The U.S. will expand its tariffs to cover products made of steel and aluminum — like nails, tacks, staples, cables, certain types of wire, and bumpers and other parts for cars and tractors — as of Feb. 8. For American companies making such products, it came as a relief. Southwire, a company in Carrollton, Ga., that makes power cable, and one of the largest manufacturers calling for the new tariffs, said the measures were necessary to ensure fair competition in the market for aluminum wire. From June 2018 to May, imports of items including steel nails and staples rose 33 percent from a year earlier, the order said. Imports of aluminum wire and cable were up 152 percent over the same period.