公称管径 Nominal Bore ; nominal pipe size

公称管壁厚度 pipe nominal wall thickness

管公称通径 Outlet Size

油管公称外径 [油气] nominal outside diameter of tubing

油管公称尺寸 [油气] nominal size of tubing

油管公称质量 [油气] nominal mass of tubing

导管的公称尺寸 Nominal dimension of tube