metal cut off wheel with the depth of the cut

metal cut off wheel can first cut the concrete to 1/4″ deep, and then see how the angle grinder and the diamond blade respond. If no problem, you can do further passes of cuttings to reach the depth of the cut you need. Each cutting pass should not be deeper than 1/2″. with the metal flap disc ，To reduce the dust, you can ask someone to spray some water onto the diamond blade and the cut during the cutting process.