Causes of the impact crusher rotor fracture:

(1) The thickness of the fractured rib plate is 150mm, and there are manufacturing defects inside the rib plate;

(2) There is stress concentration at one end of the rib plate at both ends of the crack;

(3) Each plate hammer is fixed by the inclined fastening plates under the three rib plates. The three fastening plates may have inconsistent bolt tightening forces, resulting in inconsistent stress on the rib plates. One of the fastening plates is subjected to excessive stress, causing the rib plate to fracture.

Since there are no spare parts for the rotor and the scheduled maintenance time has not arrived, coupled with heavy production tasks, only emergency measures can be taken:

(1) A 50mm wide and 50mm deep groove is cut on both sides of the crack with a carbon arc gouging machine, and the groove is polished with a grinder;

(2) The crack is welded with two-way welding, and ER50-6 welding wire is selected;

(3) The same reinforcement plate is welded on both sides of the fractured rib plate and the rib plate at the symmetrical position of the rib plate. The reinforcement plate is made of Q345B and welded with two-way welding wire ER50-6. Rotor balance was considered during welding. After the cracks were repaired, the vibration returned to normal upon startup, but the machine was put into operation without balancing.

We learned that after repairing the broken rotor of the impact crusher, the equipment has been operating normally for nearly six months, with no impact on production. Considering operational reliability and actual production conditions, the rotor was considered for replacement during the overhaul.