Have you always wondered about how rolled ring forgings are produced or the difference between open die forgings and seamless rolled ring forging? If so, let’s explore the differences between these two types of forging processes.
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Open die forging that is sometimes called free forging refers to the process that involves a piece of metal that’s being deformed between multiple dies that don’t enclose the material entirely. In other words, it got its name because of the fact that the metal that’s being used is free and is not completely confined by impression dies that restrict its form. Due to the nature of its production process, open die forging allows for a wide range of shapes and sizes. In fact, it is capable of forming forgings that are only a few pounds heavy to massive 150-ton pieces.
Seamless rolled ring forging starts with a circular preform made out our metal that’s been pierced in the middle in order to form a hollow shape that looks like a doughnut. To increase its diameter or lessen the thickness of its walls, this ring is rotated as heat is being applied to it. Rolled ring forgings that are created through this process are known to be sturdier and more reliable compared to other parts. They also feature better heat tolerance and users can be certain of the maximum heat that these rolled ring forgings are able to withstand. Most importantly, they’re also manufactured at a lower cost than other comparable products since less machining is required.
"Forged Ring" and "Seamless Rolled Ring", as two mainstream product forms of forged rings, are often considered simultaneously in structural design and process selection. Although they are similar in form and widely used in key structural parts such as connection, bearing, sealing and rotation, they have essential differences in manufacturing methods, metal streamline control, performance and applicable scenarios.
Choosing the right ring form means getting better structural strength, service life, dimensional consistency and cost control in the project. This article will comprehensively compare the similarities and differences between forged rings and seamless rolled rings from multiple dimensions such as process principles, structural characteristics, and application directions, and combined with Chalco's rich product supply capabilities, to help you make a more informed selection decision.
Put it simply:
All seamless rolled rings are forged rings, but not all forged rings are seamless rolled rings.
Although forged rings and seamless rolled rings are both forged structural parts, there are obvious differences in their forming methods, which directly affect their geometric dimensions, structural density and performance.
Free forging is one of the most traditional forging processes, suitable for a wide range of metal components in various shapes and sizes, including ring parts. This process usually uses a hydraulic press to repeatedly press the metal blank, and gradually forms it through steps such as punching, upsetting, and expanding.
Process flow diagram: heating → upsetting → punching → hole expansion/edge pressing → initial ring forming → post-processing
Technical features:
Ring rolling is an efficient forging process specially used to manufacture seamless rings. The principle is that after a circular blank is forged and punched, it is squeezed by inner and outer rollers to make the ring thinner in the radial direction and expand in the circumferential direction, forming a seamless structure with stable dimensions and uniform structure.
Process flow diagram: heating → free forging preformed blank → punching → ring rolling mill → radial rolling forming → heat treatment/post-processing
Technical features:
Although forged rings and seamless rolled rings are both forgings, they show obvious differences in metal streamline structure, stress distribution, fatigue life and subsequent assembly matching due to different forming paths.
Free forging ring has relatively low controllability of streamline direction, with possible directional deviations or local stress concentration points, and its density depends on forging experience and subsequent heat treatment.
Ring rolling forging ring achieves a more uniform structure and higher reliability through radial and axial synchronous deformation that distributes metal streamlines continuously along the circumference; such ring rolled parts can better maintain structural stability and resist fracture under long-term alternating loads.
Seamless rolled ring usually exhibits higher fatigue life and fracture resistance under the same material and heat treatment conditions, making it especially suitable for dynamic load or high-speed rotating systems.
Free forging ring is stable and suitable for thick-walled parts or large-sized special-shaped structures, but it requires higher precision in heat treatment and post-processing.
Free forgings are greatly affected by operational factors, have slightly poorer dimensional consistency and roundness, and usually require additional pre-processing.
Ring rolled forgings have a small dimensional fluctuation range and are suitable for direct use in systems requiring high assembly precision, such as wind turbine main shaft connection flanges and aviation sealing rings.
Free forging tends to produce uneven residual stress and incomplete annealing after forging, which may lead to deformation during subsequent machining or service.
Ring rolling achieves better dimensional stability, as its continuous rolling process helps release internal residual stress more effectively.
*Shopping tips*: If the project has higher requirements for structural density, fatigue life, and dimensional consistency, Seamless Rolled Ring has more advantages; if the project emphasizes structural flexibility, special-shaped customization, and strength balance, free forging is more suitable.Quick Quote
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Forged rings are widely used in wind power, aviation, military industry, rail transit, chemical industry, equipment manufacturing and other industries. Different projects have different requirements for dimensional accuracy, strength consistency, sealing performance and batch control. The following are recommended matching suggestions for several typical application environments:
Recommended: Seamless Rolled Ring
Typical components: spindle connection flange, load-bearing support ring
These components require large diameters, high fatigue life, and structural symmetry. Seamless rolled rings offer excellent dimensional consistency, a complete metal streamline, and strong crack resistance, making them ideal for long-term high-load applications.
Recommended: Seamless Rolled Ring (or die forged ring)
Typical components: engine hoisting ring, weight-reducing sealing connection ring
To meet demands for lightweight, high stability, and assembly precision, ring-rolled parts provide a dense structure and good deformation control, ensuring reliability in systems with high safety factors.
Recommended: Open Forging Ring
Typical components: titanium alloy support rings, heavy machinery interface rings
Designed for variable structures, complex materials, and high-intensity custom requirements, free forging offers strong process adaptability, supports special-shaped or thick-wall designs, and allows easy control over heat treatment.
Recommended: Open forging or ring rolling (depending on size and batch)
Typical components: bogie ring, brake bearing ring, bearing seat sealing flange
For non-standard components, free forging is preferred, while symmetrical or repetitive parts benefit from ring rolling, both processes aligning with the mechanical and structural demands of rail and heavy equipment applications.
Recommended: Open Forging Ring
Typical components: corrosion-resistant flange rings, high-pressure connecting rings
Forging processes must accommodate stainless steel, alloy steel, and corrosion-resistant titanium alloys, while also enabling pre-processing of flange grooves or welding interfaces for efficient system integration.
In the forging field, Chalco not only focuses on the manufacture of standard forged rings and seamless rolled rings, but also provides customized forgings of various structural types, covering aluminum alloy, titanium alloy, carbon steel, alloy steel and other materials to meet the diversified needs of customers under different assembly structures and special working conditions.
The following are the types of forging products we routinely supply (customization is supported):
Although Forged Ring and Seamless Rolled Ring are both forged structural parts, they have their own advantages in forming method, performance, size control and applicable scenarios:
In short: the more complex the shape and the smaller the batch size → more suitable for free forging; the larger the size and the higher the precision requirement → more suitable for ring rolling
Chalco has long provided forging solutions for industries such as wind power, aviation, rail transit, and military industry. We have:
If you have any questions about ring structure design, material selection or process path, please submit drawings or technical parameters. We will provide you with professional selection suggestions and quotation services.
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