INVESTIGATION ON THE EFFECT OF NON-UNIFORM FLASH LAND ON MATERIAL REDISTRIBUTION IN CLOSED DIE FORGING WITH FLASH

Abstract

The objective of this study is to investigate the impact of non-uniform flash land on material redistribution during closed-die forging with flash, focusing on how the use of non-uniform flash land can increase the fullering coefficient and thereby reduce the number of forging steps required. The methodology combines theoretical analysis with finite element methods, varying the geometries of both the flash land and the billet, and comparing the results obtained from these different configurations. A comparison of forming results across four different billet specifications reveals that as the initial billet cross-section increases, the material transfer rate decreases. This is primarily due to the increased material volume in the region, which reduces material transfer and enhances cavity filling rate. However, increasing the billet cross-section also leads to a decrease in the fullering coefficient and an increase in the number of forging steps required. The study also shows that non-uniform flash land, especially non-uniform flash land 3, significantly improve the fullering coefficient, reaching 1.56, an 11.4% improvement over the traditional flash land coefficient of 1.4. This enhancement reduces the number of forging steps and improves the cavity filling rate. The forming load is positively correlated with the fullering coefficient, and under identical conditions, non-uniform flash land result in a forming load that is approximately 7.6% lower than that of traditional flash land. This reduction in forming load contributes to lower energy consumption and greater process efficiency. Moreover, non-uniform flash land demonstrate a distinct advantage in axial material redistribution and cavity filling. The enhanced axial material redistribution associated with non-uniform flash land promotes more uniform cavity filling, significantly reducing the occurrence of incomplete filling, especially when the fullering coefficient exceeds 1.4. This highlights the ability of non-uniform flash land to improve the quality of forged parts by minimizing the need for excessive forging steps while optimizing material usage. In conclusion, the findings emphasize the effectiveness of non-uniform flash land in optimizing axial material redistribution, improving cavity filling rate, and increasing the overall efficiency of closed-die forging processes. These benefits contribute to the production of higher-quality forged parts, with reduced energy consumption and fewer forging steps.