News

What are the ways to polish titanium alloy?

Polishing is the process of removing defects and unevenness on the surface of titanium alloys through mechanical methods, improving surface smoothness and flatness. The main purpose of titanium alloy polishing is to improve its surface quality and aesthetics, while also enhancing its corrosion resistance and biocompatibility.
Titanium is a new type of metal, and its properties are related to the content of impurities such as carbon, nitrogen, hydrogen, and oxygen. Pure titanium iodide has an impurity content of no more than 0.1%, but its strength is low and its plasticity is high. The performance of 99.5% industrial pure titanium is as follows: density ρ=4.5g/cubic centimeter, melting point 1725 ℃, thermal conductivity λ=15.24W/(m.K), tensile strength σ b=539MPa, elongation δ=25%, cross-sectional shrinkage rate ψ=25%, elastic modulus E=1.078 × 105MPa, and hardness HB195.
Titanium has high chemical reactivity, low thermal conductivity, high viscosity, low mechanical grinding ratio, and is easy to react with abrasive tools. Ordinary abrasives are not suitable for grinding and polishing titanium. Use superhard abrasives with good thermal conductivity, such as diamond, cubic boron nitride, etc. The polishing wheel speed is generally 900-1800 mm/min. Otherwise, the titanium surface is prone to grinding burns and microcracks. All titanium alloy jewelry, watch straps, bracelets, and other titanium alloy products have certain difficulties in polishing, requiring specialized polishing materials to polish the surface bright.
The thermal conductivity of titanium is λ=15.24W/(m.K), which is about 1/4 of nickel, 1/5 of iron, and 1/14 of aluminum. However, the thermal conductivity of various titanium alloys is about 50% lower than that of titanium. The elastic modulus of titanium alloy is about half of that of steel, so its rigidity is poor and it is prone to deformation. It is not suitable for making slender rods and thin-walled parts. The springback of the machined surface during cutting is large, about 2-3 times that of stainless steel. So there are certain difficulties in polishing.
Titanium alloy polishing process flow
1. Surface pretreatment: Use acid washing, electrolytic polishing and other methods to remove harmful substances such as surface rust and oxide layer, making the surface clean and smooth.
2. Grinding: Mechanical or manual grinding is used to remove surface burrs, unevenness, and other defects.
3. Polishing: Using mechanical polishing or chemical polishing methods to improve the surface smoothness to a certain level.
4. Sandblasting treatment: Spray abrasive on the surface to remove dirt and defects.
5. Cleaning: Clean with water or solution to remove sandblasting abrasives and polishing agent residues, ensuring a clean and smooth surface.
6. Surface treatment: According to different requirements and applications, the surface is treated with electroplating, anodizing, etc. to improve its corrosion resistance and decorative properties.
Mechanical polishing (rough polishing, medium polishing, fine polishing, mirror polishing)
Polishing processed pure titanium mirror surface titanium chopsticks
1: Rough polishing: Polish the surface of the product with a titanium alloy special hemp wheel or wool wheel and a special titanium wax. Pay attention to the intensity of polishing and the direction of product polishing.
2: Medium polishing: Use a titanium alloy specific polishing coarse cloth wheel or fine wool wheel with titanium alloy specific medium polishing wax to polish, remove the patterns left by rough polishing, and make the product surface shiny.
3: Precision polishing: Use a cotton cloth wheel specially designed for titanium alloy and a precision polishing wax specially designed for titanium alloy to achieve high brightness of the titanium alloy product. There are still some slight cloth patterns on the surface of the product.
4: Mirror polishing: Use a titanium alloy specific bleached cotton cloth wheel and titanium alloy specific mirror wax polishing to remove slight cloth patterns on the surface of the product, so that the titanium alloy mirror finish is achieved.
Chemical polishing
Chemical polishing is achieved by the oxidation-reduction reaction of metals in a chemical medium to achieve the purpose of leveling and polishing. Its advantages are that chemical polishing is independent of the hardness, polishing area, and structural shape of the metal. Any part in contact with the polishing solution is polished without the need for special complex equipment. It is easy to operate and is more suitable for polishing complex structured titanium denture supports. However, the process parameters of chemical polishing are difficult to control, and it is required to have a good polishing effect on dentures without affecting their accuracy.
Conclusion
The polishing process of titanium alloy is a key process, which is of great significance for improving the surface quality and aesthetics of titanium alloy. During the polishing process, it is necessary to pay attention to the control of various technical parameters and the improvement of personnel quality, continuously improving the level and quality of polishing technology to meet the needs of different industries and fields for titanium alloy materials.

[ 上一页 ] What are the chemi...[ 下一页 ] Why are car engine...