Technically, the only two grades of anchor bolts that can be welded are ASTM F1554 Grade 36 and F1554 Grade 55, but only when Grade 55 meets the supplemental requirement (S1) for weldability. All other anchor bolt specifications are manufactured from either medium carbon or medium carbon/alloy steels that develop their strength through a heat-treating process. When high heat is introduced (as in welding) to an anchor bolt that has been quenched and tempered, the strength of the anchor bolt may be altered.