Recently high reaction rate of metals such as copper and iron in lead-free solder have been pointed out. Especially the soldering iron tip has been seriously damaged by molten lead-free solder during manual soldering. The tip is usually protected by plated iron to prevent the direct contact of copper with molten solders, however, the life of soldering iron tip is reduced by the heavy dissolution of plated iron with contacting molten lead-free solder. To prevent the dissolution of iron, the effects of iron-plated conditions and the addition of small amount of iron in solder on reactions were investigated. The reaction test was carried out in an oven in an open air and the dissolution thickness of plated iron was measured. The dissolution test was performed by using a molten solder pot and the dissolution thickness of iron wire was measured. As a result, it was found that the grain size of electroplated iron decreased with the increased current density and the dissolution thickness of plated iron increased with the increased current density during plating in the rack-type plating. And then the small addition of iron in lead-free solder was found to be effective for the reduction of dissolution rate of plated iron.