1. The cause of the rough particles on the surface of the hot-dip galvanized sheet steel is that there are a lot of iron filings connected to the substrate on the surface of the substrate. After entering the zinc pot, these iron filings react violently with the zinc solution to generate an explosive structure with a large thickness. Thus, rough small particle defects are formed on the surface.
2. The cause of deep iron filings is caused by the "pressing of scale" during the hot rolling of the substrate. In the subsequent pickling process, the scale pressed into the substrate is dissolved by the acid, and the remaining is lifted. Or the raised iron skin formed iron filings.
For the cause of rough particles on the surface of hot-dip galvanized steel products, the control measures are:
1. At the exit of the continuous casting slab or the exit of the slab heating furnace, the thick scale formed on the surface of the slab ("primary scale") should be thoroughly removed to avoid a large number of surface quality problems in the subsequent process.
2. The high-pressure water descaling in the rough rolling process should be thorough, and the quality should be strictly controlled. During the rough rolling process, the slab temperature is high, and oxide scales ("secondary scales") are easily formed between passes, so it is necessary to increase The effect of high-pressure water descaling between passes, such as the scale is not cleanly removed, is brought into the finishing rolling process, thereby causing the "scale intrusion" defect.
