How to repair cracks in the cylinder of the ball mill

Cracking of the cylinder of a ball mill is generally caused by two reasons.One is that the welding quality of the cylinder itself is poor or the quality of the steel plate of the cylinder does not meet the requirements, the bending strength is not enough, and the fatigue breaks; the other is that after the loading capacity of the ball mill is increased during the production process, the force of the steel plate of the cylinder exceeds the design specifications, or other reasons cause the cylinder to break or crack due to overload.For some mills with a long service life, due to the severe wear and tear of individual parts of the cylinder body, the strength of the cylinder body is not enough and cracks appear.What are the repair methods for cracks in the cylinder of the ball mill?

Determination of welding repair plan：

Conventional repair method: Remove the large ring gear on the cylinder body, plan out the double-sided V-shaped bevel with a gouging, and adopt a multi-layer and multi-channel welding process.The disassembly of the large ring gear takes 20 days, and the repair period is long and the cost is high.；

On-site repair method: Directly remove the liner of the mill, use a slow drive to transfer the cracks in the cylinder to a horizontal position, plan out a single-sided V-shaped bevel with a gouging, and use CO2 gas shielded welding.The oblique cracks at both ends adopt the root-clearing welding process; the copper plate joints are used on the back of the ring cracks, and the front filling layer adopts a multi-layer and multi-channel welding process.Generally, on-site repair programs are used.

For cracks in the cylinder body due to years of use and wear, a layer of 16—20mm steel plate (depending on the thickness of the steel plate of the original cylinder) should be coated on the original cylinder body during repair. The steel plate itself adopts single-sided welding at the interface along the axis of the mill.For the connection between the steel plate and the cylinder, rivets are used to rivet 2-3 circles along the edges of both ends of the steel plate, and electric welding is disabled, otherwise the welds at the lap joints are easy to crack.