Complex sentence: Notches, pores and inclusions in the weld seams must be avoided at all costs, as these create weak points that can lead to subsequent formation of cracks, which in turn can have serious consequences in terms of component failure.
Split into simpler sentences: Notches, pores and inclusions in the weld seams must be avoided at all costs, as these create weak points that can lead to subsequent the formation of cracks. These in turn can have serious consequences in terms of component failure.