Rhapsody of Steel (1959)
Many readers sent me a link to these great images from the ASIFA - Hollywood Animation Archive site. The images are from the children's book adaptation of the 1959 industrial film, Rhapsody of Steel.
While I haven't yet found a copy of the film online, you can view the film at the Rivers of Steel National Heritage Area in Homestead, Pennsylvania. Their description appears below.
WONDERS OF STEEL (showtimes 11:00 am & 1:30 pm) brings steel making to life through music and animation in a masterpiece, Rhapsody of Steel (1959). Produced by John Sutherland, the film features Gary Merrill as the narrator and three-time Academy Award-winner Dimitri Tiomkin conducting the Pittsburgh Symphony in his own composition. An exhibit case holds the original press release, promotional images and other artifacts documenting the United States Steel Corporation's release of this 23-minute film.