Closed Die Forging: How Does It Work?

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Closed die forging joins two or more dies to wholly or partly enclose raw heat resources such as aluminium or steel. Whenever the top die is placed against it, the force of the two dice is pushed against the final component’s profile, shaping it into a forging or finished product. Moreover, closed die forging can create an astonishing variety of three-dimensional forms ranging in weight from several ounces to more than 25 tonnes. Hydraulic presses, hammers, and mechanical presses with capacities ranging from 20,000 to 50,000 tonnes are often utilised. Learn more about closed die forging in this post!

How Does Closed Die Forging Work?

Closed die forging is the technique of placing metal in a die that resembles moulds linked to an anvil incorporating the forging heat treatment. Typically, the hammered die is also formed. The item is struck with a hammer, forcing the metal to move and occupy the die chambers. After milliseconds, the hammer strikes with continuous impact. Based on the size and intricacy of the item, the hammer could be dropped many times in rapid sequence. In addition, flashing is the surplus metal that is forced out of the die perforations.

Because the flash begins to cool faster than the remainder of the materials and is generally stronger than the metal in the die, it assists in preventing additional flash from developing. The flash also causes the metal to occupy the die chamber fully, and the flash is eliminated upon forging.

Common Materials In Closed Die Forging

While closed die forging is employed for any metal materials, only a portion of the materials is utilised for the various features in real manufacturing. The material used is among the most important elements influencing the price of forgings. Let us examine a few of the materials often utilised in closed die forgings.


Steel is the most often utilised material in closed die forging. Based on the application, stainless steel, carbon steel, and alloy steel can all be used. Stainless steel is frequently employed for forging heat treatments and in parts that need rust and corrosion resistance. Moreover, because of their low cost and ease of bending, carbon and alloy steel are the most often utilised materials in the closed die forging procedure.


Aluminium is widely used because of its low density, maximum hardness, and ease of machining. It is commonly utilised in closed die forging, particularly in the aerospace and automobile sectors. While it is widely used in the automotive and aerospace industries, it poses a problem for local forging owing to its tendency to distort during forging. On the other hand, forging heat treatment may enhance stiffness and other qualities.

Copper Or Brass

Brass or copper, the most costly of the three materials in this post, is also routinely utilised in closed die forging. For pump and valve fittings, brass or copper forging is usually used.

Why Choose Closed Die Forging?

Closed die forging differs from open die forging in that the die only directly interacts with a portion of the material simultaneously. Closed die forging has significant upfront costs for creating tools and processes. However, it is the most cost-effective forging technique for large-volume manufacturing because recurrent expenses for every item are relatively low. Furthermore, closed die forging may produce both non-symmetrical and symmetrical pieces. The ground-breaking closed die forging method provides several advantages, which include:


In contrast to investment casting, the startup costs of forging dies for producing metal parts in closed die forging are pretty costly. Nevertheless, if the parts are produced in large quantities, it is the most cost-effective metal forming process due to the low cost of every part.


The compression of the workpiece within forging dies throughout the closed die forging procedure refines the interior grain and improves the mechanical qualities of the closed die. 

High Tolerance

Because goods are distorted in extremely precise forging dies, the tolerances of closed die forging components are always tight. And the surface polish is usually excellent. Typically, this can regulate closed die generating components within +/- 0.5mm tolerance. This forging technique is, therefore, a nett or near nett form procedure that needs little or no modification. So, the clear benefit of closed die forging is the lower machining price for the identical components created in casting and forging.

Saving Material

When studying closed die forging, you would realise that the only material loss throughout the machining operation is flash. The trimming die will shift such a flash, and you will complete forging blanks. In closed die forging, the only excess material is flash. However, it could be repurposed.


Among the forging techniques for tiny or moderate size metal parts is closed die forging. It is a deformation method wherein the material is compelled to flow in a sealed shape referred to as die, as opposed to the open die forging procedure. Closed die forging, as opposed to open die forging, may generate more complicated designs that are incredibly close to the measurements of the completed component.

Moreover, the fabrication and design of dies, a component of the producer’s know-how, is an essential stage in closed die forging. Tool steels are the most often employed metal for forging dies. Also, these might always be more expensive due to the machining costs and high materials, but this is a one-time fee that will not be applied to our clients in the next batch of manufacturing.

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