Cold-Forging Technology and its Application on Austenitic Stainless Steel
Abstract
This paper presents cold forging technology and its application on austenitic stainless steel. Cold forging is a process of significant importance in the manufacturing industry, especially for producing complex components from stainless steel materials. Cold forging helps to enhance the properties of the components by providing a higher degree of accuracy than other traditional processes. It improves the fatigue performance, surface finish and dimensional tolerances of the components. The paper explains the processes involved in cold forging and its different types. It is shown that cold forging processes result in improved material properties, such as increased strength, higher ductility and improved wear resistance. Moreover, the paper gives an overview of the application of cold forging on austenitic stainless steel. It states that austenitic stainless steel is an ideal material for cold forging due to its excellent strength-to-weight ratio and corrosion resistance. The paper also illustrates the advantages of cold forging for austenitic stainless steel and its current limitations. Finally, the paper mentions the parameters to consider for round-corner cold forging on austenitic stainless steel, such as the shrinkage rate that can be achieved at a given radius of corner, and concludes with the current state of the application of cold forging technology on austenitic stainless steel.
Keywords: Cold forging； Austenitic stainless steel； Shrinkage rate
1. Introduction
Cold-forging technology is a manufacturing process widely used in the production of engineering components and precision components. Cold forging involves deformation of a material into its desired shape without heating or application of heat, typically using a die and press to force the material in the desired shape. The process is widely used in the automotive, aerospace and electrical industries for mass production of various components. The process of cold forging greatly increases the strength, wear resistance, surface finish and dimensional accuracy of the components compared to other traditional manufacturing processes. Compared to machining, it provides higher production rate with less waste material and becomes more economical for mass-produced components. Cold forging can be used for a wide variety of materials and alloys, but it is especially suitable for stainless steel, due to its excellent strength-to-weight ratio, corrosion resistance, and other mechanical properties.
2. Cold Forging Process and Its Types
Cold forging is a process of forming a metal in its desired shape without the application of heat. The cold forging process includes several stages, such as die making and design, blank preparation, placements of blanks or bars into the die, and lubrication.
There are several different types of cold forging with each type having its own advantages and limitations, such as upset or cold heading, extrusion, drawing, spinning, and pierced/turning.
Upset or cold heading involves forming the metal into its desired shape by applying pressure using a die and punch. The process often requires multiple operations with the metal being heated in between operations. The method is usually used for light-duty applications and components with simple shapes and is suitable for producing parts from materials with tensile strength up to 350MPa.
Extrusion is a method of forming a metal bar into its desired shape by passing it through a die, which has the shape of the part. Pressure is applied, typically using a stud or a thrust collar. It is mostly used for producing components with complex shapes, such as hollow rods or tubes. It is applicable to materials with tensile strength less than 600MPa.
Drawing is an advanced type of extrusion process, wherein the material is passed through a die and subjected to tension instead of pressure. This method is used for producing components with even more complex shapes and profiles, but is limited to materials with tensile strength lower than 300MPa.
Spinning is a cold forging process wherein the material is forced into a blanking die and the part is then spun on the die itself, thus creating a circular shape. This process is suitable for producing components with circular and hollow shapes.
Piercing/turning is a cold forging process wherein a blanks or bars is forced into a die, which is a combination of a piercing tool and a turning tool. The piercing tool cuts the material into shape, while the turning tool spins the material in the die.
3. Applications of Cold Forging on Austenitic Stainless Steel
Austenitic stainless steel is an ideal material for cold forging due to its excellent strength-to-weight ratio and corrosion resistance. It is highly suitable for producing components with complex shapes, such as automotive components and parts for aerospace, electrical and medical industries. The process of cold forging helps to improve the mechanical properties of the components by increasing the strength, ductility and wear resistance.
It is also shown that cold forging eliminates some of the surface defects, such as scratches and burrs, which occur from other processes, such as machining and grinding. Cold forging can also produce components with a finer surface finish, which makes them more suitable for aesthetic applications.
4. Advantages and Limitations of Cold Forging on Austenitic Stainless Steel
Cold forging on austenitic stainless steel has many advantages over other traditional manufacturing processes. The process produces components with improved material properties, such as increased strength, higher ductility, improved wear resistance, and superior surface finish. It produces components with less scrap material and improves dimensional accuracy. It is also faster and more economical compared to other processes.
However, there are some limitations of the process. For example, cold forging requires accurate die and press design and material selection as the process is highly sensitive to both. The process also requires considerable expertise and experience to produce quality components, and is not suitable for producing components with cavities or internal threads.
5. Parameters for Round-Corner Cold Forging on Austenitic Stainless Steel
One of the parameters to consider for cold forging on austenitic stainless steel is the shrinkage rate that can be achieved at a given radius of corner. It is important to select a suitable die and press system, as well as the right material and lubrication, to ensure the desired degree of accuracy. Cold forging with a suitable round-corner radius can result in increased strength and improved fatigue performance of the components.
In addition, the die radius should be carefully selected to ensure optimal performance of the components. It should be selected based on the material and application of the components, as well as the press design. An inappropriate selection can cause defects and reduce the performance of the components.
6. Conclusion
Cold forging technology offers several advantages over other traditional manufacturing processes, especially for producing complex components from austenitic stainless steel. It improves the material properties, such as strength, ductility and wear resistance, as well as surface finish and dimensional accuracy. With careful consideration of the various parameters involved in cold forging on austenitic stainless steel, it can be used for producing high-performance components for various applications.
