covered electrode

Coated electrode refers to a coating made by mixing chemical powders such as oxides, carbonates, silicates, organic compounds, fluorides, and ferroalloys in a certain formula ratio on the surface of the electrode. The main components of coated electrodes include the core and coating.

Basic functions of coated welding rods
Protective effect: The coating will gradually melt during the welding process, forming a protective cover that covers the arc and molten pool, preventing harmful substances in the air from directly contacting the arc and molten pool. At the same time, the coating will release gas and form slag, further protecting the arc and molten pool.
Metallurgical reaction: The coating undergoes metallurgical reaction during welding, removing impurities from the weld through processes such as deoxidation, desulfurization, and dephosphorization, and alloying the weld metal.
Optimizing welding process: Coating can improve welding process performance, making the arc easy to ignite and stable to burn, reducing welding spatter, increasing penetration depth, and ensuring the forming quality of the weld seam.
Special function: Some specialized welding rods will add special ingredients to the coating to meet specific welding needs. For example, the iron powder contained in the coating of iron powder welding rods can increase the deposition coefficient of the welding rod and improve welding production efficiency.
Classification of drug skins and their application in welding
According to the differences in mineral composition in the coating, electrode coatings are mainly divided into two categories: acidic coatings and alkaline coatings.

Acidic coating: mainly composed of acidic oxides, it has strong oxidizing properties on the weld metal and may cause the burning of alloying elements in the weld metal. Acidic welding rods have low sensitivity to porosity and are suitable for welding with AC or DC power sources.
Alkaline coating: mainly composed of alkaline oxides, with less oxidation effect on weld metal and better metallurgical treatment effect. The weld metal welded with alkaline electrodes has low hydrogen content and good comprehensive mechanical properties, especially in terms of plasticity and toughness, but is highly sensitive to porosity.
The mechanism of action of coated electrode in welding
The coating will melt and form slag during the welding process. According to the properties of slag, welding rods can be divided into acidic welding rods and alkaline welding rods. The slag of acidic welding rods is mainly composed of acidic oxides, which have strong oxidizing properties on the weld metal and may lead to the burning of alloying elements in the weld metal.