If you are like most people, and you get almost any and all needed information from Google, you’d find that investment casting has a fairly simple definition: “a technique for making small, accurate castings in refractory alloys using a mold formed around a pattern of wax or similar material which is then removed by melting.”
If you dare to go a step further, you’d find that you are just a few clicks away from a more thorough Wikipedia page devoted to the technical understanding of investment casting, which, as the page instructs you, is an industrial process based on one of the oldest known metal-forming techniques, lost-wax casting. Wikipedia has this to say about a pattern being invested with, or surrounded by, a refractory material, such as brass, carbon steel, aluminum, glass, or stainless steel alloys.: “The material is poured into a cavity in a refractory material that is an exact duplicate of the desired part. Due to the hardness of refractory materials used, investment casting can produce products with exceptional surface qualities, which can reduce the need for secondary machine processes.” While we are defining our terms, refractory materials refers to any non-metallic materials which have properties that making them conducive to applications for structures or as parts of greater systems. Typically, refractory materials are used in reactors, furnaces, kilns, or in other such applications.