Dahlia, A. H. , and Nmtzadh, F. . "Review due to leave after the welding operation Khrarty (PWHT) Shvpr nickel base alloy 520 UDIMET with tungsten arc welding method and shielding gas (GTAW)", Sharif Journal of Industrial Engineering & Management, Vol.19, No. 24, 2003, 7-14.