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What are the sandblasting processes for titanium and titanium alloy materials?

The sandblasting process of titanium and titanium alloy materials is an important surface treatment technology, which aims to remove the oxide layer and pollutants on the surface, improve the surface roughness of the substrate, enhance the adhesion of the coating, or endow the surface with specific physical and chemical properties, and improve the mechanical properties of the material.
Sandblasting treatment is the use of compressed air or water flow to rapidly spray abrasive onto the surface of titanium alloy, in order to remove the oxide layer, dirt, and impurities on the surface, thereby improving surface roughness and adhesion. This method is commonly used for surface treatment of titanium castings and forgings to ensure the adhesion effect of subsequent processing or coatings.
Sandblasting treatment is not only used for cleaning and roughening surfaces, but can also improve the microstructure of materials by adjusting parameters. For example, by sandblasting with a diameter of 0.5-2mm, the grain size of titanium alloy can be reduced to about 44 nanometers, thereby enhancing its fatigue resistance and stress cracking resistance. In addition, wet shot peening technology combined with ultrasonic vibration can reduce surface roughness while extending the life of the projectile and improving local yield strength.
Sandblasting treatment has a wide range of applications in medical implants, aerospace, and other fields. For example, sandblasting treatment on the surface of implants can increase surface area, promote cell adhesion and proliferation, and enhance bone bonding ability. In the integrated molding of composite materials and titanium alloys, sandblasting treatment can significantly improve the shear strength, which is beneficial for the connection between composite materials and titanium alloys.
Sandblasting material
The abrasive used in sandblasting process is usually white corundum or quartz sand, which have high hardness and good cleaning effect. The sandblasting pressure is generally controlled below 0.45MPa to avoid excessive damage to the titanium surface. The distance between the nozzle and the surface of the casting should be maintained between 20mm and 400mm, and the spraying angle should be controlled between 20 ° and 70 °.
White corundum abrasive has high hardness and good wear resistance, which enables it to provide strong cutting force and grinding effect during sandblasting, especially suitable for surface treatment of hard materials such as titanium and titanium alloys. White corundum sandblasting can quickly clean the surface of large areas of workpieces, improve work efficiency, and enhance the adhesion of coatings through roughening treatment, thereby improving the quality of workpieces. In addition, sandblasting with white corundum can significantly increase the roughness of the workpiece surface, allowing the coating to better adhere to the surface and extend the service life of the coating.
Quartz sand and quartz sand are usually used for relatively mild surface treatment in sandblasting technology, with relatively low hardness and wear resistance, making them suitable for some occasions where surface requirements are not high. Quartz sand particles are relatively soft and have less impact, so they may not provide strong cutting force and grinding effect like white corundum during sandblasting.
SiO2 (silicon dioxide) is also a common sandblasting material, with hardness and wear resistance between white corundum and quartz sand. The effect of SiO2 sandblasting may be between that of white corundum and quartz sand, providing a certain surface roughness to enhance coating adhesion without causing excessive damage to the workpiece surface like white corundum. White corundum is usually preferred in the sandblasting process of titanium and titanium alloy materials due to its high hardness and strong grinding effect, in order to achieve a surface treatment effect of *.
Sandblasting process
1. Dry sandblasting process:
Dry sandblasting is a common sandblasting process that uses compressed air as power to spray abrasives (such as quartz sand, diamond sand, iron sand, etc.) onto the surface of the workpiece to achieve cleaning, deburring, and increasing surface roughness.
Select abrasives of different particle sizes and compressed air pressures according to the different parts. For example, larger steel parts with a thickness of 3mm or more may use 2.5-5mm quartz sand and compressed air pressure of 0.3-0.5MPa.
2. Wet sandblasting process:
Wet sandblasting is similar to dry sandblasting, but water is added to the abrasive to form mortar, reducing dust pollution and lowering the surface temperature of the workpiece. Wet sandblasting is commonly used in situations where high environmental cleanliness is required.
