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Welding Defects of Bond Leakage Steel and Its Causes
Bonding leak steel, also known as welding slag or welding slag, is a defect that occurs during welding. Its general process is that the molten steel overflowed from the welding seam and solidified on the surface of the material. Through the metal cutting tools, it appears as leaks and rifts, fish scale shaped pits, etc. It is mostly caused by improper operation during welding.
Bonding leak steel appears in all welding processes. In particular, the appearance of bonding leak steel seriously affects the welding quality of alloy steel and steel materials. Its occurrence not only affects the aesthetics of the welded joints, but also reduces the strength, stiffness and fatigue strength of the welded joints, and even increases the risk of cracking.
So why does bonding leak steel occur? There are mainly the following reasons:
1. Improper welding speed is too fast. When welding speed is too fast, insufficient time allows welding materials to melt sufficiently, and overflow occurs along the welding seams. The welds are not full and bond leaks appear.
2. Improper welding voltage and current. Generally speaking, if the welding voltage and current are too high, the heat generated during welding is also high. If the current is higher than the recommended value, the heat generated will be too large and the welding pool will become too large. This will cause the molten material to overflow, resulting in bonding leakage.
3.Poor cleaning of welding surface. Incomplete cleaning of the weld surface will cause oxide scaling, dust, dirt and other impurities. When these impurities reach a certain level, they will affect the connection of the weld material molecules, making the welding joint production difficult, overabsorbing the charging energy, causing the weld pool to be too large, and resulting in bonding leakage.
4.Insufficient welding light. The blowhole formed by inadequate welding weight is too small, and the welding material cannot fill the gap, so that the gap is sealed.
5.Insufficient joint surface or welding gap. The welding gap should be appropriate. If the gap is too large, the contact area between the two welds is too small, and the welding material overflows after melting.
6.Impact of ambient temperature. The temperature of the environment has a great influence on welding. The temperature of the material before welding should not be lower than 0℃. If the environment temperature is too low, it will cause the surface of the material to freeze, which will reduce the adhesive effect of the welded joint surface.
7. Improper gas protection. The gas in the surrounding environment has an influence on welding. If the gas is used improperly, small bubbles or cracks will form on the surface of the weld, resulting in bonding leakage.
The occurrence of welding defects of bonding leakage steel can not only lead to a decrease in the strength of the welded joint, but also worsen the environment, greatly waste materials and reduce production efficiency. Therefore, it is necessary to improve the welding process, pay attention to the operation, ensure good welding conditions and select high-quality welding materials to make the whole welding process meet the requirements of welding quality.
