Forging is a metal forming process in which a metal workpiece is placed between two dies and pressure is applied to change its shape. This process is usually performed on a forging press, which slowly applies pressure until the workpiece is shaped into the desired new form. Compared to other forging processes, forging press has obvious cost advantages and is widely adopted in industry. More importantly, the forging process allows the final product's grain flow to align with the workpiece contour, a feature that can significantly enhance product strength.
A forging press forms metal by applying gradual and controllable pressure to a workpiece in a die through a vertical ram. This process is similar to drop forging, but the core difference is that forging press uses constant pressure rather than repeated impacts.
The stable motion provided by the ram allows deeper penetration into the workpiece, producing uniform plastic deformation. This working method ensures stable and consistent product quality.
Forging presses can be classified in multiple ways. By pressure generation method, they can be divided into mechanical, hydraulic, screw, servo, pneumatic, and extrusion types; by frame design, they can be divided into upright and C-frame basic forms. Different types of forging presses differ in working principle, performance characteristics, and applicable scenarios, and users can choose according to specific production requirements.
- Mechanical Forging Press: Mechanical forging presses are the most basic type of forging equipment, driven by an electric flywheel that transmits energy to a slowly pressing ram. It should be noted that mechanical forging presses are often confused with hammer presses, but their working methods are different. Mechanical forging presses complete forging in a single long stroke through multiple rapid impacts, controlled by an air clutch. During the stroke, the crankshaft applies stable, continuous pressure to the ram. The ram reaches its highest speed in the middle of the stroke, but maximum pressure is fully applied only at the end of the stroke, completing the forming of the workpiece. Because the movement distance of the mechanical ram is fixed, a proper gap must be left at the end of the stroke to prevent the ram from sticking to the die, which could cause stoppage or equipment damage. Mechanical forging presses can reach pressures of up to 12,000 tons, suitable for high-volume production scenarios. With the development of robotic forging automation, many forging processes can be operated automatically through computer programming, ensuring consistency and reducing the risk of human error. Despite the high cost of mechanical forging presses, they are widely used in the automotive industry, mainly for forming transmission system components. Additionally, government departments use this equipment for coin minting. Modern mechanical forging presses are highly automated, capable of up to 70 strokes per minute, widely used for mass production of automotive parts, hand tools, and hardware components.
- Hydraulic Forging Press: Hydraulic forging presses generate downward pressure through a hydraulic system and are usually used for open-die forging. Open-die forging features a flat ram that presses the metal flat, in contrast to closed-die forging, which shapes the metal into a specific form using a mold. The greatest advantage of hydraulic forging presses is precise control of stroke speed and pressure, enabling the forming of complex workpieces without opening or closing molds. Large hydraulic presses can exert pressures up to 50,000 tons or even 75,000 tons, mainly used for metals other than steel, producing large aircraft components such as turbine shafts through open-die techniques. Hydraulic forging presses are also suitable for isothermal forging and large, complex-shaped production. It should be noted that hydraulic dies are prone to wear due to longer contact with heated workpieces, so die life must be fully considered in maintenance and production planning.
- Screw Forging Press: Screw forging presses combine mechanical and hydraulic drive features, with twin flywheels and a screw mechanism converting rotational energy into downward ram pressure. During the ram's downward movement, the screw continues to rotate, generating more pressure. After one stroke, the screw and flywheel reverse to return to the starting position. Modern technology allows precise control of ram downward distance and applied pressure, ensuring uniform thickness of metal sheets during flattening. Screw forging presses can reach pressures of 31,000 tons, suitable for mass production, and can process steel, copper, aluminum, titanium alloys, as well as special aerospace and medical materials. With increasing aerospace development needs, the importance of screw forging presses may further rise. Screw forging presses are suitable for producing non-ferrous alloys, tool steel, and heavy industrial components, widely used in manufacturing large valves, flanges, and heavy machinery parts.
- Servo Forging Press: Servo forging presses use a servo motor to drive an eccentric gear, allowing precise control of slide position, speed, stroke, and pressure. This precise control makes them especially suitable for precision forging and high-mix, low-volume production scenarios. Servo presses have multiple advantages: high production efficiency, high part accuracy (up to ±0.01 mm), low noise, precise control, and energy efficiency. They are also easy to maintain and support the requirements of Industry 4.0 smart factories.
- Pneumatic Forging Press: Pneumatic forging presses operate by compressed air or gas to drive the ram, suitable for light to medium precision forging, deep drawing, stamping, assembly, and shearing operations. This type of equipment is mainly used for non-ferrous metals, aluminum, and light steel processing.
- Extrusion Forging Press: Extrusion presses are used for horizontal extrusion forging, capable of shaping rods and tubes into complex bends. During hot extrusion forging, the rod is placed between two dies, and lateral pressure is applied to bend it. Modern technology allows multiple precise bends on a single tube. Because the dies are not vertically compressed, extrusion presses can produce multiple shapes, but sometimes multiple strokes are required to achieve the desired form, up to five strokes. Extrusion presses are suitable for producing various shaft components, such as flanged shafts, gear clusters, socket wrenches, and sometimes for preparing materials for hammer, mechanical, hydraulic, or screw forging presses. Extrusion forging uses horizontal ram presses to apply axial pressure to heated workpieces, changing the end shape of the workpiece, commonly producing bolts, nuts, flanged shafts, shaft components, and special parts for automotive, aerospace, and construction industries.
