The Introduction to Various Types of Forging
Free forging refers to a method of processing forgings by directly applying external force to the billet between the upper and lower anvils of forging equipment, causing the billet to deform and obtain the required geometric shape and internal quality of the forgings. The forgings produced by free forging are called free forgings. Free forging mainly produces small-batch forgings, shaping billets through forging equipment such as forging hammers and hydraulic presses to obtain qualified forgings. The basic process of free forging includes roughing, elongation, punching, cutting, bending, twisting, upsetting, and forging. The process of free forging includes basic processes, auxiliary processes, and finishing processes. The basic processes of free forging include roughing, elongation, punching, bending, cutting, twisting, upsetting, and forging, with roughing, elongation, and punching being the most commonly used processes in actual production. Auxiliary processes include pre-deformation processes such as clipping, upsetting, and shoulder cutting. Finishing processes involve reducing surface defects of forgings, such as removing surface unevenness and shaping.
Advantages of Free forging:
1. Flexibility in production, capable of producing small parts weighing less than 100kg as well as heavy-duty parts weighing over 300t.
2. Utilization of simple, versatile tools.
3. Gradual deformation of the billet in different areas during forging, resulting in much lower tonnage requirements for forging equipment compared to die forging.
4. Low precision requirements for equipment.
5. Short production cycles.
Disadvantages and limitations:
1. Production efficiency is much lower than die forging.
2. Forging shapes are simple, with low dimensional accuracy and rough surfaces.
3. High labor intensity and technical requirements.
4. Difficulty in achieving mechanization and automation.
Die forging is a forging method that utilizes dies on specialized forging equipment to form blanks and obtain forgings. The method produces forgings with precise dimensions, minimal machining allowance, complex structures, and high productivity.
Advantages of Die forging:
High production efficiency: Metal deformation occurs during the die forging process, allowing for rapid attainment of desired shapes.
Complex forging shapes: Die forging facilitates the creation of complex shapes, resulting in more rational metal flow patterns and extended part lifespans.
Accurate dimensions and excellent surface quality: Die forging results in precise dimensions and superior surface quality, with minimal machining allowance.
Material savings and reduced machining workload: Die forging reduces material waste and machining requirements, especially for parts produced in sufficient quantities, thereby lowering part costs.
Disadvantages and limitations:
Limited by the capacity of typical die forging equipment, most die forgings weigh below 70kg.
Long production cycles and high costs associated with forging dies.
Higher investment costs for die forging equipment compared to free forging.
Roll forging is a forging process that involves plastic deformation of a workpiece using a pair of rotating fan-shaped dies to obtain the desired forged part or blank.
The deformation principle of roll forging is as illustrated above. Roll forging deformation is a complex three-dimensional process. Most of the material flows longitudinally, increasing the length of the workpiece, while a small portion of the material flows laterally, increasing the width of the workpiece. During the roll forging process, the cross-sectional area of the workpiece root continuously decreases. Roll forging is suitable for processes such as shaft stretching, plate flipping, and longitudinal material distribution. It can be used to produce connecting rods, twist drills, wrenches, knife nails, hoes, picks, flat leaves, etc. The roll forging process gradually deforms the billet using the principle of rolling forming. Compared with conventional die forging, roll forging has the advantages of simple equipment structure, stable production, low vibration noise, convenient automation, and high production efficiency.
Closed-die forging is commonly employed for producing rotary forged components such as gear blanks with protruding hubs and sometimes for non-rotary forged components. It falls under the category of flashless forging. For intricately shaped die-forged components, a combination die, comprising two half-dies (thus adding a parting line), is used to form the billet within the die cavity. The combination die typically consists of upper and lower halves, with guide pillars and pins used for alignment to prevent misalignment of the billet during forging. Compound dies are predominantly used for producing complex-shaped non-rotary forgings, such as connecting rods and fork forgings.
Advantages of Free forging:
1. Flexibility in production, capable of producing small parts weighing less than 100kg as well as heavy-duty parts weighing over 300t.
2. Utilization of simple, versatile tools.
3. Gradual deformation of the billet in different areas during forging, resulting in much lower tonnage requirements for forging equipment compared to die forging.
4. Low precision requirements for equipment.
5. Short production cycles.
Disadvantages and limitations:
1. Production efficiency is much lower than die forging.
2. Forging shapes are simple, with low dimensional accuracy and rough surfaces.
3. High labor intensity and technical requirements.
4. Difficulty in achieving mechanization and automation.
Die forging is a forging method that utilizes dies on specialized forging equipment to form blanks and obtain forgings. The method produces forgings with precise dimensions, minimal machining allowance, complex structures, and high productivity.
Advantages of Die forging:
High production efficiency: Metal deformation occurs during the die forging process, allowing for rapid attainment of desired shapes.
Complex forging shapes: Die forging facilitates the creation of complex shapes, resulting in more rational metal flow patterns and extended part lifespans.
Accurate dimensions and excellent surface quality: Die forging results in precise dimensions and superior surface quality, with minimal machining allowance.
Material savings and reduced machining workload: Die forging reduces material waste and machining requirements, especially for parts produced in sufficient quantities, thereby lowering part costs.
Disadvantages and limitations:
Limited by the capacity of typical die forging equipment, most die forgings weigh below 70kg.
Long production cycles and high costs associated with forging dies.
Higher investment costs for die forging equipment compared to free forging.
Roll forging is a forging process that involves plastic deformation of a workpiece using a pair of rotating fan-shaped dies to obtain the desired forged part or blank.
The deformation principle of roll forging is as illustrated above. Roll forging deformation is a complex three-dimensional process. Most of the material flows longitudinally, increasing the length of the workpiece, while a small portion of the material flows laterally, increasing the width of the workpiece. During the roll forging process, the cross-sectional area of the workpiece root continuously decreases. Roll forging is suitable for processes such as shaft stretching, plate flipping, and longitudinal material distribution. It can be used to produce connecting rods, twist drills, wrenches, knife nails, hoes, picks, flat leaves, etc. The roll forging process gradually deforms the billet using the principle of rolling forming. Compared with conventional die forging, roll forging has the advantages of simple equipment structure, stable production, low vibration noise, convenient automation, and high production efficiency.
Closed-die forging is commonly employed for producing rotary forged components such as gear blanks with protruding hubs and sometimes for non-rotary forged components. It falls under the category of flashless forging. For intricately shaped die-forged components, a combination die, comprising two half-dies (thus adding a parting line), is used to form the billet within the die cavity. The combination die typically consists of upper and lower halves, with guide pillars and pins used for alignment to prevent misalignment of the billet during forging. Compound dies are predominantly used for producing complex-shaped non-rotary forgings, such as connecting rods and fork forgings.