## 1 Introduction  
The effectiveness of an anti-corrosion coating largely depends on the proper pre-treatment of the substrate surface. This preparation can be performed through mechanical, chemical, or electrochemical methods, each ensuring the required cleanliness and surface roughness of the base material [1]. Mechanical pre-treatments, such as blasting or grinding, serve various industrial purposes, including rounding sharp edges after cutting, removing slag from weld joints, cleaning surfaces after flame cutting, and eliminating scale residues from hot-formed components--cases where chemical pre-treatment (e.g., pickling) may be insufficient. Additionally, surface defects such as laps or flakes, which commonly occur on forged semi-finished products, can be effectively addressed through mechanical methods [2]. Blasting treatments primarily modify the surface through mechanical action. This category includes both conventional and unconventional methods, such as machining with loose abrasive particles carried in a stream of water, air, or other gases [3]. In practice, abrasive particles are either angular or spherical and can be propelled using compressed air or rotating blades--both widely adopted in industrial applications. An alternative approach involves simulating blasting technology using specially shaped steel bristles [4; 5]. Abrasive materials can be categorized into three groups:  
* Natural abrasives (e.g., silica sand, flint, garnet, zircon). * Agricultural by-products (e.g., walnut shells, corn cobs). * Industrially manufactured abrasives (e.g., steel shots, aluminum oxide, silicon carbide, plastics, glass beads). The choice of abrasive material is critical, as different abrasives create distinct surface profiles. The resulting surface roughness depends on multiple factors, including abrasive type, size, and hardness, as well as blasting parameters such as kinetic energy, impact angle, and standoff distance. Achieving a consistent surface profile requires proper operator training and process control [6; 7; 8; 9; 10]. In addition to blasting, grinding is another mechanical pre-treatment method, where material removal predominates over surface deformation. Unlike blasting, grinding is typically performed at lower cutting speeds with intensive cooling, ensuring minimal thermal influence on surface integrity. In cases where cooling is insufficient, the process may involve a combination of mechanical and thermal effects, leading to localized grain deformation and surface irregularities [11]. In this study, grinding was performed using new abrasive inserts and a custom-designed fixture to maintain a low cutting speed. Given the fundamental differences in their mechanisms, blasting and grinding treatments were expected to yield distinct effects on surface integrity. Zinc coatings can be applied using either conventional or alternative methods, with the objective of optimizing production costs while maintaining coating quality. Conventional zinc coating processes involve multiple pre-treatment steps tailored to the specific material properties of the substrate. However, a major drawback of these methods is their extensive reliance on chemical substances, which pose environmental and health risks. Consequently, alternative mechanical pre-treatment techniques are being explored to minimize chemical usage in surface preparation [12; 13; 14; 15]. The need for alternative methods is further emphasized by the significant environmental impact of traditional galvanic coating processes. Within the European Union, approximately 100,000 tonnes of sludge are generated annually from electroplating operations, while in China, this figure exceeds 10 million tonnes, with an additional 1 million tonnes produced globally. Furthermore, wastewater volumes from these processes are estimated to be 40 times greater than sludge production. Notably, wastewater treatment technologies vary significantly across regions, with Japan, the United States, and Western Europe implementing the most advanced solutions [16].