Peening trials in No. 1 Ship Shop, Portsmouth Dockyard, Hampshire.

Two men taking accurate linear measurements of a sheet of steel after welding during peening trials held in No. 1 Ship Shop in Portsmouth Dockyard. The test piece is number 1 and it is marked "Unconstrained, not peened. Top vee complete. Root run chipped out." Peening is the process of working a metal's surface to improve its material properties, especially after welding to help relieve the tensile stresses that develop on cooling in the welded metal (as well as the surrounding base metal).