Fault Phenomenon: Bauer BG26 rotary drilling rig interlock Kelly bar sticks when extending or retracting.

Troubleshooting Process:
– Checked lubrication: lack of grease between bar sections.
– Checked deformation: one section of the Kelly bar bent.
– Checked mud: mud entering gaps between sections and drying.
– Checked feed cylinder: feed system pressure abnormal.

Root Cause: A large amount of mud entered the gaps between Kelly bar sections and dried, combined with lack of lubrication, causing excessive friction and sticking.

Required Parts: Clean Kelly bar, reapply specialized grease, straighten deformed sections.