ObjectiveThe effects of different ultrasonic impact treatment time on cross section microstructure. surface residual stress. surface microhardness. and corrosion resistance of 42CrMo4 steel sample was investigated. https://www.ealisboa.com/limited-value-Pack-Ethos-Boro-Ethos-Boro-Tank-Across-Vape-x-Dovpo-limited-super/