November 2021 Volume 3

FORGING RESEARCH

As shown in Table 1, the inherent processing characteristics of metal AM results in internal structure and surface finish that is substantially inferior to those in forged products. The non- equilibrium structural differences in metal AM products exhibit poor dynamic properties, such as fatigue resistance and fracture toughness [3- 7]. Therefore, the metal AM products cannot replace most forgings, especially when the parts are fatigue or fracture critical in service and mission and safety critical in their applications. Even the solid-state metal AM processes [8-10], where there is no melting and solidification, it is not possible to match the metal flow required in forgings to function as designed. While research and development are underway in replacing forgings with metal AM through design, material, and process innovations, there are opportunities to utilize metal AM in several phases of forging operations leading to a more competitive, agile, sustainable, and stronger forging industry. Some of the current efforts under the Forging Defense Manufacturing Consortium (FDMC) program funded by Defense Logistics Agency (DLA) and potential future developments are described in this article.

The most expensive and time-consuming part of forging operations is the die manufacturing. The greater the complexity of the forged part, the longer is the lead time and the higher is the cost of the die sets. Two recent articles in FIA Magazine [11, 12] described the Forging Die Manufacturing by metal AM project under FDMC program discussing the Technology and Manufacturing Readiness Levels (TRL and MRL) [13, 14] along with technology shortfalls and associated risks. This article also showed the path of Technology Maturation and Risk Reduction (TMRR) and Engineering and Manufacturing Development (EMD) for the near future. In this article, metal AMdie manufacturing markets and opportunities are presented based on the DLA forging database consisting of forging cost and associated production lead time (PLT). An in-depth search of the XSB database [15] for parts with DLA forging procurement history revealed a substantial market for AM fabrication of forging die sets exists with a strong potential benefit to DLA. A summary of the extracted forging procurement data is shown in Table 2.

Forging Die Manufacturing

Table 2: Number of DLA procured forgings, their average price, estimated die cost, and potential die manufacturing market for PLT of 100 to 500 days.

The die set cost in 2021 (USD) for each forging has been estimated based on the average forging price and corresponding die cost estimated using the US Navy Forging Price Fighter model that has been extensively used at FDMC to assess the forging procurement cost by DLA. As the PLT increases from 100 days to 500 days, the number of forgings decreases, and the average price of forgings increases steadily as expected, since the increase in the forging difficulties lead to production delays and an increase in forging price. This is consistent with all types of forgings whether possible,

confirmed, or safety critical forgings are considered. An increase in estimated die costs also increases when associated with larger PLTs which likely result fromlong lead times for diemanufacturing. Based on the above data, it is clear that the forging die fabrication market for DLA alone is quite large, to the order of USD 100 million to USD 1 billion for forgings with 180 days and higher PLT. Therefore, a potential demonstration project to successfully implement metal AM fabricated forging die can benefit DLA and the forging industry in becoming more agile and efficient.

FIA MAGAZINE | NOVEMBER 2021 71