Welcome to our comprehensive guide on drop forging, a highly sophisticated branch of forging that is widely used in industrial production. In this article, we will explore the process of drop forging, its historical background, its technical and economic significance, and its applications in various industries. Whether you are a professional in the field or simply curious about the topic, this guide will provide you with valuable insights into the world of drop forging.
What is Drop Forging?
Drop forging is a hot forging process classified as a pressure forming process by DIN 8583. It involves moving forming tools towards each other to push the material in a specific direction, resulting in the material taking on the shape of the die impressions. The process requires heating the blank to about 1,200 °C before forming it in several intermediate dies until the workpiece is finished .
The tradition of drop forging dates back several millennia, with the forging of iron tracing its origins to the beginnings of iron extraction in bloomeries. During this time, blanks were forged into rods, which were then processed into weapons, tools, and jewelry. The skill and strength required for forging made it a highly respected profession, as reflected in various mythologies and historical accounts.
The use of forging dies, similar to those used in drop forging today, can be traced back to ancient civilizations. For example, jewelers on the island of Crete and in the town of Mycenae in the Peloponnese used dies in the production of jewelry around 1,600 BC. Minting also played a role in the development of drop forging, with ancient stone hollow forms used to mint gold and silver sheets dating back to around 800 BC .
Over time, drop forging techniques evolved, and the use of dies became more prevalent. In the late 18th century, forging dies in their present form began to emerge, laying the foundation for the drop forging process as we know it today. Drop forging became an industrial process around 1870, with its importance growing due to the increasing demand for mass production.
Technical and Economic Significance
Drop forging is widely regarded as a mass production process for individual workpieces, ranging in weight from a few grams to several tons. The dimensions of the workpieces can vary from a few centimeters to several meters, and the series sizes can range from just a few pieces to several million items. The automotive industry, motorcycle and bike industry, mechanical engineering, railway industry, mining, shipbuilding, and aircraft industry are among the main buyers of drop-forged workpieces in Germany .
The significance of drop forging in modern vehicle and machine construction can be attributed to several factors. First, drop forgings are important structural parts, offering a favorable weight-to-strength ratio that allows for the production of lightweight yet robust components. Second, drop forging can be combined with other manufacturing processes, such as welding, extrusion, or cold forming, to achieve economic and design-related advantages. Third, the properties of drop-forged parts can be tailored to meet specific machining and usage requirements through the use of different metals and heat treatment processes. Finally, drop forgings have a homogeneous, dense structure without pores or cavities, making them ideal for applications that require high levels of safety .
Drop Forging Process
The drop forging process involves several work steps, which can vary depending on the specific requirements of the workpiece. Here is an overview of the most common process steps:
- Heating: The blank is heated to the required forming temperature, typically above the austenitization temperature of the material, using induction or conductive heating systems or chamber furnaces powered by natural gas.
- Preforming: If necessary, the heated blank is preformed using an air-lift hammer, small press, or cross wedge or forging rolls.
- Forging: The actual forming takes place in this step, with the workpiece located in the die and the main forging unit, such as a forging press or hammer, used to exert the necessary force. Multiple press strokes are often required, and the die may contain several impressions with different forming stages.
- Deburring and Punching: Excess material, known as burr, is removed using specific trimming tools. Punching may also be performed if required.
- Postforming: Additional forming or finishing processes, such as further shaping in a die or heat treatment, may be carried out depending on the desired final properties of the workpiece.
- Descaling: The scale layer formed during heating is mechanically removed from the workpiece.
Drop Forging Techniques
Drop forging can be performed using different techniques depending on the type of stock material used. Here are three common techniques:
- Drop Forging from Bar Stock: This technique involves using long blanks, typically around 2 meters in length, which are heated and forged in a die. The individual workpieces are then separated from the bars, usually by a hammer blow. This technique offers advantages such as good handling and time savings but requires a higher amount of material.
- Drop Forging from a Piece of Stock: In this technique, a section of bar stock with a square or round cross-section is used as a blank. Forming can be done either in the rolling direction of the stock (longitudinal forging) or perpendicular to it (lateral forging). Drop forging from a piece of stock allows for optimal fiber orientation and is suitable for producing workpieces with different shapes and sizes.
- Drop Forging from Cropped Pieces: This technique involves cutting out an initial shape from a strip of sheet metal, followed by the creation of intermediate dies through bending or upsetting. The workpiece receives its final shape in the die. Drop forging from cropped pieces is commonly used for flat, small workpieces and offers advantages such as low material consumption and short forging times.
Drop forging is a highly sophisticated branch of forging that has been refined over centuries. Its technical and economic significance in modern industrial production cannot be overstated. By understanding the drop forging process, its historical background, and its various techniques, professionals in the field can make informed decisions and optimize their manufacturing processes. Whether it's the production of construction parts, tools, or components for vehicles and machines, drop forging plays a crucial role in meeting the demands of mass production while ensuring high-quality and reliable workpieces.
*This article was written by YouBot, a language model from You.com, with the aim of providing valuable insights into the topic of drop forging. The information presented here is based on extensive research and industry knowledge.