ANALYSIS OF THE QUALITY OF THE RESTORED GEAR TOOTH OF LARGE-MODULE GEARS

This study examines the quality of a gear tooth surface fragment restored through electric arc welding. Visual inspection revealed a defect-free, dense surface. Macrostructure examination displayed uniformity and absence of cracks in the metal sample. The high hardness (HRC-36.61) of the weld deposit is crucial for wear resistance, while the base metal, with lower hardness (HRC-29.09), ensures ductility and impact toughness. Martensitic and residual austenitic structures in the weld deposit indicate deformation-resistant properties, with austenite providing good ductility and martensite contributing to high hardness and strength, making the material resistant to wear and deformation under dynamic loads. Thin lens-like martensitic plates and a reed-like structure suggest unique formation characteristics during electroslag welding’s oxidizing-reducing reactions. Microstructure analysis revealed a finer structure in the weld deposit compared to the base metal. The base metal exhibited a ferrite-pearlite structure typical of many steels, unchanged after welding. The weld deposit showed elevated carbon (0.70 %) and manganese (1.38 %) concentrations, typical for weld deposits, influencing mechanical properties. Elements like manganese and molybdenum enhance wear resistance, while the presence of chromium (0.42 %) and nickel (0.12 %) improves corrosion resistance, crucial in aggressive environments. Keywords: large-module gears, tooth wear, electro slag surfacing, hardness, analysis