What Is Titanium Bolt Manufacturing Process?

Titanium bolts have advantages such as light weight, high strength, corrosion resistance, and stable performance at high and low temperatures, making them critical fasteners. Their production integrates precision manufacturing technologies including materials science, precision forming, heat treatment, and surface treatment.

 

 

1. Grade Selection

Commercially Pure Titanium: High purity, excellent plasticity and corrosion resistance, moderate strength; widely used in chemical, medical, and seawater environments.

α+β Titanium Alloy: The mainstream material for aerospace fasteners, accounting for over 95% of usage. It offers high strength and exceptional specific strength, suitable for harsh working conditions ranging from -196℃ to 400℃.

β Titanium Alloy: Good plasticity at room temperature, suitable for cold heading; used for complex high-precision fasteners.

 

2. Raw Material Quality Control

Raw materials adopt titanium ingots produced by three-time vacuum consumable arc melting, ensuring uniform composition and low impurity content. Before production, raw materials undergo spectral analysis and mechanical property re-inspection to strictly control quality.

 

 

1.Forging Blooming: Heat the titanium ingot above the β-transus temperature for forging to break the as-cast structure and refine grains. After forging, scalping is performed to remove oxide scale and defects.

 

2.Rolling / Wire Drawing: The forged blank is processed into wire of the required diameter through multiple passes of hot rolling or cold drawing to eliminate stress, improve plasticity, and prevent fracture during processing.

 

3.Straightening and Polishing: Straighten the wire to ensure straightness ≤ 0.5 mm/m. Polishing removes scratches and oxide layers to obtain a clean and smooth blank.

 

 

1. Warm Heading Forming

α+β titanium alloy has high deformation resistance at room temperature, so it needs to be preheated to 200–300℃ and integrally formed into the bolt head and shank on a multi-station warm heading machine.

High efficiency and material utilization rate, continuous grain structure, and better mechanical properties than cutting. Die precision is ±0.02 mm to prevent eccentricity and cracks.

 

2. Cold Heading Forming

Suitable for β titanium alloy, which can be directly headed at room temperature due to good room-temperature plasticity. It features higher efficiency but has high requirements for material plasticity and die wear resistance.

 

3. Cutting Forming

Used for non-standard, large-size, and complex-structured bolts. Formed by CNC lathe turning with high flexibility, but low efficiency and large material loss.

 

 

1.Thread Rolling

Plastic forming of metal via pressure applied by a radial thread rolling machine, a non-cutting process.

Continuous thread fiber structure, increasing strength by 15%–20%; surface roughness Ra ≤ 1.6 μm, accuracy class 6g, and excellent fatigue resistance.

2.Thread Cutting

Applicable to large-size, special-form threads that cannot be rolled, processed by CNC lathe. Use low-speed cutting, adequate cooling, and timely chip removal to avoid work hardening and tool wear.

 

 

1.Aerospace-Grade Standard Heat Treatment

Solution Treatment: Heat to 954±14℃, hold for 1–2.2 hours, then water quench to obtain supercooled β microstructure.

Aging Treatment: Heat to 538±8℃, hold for 4–8 hours, then air cool to precipitate α strengthening phase. Tensile strength ≥ 1100 MPa, yield strength ≥ 1000 MPa.

 

2.Pure Titanium Heat Treatment

Stress relief annealing at 550–650℃ for 1–2 hours to maintain high plasticity and corrosion resistance; no strengthening treatment is performed.

 

3.Advantages of Vacuum Heat Treatment

Oxygen-free environment prevents oxidation and hydrogen embrittlement, ensuring surface quality and stable performance; an essential process for high-end titanium bolts.

 

 

1.Pickling Pretreatment

Remove oxide scale, oil, and impurities using a mixed solution of hydrofluoric acid and nitric acid. Followed by multi-stage water washing, neutralization, and pure water rinsing to eliminate residual acid and prevent hydrogen embrittlement.

 

2.Anodizing

Form a dense 5–25 μm oxide film on the bolt in sulfuric acid/phosphoric acid electrolyte.

Film hardness HV 300–500, corrosion resistance up to 480 hours of salt spray without rust; available in natural, gold, black, and other colors for identification.

 

3.Other Treatments

Spraying and passivation can be selected for special working conditions to further improve wear resistance or insulation properties.

 

 

1.In-Process Inspection

Raw material composition, blank dimensions and surface condition, forming dimensions, thread accuracy, and heat treatment hardness testing.

 

2.Finished Product Inspection

Dimensional Accuracy: Inspected by projector and coordinate measuring machine (CMM), with tolerance controlled at ±0.01 mm level.

Mechanical Properties: Tensile, yield, shear, and fatigue strength testing; 100% non-destructive testing for aerospace parts.

Surface Quality: Oxide film thickness, salt spray corrosion resistance, and surface roughness testing.

Reliability: Vibration and preload attenuation testing to ensure stable connection.

 

 

Qualified titanium bolts are packaged with anti-rust paper plus vacuum packaging to avoid surface damage and corrosion during transportation and storage. They are stored in warehouses by specification and grade with clear identification, enabling traceability of the production batch and process parameters for each product. For more details about titanium bolts, contact us via: Sam.Rui@bjrh-titanium.com.