This article was written by Brad Done and was first published on Reliance Foundry
Mankind’s industrial rise would not have been possible without the evolution of metalworking. The earliest evidence of copper working indicated our ability to manipulate metals into desired shapes. As civilization grew in trade and expansion, tools and techniques were required to form metal objects. Metalworkers grew in skill and technique; mastering the production in adornments, weaponry, artifacts, ships, and machinery. As centuries passed, various techniques in metalworking were created to meet the demands of the industrial age. These processes eventually came together under one roof.
Over time, various combinations of metals were used to meet castings desired metallurgical characteristics. Alloys were created by mixing various metal and non-metal content to enhance strength, toughness, durability, and surface hardness. Today’s industrial castings are typically iron castings or steel castings with varying ratios of additional elements.
In parallel to alloy discoveries, new processes emerged in castings. Two classes of casting methods came to be: expendable mold casting (non-reusable molds) and non-expendable mold casting (reusable molds). Expendable mold casting includes sand casting, plaster mold casting, shell molding, investment casting, waste plaster casting, and evaporative-pattern casting. Non-expendable mold casting employs methods such as permanent mold casting, die casting, centrifugal casting, and continuous casting. There are various advantages to each casting process depending on the object’s dimensional requirements, production repeatability, and physical properties.
A foundry is a factory that will house any combination of the casting processes mentioned above. Since ancient history, groups of metalworkers, metallurgists, engineers, artisans, and laborers worked together in a location that could accommodate their services. In 3000 BC the Mesopotamians discovered bronze by adding a small amount of tin with copper during smelting. The Egyptians of 1500 BC depicted tomb paintings with pictures of smelting operations, blast air, and crucibles filled with molten metal. In Ancient Greek artwork, craftsmen are seen working with hot furnaces and casting pits. For the modern day foundry, the same fundamental casting processes exist - but with advances in technology and production.