The data cover new steels that have a nanostructure but unusually contain intermetallic compounds within a carbide-free bainitic structure. This investigation deals specifically with the role of nickel aluminide precipitates on the rate of the bainite reaction, in recent alloys intended for applications at about 400°C. The data are fully reported in the associated publication, but the dataset contains much ancillary information created during the project. See the Readme file for more information about each data folder.