This is a very interesting case. There are rotary extrusion wheels made by a leading company with special and unusual pattern of round keys and keyholes. We have received a request to find out what is the cause behind the very specific way of defect of these wheels.  The cause that these wheels have to be removed and replaced usually is that from all of the 8 keyholes cracks start the same way and the cooling water leaks through this cracks.

Cracks start from keyholes
Cracks start from keyholes

Cracks start from keyholes

Cracks start from keyholes
Cracks start from keyholes

Cracks start from keyholes

Cracks start from keyholes
Cracks start from keyholes

Cracks start from keyholes

Sample Preparation
Sample Preparation

Sample Preparation

The Biggest Crack
The Biggest Crack

The Biggest Crack

Cracks All Over in the Vicinity
Cracks All Over in the Vicinity

Cracks All Over in the Vicinity of the Main Crack

Cracks All Over in the Vicinity of t
Cracks All Over in the Vicinity of t

Cracks All Over in the Vicinity of the Main Crack

Cracks All Over in the Vicinity of t
Cracks All Over in the Vicinity of t

Cracks All Over in the Vicinity of the Main Crack