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The working of metals is an ancient craft that has shaped humanity since the Bronze Age and remains central in many industrial sectors, from civil to electronic applications. This article analyzes the techniques and basic processes that enable the production of high-precision and high-quality products, starting from raw metals.
Metalworking is a broad activity that refers to various techniques used to shape the form, size, and properties of materials. These processes are mainly classified into two categories: hot working and cold working.

Hot working of metals
Hot working occurs when the metal is treated at a temperature above its recrystallization temperature, typically around 60% of the metal’s melting point. This method offers advantages such as reduced resistance of the metal, requiring less energy for deformation, and greater ductility, allowing for larger deformations. Additionally, hot working eliminates work hardening and allows modification of the metal’s microstructure, improving its mechanical properties.
Examples of hot working include forging, rolling, and hot extrusion. These processes are ideal for producing large quantities of parts due to their ability to deform the metal without causing structural damage

Cold working of metals
Cold working is performed at temperatures significantly lower than the recrystallization temperature. The main advantages include a finer surface finish, greater dimensional accuracy, and the ability to enhance mechanical properties through specific alloys. This process also prevents surface oxidation, as it does not use high heat.
Common cold working processes include wire drawing, cold extrusion, and bending. These techniques are particularly useful for creating components with high detail and very precise tolerances.

Casting
Casting is a process in which the metal is melted and poured into a mold to achieve the desired shape. It is one of the oldest and most versatile techniques, used to create complex shapes and large parts. The process involves several stages: melting the metal in a furnace, preparing the mold (which can be made of sand, ceramic, or metal), pouring the molten metal into the mold, and finally cooling and solidifying it. Once cooled, the part is extracted and subjected to finishing operations. This technique is used, for example, to produce engine blocks and structural parts.
Forging
Forging is a plastic deformation process that enhances the mechanical properties of the metal through the application of compressive forces. There are various types of forging:
Open-die forging: the metal is worked between two flat dies, ideal for large parts.
Closed-die forging: the metal is shaped in a cavity that follows the final shape of the part, ensuring maximum precision.
Hammer forging and press forging: use different techniques to shape the metal, one with rapid heavy impacts and the other with constant pressure over a longer period.

Machining
Machining involves the removal of unwanted material using cutting tools to give the metal the desired shape. The main techniques include:
Turning: where the part rotates continuously while the tool cuts.
Milling: uses a rotating tool to remove material.
Drilling: creates holes, while grinding achieves high-precision surfaces using abrasives.
The use of computer numerical control (CNC) machines has elevated these techniques to a higher level, enabling high-precision and complex work.

Welding
Welding joins two or more metal pieces using heat or pressure. Common techniques include:
Arc welding: uses an electric arc to melt the metals.
Gas welding: uses the combustion of gas with oxygen.
Resistance welding and laser welding: use electric heating and a high-energy laser beam, respectively.
The choice of welding method depends on the type of metal, its thickness, and the desired joint characteristics.

Heat treatments
Heat treatments optimize the metal’s properties by modifying its crystalline structure. Key treatments include:
Quenching: increases hardness through rapid cooling after heating.
Annealing: balances hardness and ductility with controlled heating followed by cooling.
Normalizing and other targeted treatments ensure uniformity and structural stability in metal components.

Continuous innovation in metalworking
Metalworking is a broad field that requires deep knowledge of materials and processes to achieve the desired mechanical and structural properties. Continuous innovation, such as the integration of emerging technologies like 3D metal printing and hybrid production, offers new possibilities for producing increasingly complex and high-performance components.
These processes are the heart of modern industry, enabling the development of products ranging from the smallest electronic components to large architectural structures, from spacecraft to the most advanced surgical instruments.

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