Metal Forging Tools and Equipment and Parts Supplies
This article discusses the significant factors in the selection of forging equipment for a particular process. It describes the characteristics of forging hydraulic presses, mechanical presses, screw presses, and hammers. The article discusses the significant characteristics of these machines that comprise all machine design and performance data, which are pertinent to the economic use of the machines, including the characteristics for load and energy, time-related characteristics, and characteristics for accuracy.
The forging of metals and alloys is one of the oldest metal forming techniques used by humankind. Forging processes were improved over the centuries and are still being refined. Today, we are certain that there is no limit to these improvements and that we will never reach the point when we can say that nothing more is to be done. Despite the enormous knowledge and experience gained over the centuries, we still face new challenges arising from civilizational progress. One of them is the necessity to produce parts that are more and more complex in terms of shape and properties, which requires not only a deep insight into phenomena that accompany forging processes, but also the development of new techniques, riveting machine and equipment, materials, research methods, and tools, as well as the improvement of the existing ones. With the Special Issue on “Forging Processes of Materials”, the Editorial Board of Materials offers authors the possibility of presenting their findings in this field. As the Guest Editor for the Special Issue, I would like to invite you to contribute to this publication, which, I hope, will serve as a source of knowledge for both theoreticians and practitioners. Hence, I encourage authors to submit papers exploring, in a broad sense, the theory and practice of forging metals and alloys. I wish to assure you that we will make every effort to ensure the highest quality of this Special Issue.
Forging is a hot or cold metal deformation process used to produce metal parts where strength is a paramount concern, engine connecting rods and hand tools being two such examples. The process itself involves using compressive forces to mold and deform metal into the desired shape. For most applications, forging entails heating the base metal until it is malleable enough to work with, although cold and warm forging are also done.
The forge, sometimes called a hearth, is the component that heats the metal prior to forming. In its most fundamental form, forging can be understood in the manner of making horseshoes. The blacksmith heats the metal in the hearth, then pounds it with a hammer against an anvil to flatten it, curve it, pierce it, and generally shape it, repeatedly reheating the metal to maintain plasticity. Small gas-fired forges are available for blacksmiths though many forgers choose to build their own.
Modern industrial forging relies on sophisticated, heavy-duty equipment capable of producing small accurate parts as well as large pieces weighing many tons. As with castings and weldments, many forgings are machined after they are made to achieve their final forms.
An anvil is a large slab of metal, usually made of steel, which serves as the workbench for the blacksmith or automated hydraulic closed die forging hammer device. The metal is placed on the anvil, where it is hammered into the correct shape. Anvils traditionally provide a flat hammering surface, though curved anvil tops are available. A hardy hole and punch hole can sometimes be found on an anvil – the hardy hole serves as the square socket for accepting the shank of a hardy, an interchangeable tool in a variety of shapes used for cutoff, bending, etc. The punch hole provides clearance for punching holes in the metal.
Chisels are cutting supplies that chip away at metal. They are traditionally made of high-carbon steel and consist of a long octagonal cross-section with a tapered cutting edge on one end. There are two types of chisels—hot chisels and cold chisels. Cold chisels are typically thinner in construction, and better suited for cold forging. Hot chisels, on the other hand, assist in hot forging processes. Chisels are traditionally applicable in manual forging applications.
Tongs assist in the transportation of the heated metal from the forge to the anvil. Many different tong shapes are available to provide adequate gripping of multiple metal shapes and sizes.
Forming tools that create grooves or indentions in the forging process are known as fullers. Fullers also help round out corners and stretch the metal. Traditionally used in pairs, fullers work through placing one beneath the metal, and the other on top. This enables the indentation of both sides of the metal component to occur simultaneously.
Different forging processes are appropriate for different applications—options such as hot forging, cold forging, closed die forging, upset forging, and press forging are simply a few examples. Many of these forging processes require the use of a hammer to enable compression and shaping of the metal. Forging hammers vary in shape, size, and material based on the particular application, but all industrial hammers typically apply force with a large ram. Two basic types of hammers are:
Drop hammers: Gravity allows the heavy ram to fall onto the metal.
Power hammers: Compressed air, hydraulics, or electricity drive the hammer.
Hammers are capable of delivering percussive impact blows with forces of up to 50,000 lbs. in their largest incarnations, with smaller capacity units also available. For increased forging forces, forgers turn to presses.
Closed die: Here, the metal is completely encased. When the CNC hydraulic die forging hammer or press pushes against the metal, the metal flows and fills the die cavity or cavities. Typically, the pre-forged part will have some resemblance to the final forging before it is placed in the die, preformed by a series of so-called blocker dies.