LPG storage tank raw material production

② Welding evaluation cannot cover up the whole process. The tube sheet of a heat exchanger is 40mm, the simplified is 10mm, and the connection between the simplified and the tube sheet is a corner joint butt weld. The thickness of the welding evaluation test piece is 12mm, which cannot be covered up to 40mm. The production unit mistook the corner joint butt weld seam for the corner joint. In fact full penetration fillet joints are butt welds.