Production and Applications of Special Shaped Forgings

Special shaped forgings are an essential process in metalworking. By pressing and deforming metal billets, it is possible to produce parts with complex shapes and various sizes. Compared to other metalworking methods, forged parts exhibit higher material density, stronger physical properties, and lower defect rates. This makes special shaped forgings widely used in industries such as aerospace, automotive manufacturing, military equipment, and mechanical manufacturing. With continuous advancements in technology and processes, the scope of application for special shaped forgings is expanding, and their performance requirements are becoming more demanding.

Key Controls in the Production Process

In the production of special shaped forgings, several production steps must be carefully controlled to ensure accuracy and product quality.

1. Adjusting the Slider Guide Clearance and Ensuring Rigidity

Adjusting the slider guide clearance and ensuring rigidity are fundamental to maintaining the dimensional accuracy of forged parts. By properly adjusting the clearance, errors during the manufacturing process can be minimized, ensuring that the dimensions and shapes of the parts meet the design specifications. Furthermore, controlling the system's rigidity is crucial to improving the precision and quality of the forged parts.

2. Controlling the Bottom Dead Center and Using Auxiliary Drive Systems

In the forging process, the bottom dead center refers to the extreme position of the slider's movement. It is important to control the position and movement at this point to prevent overload. Using auxiliary drive systems can reduce errors caused by overload, ensuring smoother movement of the slider. Additionally, optimizing the positioning and speed of the mold helps prevent unnecessary impact and pressure fluctuations at the bottom dead center, ensuring product accuracy and extending mold life.

3. Selecting the Appropriate Slider Motion

Special shaped forgings utilize both vertical and horizontal slider motions, with the choice of motion directly affecting production efficiency and part accuracy. Vertical motion is generally used for forging elongated parts, while horizontal motion is better suited for lubrication, cooling, and high-speed production parts. The motion type influences aspects such as forging force, process steps, and material utilization.

4. Improving Automation Levels

Introducing compensation devices and automated control systems can enhance the automation level of the forging process, ensuring more precise and efficient production. As automation technology progresses, the efficiency and quality of forged parts have significantly improved.

Material Properties and Process Selection

Material properties play a vital role in the quality and reliability of special shaped forgings. The strength, hardness, and plasticity of different materials determine their performance in various applications.

1. Strength of Forgings

The strength of a forging refers to its ability to resist damage (such as plastic deformation or fracture) under static loads. During the forging process, controlling strength directly affects the part's service life and performance. Depending on the load type, strength can be categorized into tensile strength, compressive strength, bending strength, and shear strength. In practical applications, tensile strength is often used as a basic strength indicator.

2. Hardness and Plasticity

Hardness measures a material's resistance to compression and wear, while plasticity refers to the material's ability to undergo plastic deformation without breaking under load. Special shaped forgings often require plastic deformation under high temperature and pressure, so it is crucial to control the hardness and plasticity to maintain good mechanical properties under high-strength loads.

Heat Treatment Processes for Special Shaped Forgings

Heat treatment plays a crucial role in improving the performance of special shaped forgings. By using appropriate heating and cooling methods, material hardness, strength, and plasticity can be optimized. Common heat treatment processes include quenching, isothermal quenching, step quenching, and sub-temperature quenching.

1. Quenching and Isothermal Quenching

Quenching involves evenly heating the workpiece from the surface to the core, softening the entire part. Isothermal quenching, on the other hand, heats the workpiece to the austenitizing temperature, then quickly cools it to the bainite transformation temperature range and allows it to cool slowly to achieve the desired hardness and strength.

2. Step Quenching and Sub-Temperature Quenching

Step quenching involves immersing the austenitized workpiece into a bath at a slightly lower temperature, then cooling it to an appropriate temperature before air cooling to obtain a martensitic structure. Sub-temperature quenching is suitable for hypoeutectoid steel, where the workpiece is austenitized within the Ac1 to Ac3 temperature range and then quenched to achieve both martensite and ferrite structures.

3. Indirect Quenching and Double Quenching

Indirect quenching is used for workpieces treated by carburizing, where carbon is penetrated into the surface before quenching to improve surface hardness. Double quenching involves two stages of heating and cooling at different temperatures after carburizing to further refine the workpiece structure.

4. Self-Cooling Quenching

Self-cooling quenching applies to parts that are rapidly cooled after partial or surface heating. The heat transferred from the workpiece allows it to cool on its own, achieving the quenching effect. This process is crucial for parts requiring high surface hardness and toughness.

Applications of Special Shaped Forgings

Special shaped forgings have become increasingly widespread across various industries, including mechanical manufacturing, aerospace, automotive manufacturing, military, rail transportation, pharmaceuticals, and chemicals.

1. Aerospace and Military

In aerospace, special shaped forgings are widely used in the manufacturing of engine parts, structural brackets, and connectors. These parts must exhibit high strength, toughness, and heat resistance to ensure safety and reliability under extreme working conditions. The military also requires high-precision, high-performance special shaped forgings, such as shell casings and rocket engine components.

2. Automotive and Mechanical Manufacturing

Special shaped forgings are extensively used in the automotive industry, particularly in the production of high-strength components like engine parts, chassis, and wheels. In mechanical manufacturing, forged parts such as drive shafts, gears, and bearings are capable of withstanding large loads and have longer service lives.

3. Rail Transportation and Energy Equipment

Special shaped forgings are widely used in rail transportation for components like locomotives, wheels, and bearings. In energy equipment manufacturing, forgings are used in valves, pump bodies, and other components in industries like power, petroleum, and natural gas to ensure reliability under high pressure and temperature conditions.

Conclusion

Special shaped forgings, with their excellent material properties and wide range of applications, play an essential role in modern manufacturing. By precisely controlling each production step, such as slider motion, rigidity control, and heat treatment processes, the accuracy and performance of forged parts can be ensured. As technology continues to advance, the applications for special shaped forgings will expand, driving industries towards greater efficiency and innovation. With the continuous improvement of manufacturing processes and automation technologies, special shaped forgings will play a key role in furthering the development of modern manufacturing.