Why Does Flash Rust Occur Behind Weld Seams? Qingdao Enze Chemical Tells You

Recently, a customer from Jiangsu contacted us to consult about flash rust issues. The customer reported that after applying anti-rust paint, rust spots of varying degrees appeared for unknown reasons, especially on weld seams—some even developed flash rust before the paint dried. During steel structure construction, the excessive pursuit of coating efficiency sometimes leads to direct application of anti-corrosion paint without treating the steel structure materials after welding, leaving slag on the weld seams. However, due to the high temperature of the welded area and the instability of welding materials after welding, the rough surface and impurities between the weld seams are more likely to react with water and oxygen before the water-based anti-corrosion paint takes effect, resulting in flash rust. After a period of time, the coating will also experience problems such as peeling, rusting, and bubbling, losing its protective effect.

After years of research and analysis on the causes of "flash rust", our company found that the most direct way to effectively prevent flash rust at weld seams is to use flash rust inhibitors. Finally, we recommended flash rust inhibitor CK25 to the customer, and adding only 1% solved the problem. The high-efficiency and practical CK-25 anti-flash rust agent is composed of phosphate and various organic compounds. It exhibits excellent flash rust prevention performance on metal surfaces such as weld seams and cast iron, and can also provide outstanding flash rust protection in high-temperature and high-humidity environments. Moreover, it does not affect the coating's adhesion to the substrate or its salt spray resistance. It can be added at any stage of anti-corrosion paint production, and even with a low addition amount on hard-to-treat weld seams, it can achieve excellent flash rust prevention results. Not only applicable to weld seams, but it can also effectively prevent iron ionization on cast iron parts where flash rust is difficult to avoid, inhibiting iron oxidation in the air and preventing flash rust issues.

Fear of flash rust? Choose Enze—especially suitable for weld seams.