What is the specific reason for the appearance of white spots on the surface of aluminum alloy hand boards after anodizing? For this issue, if the aluminum alloy hand board has this defect problem, it may be because its structure is too loose, causing the material's porosity to be too high. If there are too many impurities in the raw material, it can also lead to this problem. So, we need to take some necessary measures to solve and prevent:
Method 1: High voltage and high current density impulse method. In the early stage of anodizing, high voltage and high current surges are used to connect the previously separated "islands" of different sizes by impurities into pieces through high current surges. Then, after thorough cleaning, a satisfactory oxide film can be obtained, and the white spots basically disappear.
The slight drawback of the above method is that if the hand board has screw holes, it may slightly expand. Therefore, it is necessary to control the high current density, high voltage anodizing time, and prevent the temperature of the anodizing solution from rising too quickly. During continuous production, cooling measures should be taken for the anodic oxidation solution.
Method 2: Hand board surface polishing method. Polishing can fill the pores of the hand board with ground aluminum powder, serving as a bridge connecting blocks "islands" isolated by impurities.
Because the polished aluminum powder sometimes fails to serve as a true filling or bridging material, some parts of the filling material may corrode and fall off during alkaline corrosion and anodic oxidation processes.
Method 3: Hand board surface shot peening method. Before the shot peening method was tried, the author used a round headed hammer to knock on the gap that separated the "island". The original intention was to close it by knocking, achieving the goal of connecting it into pieces, and the results were significant.
What is the yield strength of aluminum alloy hand boards related to? What is the tolerance for it? And how should materials be selected in aluminum hand boards? The yield strength of aluminum alloy hand boards is mainly determined by the aluminum alloy grade. The tolerance for this type of hand board is generally 0.2-0.5 on a lathe.
The material selection of aluminum alloy hand boards depends on the specific situation. If it is a flipped part, then the molding sand used for flipping should be used. If it is a hand board, then the steel grade 3Cr2W8V should be used because it is a heat-resistant steel that is not easily deformed and cracked at high temperatures.
