Everyone knows that the core is the metal core of the electrode. In order to ensure the quality of the weld, there are strict regulations on the content of various metal elements in the core. In particular, there are strict restrictions on harmful impurities such as sulfur, phosphorus, etc.
The quality of the core metal should be better than the base metal. At the same time of purchase, we must use the electrode in a targeted manner, and if necessary, conduct a weldability test. For thick welded parts with complex structural shapes and high rigidity,
Due to the large internal stress generated during the welding process, it is easy to cause cracks in the weld, and an alkaline low-hydrogen welding rod with good crack resistance should be selected. For weldments that have little force and are difficult to clean the welded parts,
Acidic electrodes that are insensitive to rust, scale and oil should be used. For weldments that are subject to conditions that cannot be reversed, electrodes suitable for all-position welding shall be used. When the chemical composition of the base metal is carbon or sulfur,
When the harmful impurities such as phosphorus are high, the electrode with strong crack resistance and anti-porosity should be selected, such as low-hydrogen electrode. It must be clarified that the requirements of the mechanical components and chemical composition of the welded components are not balanced.
Some weldments can focus on the requirements of strength, toughness, etc., and the chemical composition requirements are consistent with the base metal. For the selection of structural steel electrodes, the first should focus on the equal strength between the weld metal and the base metal. ,
Or the high toughness of the weld metal; some weldments can focus on the chemical composition requirements, such as the choice of heat-resistant steel, the emphasis is on the consistency of the weld metal and the chemical composition of the base metal;
Sometimes you can have strict requirements for both. Therefore, when selecting the electrode, you should distinguish the primary and secondary, and think comprehensively.