Forging is a metal-forming process by plastic deformation, under impact or pressure, without melting. The metal is generally heated (around 1,100 to 1,250 °C for steel, 400 to 500 °C for aluminium) to make it malleable, then compressed between tools. The metal retains a continuous grain flow that follows the shape of the part, which improves its mechanical strength, toughness and fatigue resistance.
Open-die forging works between flat or simple tools, with a drop hammer or press: it suits large parts and one-offs, such as shafts, rings and discs. Closed-die forging (drop forging) compresses the metal between two engraved dies: the part is close to its final shape and the run is medium to large. Cold forging, which forms without heating, makes screw heads, bolts and rivets in very large volumes. After forging come trimming of the forging flash, heat treatment, then machining of the functional surfaces and a soundness check (dye penetrant, magnetic particle).
Forging is used for highly stressed or safety-critical parts: connecting rods, crankshafts, shafts, levers, flanges, pins, gears, hand tools. The sectors concerned are automotive, aerospace, energy, rail and agriculture. Compared with casting, it offers better mechanical properties but limits shapes, notably closed internal cavities. A forging often serves as the machining blank for CNC machining. See the guide materials for machined parts.
In a quote request. Specify the grade (for example 42CrMo4 or C45), the mass, the quantity, the mechanical properties and the hardness expected after quenching and tempering, the forging tolerances and the machining allowance, as well as the inspections and the material certificate (EN 10204 type 3.1). For closed-die forging, agree on the ownership and service life of the dies.