The difference between hot dip galvanized bolts and Dacromet bolts

Thread Content

　　The difference between hot-dip galvanized bolts and Dacromet bolts As more and more people are engaged in the fastener industry, the types of products are becoming more and more complicated. Hot-dip galvanized and Dacromet are both used for surface treatment of bolts. Usually many friends will compare hot-dip galvanized bolts and Dacromet bolts. Which one has better rust and anti-corrosion, generally Dacromet bolts will be chosen, and the advantages are also more obvious. 　　Hot-dip galvanized bolts are also called electroplated bolts because hydrogen embrittlement occurs during pickling and electroplating. On the other hand, the entire process stage of Dacromet bolts is not designed to include electrochemistry, which is the chemical reaction we saw in physics class. The rust removal of Dacromet is carried out by mechanical shot blasting, so Dacromet will not cause any hydrogen embrittlement phenomenon. 　　Bolts must be passivated after hot-dip galvanizing, but passivation is generally performed at room temperature, and the highest temperature will not exceed 100°C, so there will definitely be crystal water in the passivation film. Therefore, the passivation film of hot-dip galvanizing is not resistant to high temperatures. Generally, the skin will crack at around 70°C, because of the presence of crystal water in the film. The film-forming temperature of Dacromet is relatively high (around 280°C), so during the preheating process, the moisture in the film layer has already evaporated. Therefore, the Dacromet film layer is denser than the passivation layer, so it has better corrosion resistance, especially high temperature corrosion resistance. After all, hot-dip galvanizing of bolts is also electroplating, so there will be problems with power line distribution. Dacromet is a kind of paint, so it can be coated by spraying, centrifugal drying, and dipping. The coating is more uniform than electroplating. Therefore, Dacromet is more environmentally friendly than hot-dip galvanizing. But the disadvantage of Dacromet bolts is that they contain chromic anhydride, which pollutes the environment just like electroplating. In addition, Dacromet's zinc powder has very high requirements and high manufacturing costs. Finally, the calcining temperature is higher than that of hot-dip galvanizing, and the cost is also higher than that of hot-dip galvanizing. Therefore, many buyers usually choose hot-dip galvanized bolts, but few choose Dacromet bolts. Compared with ordinary environments, hot-dip galvanized bolts are sufficient. If you choose Dacromet bolts under high temperature or special environment, I hope the above content can clear #FormatImgID_0# clearly illustrates the quality of hot-dip galvanized bolts and Dacromet bolts.