TC4 pull-out breakthrough: new technology help
To overcome the problem of TC4 titanium alloy wire drawing, these new technologies are too powerful!Titanium alloys are highly favored in high-end fields such as aerospace due to their excellent strength, corrosion resistance, and other properties. However, TC4 titanium alloy wire, faces many "roadblocks" during cold drawing processing as an important titanium alloy product. But researchers have continuously explored and innovated, developing various breakthrough technologies. Let's take a look~
The "old and difficult" problem of TC4 titanium alloy wire drawing
In the process of cold drawing of TC4 titanium alloy wire, except the headache of sticking mold, there are two key problems that restrict its development:
1. The continuous cold drawing strain variable of the existing process is generally small, and it is difficult to meet some high-precision and high-performance requirements.
2. Medium and high temperature annealing treatment to restore drawing plasticity will eliminate the work hardening effect, resulting in the loss of strength of the wire and affecting its performance in high-strength applications. Innovative technology solves problems, each with its own tricks
In the face of these challenges, scientific research teams at home and abroad have launched a series of new technologies:
(1) Pulsed current cold pull-out (EPT): a new idea of low-temperature precision forming
Zhou Yan et al. of Dalian University of Technology used the method of cold drawing TC4 titanium alloy with pulsed current to exert a "magical effect" through pulsed current - suppressing high-energy cones. After EPT treatment, although the tensile strength of the specimen was reduced by 42MPa, the elongation was significantly improved. This discovery not only opens up a new path for low-temperature precision forming of TC4 titanium alloy, but also reduces energy consumption and high-temperature oxidation risks, further expanding its application potential in aerospace and other fields.
(2) Stepped mold layout (ADD): to achieve large strain while balancing strength and plasticity
J. Kawalko and colleagues at AGH University of Technology in Poland took a different approach, using an ADD (Advanced Die Layout) method to draw TC4 alloy wire. This process successfully achieved large strain (ε=0.51) by introducing multi-directional strain paths.
The AAD process can significantly refine grains (from 2.68 μm to 2.01 μm), promoting the development of prismatic and conical surfaces.
(3) Fixed die drawing technology: creating ultra-high strength wires
The Southeast University team took a "refined approach," employing a simple fixed-die drawing technique and successfully developing a technology for preparing ultra-high-strength TC4 titanium alloy wire by precisely controlling the parameters of the cold drawing process and heat treatment process.
The TC4 titanium alloy wire prepared using this technology has a tensile strength exceeding 1400MPa and a uniform elongation exceeding 3%, which are quite impressive.Titanium alloys also have these other "ruthless" deformation methods.
Besides cold drawing deformation, titanium alloys have many other powerful deformation methods that excel in improving performance:
(1)Equal Angled Extrusion (ECAP): Ata Radnia et al. used equal angular extruded extrusion (ECAP) to deform Ti-6Al-4V alloy in two passes at 540℃, followed by annealing at 340℃/1h. The results showed that ECAP + annealing refined the α grain size from 970nm to 550nm, significantly improved mechanical properties, increased yield strength by 15-25% (reaching 1084MPa), increased compressive strength to 1843MPa, and improved toughness by 39%.
(2)Multi-directional forging (MF): Zherebtsov et al. prepared ultrafine-grained Ti-6Al-4V by multi-directional forging and warm rolling. Under the conditions of 550℃ and 2×10⁻⁴s⁻¹, the alloy exhibited excellent low-temperature superplasticity and the elongation reached 1000%. Among them, the β phase transformed from a tripartite grain boundary to a continuous network structure, which promoted grain boundary slip and made the dynamic coarsening rate 100 times faster than the static rate.
(3) Plastic Deformation Technology Based on Machining: M. Ravi Shankar et al. used this technology to perform near-room temperature intensive plastic deformation (SPD) on pure titanium, successfully preparing an ultrafine-grained structure. By controlling the tool rake angle (+20° and -20°) to regulate the strain, equiaxed grains of about 100 nm were obtained in the chip region, and the hardness was significantly improved to 230-247 HV (the original material was 144 HV). Compared with high-temperature equal diameter angular extrusion (ECAP), near-room temperature deformation can suppress dislocation annihilation, resulting in finer grains and better mechanical properties.
Titanium alloys are widely used in aerospace and other fields, but the cold drawing process of TC4 titanium alloy wire faces challenges such as the difficulty of large-strain drawing and the strength loss caused by medium- and high-temperature annealing. Baoji Mingjie, as a leading titanium alloy processing enterprise in China, has successfully overcome these challenges thanks to its strong R&D capabilities.
Baoji Mingjie employs pulsed current cold drawing (EPT) technology to improve elongation and reduce energy consumption; utilizes stepped die layout (ADD) technology to achieve high-strain drawing and refine grain size; and employs fixed die drawing technology to develop ultra-high-strength wires. These innovative technologies demonstrate Baoji Mingjie's outstanding advantages in the titanium processing field: strong R&D capabilities, rich practical experience, strict quality control, and wide product applications. In the future, Baoji Mingjie will continue to innovate, providing customers with even better products and services.
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