Stainless steel sieve plates must withstand the combined effects of particle impact, friction, and corrosive media during material screening. Their surface wear resistance directly impacts equipment lifespan and production efficiency. Optimizing surface treatment processes can significantly improve wear resistance without altering the substrate material. The main technical approaches revolve around surface strengthening, structural modification, and composite protection.
Aluminizing is a core method for enhancing wear resistance, as it involves high-temperature diffusion to form an aluminum-iron alloy layer on the stainless steel surface. This process allows aluminum atoms to diffuse into the substrate, generating an intermetallic compound layer with a hardness of HV755, far exceeding that of ordinary stainless steel and common wear-resistant steels. The alloy layer is metallurgically bonded to the substrate, possessing both high hardness and anti-scraping properties. It effectively resists particle erosion under harsh conditions such as dust and high temperatures, making it particularly suitable for screening equipment in industries like coal and metallurgy.
Physical vapor deposition (PVD) technology, by depositing a high-hardness ceramic coating in a vacuum environment, allows for customized improvements in surface properties. For example, after depositing titanium nitride (TiN) or titanium carbide (TiC) coatings, the surface hardness can reach over HV2000, while also exhibiting excellent corrosion resistance and thermal stability. PVD coating thickness is typically controlled to a few micrometers to tens of micrometers, neither significantly increasing the weight of the sieve plate nor hindering direct material contact with the substrate, making it suitable for precision screening or high-value-added material handling.
Sandblasting, by high-speed abrasive jetting, forms a uniform uneven structure on the surface, significantly enhancing wear resistance. This process removes the surface oxide layer and microscopic defects, reducing stress concentration points; the resulting compressive stress layer inhibits crack propagation. Optimizing sandblasting parameters (such as abrasive particle size and jet angle) controls surface roughness, improving material flowability while enhancing wear resistance and preventing clogging, making it particularly suitable for screening wet or sticky materials.
Chemical passivation indirectly improves wear resistance by forming a dense oxide film on the stainless steel surface. Although the passivation film is only nanometer thick, it isolates corrosive media, preventing surface quality degradation caused by corrosion. For example, in environments containing corrosive gases such as sulfur and chlorine, passivation treatment can extend the lifespan of screen plates several times over. Furthermore, the passivation film reduces the surface friction coefficient, decreases material adhesion, and maintains long-term stable screening efficiency.
Surface brushing technology creates a regular textured structure through mechanical friction, which can improve wear resistance to a certain extent. The brushing process creates micro-grooves on the surface, guiding material flow, reducing disordered friction, and concealing minor scratches through texture, maintaining a consistent appearance. This process is simple to operate, low in cost, and suitable for scenarios with moderate wear resistance requirements and aesthetic considerations, such as screening equipment in food processing or building decoration.
Composite treatment processes combine multiple surface technologies to achieve a synergistic improvement in wear resistance. For example, sandblasting can be performed first to enhance surface activity, followed by PVD deposition of a wear-resistant coating, and finally passivation treatment to improve corrosion resistance. This multi-layered composite structure can simultaneously address multiple failure modes such as wear, corrosion, and fatigue, significantly extending the service life of the screen plate. Although composite processes are more expensive, they have irreplaceable advantages in high-end equipment or extreme operating conditions.
Optimizing the surface treatment process for stainless steel sieve plates requires selecting the appropriate technical path based on specific operating conditions. Aluminizing and PVD processes are suitable for harsh environments with high wear and corrosion; sandblasting and wire drawing are more suitable for cost-sensitive or medium-load scenarios; and composite processes provide comprehensive solutions for high-end applications. Through innovation and application of surface treatment technologies, the wear resistance of stainless steel sieve plates has shifted from simple material dependence to functional design, providing crucial support for the reliable operation of industrial screening equipment.