3. Shot peening process:
Shot blasting is similar to sandblasting, but uses spherical abrasives (such as steel or glass pellets) instead of sandy abrasives. Shot peening can generate compressive stress, improve the fatigue strength and stress corrosion resistance of parts, and is commonly used for surface treatment of precision parts.
4. Siphon sandblasting:
Siphon sandblasting uses a siphon tube to suck abrasive into the airflow, suitable for surface treatment of small parts with complex shapes.
5. Pressure sandblasting:
Pressure sandblasting uses a pressurized container to rapidly push out abrasive materials, suitable for large-area surface treatment with high efficiency, but also requires high equipment requirements.
6. Wet sandblasting:
Wet sandblasting combines water with abrasive materials to reduce dust and clean surfaces, making it suitable for occasions that require environmental cleanliness.
7. Spray beads:
Spray beads use glass beads to gently clean and polish surfaces, suitable for fine surface treatment such as jewelry and precision instruments.
8. Dry ice blasting:
Use dry ice pellets for cleaning without leaving any residue, suitable for applications that require residue free cleaning, such as food processing equipment. The choice of sandblasting process depends on the type of material to be treated, surface condition, treatment purpose, and environmental requirements. Each sandblasting process has its unique application scenarios and advantages. Choosing the right sandblasting process can greatly improve the efficiency and quality of surface treatment.
Extended Reading
The influence of different sandblasting materials on surface treatment effect
1. White corundum:
White corundum abrasive has high hardness and good wear resistance, which enables it to provide strong cutting force and grinding effect during sandblasting, especially suitable for surface treatment of hard materials such as titanium and titanium alloys.
White corundum sandblasting can quickly clean the surface of large areas of workpieces, improve work efficiency, and enhance the adhesion of coatings through roughening treatment, thereby improving the quality of workpieces.
In addition, sandblasting with white corundum can significantly increase the roughness of the workpiece surface, allowing the coating to better adhere to the surface and extend the service life of the coating.
2. Quartz sand:
Quartz sand is usually used for milder surface treatments in sandblasting processes, with relatively low hardness and wear resistance, making it suitable for some occasions where surface requirements are not high.
Quartz sand particles are relatively soft and have less impact, so they may not provide strong cutting force and grinding effect like white corundum during sandblasting.
3. SiO2 (silicon dioxide):
SiO2 is also a common sandblasting material, with hardness and wear resistance between white corundum and quartz sand.
The effect of SiO2 sandblasting may be between that of white corundum and quartz sand, providing a certain surface roughness to enhance coating adhesion without causing excessive damage to the workpiece surface like white corundum.
Specific application of high-frequency vibration sandblasting technology in surface treatment of titanium alloy
High frequency vibration sandblasting technology can significantly reduce the surface roughness, enhance surface hardness and corrosion resistance of titanium alloy by applying high-frequency vibration to its surface. This technology has gradually developed in recent years, especially in the fields of medical devices and precision machining, where it has been widely applied.
In addition, surface treatment methods such as sandblasting can reduce the occurrence of microcracks on the material surface, thereby improving the torsional fatigue life. This indicates that high-frequency vibration sandblasting technology not only improves the surface quality of titanium alloys, but also enhances their mechanical properties.
Mechanism of wet shot peening technology combined with ultrasonic vibration to improve local yield strength of titanium alloy
1. Formation of surface hardening layer: Wet shot peening technology rapidly sprays mixed liquid onto the surface of the material through high-pressure compressed air flow, forming a uniform liquid film and achieving strengthening effect. This liquid film forms a hardened layer on the surface of titanium alloy, significantly improving surface hardness and strength. Ultrasonic vibration further enhances this effect by applying high-frequency vibration impact loads to the surface of metal materials, making the hardened layer more uniform and dense.
