Hardness of Welded Joints
Generally the grain size of the weld metal is smaller than that of the parent metal - its strength is greater
Pores and defects can reduce its fracture and fatigue resistance
Formation of high hardness (BHN) layers in the HAZ due to martensite formation can be a problem
Excessive grain growth in the HAZ can reduce joint strength in slow welding processes (e.g. electroslag)