The manufacturing of titanium bolts is a lengthy process that transforms titanium sponge into precision fasteners. The core steps are: smelting and forging → preparation of billets and wire → cold/hot heading → threading → heat treatment → surface treatment → inspection.
Titanium Bolt Manufacturing Process
1. Raw Material Preparation
Material Selection: Commonly used materials include Grade 2 pure titanium (Gr2, high corrosion resistance) and Grade 5 titanium alloy (Ti-6Al-4V, high strength)
Melting and Ingot Casting: A vacuum arc remelting (VAR) furnace is used for three rounds of vacuum arc remelting to ensure material purity
Bar Preparation: Titanium bars are produced through billet forging (1080–1180°C), reversible block drawing (three blocks and three draws), and bar rolling (950°C)
2. Cutting
Precision cutting of titanium rods to bolt length using:
Sawing/CNC lathe cutting (high precision ±0.1 mm)
Surface treatment: Sandblasting or acid washing to remove scale and prevent contamination during subsequent processing
3. Head forming (hot heading/cold heading)
Hot Forging Process (Suitable for High-Strength Bolts):
Heat to 850–950°C (Gr5) in an argon atmosphere to prevent oxidation
Form the bolt head using a die forging process to refine the grain structure and enhance mechanical strength.
Cold heading process (small diameters or pure titanium):
Formed at room temperature; the deformation rate must be controlled at ≤30% to prevent cracking.
4. Thread Forming
Rolled threads (preferred): A cold forming process in which threads are formed through plastic deformation using a thread rolling machine, resulting in work hardening that enhances thread strength and fatigue resistance. Surface roughness can reach Ra 1.6.
Machined threads: Single-point turning on a CNC lathe, suitable for large-diameter or special threads.
5. Heat Treatment
Solution Treatment: TC4 is heated to 900–950°C and then water-quenched to obtain a martensitic microstructure.
Age Hardening: Held at 480–560°C for 4–8 hours to precipitate strengthening phases, increasing hardness to HRC 36–40.
Annealing: Heated in an inert gas atmosphere at 480–700°C to improve ductility and relieve internal stresses.
6. Surface Treatment
Descaling: Acid pickling with a mixed solution of hydrofluoric acid and nitric acid, or electrolytic polishing
Anodizing: Electrochemical treatment to form a wear-resistant oxide film (blue, gold, etc.), with voltage controlled at 30–60 V
PVD Coating: Physical vapor deposition to form a high-hardness, high-wear-resistant thin film.
7. Quality Inspection
Three-tier inspection system:
Dimensional inspection: Thread plug gauges, projection projector measurement of geometric tolerances
Mechanical testing: Tensile testing, hardness testing, torque testing
Non-destructive testing: Ultrasonic testing, fluorescent penetrant testing, magnetic particle testing (for iron contamination screening)
8. Packaging and Storage
Individually packaged to prevent surface abrasion
VCI vapor-phase rust-preventive paper used
Vacuum-sealed packaging for long-term storage to prevent moisture
In summary, thanks to these precision manufacturing processes, titanium bolts are 40% lighter than steel bolts while offering higher specific strength and corrosion resistance, making them suitable for extreme environments.
E-mail: garychen3215@hotmail.com
Address: No.35, Baoti Rd, Baoji city, Shaanxi Province, China
Contact: Mr. Gary Chen
Phone: +86-917-8883215
Mobile/WhatsApp: +86 13092900605
