Open Die Forging – The All-Around FAQ Guide

If you’re unable to find a good website to learn open die forging from, you’re just in the right page! For today’s guide, we’ll be walking you through what open die forging is – and even teach you too few things that relate to it as well!

Without further ado, let’s head right onto the guide!

What is Open Die Forging?

Open die forging is the process you use to deform a metal piece using more than one (1) die.

In the process, the dies don’t enclose the material completely, hence the term, open die forging. Furthermore, the dies either stamp or hammer the metal piece as it goes through different types and kinds of movements until you get the shape and the form you’re looking for.

How Does Open Die Forging Work?

Open die forging works similar to how the traditional forging procedure works.

Sample image of what the open die forging process is

It involves the shaping and the forming of the metal parts that are pre-heated through the use of multiple dies.

Open Die Forging vs. Closed Die Forging

You’ll be able to figure out what the processes mean by looking at the terms alone.

Quick comparison of how closed die and open die forging works (how they’re different)

But, for the benefit of people who aren’t well versed with it, here’s how you can differentiate them.

In open die forging, the metal piece or the billet is positioned in between more than one die. The procedure is accomplished without fully enclosing the material.

Closed die forging, on the other hand, compresses the billet or the piece of metal under high-pressure instances to fill the needed shape or form.

Part of their differences is their process. They do not employ the same procedure on how they’re completed and accomplished.  After the closed die forging process is completed, it needs little-to-no machining requirements due to high accuracy rates.

Following open die forging, on the opposite end of the rope, would require highly accurate machining processes to achieve the desired shape.

What is Die Forging Used For?

Die forging is the process of forging, forming, or shaping metal pieces that are heated to a desired shape.

Quick guide on how open die forging works based on a labeled diagram

You’ll usually use it to produce large parts that cannot be formed by manual labor.

What Are the Different Types of Forging?

There are about four (4) different processes or methods of producing or making a part.

Cold forging – one of the most common forging processes existent

Cold Forging

Cold forging is one of the many types of forging. It is the type of forging where any type of metalworking procedure is shaped below the temperature of recrystallization.

In simpler terms, it’s the process where a metal material or a billet is formed and shaped in room temperature.

It’s not a process that involves ice and below zero temperatures, just like what many people believe it to be.

Open Die Forging

It’s the procedure of forging a metal piece or material without it being enclosed fully.

This technique is often employed to roughly finish the forming and the shaping of the metal. In addition to that, you’ll want to perform it so that the billet can move freely when struck.

Impression Die Forging

Also more commonly referred to as closed die forging, impression die forging is the complete opposite of open die forging.

In this process, the metal piece is placed in an enclosed die, which resembles a mold. Moreover, the hammer die in this forging classification is shaped as the die as well.

Seamless Rolled Ring Forging

Last but definitely not least is seamless rolled ring forging. It is a process where you need the billet or the metal piece to be cut to the size exactly, then upset it so that it gets the mechanical properties you’re looking for.

The workpiece results in a ring-like shape because it’ll be placed in between axial rolls, idler rolls, and drive rolls.

These are the most known and most customary classifications of forging.

Open Die Forging vs. Cold Forging

Ideally speaking, cold forging is the method or the process you’ll want to use if you’re looking for strength and increased metal toughness and hardness.

A worker preparing the material or the billet for the open die forging process

Open die forging, being one of the hot forging processes, might not get you extremely toughened and hardened steel. However, it’s a technique that will allow your metal piece to move freely, making them easier to be machined.

Common Examples of Open Die Forging

Open die forging is a widespread process in shaping and forming industrial parts.

A material undergoing open die forging for the forming or the complete shaping of it

As a matter of fact, there are products and components that are considered common in terms of undergoing open die forging.

These products and components include:

1. Flange Coupling
2. Large and Medium-Sized Motor Shafts
3. Chain Links and Rings
4. Flat Drills
5. Centre Punches

These products aren’t the only things you can produce through open die forging. They’re just considered the most common products and components.

Is There Flash in Open Die Forging?

Flash is known to be the material or metal buildup that is in excess of the raw materials. So, since open die forging does not fully enclose the material, does it produce flash?

The excess molten material you see on the sides is the “flash” in metallurgical process

Yes, flash will be present after the open die forging process. As a matter of fact, both impression or closed die forging and open die forging produce thin layers of flash. But, the former can use this as an advantage because the flash can be led into details and crevices of the mold.

What Are the Limits of Open Die Forging?

Yes, there are certain limitations if you choose open die forging as the forging process.

As a matter of fact, here are some of the limitations in open die forging.

Complex Shapes Limitation

Since open die forging can’t guarantee 100% precision and accuracy, it is not the most recommended forging process for complicated and complex shapes and components.

