The effects of functionally graded material structure on wear resistance and toughness of repaired weldments

摘要

To perform a long lasting, crack-free repair welding on ultrahigh strength steels, the filler metal must be chosen and applied properly. Avoiding several short-term repairs or replacements, the repaired weld-ment should reveal comparative characteristics such as wear resistance, toughness and hardness to base metal. In the present study, a novel functionally graded material have been introduced to obtain enhanced wear resistance and hardness at surface as well as improved fracture toughness at fusion line of repaired weldments. A comparative study of wear resistance of repaired weld metals has been carried out by pin-on-disk apparatus at 5 N normal load and 0.14 ms~1 sliding speed. Fracture toughness of weld metal was also evaluated by charpy absorbed fracture energy tests and scanning electron microscopy fractograghs. The results show that by employing functionally graded layers, toughness was enhanced significantly while retaining the surface wear resistance.