hitsaaminen

Hitsaaminen, or welding, is a fabrication process that joins two or more pieces of material, typically metals, by coalescence. The joining occurs by heating the workpieces to the melting point, applying pressure, and/or introducing a filler material, with shielding to prevent contamination. The result is a strong bond that, depending on the process and materials, can be as strong as the parent metal.

Common welding methods include arc welding (shielded metal arc welding SMAW; metal inert gas MIG/MAG welding; flux-cored FCAW; tungsten inert gas GTAW/TIG), which use an electric arc as the heat source. Other methods are resistance welding (spot and seam welding), laser welding, plasma arc welding, friction welding, and ultrasonic welding for plastics. Each method has different heat input, speed, protection, and suitability for materials and joint types.

Materials commonly joined by welding include carbon steel, stainless steel, aluminum, and other metals; some thermoplastics can be joined by ultrasonic welding. Successful welding requires proper joint design, surface preparation, and compatibility of materials. Quality is assessed by inspection and testing for defects such as porosity, cracks, and inclusions, as well as dimensional accuracy. Safety concerns include exposure to fumes and radiant energy, burns, and fire hazards; operations require protective gear, ventilation, and adherence to relevant standards and procedures.