Open-Die Forging Operations Of Metals; Classification, Application, Design

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In the metal industry, open-die forging operations are very important. Lots of kinds of primary shapes of the metal parts are produced with the open-die forging operations. Here you can find detailed information about the open-die forging operations such as; application, classification, and process design. 

Open-Die Forging Operations

Open-die forging operations are applied in an open environment with several workforces. There is a ram or hydraulic press that shapes the hot bulk metal into desired shapes. The most common practice is decreasing the height of the metal billet and increasing the diameter of that billet. The obtained shape is shaped into exact shapes with additional processes. 

Open-die forging operation(Image Source:alldifferences.net/difference-between-open-die-and-closed-die-forging/).

The workforce is very important in open-die forging processes. Because, the workpiece must be manipulated, moved rotated, etc. via a worker or operator. The ability of the worker is very important. 

Types Of Open-Die Forging Operations

According to the application, there are three types of open-die forging operations commonly. 

The first one is the fullering operations in which the starting material’s cross-section is reduced. The products of fullering operations are sent to additional shaping operations to obtain the required final shape. Dies have convex surfaces in fullering operations and they are generally multi-cavity impression dies. So the final shape of the fullering operation has a rough surface for the additional machining operations. 

The second type of open-die forging operations is the edging process. Edging processes are the same with the fullering operations with a slight difference in the die shape; dies have concave surfaces in edging operations. 

The third type of open-die forging operations is the cogging operations which are also called incremental forging. In this type of open-die forging operations, the length of the starting cast ingot is increased and the cross-section of this cast ingot is decreased. So bar-shaped blooms slabs are obtained to use in other operations. 

Open-Die Forging Process Parameters And Design In Engineering Level

The deformation in open-die forging processes is homogenous if there is no friction between the process materials. So, true strain occurs in the deformation of the metal workpiece in the open-die forging process. As you know from the engineering practice, at the final height of the workpiece, true strain reached its maximum. 

In a real application, the height of the workpiece does not change abruptly from the starting height to the last height. Intermediate heights are obtained with the application of impacts of the ram. If the process is applied in hot conditions, the strain hardening coefficient to calculate the required yield stress to deform the metal is 0. In cold working, it was not zero and we need to consider the strain hardening effect with this exponent. 

So, in hot deformation processes of metals, we can take the yield strength of metal directly in the calculation of the required forces. 

You can use the calculator below to calculate the required force to deform the metal workpiece in open-die forging processes at each impact step. 

Required Force Calculation For Open-Die Forging



















The use of this calculator is very simple. You just need to enter the required values inside the brackets and click on the ‘Calculate!’ button to see the result. If you want to make another calculation, click on the ‘Reset’ button then re-enter the values. 

You can use the recommended units inside the parentheses. Or you can use the MB-Unit Converter tool to convert the units into consistent sets of units.

In this calculator, the first value is the coefficient of friction. This is the friction between the work and dies surfaces. This value must be precise and must be well defined for the correct calculations. 

The second value is the diameter of the work part to be force will be applied. And the third value is the height of the work part. Enter the yield strength and the surface area of the part. 

Barreling In Open-Die Forging

There is another phenomenon called barreling in which the part will take shape as a barrel with the force application. Barreling is the indicator of the deformation difficulty. The external surfaces of the metal part are cooler than the internal side. So, the internal side of the work deforms with the application of force but the external surface does not deform like the internal side. This adds difficulty to the deformation of the metal. 

Conclusion

The general explanation of the open-die forging operations can be made like this. 

Mechanical Base does not accept any responsibility for calculations made by users in calculators. A good engineer must check calculations again and again.

You can find out much more calculators like this in Mechanical Base! Take a look at the other engineering calculators available in Mechanical Base!

Do not forget to leave your comments and questions below about the open-die forging operations. 

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