Investigation of burr formation in forging under different conditions
One of the methods used for the production and shaping of metal parts is forging, which is based on compressive forces. These forces can be applied by a forging hammer or a die. In parts produced by the forging method, the finer the grain structure and the more uniform and homogeneous the phases formed within them, the better their mechanical properties will be. Additionally, reducing the amount of flash due to decreased material flow leads to an increased lifespan of the die in terms of wear. In forging, a series of methods can be employed to reduce or eliminate flash. Mechanical properties have an inverse relationship with flash, meaning that the less flash there is, the finer and more homogeneous the phase grain structure will be, resulting in the produced part having more desirable mechanical properties.
What is the cause of flash in forging?
There are various factors and parameters that can significantly impact the forging operation of a produced part. One of the most important factors affecting the forging process is the flow of materials within the die. This means that an improper shape of the initial piece (billet) or the way the billet is positioned in the die may lead to incorrect and poor distribution of material flow, resulting in the production of a defective part. This defect can include burrs (wrinkles), overlapping, and surface cracks in the produced part. Additionally, there may be points where excessive stress and pressure exist, or the temperature may rise too high, which can create issues with the quality of the produced part. During closed-die forging operations, the parting line of the die affects the control of material flow within the cavity, leading to the emergence of burrs, the amount and weight of the burr material required for filling, and the lateral forces on the upper and lower dies. The selection of the parting surface can play a significant role in achieving optimal flow. There are changes in the direction of material flow at certain points in the die that can adversely affect the mechanical properties of the part and cause material overlapping.