Welding terms related to weld joints and welds that every welder must know

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Special welding terminology – Termination joint 1. Termination joint: An end joint formed by placing two pieces on top of each other or with an angle between their surfaces of no more than 30°. 2. Crimped joint: A joint in which the ends of the parts to be welded are pre-crimped, and the crimp melts only partially after welding. 3. Sleeve joint: A joint formed by fitting a short tube with a slightly larger diameter over the ends of the two tubes to be connected. 4. Oblique butt joint: A butt joint in which the joint seam is arranged at an angle to the plane of the welded parts. 5. Lock-bottom joint: A joint formed when the end of one piece is placed on the pre-cut bottom edge of another piece. 6. Base metal: A general term for the metal material to be welded. 7. Heat-affected zone: The area in a material where changes occur in its microstructure and mechanical properties as a result of heat exposure during welding or cutting, without the material melting. 8. Overheated zone: In the welding heat-affected zone, the area with overheated structure or significantly enlarged grains. 9. Fusion zone (fusion welding): The transition area where the weld seam meets the base metal; in other words, the partially melted region of the base metal as microscopically observed at the fusion line. 10. Fusion line (fusion welding): The weld contour as observed under macroscopic corrosion on the cross-section of the welded joint. 11. Weld seam: The joint formed in a welded piece as a result of welding. 12. Weld zone: A general term for the weld and its adjacent areas. 13. Weld metal zone: The area of the weld metal measured on the cross-section of the welded joint. During fusion welding, it refers to the area enclosed by the weld surface and the fusion line. In resistance welding, it refers to the molten pool formed after welding. 14. Tack welds: Short welds made prior to welding in order to position and secure the joints of components. Special terms in welding – Load-bearing weld 1. Load-bearing weld: A weld on a welded joint that is used to bear loads. 2. Continuous weld: A weld that is continuously welded. 3. Interrupted welds: Welds that are created at certain intervals apart. 4. Longitudinal welds: Welds that run along the length of the welded piece. 5. Transverse weld: A weld that is perpendicular to the length direction of the welded piece. 6. Circumferential seam: A closed weld that runs around a cylindrical welded part, with its ends connecting to each other. 7. Spiral weld: A weld obtained by welding tube joints formed by winding sheet metal in a spiral pattern. 8. Seal welds: Welds primarily used to prevent fluid leakage. 9. Butt weld: A weld formed between the groove surfaces of welded parts, or between the groove surface of one part and the surface of another part. 10. Fillet weld: A weld formed along the line of intersection of two parts that are perpendicular or nearly perpendicular to each other. 11. Fillet weld with a vertical axis: A fillet weld whose weld axis is perpendicular to the direction of stress in the welded parts. 12. Fillet weld: A fillet weld whose weld axis is parallel to the direction of stress in the welded parts. 13. Parallel intermittent fillet welds: Intermittent fillet welds that are symmetrically arranged on both sides of a T-joint and have essentially equal lengths. 14. Interlaced intermittent fillet welds: Intermittent fillet welds that are arranged alternately on both sides of a T-joint, with essentially equal lengths. 15. Convex fillet weld: A fillet weld whose surface is raised. Special welding terminology: Concave fillet weld 1. Concave fillet weld: A fillet weld whose surface is concave. 2. Terminal weld: The weld formed to constitute a terminal joint. 3. Plug weld: Two parts are overlapped, with a circular hole made in one of them; the weld formed by welding the two plates within that hole is called a plug weld. A weld that is created only at the edges inside the hole is not considered a plug weld. 4. Groove weld: The plates are overlapped, with a long hole made in one of them; a weld is formed by welding the two plates within this hole. A weld that consists only of fillet welds is not considered a groove weld. 5. Weld front side: The surface of the weld as seen from the side of the workpiece where welding was performed, after welding. 6. Back side of the weld: The surface of the weld as seen from the back side of the welded part, after welding. 7. Weld width: The distance between the two weld toes on the surface of the weld. 8. Weld thickness: In the cross-section of the weld, it is the distance from the front side of the weld to the back side of the weld. 9. Calculated weld thickness: The weld thickness used in the design of the weld. When the butt weld is fully penetrated, it is equal to the thickness of the welded parts ； In the case of fillet welds, it corresponds to the length of the perpendicular line from the vertex of the right angle to the hypotenuse in the largest right-angled isosceles triangle drawn within the cross-section of the fillet weld; this value is also commonly referred to as the throat thickness. 10. Weld bead convexity: The maximum distance between the line connecting the weld toes and the weld surface in the cross-section of a convex fillet weld. 11. Weld concavity: In the cross-section of a concave fillet weld, it is the maximum distance between the line connecting the weld toes and the weld surface. 12. Weld toe: The junction between the weld surface and the base metal. 13. Root gap: In the cross-section of a fillet weld, it is the minimum distance from the weld toe on one right-angled face to the surface of the other right-angled face. 14. Leg size: The length of the legs of the largest isosceles right triangle drawn in the cross-section of a fillet weld.