A Comparison of Open Die and Seamless Rolled Ring Forging

26 May.,2025

 

A Comparison of Open Die and Seamless Rolled Ring Forging

In this blog post, we’re going to explore the differences between two types of forging: open die and seamless rolled ring.

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Open die forging

Open die forging gets its name because the metal being used is not confined by impression dies. This process molds the starting stock into the desired shape, typically between flat-faced dies.

Open die forging allows for a vast range of shapes and sizes, from forgings that weigh just a few pounds to massive pieces that tip the scales at 150 tons.

When your design calls for optimum structural integrity in a large metal component, the size capability of open die forging makes it your best choice.

Open die forging allows you to produce several different shapes:

  • Basic shapes such as square, round, rectangular and hexagonal bars
  • Sold shafts
  • Contour-formed metal shells, such as pressure vessels
  • Hollow cylinders

Seamless rolled ring forging

Seamless rolled ring forging begins with a circular preform of metal that has already been pierced to form a hollow “doughnut” shape. This ring is heated, then rotated to lessen its wall thickness and increase the diameter of the resulting ring.

Among the advantages of using these rings:

  • Strength – Forgings are sturdier than other components, maintaining their strength through elevated temperature fluctuations.
  • Cost effectiveness – These rings are manufactured at a lower cost than comparable products. There’s less machining involved because the rings closely match the contour of the finished shape.
  • Reliability – The high temperatures needed to make rolled rings means the grain pattern used in creating them provides greater strength and resistance compared to other components.
  • Better heat tolerance – It’s easy to predict how rolled rings will react to heat. With most other components, users need to take care when applying heat to keep the component from melting or otherwise deforming. With forgings, users can be sure of the maximum heat it can withstand.
  • Wider range of materials – These rings can be made from any forgeable material – alloy, stainless steel, carbon, aerospace metals. This versatility makes them a flexible and responsive answer when manufactures need components in markets such as power generation, chemical and refinery industries.

For expert seamless rolled ring forging capabilities, turn to Specialty Ring Products. We’ve spent more than a century perfecting our process, combining an old-fashioned commitment to quality with forward-thinking technology.

Everything About Rolled Ring Forging - Sumitec Inc

Everything About Rolled Ring Forging

The following guide will walk you through the introduction of rolled ring forging, how it is done, and its uses in various industries. So, keep reading:

What is Rolled Ring Forging?

Rolled ring forging is a specialized method of metal shaping that yields seamless, cylindrical pieces with better surface quality and more strength than traditional casting. It is often used to make rings for connecting rods, bearings, shafts, gears, and automotive and aerospace components.

A preform, or metal disk, is first inserted into the centre of two revolving dies to start the roll ring forging process. The die surfaces are formed to fit the intended final product profile. The preform is cold-forged into shape at room temperature under severe pressure in numerous degrees of movement, including axial loading that is both perpendicular to and parallel to the axis of rotation.

Compared to traditional open die forgings, which have more stress concentrations due to grain flow directionality throughout their length in just one plane along their length, this multi-step method helps reduce grain flow directionality in all directions, creating uniform equal strength in all planes. Rolled rings can also be forged up to 20 feet in diameter, which makes it possible to create more significant components like landing gear struts or wing spars.

This is because open die forming becomes two-dimensional in these cases because the shorter lengths of the rings cannot handle large section sizes without becoming too thin about the opening size, which makes them prone to mechanical failure while maintaining the minimum material thicknesses needed for structural integrity.

What is the Process of Seamless Rolled Ring Forging?

A device known as a rolling mill is used to produce seamless rolled rings. The rolling mill can make rolled rings in a range of diameter and weight. The seamless rolled ring forging technique is the most popular and advanced form of ferroalloy and is crucial for producing certain parts. Forging is a process used to create naturally stronger machine parts. The seamless rolled rings forging procedure creates excellent pieces when high-quality gears are needed for mechanical parts or for developing wind turbines.

Here are the steps involved:

  1. Upsetting

A forging is a process in which the goal of rolled ring forging suppliers is to compress the workpiece’s length to increase its diameter. In essence, it is the process of “upsetting” the shape of a substance, usually to collect more material or increase the cross-sectional area.

2. Piercing

It is a process of making an aperture or hole in a workpiece. It is a first stage in many forging operations, particularly in procedures where a solid cylindrical billet is perforated to form a hollow tube, such as tube manufacturing.

3. Shearing

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This stage is for sizing the material. Shearing is frequently the initial stage of the forging process, in which big metal slabs or billets are divided into tiny pieces for further processing.

4. Idler roller, or mandrel 

During manufacturing, a workpiece is shaped or supported by a cylindrical item. A mandrel aids in ring rolling by helping to measure the ring’s inner diameter.

5. Primary Roller and Shaping Procedure

The main roller that molds the workpiece and applies force. Ring rolling involves the roller and mandrel working together to provide the correct size and form.

6. Axial Rollers

These rollers are arranged so that they are perpendicular to the main roller. They regulate the ring’s height throughout the ring-rolling process and cooperate with the main roller to produce the required cross-sectional form.

7. Finishing the Rotation

This is when a workpiece finishes one full turn or rotation in a rolling operation. It designates a particular point in the shaping process, following which modifications or new steps might be taken.

Every one of these phases is essential to different forging and metalworking processes, assisting in the accurate and consistent conversion of raw materials into completed or semi-finished goods.

What is the Use of Ring Rolling?

Products from rolled ring forging are widely employed in various industries, including wind power, atomic energy, machinery, cars, trains, ships, and petrochemical industries. Here are some of the use cases:

  • Automobile Sector

Forged rolling rings are used in almost every major structural or rising component found in trucks and other automobiles. Not only can forged components endure more torque, high-pressure resistance, and general wear and tear than other components, but they are also significantly lighter.

  • Gas and Oil Sector

In the oil and gas sector, rolled rings are widely known for their applications as pressure vessel ring connections for pipelines, flanges, and pipe connectors. Because connections in this system are known to break, using forged rolling rings is even more crucial because they can withstand high temperatures, pressures, and corrosive chemicals. Thus, this industry is always looking for efficient rolled ring forging suppliers.

  • Petrochemical Industry

Equipment used in petrochemical processes often uses forging. Forgings include, for instance, the manholes and flanges of spherical storage tanks, the tubes and plates required by heat exchangers, the barrel joints used in hydrogenation reactors, the top, bottom, and head covers required by chemical fertiliser equipment, and entire forged cylinders (pressure vessels) of catalytic cracking reactors with butt welded flanges.

  • Aviation Sector

Seamless rolled rings are used regularly in several industries, including aviation. Every aircraft, from key mechanical parts to main bearings, uses rolled rings and forged objects. The variations in air pressure put aircraft components under almost constant stress. The potential for failure, if forged rolling rings weren’t employed is one of the reasons that jet turbines, helicopter gearboxes, and aircraft engines in the aviation industry use them.

  • Industry of Electric Power Generation

In the highly technical field of power generation, forged parts like rolling rings are essential and need to endure extended exposure to extreme heat, wind, weather, and various chemicals. The open-die forge method is frequently used in the power generation industry to create rolled rings from various alloys.

  • The Shipbuilding and Marine Sector

Marine systems operate under various loading circumstances, such as transversal load, axle drive, and bending. Weather, sea conditions, corrosion, wear and tear, and load stress shorten the propulsion shaft’s lifespan. Finding the best rolled rings is essential for all of these reasons.

Conclusion