Disk roll exchanging apparatus for vertical piercing mill and disk roll exchanging method

A disk roll exchanging apparatus for use in a vertical piercing mill containing a pair of piercing rolls and a pair of disk rolls in a mill housing such that the piercing rolls are opposingly arranged in a vertical direction with a pass line of the material to be rolled running in-between and that the disk rolls are opposingly arranged in a manner perpendicularly intersecting with the piercing rolls, and are integrally formed with a shaft, supporting the shaft at both ends via chocks, the disk roll exchanging apparatus comprising:

• a pair of disk frames each of which supports one of the disk rolls and is located at the side of the mill housing and supported by a pivot shaft so that it can swing open away from the pass line;
• a disk roll lifting device for mounting the disk roll to and demounting it from an opened disk frame;
• and
• a horizontally moving device for carrying and horizontally moving the disk roll lifting device, thereby allowing the disk roll to be mounted to and demounted from the opened disk frame,
• wherein the disk roll lifting device has a structure such that the chocks provided at both shaft ends and the disk roll are properly positioned when the disk roll lifting device supports the disk roll.

A disk roll exchanging method for use in a vertical piercing mill containing a pair of piercing rolls and a pair of disk rolls in a mill housing such that the piercing rolls are opposingly arranged in a vertical direction with a pass line of the material to be rolled running in-between and that the disk rolls are opposingly arranged, each in a disk frame pivotally attached to said mill housing, in a manner perpendicularly intersecting with the piercing rolls, the disk roll exchanging method comprising the steps of:

• swinging open a disk frame;
• moving a disk roll lifting device with respect to said opened disk frame to a disk roll exchange position;
• releasing the disk roll from the disk frame;
• lowering the disk roll to support a lower end thereof in said lifting device;
• fixedly supporting an upper end of said disk roll by the disk roll lifting device;
• and
• moving the disk roll lifting device away from the disk roll exchange position.