The utility model relates to a die casting uses internal diameter to be quincunx lower mouth of a river brick, include the mouth of a river brick body, box hat and stream steel hole down, flow the steel hole and be the plum blossom physique, with R angle transition between the petal. The plum blossom physique is five lamellas, six lamellas or eight lamellas, and angle between the adjacent petal is 72, four to six -tenehs 0 or 45. The R angle be R5-R10. The utility model discloses water the gathering class of steel process, rectification effect from the optimization of molten steel hydrodynamics angle, prevent to water the steel splash, reduce the molten steel vortex the emergence and to the abnormal erosion at the mouth of a river down, realize the die casting and water the steel security control, lower mouth of a river internal diameter behind the modification overcomes watering that the circular aperture of steel in -process can not be gathered class, the drawback of rectification, prevents the bias flow, reduces and stops up, forms centripetal force, and control potting syrup ground roll moves, guarantees that the liquid level is steady, and it is stable to water the steel, effectively prevents to water the emergence and the aggravation of steel splash phenomenon, guarantees the die casting and waters the security of steel process, improves life.