The safety and durability of engineering structures, like bridges, which are designed from weathering steels, are conditioned by the development of a sufficiently protective layer of corrosion products. Air pollution, the microclimate around the bridge, the time of wetness, the structural solution of the bridge, and the position and orientation of the surface within the bridge structure all influence the development of protective layers on the surface of the weathering steel. The condition of the formed patina relies on the working conditions of the structure. In fact, it is exposed to various types of salts that appear during the operation of the facility. In this article, the strength parameters of uncoated weathering steel were tested after accelerated aging of welded steel samples in a salt spray chamber. The tests showed the expected degradation of steel after long-term exposure to salt and changes in the strength parameters such as tensile strength, yield strength, and, importantly, impact strength, both in the steel itself and in the elements of the welded connection. The obtained results showed that the change is influenced by both the conditions in which the samples are made (welding method) and the direction of the welded joint (along or across the rolling direction).