Manufacturing Process for Titanium Alloy Screws

The process involves two main materials: TA2 pure titanium and TC4 titanium alloy. It consists of a total of nine steps, with specific requirements for the titanium materials clearly highlighted.

I. Complete Production Process

Raw Material Inspection → Wire Drawing and Sizing → Acid Pickling + Lubrication → End Forming → Chamfering and Deburring → Thread Rolling → Cleaning and Degreasing → Heat Treatment + Surface Treatment → 100% Inspection + Packaging

II. Explanation of Each Process Step

1. Raw Material Inspection

Titanium wire rod or titanium bar is used, primarily TA2 pure titanium and TC4 (Ti-6Al-4V). Upon arrival, the material composition, hydrogen and oxygen content, and surface condition are tested. Raw materials with cracks or impurities are immediately rejected to prevent brittle fracture in the finished product.

2. Wire Drawing and Sizing

Rough titanium material is cold-drawn through multiple passes to achieve the standard diameter for the screw shank. Due to titanium’s high resistance to deformation, the amount drawn in a single pass is strictly controlled, with annealing for softening performed intermittently to prevent wire breakage.

3. Acid Pickling + Specialized Lubrication

First, an acid solution is used to remove surface scale, followed by thorough rinsing and drying; then, a high-temperature lubricant specifically designed for titanium is applied. Since titanium adheres very easily to dies, this step is critical for ensuring a smooth surface and minimizing drawing marks.

4. Head Forming (Head Forming)

There are two processes based on material type:

TA2 Pure Titanium: Cold heading at room temperature, using equipment to extrude and form structures such as pan heads, countersunk heads, flanged heads, star slots, and straight slots. The process is performed in stages to prevent head cracking.

TC4 High-Strength Titanium Alloy: Due to its high room-temperature hardness and poor ductility, this material requires localized heating (300–700°C) followed by warm heading and extrusion. High-temperature-resistant carbide dies must be used.

5. Chamfering and Deburring

Remove flash and sharp edges created during forming. Chamfer the entire shank and head to ensure a clean appearance and prevent assembly scratches and stress concentration. At the same time, a preliminary visual inspection is conducted.

6. Thread Rolling

Titanium screws are produced exclusively using the thread rolling process; thread cutting is not used. High-precision thread rolling wheels form the threads through low-speed extrusion, resulting in intact metal fibers, high thread strength, full-profile threads, and no burrs. The precision can meet the Industrial 6g standard.

7. Ultrasonic Cleaning

Removes residual lubricants and metal dust from the surface to ensure the workpiece is clean, preparing it for subsequent heat treatment and surface treatment.

8. Heat Treatment + Surface Treatment

Heat Treatment

TA2 Pure Titanium: No strengthening heat treatment required.

TC4 Titanium Alloy: Place in a vacuum furnace or argon-atmosphere furnace for solution treatment and aging to enhance overall strength and fatigue resistance; Ordinary air furnaces are strictly prohibited, as they cause oxidation and hydrogen absorption, leading to embrittlement.

Surface Treatment

Natural Passivation: Reinforces the corrosion-resistant layer; the preferred option for general-purpose applications;

Hard Anodizing: Available in colors such as blue, gold, and black; wear-resistant and aesthetically pleasing; commonly used for automotive and motorcycle modification screws;

Mirror Polishing: Primarily used for medical and precision instruments.

9. 100% Inspection, Sorting, and Packaging

100% inspection of dimensions, thread clearance, and appearance; additional crack testing for aerospace and medical components. Qualified products are sorted by specification, sealed in moisture-proof packaging, and accompanied by a material report and 3.1 certificate.

III. Comparison of Two Materials: Manufacturing Processes & Applications

1. TA2 Pure Titanium Screw Manufacturing Process:

Cold heading → Roll threading → Passivation / Oxidation

Features: Easy to process, high corrosion resistance, lightweight

Applications: General machinery, outdoor equipment, general lightweight components

2. TC4 Titanium Alloy Screws

Process: Warm forging → Roll threading → Vacuum heat treatment → Surface treatment

Features: Complex manufacturing process, high strength, vibration resistance, high-temperature resistance

Applications: Aerospace, automotive wheels, high-end modifications, heavy-duty fasteners