Plastic deformation in the 304L dish head of a pressure vessel occurs both during production and as part of the strain-strengthening process. Often, the plastic deformation that happens during production is overlooked, even though it can be significant, reaching up to 40%. Different parts of the head experience varying degrees of plastic deformation. The most noticeable effect is the variation in wall thickness: it is thinnest at the small arc, thickest at the straight side, and constantly changing along the large arc. The top area of the head also has a smaller wall thickness. Due to the substantial plastic deformation during forming, the mechanical properties of the head are affected, and 304L undergoes work hardening, which increases its yield strength.