Ouyigang Stainless Steel 8K Mirror Polishing Process

The Meaning of "8K": The "8" denotes the proportion of alloying elements (primarily referring to nickel content), while the "K" indicates the reflectivity grade achieved after polishing (Grade K signifies a mirror-finish reflectivity level). A higher numerical value corresponds to a finer surface finish (e.g., 10K, 12K); however, 8K is already sufficient to meet the requirements of most high-end decorative applications.

I.Stainless Steel 8K Mirror Finish Production Process Flow

Material Selection for the Pre-treatment Phase: Select 304 or 316 stainless steel sheets, ensuring the surface is flat, free of scratches, and devoid of oxidation spots. Surface Cleaning: Employ chemical or physical methods (such as acid pickling, electrolytic polishing, etc.) to thoroughly remove impurities such as grease, dust, and mill scale.

Ⅱ.Grinding and Polishing Stage (Core Process)

Coarse Grinding: Use an 80–120 grit sanding belt to remove oxide layers, weld spots, and scratches.

Medium Grinding: Use a 400–600 grit sanding belt to eliminate coarse grinding marks and further smooth the surface.

Fine Grinding: Use an 800–1000 grit sanding belt to create a refined base surface.

Mirror Polishing: Use a cloth wheel combined with polishing paste or nano-alumina polishing fluid to achieve a final, high-gloss mirror finish.

Ⅲ.Key Process Points

Equipment Requirements: Utilize an 8K surface polishing machine (mirror-finish steel machine), typically comprising 10 to 15 sets of polishing discs; each set consists of 8 discs, with different specifications of polishing heads selected for fine and coarse grinding stages.

Pressure Control: Maintain uniform pressure during polishing; excessive pressure will, in fact, reduce reflectivity.

Temperature Management: Prompt cooling is essential to prevent material overheating, which can lead to oxidation and color discoloration.

Directional Consistency: All grinding steps must be executed in the same operational direction.

Cleaning Requirements: The surface must be thoroughly cleaned of all residues following each processing stage.

Ⅳ.Quality Inspection Standards: Surface Roughness

Ra ≤ 0.05 μm. Gloss: ≥ 700–900 GU (Gloss Units) at a 60° measurement angle; exceeding the 8K standard, it can reach ≥ 900 GU. Reflectivity: The 8K standard signifies that the clarity of the surface's reflected image achieves a resolution level of 8,000 lines.

8K Mirror Polishing Machine

Ouyigang has independently developed an 8K surface polishing machine. The current facility houses three mirror-polishing production lines capable of performing stainless steel surface polishing operations. These lines are capable of achieving various grades of polishing finishes—meeting the diverse requirements of a wide range of clients—and cover grades ranging from 6K, 7K, and 8K to the ultra-precision 12K standard.

The mirror polishing machine is simple to operate; the operator merely needs to place the stainless steel coil onto the loading trolley and secure it to the tension table using the pinch-and-leveling mechanism. Once the automatic mirror polishing machine is started, the processing sequence can be controlled via an electronic touch screen, allowing for adjustments based on the specific operating conditions of each polishing unit. The machine automatically completes the polishing task within the preset timeframe and then shuts down, at which point the stainless steel coil can simply be unloaded from the worktable. The objective of coarse polishing is to remove the surface damage layer resulting from prior grinding; consequently, this stage requires the maximum possible polishing rate. While surface damage induced by coarse polishing is a secondary consideration, it should nonetheless be minimized to the greatest extent possible. This is followed by fine polishing (also known as final polishing), the purpose of which is to eliminate the surface damage generated during the coarse polishing stage and to reduce overall polishing-induced damage to an absolute minimum.

Ouyigang holds ISO 9001:2015 and CE certifications and strictly adheres to international polishing process standards. All mirror-finish steel leaving our facility undergoes a rigorous triple-stage optical inspection to ensure that every batch meets the required standards for gloss, flatness, and reflective consistency.