Hitsisauma

Hitsisauma, in Finnish welding terminology, refers to a weld seam—the fused line where two metal parts are joined by welding. The seam results from processes such as shielded metal arc welding (SMAW), gas metal arc welding (GMAW/MIG), and gas tungsten arc welding (GTAW/TIG). Depending on geometry, hitsisauma can be a butt weld, fillet weld, or a long seam weld along the joint. The quality of the seam depends on edge preparation, fit-up, heat input, filler material, and welding parameters. A sound hitsisauma forms a continuous fusion zone with a detectable weld bead on the joint face; improper technique can produce porosity, lack of fusion, cracks, or excessive reinforcement.

Inspection and standards: Weld seams are evaluated through non-destructive testing and visual inspection, with radiography, ultrasonic testing, dye penetrant testing, and magnetic particle testing used as appropriate. International and national standards provide criteria for weld size, reinforcement, and acceptance. Commonly used references include ISO welding standards and industry norms such as AWS or EN specifications. The welder's qualification and the welding procedure specification govern how a hitsisauma is produced and assessed.

Applications and maintenance: Hitsisauma is found in construction, manufacturing, and shipbuilding where metal joints must withstand loads, corrosion, and fatigue. Proper surface preparation, post-weld cleaning, and, when required, post-weld heat treatment help ensure long-term performance.

Etymology: The term derives from Finnish hitsata, "to weld," and sauma, "joint" or "seam."