Parameters Governing the Structure and the Mechanical Properties in the Heat-affected Zone of Structural Steels.

Fusion-type welding causes changes to occur in the structure of the heat-affected zone, thus influencing the properties of the steels. The changes in the properties of the structural steels are most pronounced in the coarse-grained area of the heat-affected zone. The factors governing the mechanical properties there are the chemical composition of the base metal and the welding conditions. Increasing the cooling time during welding results in a reduction in the maximum hardness of the heat-affected zone. Increasing the cooling time simultaneously affects the toughness of the heat-affected zone.