTM B348 / SB-348 Gr.2, Gr.5, Gr.23, Gr.7, Gr.9, Gr.12
• Round φ3–300 mm, square, hex, flat, billet up to 350 mm
• Hot-rolled, forged, pickled, rough-turned, centerless ground, polished
• CNC turning, milling, drilling, threading, 5-axis machining
• Billet → forged flange blank → machined flange in one chain
• UT / ET, alpha-case review, full MTR bundle
• Laser marking: grade + size + heat no. + PO no.
• Export pack: VCI paper, end caps, sealed PE, ISPM-15 crate

We don’t just sell titanium bar — we sell machine-ready, traceable titanium stock and finished parts.

10. FAQs

Q: Is ASTM B348 the same as ASTM F67?

No. B348 is industrial bar; F67 is surgically implanted unalloyed titanium. Medical projects usually need F67/F136 even if the alloy looks the same.

Q: Can I use Gr.5 bar for implants?

Only if specified to ASTM F136 / ISO 5832-3. Industrial Gr.5 (B348) is not automatically implant-qualified.

Q: What tolerance do I need for Swiss-type automatic lathes?

Usually h9 as minimum, h7/h6 for tight shaft fits. Centerless-ground bar with Ra ≤1.6 µm is common.

Q: Do billets come with the same certificate as bar?

Yes — same heat, same EN 10204 3.1. Billets often get UT because of their cross-section.

Q: Should I buy bar or forged blank for flanges?

Small low-pressure flanges: machined from bar. Large WN flanges / high-pressure: forged billet per ASTM B381 gives better grain flow.

11. Related Standards

• ASTM B265 Titanium Plate, Sheet & Strip — plate stock and tube sheets
• ASTM B338 Titanium Heat Exchanger Tubes — tube-side equipment
• ASTM B861 Titanium Seamless Pipe — process piping
• ASTM B862 Titanium Welded Pipe — large-diameter piping
• Titanium Standards Hub — all ASTM/ASME titanium articles
• ASTM B863 Titanium Wire — ERTi filler and precision wire, coming soon
• ASTM B381 Titanium Forgings — flange/ring forgings from billet, coming soon
• ASTM B363 Titanium Fittings — elbows/tees/reducers, coming soon
• ASME B16.5 Titanium Flanges — flange dimensions, coming soon

Request ASTM B348 Titanium Bar Quote

Send us:

• Grade & standard (B348 / SB-348 / F136)
• Shape & size (round/square/hex/flat/billet)
• Tolerance (h9 / h7 / h6 / ASTM B348 default)
• Condition (annealed / ground / polished)
• Length & quantity
• NDE & certificate (3.1 / 3.2)

We reply within 4 business hours with stock status, machining allowance, and lead time.