Through-thickness cutting of 110-mm-thick SUS304–SS400 clad plates using a 6-kW laser oxy-fuel and oxy-flame hybrid process

This study examined through-thickness cutting of 110-mm-thick SUS304–SS400 clad steel (10 mm SUS304/100 mm SS400) using a 6-kW laser oxy-fuel and oxy-flame hybrid (LOXAFH) process. With SUS304 facing the cutting head, oxy-fuel heating formed no measurable entrance kerf. Three laser-assisted oxygen cutting (LASOX) trials failed to penetrate at 6 kW, 0.70 MPa(g) cutting-oxygen pressure, 50 mm min−1, and 10 mm standoff distance. At the same principal settings, one LOXAFH trial achieved full penetration with an O2–liquefied petroleum gas flame and approximately 30 s of stationary preheating. Two additional LOXAFH trials produced through cuts at selected settings. Across these three cuts, top and bottom kerf widths were 6.80–7.75 and 9.55–10.38 mm, respectively. At otherwise nominally identical LOXAFH settings, one 6-kW trial penetrated, whereas eight 3-kW trials failed. At 3 kW, three SS400-up trials penetrated, while eight SUS304-up trials failed. These comparisons indicate that laser power and incident material affected penetration. The matched LASOX–LOXAFH comparison supports feasibility, but the effects of stationary preheating and continuous flame assistance could not be separated. Improved oxygen access remains a possible explanation because in-kerf flow and cut-front motion were not measured. Repeatable penetration was observed at selected conditions, but repeatability at a fixed successful setting for the standard SUS304-up plate remains unverified. Comprehensive cut-quality assessment and suitability for nuclear dismantling require further evaluation.