The surface treatment of a stainless steel rolling grill directly affects its stain resistance, a crucial characteristic for outdoor grilling. Oil, seasoning residue, and high-temperature carbon deposits generated during grilling easily adhere to the grill's surface. Improper treatment not only increases cleaning difficulty but can also lead to material corrosion due to stain penetration, shortening its lifespan. Therefore, the choice of surface treatment process must balance stain resistance, corrosion resistance, and ease of use.
Mechanical polishing is a common surface treatment method. Using tools such as sandpaper and grinding wheels, the stainless steel surface achieves a mirror or matte finish. This process significantly improves surface smoothness and reduces the area for oil stain adhesion. For example, a finely polished stainless steel rolling grill can have a surface roughness reduced to below Ra0.2μm, making it difficult for oil stains to embed in the microscopic irregularities. Cleaning only requires wiping with a damp cloth to remove most residue. However, improper mechanical polishing can leave micro-scratches on the surface. These scratches become "channels" for stain accumulation, ultimately reducing stain resistance over long-term use.
Chemical polishing dissolves surface impurities using a specific solution, achieving an overall smooth finish. Compared to mechanical polishing, chemical polishing can handle complex structures, such as the hinges and supports of a rolling grill, ensuring thorough cleaning. However, chemical polishing requires strict control of the solution composition and temperature; otherwise, it may lead to excessive surface corrosion, forming a microporous structure and increasing the risk of stain penetration. Furthermore, the acid fumes generated during chemical polishing must be exhausted through ventilation equipment; otherwise, they may pose a hazard to the environment and operators.
Sandblasting uses high-speed jets of glass beads or quartz sand to create a uniform matte texture on stainless steel surfaces. This process increases the surface friction coefficient, preventing food from slipping, while also concealing original defects and improving aesthetics. For rolling grills, sandblasting also enhances surface hardness, resisting scratches from grilling tools and reducing the chance of stain adhesion. However, the surface roughness after sandblasting is relatively high. If no subsequent passivation treatment is performed, iron elements from the sand particles may remain, forming micro-batteries with the stainless steel, causing galvanic corrosion and reducing stain resistance and durability.
Passivation is a crucial step in stainless steel surface treatment. It forms a dense chromium oxide protective film, preventing corrosive media from contacting the substrate. For rolling grills, passivation significantly improves their resistance to salt spray and oil stains. For example, passivated stainless steel exhibits a corrosion rate reduction of over 80% in humid environments, and oil stains are more easily washed away with water. Passivation must be combined with preceding treatments (such as sandblasting and polishing). Residual impurities from previous processes can damage the passivation film, leading to localized decreased stain resistance.
Brushing creates straight lines on the stainless steel surface through mechanical friction, enhancing both aesthetics and providing some anti-slip properties. For rolling grills, brushing can conceal minor scratches and reduce the visibility of fingerprints and oil stains. However, the depth and direction of the brushed lines must be strictly controlled. Overly deep or irregularly oriented lines can become a breeding ground for stains, increasing cleaning difficulty.
Food-grade coating is a direct means of improving stain resistance. By applying fingerprint-resistant paint or ceramic coatings via roller coating or spraying, a hydrophobic and oleophobic layer is formed on the stainless steel surface, making it difficult for oil stains to adhere. For example, stainless steel rolling grills with nano-ceramic coatings can have a contact angle of over 110°, causing oil stains to easily form water droplets that roll off, requiring only rinsing with water for cleaning. However, the coating thickness must be uniform; if it is too thin in some areas, wear may cause it to lose its anti-fouling properties.
The anti-fouling properties of stainless steel rolling grills require a multi-stage surface treatment process. Mechanical polishing or sandblasting provides basic smoothness and hardness, passivation builds a corrosion-resistant barrier, and brushing or coating enhances aesthetics and ease of cleaning. In actual production, the appropriate combination of processes should be selected based on the usage scenario (e.g., outdoor or indoor) and cost budget. For example, outdoor barbecue grills can prioritize a sandblasting + passivation + coating process, balancing weather resistance and anti-fouling properties; indoor household products can simplify the process, primarily using mechanical polishing + passivation to reduce costs while meeting daily cleaning needs.
