We don't sand blast to remove pitting, we are cleaning the pipe (deposits and scale out of the corrosion pitting) to be able to measure the pitting accurately. If you remove the pitting, the pipeline is as weak as it was with the pitting (or weaker since you have potentially removed more metal). A way to repair the pipeline is with sleeves, either type A, type B, (fibreglass, metallic, compression sleeves etc.) depending on how severe the pitting is. You don't have to remove the pitting to make a repair, but you will want to clean this area first. A 4.5 inch angle grinder with a wire wheel can clean the pitted area instead of sand blasting.