November 2021 Volume 3

FORGING RESEARCH

Utilization of Metal Additive Manufacturing in Forging Industry By Dr. Prabir K. Chaudhury and Dekland D. H. Barnum Utilization of Metal Additive Manufacturing in Forging Industry By Dr. Prabir K. Chaudhury and Dekland D. H. Barnum

Additive Manufacturing or Direct Manufacturing, popularly known as 3DPrinting, has become the leading-edge manufacturing technology. With advances in the ability to direct, control, and manage high energy sources such as electron beam, laser, plasma, and electric arc to rapidly melt and solidify metals in a thin layer made metal AM possible. Today Metal AM is a reality, not only for prototype fabrication, also for functional parts in all industrial sectors [1]. Currently, it is well established that the metal AM is most suitable for production of highly engineered parts with complex geometry, low volume, prototype, custom parts, and parts made from expensive materials [2]. Application of metal AM has Additive Manufacturing or Direct Manufacturing, popularly known as 3D Printing, has become the leading-edge manufacturing technology. With advances in the ability to direct, control, and manage high energy sources such as electron beam, laser, plasma, and electric arc to rapidly melt and solidify metals in a thin layer made metal AM possible. Today Metal AM is a reality, not only for prototype fabrication, also for functional parts in all industrial sectors [1]. Currently, it is well established that the metal AM is most suitable for production of highly engineered parts with complex geometry, low volume, pr totype, custom pa ts, and parts made from

now spread in all industrial sectors, especially where advantages of AM can be taken immediately, when just in time manufacturing and lead time reduction are critical. The majority of these parts are functional but non-critical or have large factors of safety because of the limitations in the microstructural and structural deficiencies inherent in metal AM, especially when full or partial melting followed by rapid solidification is the principal shape making principle. A comparison betweenmajor metal AMand conventional forging processes have been compared from the process, structure, and properties points of view. expensive materials [2]. Application of metal AM has now spread in all industrial sectors, especially where advantages of AM can be taken immediately, when just in time manufacturing and lead time reduction are critical. The majority of these parts are functional but non-critical or have large factors of safety because of the limitations in the microstructural and structural deficiencies inherent in metal AM, especially when full or partial melting followed by rapid solidification is the principal shape making principle. A comparison between major metal AM and conventional forging processes have been compared fro t e process, structu e, and properti s points of view.

Table 1: Comparison of metal AM process characteristics with forging characteristics. Major Metal AM Processes Forging and Wrought Metal Process

Selectively melted on a substrate with no shaping tool

Deformation of solid metal in a closed or open die (tooling) set to make the shape

Very small melt pool

No melting

Very fast local cooling from liquid and solid state Shaping time is in several hours to weeks depending on size Suitable for in-situ process control as well as by prior simulation and design

Slow global cooling in solid state

Shaping time is in seconds or minutes depending on process

Not suitable for in-situ process control

Structure

Homogeneous microstructure and inhomogeneous chemistry

Homogeneous microstructure and homogeneous chemistry Fine microstructure from recrystallization Defects are healed in macro-, micro- and meso- scale, generated in nano-scale, and avoided by pre-forming and controlling chemistry Macro- and micro-scale structures define the properties

Very fine dendritic microstructure

Defects are generated in meso- and nano-scale and avoided by controlling raw material quality and processing parameters Meso- and nano-scale structures and defects define the properties Poor surface finish requiring significant finish machining

Better surface finish requiring limited or no finish machining Structure and defect generation is highly localized Structure and defect generation is global Properties Comparable static mechanical properties, but poor fatigue and fracture toughness Excellent mechanical properties, strength, ductility, fatigue, fracture toughness

Anisotropic properties depending on meso-scale defect alignment along the solidification direction.

Anisotropic properties are caused by nano-scale defect alignment along the metal (grain) flow direction

Table 1: Comparison of metal AM process characteristics with forging characteristics.

FIA MAGAZINE | NOVEMBER 2021 70