A method including obtaining a metal pipe with a longitudinal submerged arc weld, an axis of the longitudinal submerged arc weld being oriented parallel to a rotationally symmetric axis of the metal pipe and cutting a first test beam and a second test beam from the metal pipe with each test beam extending on both sides of the axis of the longitudinal submerged arc weld and has a cuboid shape. The method further including forming a double-beam assembly by clamping two spacers between the first and second test beams such that the two spacers are symmetrically disposed at an equal distance on either side the longitudinal submerged arc weld. The method further including immersing the double-beam assembly in a liquid test solution for a predetermined period of time before removing it from the liquid test solution and disassembling the double-beam. The method further including examining the first and the second test beam using a metallographic sectioning method.