Each kind of test measurement such as Technical Properties (Flattening Test, Bending Test, Blow Test, Impact Test), Exterior Size Inspection, Hydrostatic Test, X-ray Test would be necessary for guarantee of the high quality of steel pipe like seamless steel pipe, galvanized steel pipe. There are some characteristics for visual inspection of non-destructive testing: 1.Weld surface defects test: surface cracks would be the first step for check of the steel pipe and then the impermeability and weld quality of the leak. 2.Detailed exam for raw material for steel pipes production, such as the surface cracks, peeling, cables, scratches, dents, bumps, spots, corrosion and other defects. 3.Cavity detection. This test would carry out according to the engineering projects demand and the engineers requirement. 4. Additional material inspection. Inspect the product for dust, foreign matter and other residues in the cavity.