FORGING & FORMING

Both forging and forming are designed to manipulate the size and/or shape of metal workpieces. Forging is a metalworking process that involves the use of pressurized blows to deform and, therefore, manipulate the shape of a metal workpiece.

Forming, on the other hand, is a metalworking process that involves the use of mechanical deformation to deform a metal workpiece.

COLD FORMING

Cold forming, also called Cold Forging, refers to various forming below the recrystallization temperature of metal, which is a manufacturing process and a processing method.Basically same as the stamping process, cold forging is also composed of three elements: materials, molds and equipment. One of the primary difference is that the material in stamping processing is mainly plate, while the material in cold forging processing is mainly disc wire.

It can be known from the theory of metallography that the recrystallization temperatures of various metal materials are different. Even at room temperature or normal temperature, the forming of lead and tin will be named hot forging rather than cold forming. However, for iron, copper and aluminum, the process can be called cold forging when they are formed at room temperature.

Advantages of Cold Forming

Cold forming has many different advantages, and it is suitable for mass production of fasteners. Its main advantages include below aspects:

  • High utilization rate of steel: cold heading is a less and even no cutting processing method, such as processing rod-type hexagon head bolts, cylindrical head hexagon socket head screws, using cutting processing methods, the steel utilization rate is only 25% to 35%, while for the Cold heading method, its utilization rate can be as high as 85% to 95%, only some process consumption of material head, material tail and cutting hexagonal head edge.
  • High productivity: Compared with general cutting, the efficiency of cold heading is dozens of times higher.
  • Good mechanical properties: The parts processed by the cold heading method have much better strength than those processed by cutting because the metal fibers are not cut.

Typical Application Areas

Ideal for a variety of applications and industries, including automotive, agricultural, defense, civil, and construction.

HOT FORGING

There are three types of forging according to the deformation temperature: Hot Forging, Warm Forging and Cold Forging. Hot Forging and Warm Forging require heating, while Cold Forging does not require heating. Whether heating, what is the heating temperature and holding time, as well as the initial forging temperature and final forging temperature have a great relationship with forging quality and cost reduction.

The forging manufacturing process is performed above the recrystallization temperature and below the solidus line, which does not destroy the metallurgical features of the metal. At present, the forgings used in most industries are hot forgings, and warm forgings and cold forgings are mostly used in the mass production of parts such as automobiles and general machinery.

Why heat it up?

Heating can reorganize and recrystallize metal lattice, improve metal plasticity, reduce deformation resistance, facilitate metal deformation, and obtain good post-forging microstructure and mechanical properties. Heating has a great contribution to improving forging productivity, ensuring the quality of forging and saving energy. Direct forging without heating requires larger tonnage of equipment, and easily leads to lattice distortion of the material, resulting in internal stress, which is easy to cause cracks or ruptures in the forgings.

Advantages and Shortcomings of Hot Forging

Advantages

If the temperature of the forging material is still much higher than the recrystallization temperature after the processing is completed, the grains will grow for a longer time, and coarser grains will be obtained, which can increase the fracture toughness.

Shortcomings

1. Due to high temperature operation, the danger to personnel safety and material safety is greatly increased.
2. The material is prone to oxidation at high temperature, resulting in oxide scale, resulting in surface scale, poor finish and flatness.
3. After the Hot Forging is completed, the forging material has a phenomenon of cold shrinkage during the cooling process, which affects the accuracy of the forging size.
4. The equipment and maintenance costs required for high temperature operation are relatively high.

Typical Application Areas

Automobile

  • Brake system: brake disc, brake frame, brake cylinder, brake handle
  • Drive gears: pinions, synchro rings, continuously variable transmissions
  • Powertrain: flange yoke, pin frame, hub, drive shaft, universal joint, connecting plate
  • Chassis: Wheel frames, journals, pivot bearings, bearing bushes, ball joints, steering rods, steering rods, front bridges, Y-forks
  • Engine parts: pistons, connecting rods, cams, camshafts, crankshafts, valves, distributor housings, balance shafts

Aerospace

  • Rotor systems: system accessories, rotor hubs, gearbox covers
  • Fuselage parts: cabin doors, wings, window frames and other accessories
  • Engine turbine blades, propulsion cones, control discs, control rods
    Tail rail and its accessories
  • Landing gear: brackets, some fasteners