- Upright Press: Upright forging presses provide maximum rigidity, suitable for high-tonnage, high-volume forging operations. This design can withstand extremely high pressure and ensures stability during production.
- C-Frame Press: C-frame presses have an open side, facilitating small-batch production, maintenance, and die replacement. This design provides better operational convenience, suitable for scenarios requiring higher production flexibility.
Forging offers significant advantages in metal processing, mainly in material performance, production efficiency, and safety. Compared to casting and traditional machining, forging can utilize materials more efficiently and produce metal parts with higher strength and more stable performance.
Forging is more efficient and economical than casting and traditional machining, and the finished product has higher strength. Through plastic processing, forging rearranges the metal grain flow, improving mechanical properties and fatigue life. Continuous grain structures eliminate weak points, making forgings widely used in aerospace, automotive, oil & gas, agriculture, and heavy machinery industries.
Forging provides high strength-to-weight ratio, reduces defects, and improves subsequent machining accuracy. Preheating workpieces optimizes grain flow, reduces forging force, and maintains metal integrity, improving tensile strength, fatigue resistance, and durability.
Modern forging presses can achieve high output, producing 40 to 50 forgings per minute. Products include bolts, nuts, valves, shafts, and structural brackets. Die design enables complex shapes and precision control, with deep drawing up to six times the material thickness while maintaining tight tolerances.
Forging extends die life and saves costs. With CNC automation, forging presses can achieve precise control, traceability, and high repeatability, ensuring uniform plastic deformation and optimized mechanical properties such as yield strength, ductility, and impact toughness.
High operator safety is an important feature of modern forging presses. Modern presses are mostly automatic or semi-automatic, reducing manual operation and risk. Forgings have excellent mechanical properties, including strength, impact toughness, ductility, and fatigue life, and can be optimized for specific stress directions.
The forging process ensures part consistency and uniformity, and strict quality control meets high standard processing requirements. Forging presses can process carbon steel, alloy steel, stainless steel, aluminum, copper, brass, titanium, and other non-ferrous metals, with a very wide application range.
Forging technology, with its efficiency, economy, and high quality, has been widely used in multiple key industrial fields. From automotive manufacturing to aerospace, from heavy machinery to medical devices, different industries choose suitable forging equipment and processes based on production needs.
Mechanical forging presses are most widely used in the automotive industry, mainly for forming transmission system components. High automation of modern mechanical presses allows meeting high-volume production requirements, with speeds up to 70 strokes per minute ensuring efficient output.
Hydraulic forging presses play a key role in aerospace, especially large hydraulic presses with pressures up to 50,000 tons, used for large aircraft components such as turbine shafts. Screw presses are also widely used for processing special aerospace materials. With increasing aerospace demand, the importance of relevant forging technology continues to rise.
Screw presses are widely used for large valves, flanges, and heavy machinery parts. Friction-driven, direct electric, and gear-driven presses achieve high-tonnage forging through different transmission mechanisms, meeting heavy industrial manufacturing needs.
Screw presses can process specialty medical materials, providing high-precision, high-quality metal parts for medical device manufacturing.
Forging technology is used to produce bolts, nuts, flanged shafts, shafts, and special parts for construction. Mass production of hand tools and hardware also relies on the high efficiency of mechanical forging presses.
Government departments use mechanical forging presses to mint coins, reflecting the value of forging technology in precision manufacturing.
Choosing the appropriate forging process requires consideration of multiple factors:
First is production volume. Mechanical forging presses are suitable for large-scale production, while servo presses are suitable for high-mix, small-batch production. C-frame presses are convenient for small-batch production and die changes.
Second is workpiece material and size. Hydraulic presses are suitable for metals other than steel and large, complex shapes; screw presses are suitable for non-ferrous alloys and special materials; pneumatic presses are suitable for non-ferrous metals, aluminum, and light steel.
Third is precision requirements. Servo presses provide the highest precision, suitable for precision forging. For complex-shaped workpieces, extrusion presses may be considered, though multiple strokes may sometimes be required to achieve the desired shape.
Fourth is cost consideration. Mechanical presses are costly but suitable for large-scale production to spread costs, while hydraulic presses require consideration of die wear and maintenance costs.
Forging, as an important metal forming process, changes the shape of metal workpieces by applying pressure between dies, offering relatively low cost and high product strength. Forging presses are classified by pressure generation method into mechanical, hydraulic, screw, servo, pneumatic, and extrusion types, and by frame design into upright and C-frame types.
Different types of forging presses have distinct characteristics in industrial applications: mechanical presses are suitable for mass production, hydraulic presses for large complex parts, screw presses for special material processing, servo presses for precision control, pneumatic presses for light to medium operations, and extrusion presses for horizontal extrusion and bending.
The forging process rearranges grain flow through plastic deformation, improving mechanical performance and fatigue life, with wide applications in automotive, aerospace, heavy machinery, medical devices, construction hardware, and other fields. With the development of automation, intelligence, and precision control, forging technology will continue to provide efficient, economical, and high-quality metal forming solutions for modern manufacturing.
