Research on the Application of Laser Cleaning Technology in Green Remanufacturing of Used Oil Tubing

Addressing the prominent issues of severe pollution and substrate damage associated with traditional cleaning technologies in the remanufacturing process of used tubing, this study focuses on the Φ60.32×4.83 mm EU N80 used tubing, which is most extensively used in western oilfields, to conduct research on process parameter optimization and automated equipment development for inner wall laser cleaning. Firstly, a self-developed pipeline inner wall laser cleaning system was established. The single-factor control variable method was employed to systematically investigate the effects of laser power and irradiation time on cleaning effectiveness. The "center-priority" ablation characteristics of the Gaussian beam and the substrate damage mechanism were revealed, and a power function-based quantitative model of cleaning depth versus process parameters was established (prediction error < ±8%). Subsequently, integrating field industrialization requirements, an integrated automated cleaning device was developed, incorporating a laser cleaning unit, an adaptive mobile execution unit, a closed-loop control system, and a visual monitoring system. Through a 3° inclined layout and an adaptive tensioning traveling mechanism, the "circular zebra stripe" defect was effectively eliminated. Experimental results indicate that the optimal process window is a continuous wave laser power of 1000-1500 W or a pulsed laser power of 100-300 W. The developed equipment enables post-cleaning surface cleanliness to reach Sa2.5 level, with no significant changes in metallographic structure or substrate hardness. This research provides a parameter-controllable, efficient, and environmentally friendly laser cleaning technical solution and complete equipment set for the green remanufacturing of used tubing, offering significant engineering value and theoretical guidance for promoting the large-scale application of this technology in the field of petroleum tubular goods.