Final answer:
To reweld a welded joint, first remove existing defects and old weld material, then clean and prepare the joint for rewelding according to specified techniques and standards.
Step-by-step explanation:
When a welded joint needs to be rewelded, it is crucial to first thoroughly remove any existing defects and old weld material to ensure the integrity of the rewelding process. This typically involves grinding down or cutting out the defective weld and then cleaning the area to remove any contaminants or impurities that might affect the quality of the new weld. The joint should be prepared following the specifications for the weld, which may include proper beveling or joint configuration to accommodate the new weld.
Furthermore, the metal surfaces should be appropriately aligned and held securely during the welding process to prevent any misalignment or welding stress issues. It's essential to follow a welding procedure specification (WPS) that outlines the specific techniques, materials, and steps necessary to produce a quality weld that will meet or exceed the required performance standards.
If a welded joint needs to be rewelded, several steps should be taken to ensure a successful rework. First, the old weld should be removed completely using methods like grinding or gouging. This is important to eliminate any defects, contaminants, or weak spots in the joint. Then, the surface should be cleaned to ensure proper fusion and penetration during the rewelding process. Finally, the joint should be preheated if necessary, and the appropriate welding technique and parameters should be used to create a strong and durable new weld.