what is Heat affected zone

what is Heat Affected Zone – HAZ in welding?

Base metal vs HAZ Metals in welding results can be categorized into 3 parts, namely: base metal (initial workpiece), heat affected zone (heat affected area) and weld metal (weld metal). The base metal is a base metal part where heat and welding temperature do not cause changes in the structure or properties of the metal. The heat affected zone (HAZ) is a base metal that is adjacent to the weld metal which undergoes a thermal cycle of heating and cooling during the welding process so that this area is the most critical of the welded joint. Weld metal is a part of metal which at the time of welding melts and then freezes, the composition of the weld metal consists of the parent metal component and the added material from the electrode. The heat affected zone is formed during welding and includes the area of the material next to the weld, in which metallographic examinations can still detect structural changes through the welding process. These microstructural changes also change the properties of the material, so that the smallest possible HAZ is sought. This is achieved with low energy range, ie as concentrated as possible heat input at high welding speed,[…]

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