What is a welded joint?

Definition of a Welded Joint: A welded joint is a point where two or more parts are joined by welding. Alternatively, it refers to a joint where two or more parts are connected by welding, including the weld, fusion zone, and heat-affected zone. Fusion welding joints are formed by localized heating from a high-temperature heat source. A welded joint consists of weld metal, fusion zone, heat-affected zone, and base metal.

Components of a Welded Joint: A welded joint includes the following components:

Weld: During welding, the workpiece is heated by an electric arc, and the base metal and filler metal melt to form a molten pool. After the heat source is removed, the molten metal cools and crystallizes, forming the weld.

Fusing Zone: The fusion zone is a narrow area between the weld and the base metal. The metal is partially molten, with larger grains, and its plasticity and toughness are reduced. It is the weakest area in the welded joint and the transition zone between the weld and the heat-affected zone.

Heat-affected zone: During the welding process, the base material near the weld is also subjected to the heat of the electric arc. The microstructure and properties of this part of the base material will change. This changed base material area is called the heat-affected zone of the weld.