Study of factors affecting the weld of M42 cobalt band saw blades using a laser welding process

Abstract

This study aimed to investigate and analyze the factors affecting the tensile stress of Cobalt M42 band saw blades after being welded using a UG-1000LW laser welding machine, employing flux-cored filler wire. The tensile testing was performed using a WAW-1000 Electro-Hydraulic Servo Tensile Testing Machine following the DIN EN ISO 6892-1 standard. The average tensile stress observed was 72 MPa. The experimental factors included laser power (20%, 30%, and 40%), wire feed rate (6, 8, and 10 meters per minute), and joint gap distance (0.3, 0.6, and 0.9 millimeters). A full factorial experimental design was employed, comprising 81 trials with a confidence level of 95%. The results of an ANOVA analysis revealed that all three factors, as well as one interaction between laser power and wire feed rate, significantly affected the tensile stress. The P-values for laser power, wire feed rate, and joint gap distance were 0.033, 0.000, and 0.034, respectively. Additionally, the interaction between laser power and wire feed rate yielded a P-value of 0.000. The model showed a coefficient of determination (R²) of 92.86%, indicating a high degree of fit. Optimal welding parameters identified using the Response Optimizer were laser power at 40%, wire feed rate at 10 m/min, and joint gap distance at 0.3 mm. These conditions yielded a maximum tensile stress of 77.33 MPa, which is higher than the pre-weld tensile stress, confirming that the optimized parameters enhance the mechanical integrity of the welded joint. Consequently, it can be concluded that the optimized welding parameters enable the reuse of band saw blades, prevent failure at the original weld joint, and reduce the cost of purchasing new blades.