Historically, metalworking possesses one of the key domains in materials science, and it is the process of working with metals to create individual parts, assemblies, or large-scale structures. Materials science is one of the oldest forms of engineering and applied science, and the material of choice in a given era is often a defining point (e.g., Stone Age, Bronze Age, Iron Age). The processing of metals in the solid state can be divided into two major stages:
- Hot working. First, the raw material in the form of large ingots or billets is hot-worked, usually by rolling, forging, or extrusion, into smaller shapes and sizes. These processes occur at a temperature above that at which recrystallization occurs. Being above the recrystallization temperature allows the material to recrystallize during deformation. This is important because recrystallization keeps the materials from strain hardening, ultimately keeping the yield strength and hardness low and ductility high. For hot-working operations, large deformations are possible, which may be successively repeated because the metal remains soft and ductile. In general, metals are shaped by processes such as:
- Forging
- Rolling
- Extrusion
- Drawing
- Casting