Metal forging: what is it and what is it for?

Metal forging (or metal shaping) is an ancient and fundamental process of metal materials, used to shape and form metals into desired shapes through the application of heat and pressure. This process gives metals greater strength, durability, and superior mechanical properties compared to other processing methods.

The pressure required to form the metal is applied using a press, mallet, hammer or die. In the forging processes of industrial steels and metals, the tool that performs the compression is powered by compressed air, electricity, or hydraulic power. Its purpose is to change the shape of the metal piece without causing breakage of any kind, this is possible thanks to the heating of the material to very high temperatures. Clearly, we are not talking about ordinary hammers, but about equipment that uses lots of force, up to tens of thousands of kilos. 

Temperature, as mentioned above, is of vital importance in metal forging.

The first classification is to distinguish between hot or cold forging. Hot forging is faster and more precise, the metal is usually heated in a forge, while cold forging involves manipulating the metal at room temperature or slightly higher. Due to the absence of high temperatures, cold forgings are limited to metals with good ductility and malleability at room temperature, such as carbon steel alloys, aluminum alloys, copper and brass alloys.

Forging of metals: a brief history

These days, metal forging has become of fundamental importance for several industries, but its origins go back a long way. The forging of metals is in fact one of the oldest production processes and was already practiced by blacksmiths in ancient Greece and Rome for the creation of various tools, edged weapons and even jewelry.

During the Industrial Revolution, metal forging underwent a radical transformation. The advent of steam engines and the introduction of new technologies allowed for the large-scale production of forged parts for manufacturing industries, such as machinery parts, trains, ships, and other means of transportation.

Steel and Metal Forging Processes

It all starts with the preparation of the metal material, usually in the form of ingots, billets or bars. The metal is then heated to high temperatures, to make it malleable and facilitate plastic deformation. Once the proper temperature is reached, the steel, or other type of metal, is ready to be shaped. There are several hot metal forging techniques, let’s see some examples.

Hammer Forging

Hammer forging is one of the most traditional techniques, where metal is shaped using hammers on an anvil or in dies. The piece of metal is heated to a temperature that makes it malleable, then the blacksmith or operator strikes the metal with the hammer to shape it.

Press forging

Press metal forging involves using hydraulic or mechanical machines that apply pressure to a piece of heated metal. This process can take place either hot or cold, depending on the material properties and the desired shape.

Open-Die Forging

In the open-die forging process, metal is squeezed between two dies without a predetermined shape, allowing for a wide range of shapes and sizes. This method is often used to produce large-scale components such as crankshafts or bolts.

Closed-Die Forging

Closed-die forging of steel or metals involves the use of closed dies that give the metal piece a specific shape. Heated metal is placed between the two molds, and high pressure is applied to achieve the desired shape.

Forgiatura acciaio

Metal Forging Techniques

There are many forging techniques to obtain forged metals or steels, each with a very specific purpose. In fact, depending on the final product to be obtained, different processes can be used. Below we will try to show you the most commonly used.

Rolling

Rolling is a forging technique that involves the deformation of metal via multiple passes between rotating cylinders. This process can produce flat-shaped plates, sheets, bars, and other metal products.

Extrusion

Extrusion is a technique in which metal is pushed through a die to produce specific and complex cross-sections. It is commonly used to produce complex metal pipes and profiles.

Drawing

Drawing is a metalworking process that involves deforming metal through a series of passes through a die, or a series of dies, with holes of decreasing diameter. This process is commonly used for the production of metal wires, tubes, rods, or profiles with uniform cross-sections and precise dimensions.

Punching

Punching, also known as shearing or embossing, is a forging process that involves removing material by compression between two punches or between a punch and a die. This process is used to create complex shapes, holes, recesses, or ridges on metal parts.

Advantages of Metal Forging

The advantages of metal forging are many, starting with the improvement of mechanical properties to the reduction of impurities. Forging, in fact, increases the strength, toughness, and durability of metals, making them suitable for high-pressure and high-stress applications. In addition, metal or forged steel has better dimensional accuracy than other machining processes, reducing the need for follow-up. Finally, during the forging process, impurities and voids in the metal are eliminated through deformation, producing a more homogeneous structure that is optimized for its subsequent use.

Why Use Protective Coatings When Forging Metal?

During the forging process, oxidation processes may occur or the metal may come into contact with contaminants. Advanced Technical Products has developed forging coatings that can withstand the intense heat required by the hot working process, which allow metals and alloys to be protected from these drawbacks and at the same time prevent the diffusion of gases within the material.

If you need information about our products for metal protection during forging, please do not hesitate to contact us! We are always available to answer your questions and concerns.