YES YOU CAN WELD SS, TO CARBON STEEL, USING AN 309L SS ROD OR SIMILAR WIRE WELDING ALSO DO KNOW WHAT PROCESS YOU ARE USING MIG , STICK, TIG??? HOPE THIS HELPS, TANKIE
you can most certainly braze s.s and carbon steel to copper with silver solder. you can even solder copper to aluminum, using steel wool, flux, and tin - lead or tin-antimony wires