The technical forging

Drop forging and die forging

Die forging or drop forging is a hot forging process causing plastic deformation of a metal between 2 tools, forcing it to take on the required shape.

Parts obtained using this technique have high resistance to mechanical stresses, as forging causes :

  • Cold working, which, by compression and deformation of the material, stops the formation of internal defects, such as bubbles or inclusions, which could adversely affect the internal uniformity of the parts.
  • Grain flow of the metal: the internal structure of the metal forms fibres according to the flow of the material and the stresses applied to the part. Our forging expertise enables us to determine the orientation of the grain flow according to the expected stresses on the finished part, which gives it particularly good mechanical properties.

The raw material used already has a longitudinal grain flow before forging (metal bars), which is modified as required during the forging operation.

The challenge of manufacturing parts by forging is particularly related to the type of raw material used. For example, titanium forging or stainless steel forging are complex, because these materials are abrasive and do not flow easily in the tools, which can quickly lead to defects and / or damage of the tools.

Grain flow of the metal

The internal structure of the metal forms fibres which are oriented according to the expected stresses on the finished part.
This gives the forged parts particularly good mechanical properties.

Forging is the best technology for obtaining parts with good mechanical strength due to the grain flow


Drop forging vs foundry

The main advantage of drop forging as against foundry is the forming of the internal structure of the material, the grain flow of the metal, resulting in better mechanical properties.

In foundry, the raw material is poured into a die. The structure of the part is therefore crystalline with no particular direction of flow in the structure of the metal.

In addition, the foundry manufacturing process can create bubbles, impurities or casting defects in the internal structure of the parts, unlike forging, which by definition, does not cause this type of problem.

Structure of a cast part

Crystalline structure, no internal orientation of the metal’s structure. Subject to inclusions and impurities


Drop forging vs machining from sold bars

The raw material – solid bars – already has longitudinal fibres. This is associated with the process used to produce the metal bars, which are drawn or rolled to obtain the required diameter.
When parts are machined from this raw material, the grain flow of the metal is cut, which significantly reduces the mechanical properties of the parts.
Although it is true that machined parts achieve very tight dimensional tolerances, they are much less strong than those produced by forging.

Therefore, machining a rough forged part achieves the best compromise between mechanical properties and precision.

Structure of a cut part

Cut fibres. No internal orientation of the metal’s structure


FORGINAL industrie’s specialisation : precision drop forging

Precision drop forging

FORGINAL industrie uses Montbard board drop hammers: 600 kg and 1,200 kg, and compressed air drop hammers: 2,500 kg and 3,600 kg. Using this type of equipment it is possible to obtain thickness tolerances that are among the tightest on the market, as well as a precise, regular finished appearance.

Forging drop hammers can produce parts with tolerances as small as 0.4 mm without sizing. The gross raw material weight is much lower than with other forging technologies (around 20% less), due to the specific feature of drop hammers which enables percussive hammering to be carried out, insert against insert.

Forging of small series

Our production facilities give us unequalled flexibility to offer our customers very small series, starting at 50 parts. This is because :

  • All our machines are manually controlled. They do not need long adjustment or set-up times like automated production machines.
  • Our tools have been designed for quick assembly and adjustment, which makes fast production series changeovers easier.
  • FORGINAL industrie has adapted the equipment of all the drop hammers so that the tools are small and interchangeable.
  • The design office and the tooling department have been strengthened so that a large number of tool manufacturing or refurbishment operations can be dealt with quickly (up to 150 per month).

High technology forging

FORGINAL industrie is your subcontracting partner for forging. We are dedicated to supporting you in carrying out your projects in strict compliance with your drawings and specifications.

To do this, we provide you with all our forging know-how and expertise :

  • Technical advice prior to projects
  • Creation of the forging drawings for your parts
  • Creation of your customised production processes
  • Modification of your projects over time according to your requirements
  • Regular optimisation as a result of continuous quality improvement