The drawing process is critical in the production of titanium and titanium alloy wire. The process is a plastic processing of metals in which coils or wire blanks are passed through mold holes and gradually drawn into small sections using drawing forces to reduce their diameter and increase their strength and surface finish.
Drawing process classification
According to the lubrication state points Titanium wire drawing can be divided into wet drawing and dry drawing of two kinds. Wet drawing uses liquid lubricants, while dry drawing uses solid lubricants.
According to the drawing process points Titanium wire drawing process, according to the wire at the same time through the number of molds can be divided into single-pass drawing and multi-pass continuous drawing. Single pass drawing is usually used for the production of large diameter, low plasticity and shaped wires, while multi-pass continuous drawing is suitable for the production of smaller diameter titanium wires. It can also be divided into non-sliding continuous drawing and sliding continuous drawing according to the state of the lubricant used in drawing.
Cold drawing is the most common method of titanium wire production and is suitable for most situations. Hot drawing requires heating of the titanium wire to accommodate the drawing of high melting point metals such as tungsten and molybdenum. Drawing above the recrystallization temperature is known as warm drawing, and this method is mainly used for the processing of certain specific materials.
Key Steps
Material Preparation: Selection of titanium feedstock suitable for drawing, usually ingots or rods. The material is heated to improve its plasticity and workability.
Pre-treatment: The material is pickled to remove surface oxides and impurities. Lubrication is applied to minimize friction during the drawing process.
Initial Drawing: Initial drawing is performed using a larger die aperture to draw the titanium raw material into a coarse wire. After initial drawing, the titanium wire may be annealed to restore its plasticity.
Intermediate Annealing: An annealing process reduces work hardening and improves the plasticity of the titanium wire for further drawing.
Multiple Drawing: The diameter of the titanium wire is progressively reduced by multiple drawings through a series of dies that progressively reduce the diameter of the hole. After each drawing, the wire is checked for diameter and surface quality.
Lubrication and Cooling: The wire is continuously lubricated and cooled during the drawing process to minimize friction and heat build-up.
QUALITY CONTROL: The diameter, surface finish, strength and elongation of the wire are checked periodically to ensure compliance with quality standards.
FINAL ANNEALING: At the end of the drawing process, a final annealing treatment is carried out to remove residual stresses and to improve the plasticity and toughness of the titanium wire.
Winding: The drawn titanium wire is wound into coils for subsequent processing or use.
Post-treatment: Depending on the requirements, the titanium wire may be subjected to surface treatments such as pickling, polishing or coating to meet specific application requirements.
Packaging and Storage: Finished titanium wire is properly packaged to prevent contamination and damage and stored in a suitable environment.
Considerations
Tooling design The design and material selection of the tooling is critical to the drawing process, ensuring that the hole size, shape and hardness of the tooling is suitable for drawing the titanium wire.
Drawing speed The drawing speed needs to be adjusted according to the diameter of the titanium wire, the material properties and the design of the mold to avoid breaking the wire by drawing it too fast.
Temperature Control Titanium wire may become hot during the drawing process and requires appropriate cooling measures to control the temperature.
Environmental Control Titanium wire may react with oxygen in the air during the drawing process to form an oxidized layer, so it may need to be done in a controlled environment.
