Located in Longview, Texas, Southwest Steel Casting Company was founded in 1971. In 1974, it was bought-out by Texas Steel, who owned SWS until December 1989. It was purchased by American Car Foundry (ACF), and under whose ownership it remains.

At the time of its purchase by ACF, Southwest Steel was shipping approximately 180 tons/month. This number has since been increased to approx. 700 tons/month, and the number of employees has almost doubled from 120 to well over 300 since 1989.

When founded in 1971, Southwest Steel Casting Company consisted of one manufacturing building, Plant 1, and the Administrative offices. Plant 1, at that time, was a green sand casting facility with one arc furnace and a shell core department with modest pattern repair capabilities. Since that time, Plant 1 has been expanded 3 times.

The original green sand system has been replaced by a modern NoBake molding system and includes a state-of-the-art sand reclamation system. The core making facilities have been enhanced with the addition of a phenolic urethane coldbox core blower. In addition, amine gassing and scrubber support equipment have also been installed.

In 1976 additional manufacturing facilities where required to meet increasing customer demands. A second manufacturing facility was constructed - Plant 2. Plant 2 was designed, from the beginning, as a NoBake foundry. It housed, when built, an arc furnace, core making, molding loop, pouring area, shakeout, casting cleaning room and shipping facilities.

As with Plant 1, Plant 2 has undergone several expansions which include additions to the cleaning room, furnace department and shipping docks. In 1997, the existing attrition reclamation system was moved and expanded into an adjoining building. In 1998 a Gudgeon thermal sand reclamation system was installed to improve the quality of the sand and to reduce Southwest Steel's waste stream.

To support the manufacturing plants, additional facilities have were added in 1997/98. These facilities included a pattern storage building, with a fire suppression system, a services building which houses the testing facilities, stores and maintenance, and a new 6,000 sq. ft. Administrative Offices building. To handle the additional traffic, a new access road and parking lot expansion was completed in 1998.