Experimental Study on the Influence of Chip Morphology in Single Cutter Milling of Super 13Cr Oilfield Tubing

Summary During workover operations, super 13Cr oil tubes present challenges in abrasive debris morphology control due to poor chip fragmentation, leading to failed evacuation and reduced milling efficiency. This study establishes a mechanical model for single abrasive grain milling of super 13Cr tubing and investigates the abrasive wear behavior under varying tribological conditions. Experimental data, including weight on bit (WOB), torque, and debris morphology, were systematically analyzed across five tooth arrangement angles (−15° to 5°). The results reveal that negative inclination angles (−15° to −10°) induce severe abrasive wear regimes, generating small C-shaped chips with effective fragmentation but higher mechanical loads. The −5° inclination produces stable “clock-spring-shaped” chips, indicating balanced wear conditions. Optimal performance was achieved at −10° inclination with 55 r/min rotational speed and 0.18 mm/r feed rate, enabling controlled debris morphology while balancing milling efficiency and mechanical stability. This work provides insights into wear-mediated chip formation and practical solutions for downhole milling operations.