Dr. Ziad Shakeeb Al Sarraf, Dr. Ahmed Fattah Ahmed, and Mr. Khalid Alias Hammo , trans. 2023. “Evaluation of Vibration Amplitude Stepping and Welding Performance of 20 KHz and 40 KHz Ultrasonic Power of Metal Welding”. Indian Journal of Production and Thermal Engineering (IJPTE) 1 (2): 11-15. https://doi.org/10.54105/ijpte.B2009.061221.