... , thus it has excellent mechanical properties. D: Compared with the centrifugal cast pipeThere is no concentration gradient of alloying ... osteoporosis, trachoma, porosity and other casting defects. E: Compared with sand casting There is no slag, clamping sand, porosity, ... 7 class for the ball diameter, ball number 400-600/ mm2 Compared with sand casting, when the same strength, elongation increased ...