From its roots as the Bethlehem Iron Co. in 1857, to its final closing in 2003, Bethlehem Steel was an integral part of the Lehigh Valley and the nation. For a good part of its life, the company was the country’s second-largest producer of steel, and the area’s major employer.

During World War II, employment at the Bethlehem plant surged to more than 30,000.

Today, the legacy of Bethlehem’s steelmaking is preserved and celebrated at the National Museum of Industrial History (NMIH), a Smithsonian Institution affiliate located appropriately in a renovated 100-year-old building on the grounds of the original steel plant in South Bethlehem. Dedicated to showcasing America’s industrial heritage, the 18,000-square-foot facility has special exhibits, plus four galleries dedicated to the stories of heavy machinery, silk, propane and of course, iron and steel.

For the past 11 years, the museum has hosted an annual Steel Weekend, sponsored by the American Institute of Steel Construction. This past September, the two-day event featured smelting and forging demonstrations, a riveting workshop and presentations on steelmaking and the bridges built with Bethlehem steel.

A highlight on both days was the startup of the museum’s massive 115-ton steam engine, that laydormant for decades after faithfully pumping millions of gallons of water every day to customers in York. After thousands of hours of labor, it has now been meticulously restored to working order by NMIH.

In his slide presentation on Steelmaking 101, guest speaker Chuck Higdon explained in some detail how steel is made in blast furnaces, and the role of iron ore, carbon, coal and limestone in the steelmaking process. A chemical engineer, Higdon worked for 26 years with Air Products and Chemicals Inc., helping the steel industry improve its energy efficiency and blast furnace performance.

Higdon said three types of carbon are needed to heat blast furnaces: charcoal, anthracite coal and coke. In 1840, huge deposits of anthracite coal were discovered in northeast Pennsylvania, and canal boats and later the railroads were able to transport the coal south.

Early on, only small amounts of steel could be made at the time. Steelmaking in large quantities became possible in the 1850s with the development in England of the Bessemer process, which blew huge amounts of air into the blast furnaces to remove impurities in the iron ore. “This changed the world,” Higdon said.

In 1863, Bethlehem Steel switched from making wrought iron to steel by adopting the Bessemer blast furnaces, but two years later the company switched to open hearth furnaces that produced more and better-quality steel, but took a lot of time and manpower. When the doors opened, workers were walking into up to 2,500 degrees of heat, Higdon noted. “You can imagine how dangerous that was.”

After 70 years, Bethlehem Steel switched back to using the 100-foot blast furnaces that still dominate the skyline on the SteelStacks campus. Higdon said, “they were the heart of steelmaking.”

Despite the demise of Bethlehem Steel, he said, “We are still making a lot of steel in the U.S. Seven million tons last year.” Today, Higdon said, most steel is made from scrap in mini mills using electric arc furnaces.