Top 10 Titanium Alloy Fasteners Factories & Exporters

Galling is a micro-welding phenomenon caused by the spontaneous rupture of titanium’s thin protective oxide film (TiO2) under high contact friction. To prevent thread seizure during torquing:

1. Surface Treatments: Specify Type II anodizing (AMS 2488), micro-arc oxidation (MAO/PEO), or bonded dry-film MoS2 (molybdenum disulfide) coatings.
2. Dissimilar Metallurgy: Mate Titanium Grade 5 bolts with hard-lubricated high-nickel alloy nuts (e.g., Inconel 718) or aluminum-bronze nuts where galvanic conditions permit.
3. Controlled Tightening: Employ low RPM installation speeds without impact wrenches, and utilize anti-seize paste containing PTFE or nickel particles.

Both alloys share the nominal 6% Aluminum, 4% Vanadium chemical balance. However, Grade 23 (UNS R56407) is designated as "ELI" (Extra Low Interstitial). The allowable limits of oxygen, nitrogen, carbon, and hydrogen are strictly lowered:

• Oxygen Content: Maximum 0.13% in Grade 23 vs 0.20% in standard Grade 5.
• Fracture Toughness: Grade 23 yields substantially higher K1C fracture toughness and resistance to stress-corrosion cracking (SCC).
• Cryogenic Reliability: For liquefied gas (LNG) systems or aerospace cryo-tanks operating at -196°C to -250°C, Grade 23 prevents the ductile-to-brittle transition observed in higher-oxygen interstitial grades.

Yes. Under NACE MR0175 / ISO 15156-3, Titanium Grade 5 (UNS R56400) and other selected titanium alloys are qualified for use in sour (H2S-containing) oil and gas extraction environments without environmental limits on partial pressure of H2S, provided that the material is in the annealed condition and its hardness does not exceed specified thresholds (typically 35 HRC for annealed Ti-6Al-4V). Always state the sour service requirement during RFQ so that solution annealing and individual lot hardness surveys are certified accordingly.

For mission-critical engineering projects, your purchase order should stipulate:

1. EN 10204 Type 3.1 Mill Test Certificate: Stating chemical composition, tensile strength, yield strength, reduction of area, elongation, and heat treatment batch.
2. EN 10204 Type 3.2 Certificate: If third-party independent witnessing (e.g., TÜV, DNV, ABS, Lloyd’s) is mandated by the project owner.
3. PMI Spectrometry: 100% positive material identification test reports on finished fastener lots.
4. Raw Ingot Provenance: Verifiable mill melt source confirming avoidance of unrefined scrap additions.

Due to titanium's higher coefficient of friction compared to plated carbon steel, standard torque lookup charts will severely under-tension a titanium joint or cause thread galling before reaching preload. An unlubricated titanium fastener exhibits a nut factor (K) between 0.30 and 0.40. Applying high-performance anti-seize or PTFE coating stabilizes the K-factor to 0.12–0.15, allowing predictable axial bolt tensioning without exceeding the yield point during installation.

Titanium sits at the noble (cathodic) end of the galvanic series. When placed in electrical contact with less noble metals (such as carbon steel or aluminum) in an electrolyte (such as seawater), the mating metal will suffer accelerated galvanic attack while the titanium remains untouched. When connecting titanium bolting to stainless steel flanges, the galvanic potential difference is small and often acceptable in ambient industrial atmospheres; however, in continuous marine immersion, insulating sleeves (Mylar/G10) and isolating washers must be specified to break electrical conductivity.