Electrogas welding can be applied to most steels, including low and medium carbon steels, low alloy high strength steels, and some stainless steels. Quenched and tempered steels may also be welded by the process, provided that the proper amount of heat is applied. Welds must be vertical, varying to either side by a maximum of 15 degrees. In general, the workpiece must be at least 10 mm (0.4 in) thick, while the maximum thickness for one electrode is approximately 20 mm (0.8 in). Additional electrodes make it possible to weld thicker workpieces. The height of the weld is limited only by the mechanism used to lift the welding head—in general, it ranges from 100 mm (4 in) to 20 m (50 ft).