Titanium Stud Bolt for Chemical Flange \| Gr2/R50400 & Gr7/R52400, ASTM F468, B16.5 Length, Double Heavy Hex Nut, EN 10204 3.1, Baoji

Обзор продукции

Проверено и поддерживается инженерной командой Shaanxi Qianyi Tuoda Technology Co., Ltd.

Titanium Stud Bolt for Chemical Flange | Gr2/Gr7, ASTM F468, B16.5 Length, Double Heavy Hex Nut, MTC 3.1

Meta Description: Titanium stud bolts for chemical flanges — Gr2 (R50400) chloride/oxidizing duty, Gr7 (R52400/Ti-Pd) reducing-acid crevice, Gr5 high-preload. ASTM F468/F468M, full/half thread, ASME B16.5 stud length per joint stack, matched heavy hex nuts, rolled thread, 100% PMI + GO/NO-GO gauged, EN 10204 3.1.

Stud Bolt vs Hex Bolt — Why Flange Joints Use Studs

• Stud: threaded both ends + plain shank center → 2 heavy hex nuts, even clamp, reusable
• Hex bolt: head one end, thread one end → less uniform preload on wide flange faces
• B16.5 pressure flanges default to stud + 2 heavy hex nuts; machine bolt secondary
• Plain shank = accurate grip length, lower stress concentration at thread root

Grade Selection by Medium (the real spec driver)

Rule: medium + temperature decide grade, not "stronger = better". Gr7 Pd content must be verified by chemistry, not sticker.

Standards Chain (no mixing)

• Finished stud: ASTM F468 / F468M (bolts, screws, studs)
• Bar feed: ASTM B348 Gr2/Gr5/Gr7
• Forging blank (large dia): ASTM B381 — only when PO invokes forging route
• Dimension/thread: ASME B18.31.2 (stud), ASME B1.1 (UNC/UNF 2A), ISO 261/965 (metric 6g)
• Nut: ASTM F467 heavy hex, same grade as stud
• Flange class reference: ASME B16.5 (NPS ½-24, Class 150-2500)

Stud Length — How We Size It

B16.5 tabulated length already includes two heavy hex nuts. For non-standard gasket/insulation/RTJ, use the joint stack:

L = 2×flange thickness + gasket compressed thickness
  + 2×washer + 2×heavy-hex-nut height + protrusion allowance
Protrusion: min 2 thread pitches beyond nut face after tightening.
RTJ facing lengths differ from RF — confirm facing before cut.

We do NOT guess length from "M20×80" alone — flange thickness + gasket + nut height must be on the RFQ.

Full Thread vs Half Thread

• Half-thread (preferred for flange): plain shank = grip length, threads only at ends → better fatigue, accurate clamp
• Full-thread: for tap-end, double-end, threaded-rod-style joints or custom engagement
• Rolled thread default (grain flow at root → fatigue + anti-gall); cut thread on non-standard pitch

QC Before Pack (flange-grade release)

1. 100% PMI/XRF — Gr2 vs Gr5 vs Gr7 look identical, grade-mix = joint failure
2. Heat No. bar → stud laser mark → bag tag (parent = finished)
3. GO/NO-GO ring + plug gauge (pitch dia + major/minor)
4. Shank straightness, chamfer, burr-free, pickled/clean, ferroxyl iron-check on request
5. Tensile/Yield from bar heat; Gr2 ≥345/275 MPa, Gr7 ≥345/275 MPa, Gr5 ≥895/828 MPa
6. EN 10204 3.1 QA-signed; 3.2 (SGS/BV/TÜV/DNV) PO-fronted

Anti-Galling + Joint Notes (shipped in pack)

