Screw rod for screw extruder

The utility model relates to a screw rod for a screw extruder, belonging to the technical field of extruder equipment. The screw rod for the screw extruder comprises a screw rod body (1), wherein the rear section of the screw rod body (1) is provided with a key slot (3); the front end of the screw rod body (1) has a mounting hole (4); the mounting hole (4) is internally provided with a mixing extrusion head (2); the mixing extrusion head (2) is connected with the screw rod body (1) by threads; the outer surface of the screw rod body (1) is provided with a first thread (5); the first thread (5) is divided into three sections; the screw pitches of the three sections of threads of the first thread (5) are gradually increased from front to back; the depth of a spiral groove is gradually increased from front to back; the head of the mixing extrusion head (2) is conical; the surface of the conical head of the mixing extrusion head (2) is provided with a second thread (6). The screw rod for the screw extruder is large in compression ratio and high in propelling force, and is closely matched with a machine barrel flange; after the screw rod is used, materials are not remained, and a blind angle does not exist.