Size Limitations

Unlike closed or impression die forging, there exists size limits in open die forging because of its nature of not fully enclosing the material.

For some materials, closed die forging will be the better option.

Small Material Quantities Limitation

If you are to perform open die forging, it’ll be best to produce a high number of volume and amount for economical purposes.

Open Die Forging Applications

You can find a ton of different applications for open die forging. Among the most common applications include:

• Manufacturing of medium-to-large-sized components
• Production of Plant Building Industries
• Shaping of cylinders or shafts
• Forming of discs, sleeves, and rings
• Production of simple-shaped parts and components

Apart from these, performing open die forging can help you produce step shafts and solid shafts where the diameters are stepped at multiple locations; ring-like parts and components; contour-formed metal shells, and many more!

Weight of Open Die Forging Products

You can perform open die forging and produce parts and components in astounding weight

Finishing a product through open die forging can produce parts and components that weight anywhere in the range of one (1) kilogram or less, up to more than 100 metric tons.

The weight will actually depend on type of metal piece you’ll use, as well as the expected finished product.

What Are the Advantages of Open Die Forging?

Choosing to go with open die forging can welcome a ton of benefits and advantages. Some of these advantages include, but are not limited to:

• Less Material Waste
• Increased and Developed Strength
• Longer Life of the Metal Part or Billet
• Better Resistance Against Fatigue
• Decreased and Reduced Chance of Deformation
• Finer Grain Size
• Continuous Grain Flow

Are There Disadvantages in Performing Open Die Forging?

Just like any other process, open die forging can also have disadvantages. These disadvantages include:

• It is incapable of forming higher accuracy and precision parts
• After the process, machining will be required
• The process does not produce consistent and the same exact results

Another one of the most overlooked drawback is that in open die forging, you would have to move and be locomotive with the material you’re working on. Therefore, it would need interaction and intervention of a worker.

Open Die Forging Process Steps

For you to be able to understand the open die forging process, it is imperative that you’re knowledgeable about how the open die forging process works.

Worker assesses the procedure of open die forging in creating the large part or component

The first step is preparing the metal piece. Preparation could include pre-heating it to a certain temperature in order for it to be forged easily, and other processes to make the forging lighter.

After that, the billet or the metal piece is prepared and positioned unto the anvil of the machine. Then, the hammer will be the one to carefully strike and deform the workpiece.

After a few turns and impacts, the metal piece will be formed all according to the desired shape and dimensions.

When the forging process is finished, the newly forged billet must undergo machining. Machining is the procedure in which all small details will be fixed and directed to its precise shape.

Can Open Die Forging Save You Money?

Compared to impression die forging, open die forging will almost always require you to perform machining after the process.

So, you might think it’s more expensive because of this, right? However, if your parts and components only require short runs and processes, open die forging will be your money-saving process.

It doesn’t require any expensive mold, nor do you need to have an extremely safe working environment for it.

However, you’d still have to perform machining, which can add up to the expenses or the costs you’ll need.

What is the Barreling Effect in Metal Forging?

The barreling effect is exactly what it is called. It is the metal piece’s deformation due to the friction of the forging process.

Quick illustration of how the barreling effect happens during open die forging

Barreling is the result in which the metal piece will be in a curved trend, rather than a straight line. Due to the fact that the height remains unchanged in the process, the overall material will be cylindrical, thus, the term, barreling effect.

Avoiding Barreling Effect

Through open die forging and the use of the correct lubricants, barreling can be mitigated and minimized. In addition to that, pre-heating the dies can also help and assist in the process too.

Therefore, for you to avoid barreling effect:

1. Choose the correct type of lubricant for the process
2. Make open die forging your best choice
3. Pre-heat the workpiece in line with the temperature of the dies

What Are Common Open Die Forging Lubricants?

As of today, there are a couple of die lubricants considered the most common.

Water-based graphites – one of the most common lubricants in the open die forging process

They include water-based graphites, water-based synthetics or non-graphites, water-based graphite emulsions, and oil-based graphites.

NOTE: These are only “the most common” or “the most used” lubricants. You can choose and refer other types of materials as lubricants for it.

How Much Energy Will It Take to Run Open Die Forging For a Day?

The energy that will be consumed in open die forging will depend on too few factors. It can involve the size of the metal piece or the workpiece, the frequency, and others.

Ideally, though, the amount of energy you’ll use will be based off of the force required in forging.

Can You Produce Complex Shapes and Components Through Open Die Forging?

Yes, however, it will require you to perform advanced open die forging techniques and strategies to be able to produce complex shapes for large parts and components.

The basic and the simple open die forging process wouldn’t – you’ll need certain strategies and additions to it like rounds, bars, and ingots.