2. Grain refinement: Ultrasonic vibration plays a role in refining the grains during the surface treatment of titanium alloys. Research has shown that ultrasonic vibration assisted (UVA) significantly improves the grain structure of deposited components, making them finer and more uniform. This grain refinement not only improves the mechanical properties of the material, but also enhances its local yield strength.
3. Formation of gradient nanoparticles: The superposition of high-temperature field and ultrasonic vibration kinetic energy produces annealing effect in local areas, thereby forming more stable gradient nanoparticles. These gradient nanoparticles can further enhance the local yield strength of materials, as nanomaterialization can significantly improve the mechanical properties of materials.
4. Homogenization of microstructure: Under the combined action of wet shot peening and ultrasonic vibration, the microstructure of titanium alloy surface becomes more uniform and dense. This homogenized microstructure helps to improve the overall mechanical properties of the material, including local yield strength.
In the field of medical implants, the mechanism of sandblasting treatment in improving osseointegration ability
1. Increase surface roughness and surface area: Sandblasting treatment uses a high-speed jet formed by compressed air to spray materials of different particle sizes onto the surface of the implant at high speed, thereby changing its surface roughness and increasing its surface area. This surface roughness helps to improve the adhesion and proliferation ability of cells, thereby enhancing bone binding capacity.
2. Improve surface activity: Sandblasting treatment not only increases surface roughness, but also improves material surface activity by forming a residual compressive stress layer. This improvement in surface activity helps promote the attachment of osteoblasts and induce bone integration.
3. Promote new bone formation: Studies have shown that the surface of implants treated with sandblasting can be surrounded by newly formed bone trabeculae and exhibit a large amount of new bone formation within a certain period of time. This indicates that sandblasting treatment can effectively promote the integration between bone tissue and implants.
4. Use of biocompatible media: Some studies use biocompatible and bioabsorbable media for sandblasting treatment to ensure long-term safety. For example, implants treated with hydroxyapatite (HA) particles by sandblasting showed high osseointegration ability, further demonstrating the effectiveness of sandblasting in improving osseointegration.
Sandblasting treatment improves shear strength in the integrated molding of composite materials and titanium alloys
The reason why sandblasting significantly improves shear strength in the integrated molding of composite materials and titanium alloys can be explained from the following aspects:
1. Increase in surface roughness: Sandblasting treatment increases the roughness of the titanium alloy surface by creating tiny voids and uneven surface structures. The increase in roughness is beneficial for the resin to form more contact points on the surface of titanium alloy, thereby improving the adhesive strength.
2. Removal of oxide layer and impurities: Sandblasting treatment can effectively remove the oxide layer and some impurities on the surface of titanium alloy, which usually hinder the adhesion between resin and metal surface. By removing these unfavorable factors, sandblasting treatment helps to improve the bonding effect between composite materials and titanium alloys.
3. Mechanical interlocking effect: The microstructure formed by sandblasting treatment can provide mechanical interlocking effect for resin, that is, resin molecules can embed into the holes on the surface of titanium alloy, thus forming a more solid connection after curing. This mechanical interlocking effect significantly improves the shear strength of composite/titanium alloy specimens.
4. Effect of sandblasting time: Studies have shown that as sandblasting time increases, the shear strength of the sample first increases and then decreases. When the sandblasting time increased from 15 seconds to 60 seconds, the shear strength increased from 29.7 MPa to 33.9 MPa, but when the sandblasting time was further extended to 180 seconds, the shear strength decreased again to 32.4 MPa. This indicates that the sandblasting time has an * value, within which sandblasting treatment can significantly improve the roughness and adhesion performance of titanium alloy surfaces.
5. Changes in microstructure and element distribution: After sandblasting treatment, the microstructure and element distribution of the titanium alloy surface have changed. For example, after sandblasting treatment, the content of Si and O elements on the surface of titanium alloy increases, and the distribution of these elements is related to the depth of surface voids, indicating that debris generated during sandblasting may be trapped in the voids, which may have adverse effects on subsequent bonding. However, appropriate sandblasting treatment can still significantly improve shear strength.

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