Recently, many kinds of weathering steel were widely used in steel bridges. Ni-advanced weathering steel are new types of weathering steel. It was considered that the quality of these steels has been remarkably improved. However, when it had come to how much, it had not been clarified. Therefore, in the past, we had investigated Nickel-advanced weathering steel on the basis of the mill sheet in order to clarify their quality, and these steel mechanical properties had been shown[1] [2]. In this paper, we investigated the chemical compositions of these steels. Investigated component were Carbon, Silicon, Manganese, Phosphors, Sulfur, Copper, Chrome, Nickel including PCM(Cracking Parameter of Material), Ceq(Carbon equivalent) and V-value (Weathering Alloy Index), and these results were shown. We also showed the improvement factor in the quality, comparing with the conventional weathering steel data.