• Clean threads + MoS₂ / PTFE / dry-film anti-seize — never assemble dry
• Matched nut grade (Gr2 stud+Gr2 nut, Gr7+Gr7, Gr5+Gr5); Gr5 stud+Gr2 nut = strip/gall risk at high preload
• Galvanic: Ti is noble in chloride — isolate from CS/Al flange with PTFE sleeve or dielectric washer
• Torque from validated preload (Ti E≈103-112 GPa, half of steel) — not steel torque table
• Re-check torque 24h after PTFE lube (stress relaxation)
• Reuse of titanium studs under high preload — engineer's call, not default

Typical Chemical Flange Applications

• Reactor manhole / nozzle WN flange
• Heat-exchanger bonnet flange, tube-sheet clamp
• Desalination skid RF/RTJ joints
• Chlor-alkali, wet Cl₂, hypochlorite lines
• Reducing-acid headers (Gr7) with PTFE gasket + insulated kit

RFQ Template (copy-paste)

Flange standard: ASME B16.5 / EN1092 / drawing ___
NPS × Class: ___ (RF / RTJ / FF)
Stud: half-thread / full-thread / double-end / tap-end ___
Dia: M___ (or __" UNC/UNF)
Overall length: ___mm  Thread length each end: ___mm
Grade: Gr2(R50400) / Gr7(R52400) / Gr5(R56400) / Gr12 ___
Thread: metric 6g / UNC 2A / UNF ___
Nut: heavy hex F467 same grade, qty 2/stud ___
Washer: flat+spring / PTFE sleeve / none ___
Surface: pickled / passivated / dry-film lube ___
Medium + temp: ___ (drives grade)
Qty: ___ sets (stud+nuts)
Cert: 3.1 / 3.2 (TPI ___)
Incoterm: EXW Baoji / FOB Shanghai / DAP ___

FAQ — Titanium Stud Bolt for Chemical Flange

Q1: Stud or hex bolt for B16.5 flange?
A: Stud + 2 heavy hex nuts is the B16.5 default for pressure flanges — even clamp, reusable, better thermal-cycle preload retention.

Q2: How to get stud length right?
A: Send flange thickness + gasket compressed thickness + nut height + facing (RF/RTJ). We calc from joint stack; "M20×80" alone is not enough.

Q3: Gr2 or Gr7 for chemical flange?
A: Gr2 for oxidizing chloride/seawater; Gr7 when reducing acid or hot crevice is in play. Pd must be chemistry-verified, not assumed.

Q4: Can Gr5 stud replace Gr2?
A: Only on engineering review — Gr5 wins strength/weight but hot-chloride SCC needs design sign-off. Corrosion-first = Gr2/Gr7.

Q5: Dry assembly OK?
A: No. Ti-on-Ti or Ti-on-steel under load galls. Anti-seize mandatory, written in every pack.

Q6: Nut grade must match?
A: Yes for high preload. Gr5 stud + Gr2 nut risks thread strip/galling.

Q7: Galvanic with steel flange?
A: Ti is noble — steel flange corrodes, not the stud. Isolate with PTFE sleeve/dielectric washer.

Q8: Rolled or cut thread?
A: Rolled default (fatigue + anti-gall); cut for fine/non-standard.

Q9: 3.2 possible?
A: TPI at PO stage; cannot be back-built from 3.1.

Q10: HF / dry chlorine / red fuming nitric?
A: Titanium excluded — red line, no workaround.

Request a Quote

Email: sales@[yourdomain].com

Send NPS×Class + flange thickness + gasket + grade + medium/temp + qty. Reply in 24h: bar-heat status, EXW/FOB price, stud length calc, cert scope, dispatch window.

About: Baoji Titanium Valley chemical-flange stud line — Gr2/R50400, Gr7/R52400 (Pd chemistry-verified), Gr5/R56400, ASTM F468/F468M + B348/B381 route clarity, ASME B16.5 stud length per joint stack, matched F467 heavy hex nuts, rolled thread, 100% PMI + GO/NO-GO gauged, EN 10204 3.1. Anti-galling + galvanic isolation guidance in every pack. No dry assembly, no guessed length, no grade mix, no cert downgrade. Lot confirmed before PI; stud mark = MTC = heat.