Titanium Wire Processing: Defects & Solutions

Titanium wire has a complex preparation process and strict requirements for precision and performance. During the production process, it is easily affected by multiple factors like raw materials, equipment, and process parameters, resulting in various defects that directly affect product quality and subsequent applications.

1. Surface Defects

• Scratches and Pits: Rough and worn dies with attached impurities; incomplete pretreatment of titanium rods; wear and contamination of guide wheels and take-up wheels.
• Oxide Scale: Titanium is highly reactive. During high-temperature processing, inadequate protective atmosphere, excessively high temperature, and longtime holding time lead to the formation of TiO₂ and Ti₂O₃ oxide scales on the surface, which are easy to peel off and cause excessive die wear.
• Surface Cracks: Improper cold drawing parameters and failure to perform timely intermediate heat treatment; uneven temperature and heating/cooling rates during heat treatment leading to thermal stress concentration, or excessively high temperature causing coarse grains and reduced plasticity.

2. Internal Defects

• Shrinkage Cavities and Porosity: Insufficient feeding caused by improper smelting and ingot casting parameters or mold design leads to shrinkage cavities; porosity is a refined form of shrinkage cavities that are not fully compacted during rolling and wire drawing and remain inside the titanium wire.
• Coarse Grains and Uneven Microstructure: Abnormal grain growth caused by excessively high temperature and prolonged holding time during hot rolling/heat treatment; uneven distribution of rolling deformation and failure to perform timely homogenization heat treatment result in microstructure disorder and fluctuations in mechanical properties.
• Internal Inclusions: Impurities in raw sponge titanium not completely removed during smelting; wear debris from equipment and mold particles embedded during processing, which destroy the continuity of the matrix and are prone to inducing cracks.

3. Dimensional Accuracy Defects

• Diameter Out-of-Tolerance: Die wear, improper control of deformation, and deviations in roll gap.
• Poor Roundness: Uneven die wear, asymmetric force, and offset guide wheels leading to eccentricity.
• Straightness Deviation: Unstable take-up tension, cooling deformation during heat treatment, and unreasonable straightening parameters.

1. Surface Defect Prevention

• Pretreatment and Die Management: Remove oxide scales and impurities from titanium rods by pickling and grinding; select high-precision diamond dies and perform regular polishing and lubrication; timely clean guide wheels and take-up wheels to avoid contamination and wear.
• Atmosphere Control in High-Temperature Processing: Adopt ≥99.999% high-purity argon protection for hot rolling/heat treatment; optimize the heating process by reducing the upper limit temperature and shortening the holding time; remove slight oxide scales by pickling/electropolishing, and strictly control parameters to prevent matrix corrosion.
• Control of Cold Drawing and Heat Treatment Parameters: Adopt the "small deformation and multi-pass" method for cold drawing, and perform intermediate heat treatment between passes to eliminate work hardening; adjust the temperature according to the grade and control the heating/cooling rate to ensure uniformity.

2. Internal Defect Prevention

• Improve Smelting and Ingot Quality: Select high-purity sponge titanium, screen out impurities, and dry it; perform 2-3 times of vacuum arc/electron beam remelting to homogenize the composition and refine grains; optimize the ingot mold, control casting and cooling parameters, and add feeding risers; conduct non-destructive testing on ingots to reject unqualified products.
• Optimize Rolling and Heat Treatment Processes: Uniformly distribute the deformation amount in each rolling pass to avoid local stress concentration; set the hot rolling temperature within the recrystallization range; perform homogenization heat treatment after wire drawing, and adopt solution and aging treatment for high-precision titanium wire to achieve uniform grains and stable microstructure.
• Processing Cleanliness Control: Regularly inspect and maintain rolling and wire drawing equipment, and replace worn parts; adopt closed processing to reduce impurity; Use ultrasonic non-destructive testing on finished titanium wire.

3. Dimensional Accuracy Improvement

• Precise Control of Wire Drawing and Rolling Parameters: Regularly calibrate and replace wire drawing dies, adjust the deformation amount of each pass according to the titanium wire diameter, and make real-time parameter corrections combined with online detection; accurately adjust the roll gap during rolling, control the speed and stabilize the tension to ensure uniform titanium rod diameter.
• Optimize Equipment Positioning and Tension Control: Adjust the coaxiality of guide wheels and take-up wheels to avoid eccentric force; adopt a constant tension take-up system to reduce deformation; use high-precision straightening equipment to adjust pressure and speed after forming to ensure qualified straightness.

4.Full-Process Quality Control

A full-process quality inspection system is required:

• Inspect the composition and purity of raw materials before warehousing;
• Conduct appearance, dimensional, non-destructive, and mechanical testing on ingots, titanium rods, and finished products timely detect defects and trace the source;
• Regularly check equipment, optimize the process parameter database, and formulate standardized processes according to grades and specifications to reduce human errors.

Titanium Wires of Different Grades

Ruihang is a professional manufacturer of titanium and titanium alloy products, supplying high-quality titanium wires. For more details,please contact us via the Email: Sam.Rui@bjrh-titanium.com