In recent years, big data and artificial intelligence (AI) have received a great deal of attention in manufacturing industries by means of smart factory; however the interesting connection among the two hasn’t often appeared in practice. This presentation introduces a practical AI application to the steel industry, where a big amount of process data is used to train the AI. It is an automated coating weight control system for continuous galvanizing line in which the algorithm was designed to accurately predict and control coating weight in real time. To effectively deliver this case to the audience, the followings are included in the presentation: a) what the problem to solve is, b) how machine learning and other analytics methods can be used, and c) data flow and system design. At the end of the talk, some lessons experienced from the project will be discussed.