Drawing process of conical ductile cast-iron pipe

The invention discloses a drawing process of a conical ductile cast-iron pipe cast by devices, including a sand mold core, a cast-iron core frame, pipe-drawing calipers, a casting mold and a centrifugal pipe-casting machine. The drawing process comprises the following steps: firstly, putting the dotted casting mold in the centrifugal pipe-casting machine; leading cooling water to the outer wall of the casting mold; mounting the casting mold in the centrifugal pipe-casting machine; mounting the sand mold core on the cast-iron core frame; arranging the cast-iron core frame in the bearing port of the casting mold; pouring molten iron in the fan-shaped ladle of the centrifugal pipe-casting machine; then, starting the automatic pipe-drawing system of the centrifugal pipe-casting machine; drawing to mold; and drawing out the conical ductile cast-iron pipe with the pipe-drawing calipers. In the pipe-drawing process, the drawing speed curve of the automatic pipe-drawing system of the centrifugal pipe-casting machine