Comprehensive Analysis of Ring Rolling Processes for Rolled Rings
In the field of modern industry and manufacturing, ring forgings, as ideal and crucial components, are widely used in various equipment and parts. Therefore, the quality of rings is of utmost importance. To achieve high-quality rolled rings, mastering the optimal ring rolling process is essential. This article will introduce the main ring rolling processes used by Songjie in manufacturing such rings, providing you with the best ring products.
Full Process of Ring Rolling Technology
Ring rolling technology, also known as ring rolling, ring expanding, or hole expanding process. It is a key processing technology that uses a ring rolling machine to perform a series of continuous rotation and radial feeding actions on a ring-shaped blank to achieve local plastic deformation, thereby reducing the wall thickness, expanding the diameter, and forming the cross-sectional profile of the ring. In essence, it is a process of gradually processing a blank ring into a high-precision rolled rings. The main core processes include:
1. Billet Preparation
First, suitable and high-quality raw materials must be selected and processed into cylindrical billets. Materials commonly used include alloy steel, stainless steel, aluminum alloy, etc. These materials must undergo rigorous chemical composition analysis, mechanical property testing, and flaw detection to ensure they meet rolling requirements. It should be noted that the blanking weight is generally 103%–106% of the finished product weight to compensate for punching losses and heating oxidation, ensuring the smooth progress of subsequent processes.
2. Heating Pretreatment
The initial blank ring is heated to an appropriate temperature range (e.g., 1100°C–1200°C for 42CrMo material), allowing the metal to enter a “soft state” to reduce deformation resistance and achieve good plasticity and forgeability for subsequent rolling. This step requires strict temperature control: excessively high temperatures easily cause coarse grain growth, affecting strength; excessively low temperatures increase equipment load and may even cause cracks.
After the rolled ring is heated to the suitable rolling temperature with precise temperature control, it needs to be kept at temperature for a certain period to ensure uniform internal and external temperatures of the material and reduce deformation resistance during rolling.
3. Ring Rolling Process
This process can be divided into axial rolling and radial rolling, both of which are rotational plastic forming technologies. In these processes, rotating rolls in ring expanding equipment apply continuous local pressure to the ring-shaped blank to obtain rolled rings of the required dimensions and shapes. Before rolling, the heated billet needs to undergo operations such as upsetting and punching to obtain the ring blank.
(1) Axial Rolling:
The ring blank is installed on a axial ring rolling machine. Through the coordinated action of components such as the driving roll and core roll, the rolled ring is gradually deformed during the rolling process to achieve the required dimensions and shape.
(2) Radial Rolling:
Radial pressure is applied to the ring-shaped blank through rotating rolls, causing its diameter to expand and wall thickness to thin. Meanwhile, this process achieves grain refinement and densification, improving material performance.
The ring rolling process mainly involves first putting the heated ring blank on the driven roller; then, the active roller drives the ring blank to rotate, and at the same time, the oil pressure is used to feed it axially or radially, so that the blank is extended under the pressure, the wall thickness is reduced, and the inner and outer diameters are increased at the same time. The guide roller is always close to the workpiece to ensure its smooth rotation and shape the workpiece. When the outer diameter of the workpiece reaches the predetermined size, the control roller will sense and contact the workpiece, thereby triggering the return action of the active roller, marking the end of the hole expansion process. And usually, on the basis of the initial rolling, the finishing rolling is performed again to improve the dimensional accuracy and surface quality of the rolled rings. Here, special attention should be paid to parameters such as rolling speed, roller spacing and pressure.
4. Cooling and Post-Processing Technology
After rolling is completed, a suitable cooling method (such as water cooling or air cooling) is adopted to allow the metal to “cool down” and form a stable organizational structure. Different cooling rates directly affect the mechanical properties of the ring, such as hardness and toughness.
Post-cooling processing includes subsequent procedures such as cleaning, machining, surface treatment, heat treatment, and flaw detection, so as to meet the technical requirements, dimensional accuracy, and precision of the final rolled rings. Only after ensuring that the product meets customer requirements can it be packaged and delivered from the factory.
Conclusion
In summary, the main process flow of the ring rolling technology for rolled rings is: raw material preparation → heating → upsetting → punching → ring rolling (primary rolling and finish rolling) → cooling → post-processing. This process is complex and meticulous. Songjie strictly controls the details of each link and has a profound grasp of the characteristics, optimization methods, common problems, and solutions of the ring rolling process for rolled ring forgings, committing to producing the highest quality ring forgings to meet the needs of more customers.