http://www.encyclopediaofalabama.org/article/h-1638
After the civil war, Birmingham became the largest steel producing area in the south east. Steel production requires iron ore, coke, coal, limestone and dolomite. Postbellum steel production technology involved the use of blast furnaces, and limestone and dolomite were used with the iron ore to carry away impurities, like a flux, except in this case it was called slag. Raw material were found in the unique geology of the region, and an abundance of railroads allowed for the transport of raw materials and finished product.
Like building Pullman rail cars and coal mining, a ‘company town’ aspect of production arose. Critics point to high mortality rates in the growth of the industry, but this was also true of the age, and of steel production in northeastern centers. Later, industries developed that produced pipe and fittings.
Early Birmingham pipe producers made cast iron, or ductile pipe. Later, a large production and distribution of steel pipe evolved. Many people forget that most of the pipe for the Alaskan pipeline was purchased from Japan, the pipeline was built in the 1970’s.
There is still a large steel pipe distribution network centered in Birmingham, with a great deal of the pipe being imported and some produced domestically. With it’s centralized shipping points, Birmingham ships the most pipe in the southeast by rail and truck. Major shippers include U.S. Pipe, Nucor, American Pipe and Supply and Consolidated Pipe & Supply.
The modern steel pipe industry serves the pipeline industry, refinery and chemical plant construction and vessel manufacturing. Modern steel pipe is produced in two formats in general, ERW and Seamless. ERW is Electric Resistance Welded and produced by folding sheets of metal into a pipe and welding the seam. Seamless pipe is extruded.