May 2021 Volume 3

FORGING RESEARCH

Finite Element Analysis in the Metal Forming and Forging Industries: What to Know and Where to Apply By Ming (Henry) He, Ph.D.

Abstract Applications of finite element analysis have tremendously reshaped the metal forming and forging industries in recent decades. Today, finite element modeling has become an indispensable and powerful means of assisting process and design engineers: (1) in the conceptual development or virtual prototyping phase to precisely examine the behavior of the part to be formed so the tools can be correctly designed; and (2) in the product improvement phase to correctly and effectively identify the root causes of product defects and provide solutions. This article presents a high-level introduction to the basic concepts and principles of metal forming, plasticity and finite element analysis. It focuses primarily on ferrous metals (mostly steels), but the theories and methodologies in general are applicable to any metal. Examples are provided to demonstrate how finite element modeling techniques are applied in the modeling of metal forming processes and products. 1. Introduction In the metal forming industry, finite element methods (including finite difference and boundary element methods) have taken the lead among all theoretical and analytical approaches in process simulation and modeling. A handful of finite element software packages, through competition, rose strongly through the ranks and now hold most of the market share. Scientists and researchers in the finite element field work tirelessly and closely with the metal forming industry to develop new solution methods and more efficient algorithms to meet the ever-increasing demands. Today, many forming and forging companies, large and small, have implemented finite element analysis in their daily activities (the author has seen it is used even in some tiny forge shops). They realize that finite element analysis can not only save them significant time and money, but can also boost their production capability and quality. However, because they lacked a complete understanding of this virtual numerical simulation tool’s fundamentals, not all process engineers and design engineers were successful in their attempts to replace the previous trial-and-error practice. Thus, while the initial success in some simple cases thrilled the users, the unmatched or unexplainable results and the repeated interruptions or non-convergences of the simulations often overwhelm and discourage them. The author will share some insights on how to unify the finite element modeling methods with the metal forming processes seamlessly and effectively, based on decades of experience

working in developing metal forming technologies and in applying finite element modeling techniques to these jobs. 2. A Brief History of Metal Forming and Forging Metal forming and forging is one of our oldest and simplest processes (Figure 1). More than 6,000 years ago, mankind started forming some very basic and simple items for daily tasks and decorations by using elementary metals such as gold, silver or copper. When bronze was created by melting copper and tin ores together [1] in the Bronze Age, around 2,500 BC, hand tools with improved strength and durability became available. Following the Bronze Age, iron gradually replaced bronze in the Iron Age between 700 and 500 BC. Forging process first appeared during this time (Figure 2). The very first forging process was to simply work a piece of solidified wrought iron by repeatedly hammering and folding to purify the workpiece and form the desired shapes.The tools and weapons made in this era were stronger than ever before. In the Industrial Age, water-powered and steam-powered hammers first appeared (Figure 3), enabling increasing numbers of forming machines to be built. These machines were able to replace human hands to enormously expand the types, sizes, capacity and complexity of the forged products.

(1450 BC) Figure 1. Forging: One of mankind’s oldest technological processes [2]

FIA MAGAZINE | MAY 2021 67