Steel casting and molding - Evolution of manufacturing processes

The art of the foundryman consists in reproducing, with more or less fusible materials, the shapes and dimensions of all the modeled or sculpted objects that may appear". This is the definition given in the famous Dictionnaire des Arts et Manufactures published in 1877 by Charles Laboulaye, secretary of the Société d'Encouragement pour l'Industrie Nationale. Much more prosaically, to make castings, liquid metal must be available and poured into a container that roughly follows the shape of the product to be produced. The casting technique has been around for a very long time, dating back to copper metallurgy several millennia (5,000 years) BC. The first molds were designed, in a very rudimentary way, by digging simple cavities in sand, clay or stone. A little later, inspired by the potter's experience, the bivalve mold created from a lost-wax model surrounded by clay appeared to cast bronze pieces. To obtain liquid metal, two essential processes were developed: the smelting of metals and the reduction of ores to a liquid state. These operations are relatively simple and can be carried out fairly easily in charcoal-fired potteries when they take place at around 1,000/1,200°C, which explains the very early development of copper metallurgy, which melts at around 1,085°C. On the other hand, the melting of iron and steel requires much higher temperatures (in excess of 1,500°C), and the much more sophisticated means of doing so would not appear until much later.