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1 What is an acidic welding electrode? Answer: Welding electrodes whose flux contains large amounts of acidic oxides, such as Jie 422 (E4303) and Jie 502 (E5003), which are suitable for both AC and DC welding. 2 What is an alkaline welding electrode? Answer: Welding electrodes whose flux contains large amounts of basic oxides as well as fluorides, such as Jie 507 (E5015) and Jie 506 (E5016) and other similar welding electrodes. 3 What is a cellulose-type electrode (specific for vertical down welding)? Answer: Welding rods with a flux coating containing large amounts of organic substances, designed specifically for vertical welding in pipeline and thin-plate structures. 〈1〉E6010 (equivalent to E4310, J425G) is suitable for root welding, heat welding, and fill welding. 〈2〉E8010 (equivalent to E5511, J555) is suitable for hot welding, filler welding, and surfacing layers. Generally, low-hydrogen downward welding electrodes are used for the overlay weld ； The weld shape of E7048 (equivalent to J506X) is neat and aesthetically pleasing. 4 Why must welding rods be dried thoroughly before welding? Answer: Welding electrodes often experience a deterioration in their performance due to moisture absorption, which leads to an unstable arc, increased spatter, and an increased likelihood of defects such as pores and cracks. Therefore, the welding rod must be thoroughly dried before use. Generally, the drying temperature for acidic welding electrodes is 150–200°C, with a duration of 1 hour ； The drying temperature for alkaline electrodes is 350–400°C, with a drying time of 1–2 hours. After drying, they are placed in an incubator at 100–150°C and can be retrieved as needed. Image 5: What is welding wire? Answer: The metal wire used as filler material during welding and also for conducting electricity is called welding wire. It is divided into solid wire and flux-cored wire. Common solid wire grades: ER50-6 (grade: H08Mn2SiA). 6 What is flux-cored wire? Answer: It is a type of welding wire made by rolling thin steel strips into circular steel tubes and then filling them with powder of a specific composition, followed by drawing. 7 Why is CO2 gas used for shielding flux-cored wires? Answer: Based on the protection method, flux-cored wires are divided into two types: flux-cored gas-shielded welding wires and flux-cored self-shielded welding wires. Flux-cored gas shielded welding wires generally use CO2 gas for protection, belonging to the combined gas-slag shielding method; they yield welds with good shape and high overall mechanical properties. 8 Under what circumstances should welding materials be scrapped? The welding core is corroded, the flux is stuck to it or has peeled off, and it is severely damp (especially in the case of low-hydrogen electrodes, electrodes for heat-resistant steel, and electrodes for low-temperature steel). Such electrodes cannot be used any longer and must be discarded. 9 What are the effects of damp welding rods? When a welding rod becomes damp, its coating usually turns darker; when the rod is tapped, it no longer produces a clear metallic sound, and in some cases alkali reappears, resulting in \"white spots\" on the surface. Impact of moist electrodes on welding processes: (1) Unstable arc, increased spatter, and larger spatter particles. (2) Large penetration depth, prone to edge chipping. (3) The slag coverage is poor, and the weld bead is rough. (4) Slag removal is difficult. The impact of moist electrodes on welding quality: (1) They tend to cause welding cracks and pores, especially with alkaline electrodes. (2) The values of various mechanical properties tend to be low. 10 What are the effects of moisture on welding wire? Moisture-absorbing welding wire can increase the content of diffused hydrogen in the deposited metal, resulting in defects such as pits and pores. This deteriorates the welding process parameters as well as the mechanical properties of the weld metal; in severe cases, it can even cause the weld to crack.