IRAETA Shield Machine Cutter Flange ---- The Hard "Gums" On the Shield


With the implementation of the "transportation power" strategy, domestic transportation routes and urban construction are changing with each passing day. The huge market has spawned a huge demand for shield machines, and the demand for various parts is urgent. Under this circumstance, all kinds of cutter flanges, drive disc flanges, outer sealing grease rings, etc. manufactured by IRAETA using the radial and axial rolling process are bringing fast service to customers.

Cutter Flange

Driving Box Flange

The working principle of the shield machine is to use the front "teeth"-the cutter head, to continuously cut the soil and gravel in the front through the propulsion force and the whirling force of the cutter head, and transport it to the tail to be transported out.

But just like animals, only hard "teeth" are not enough. You must also have a firm "gums", which are various forgings such as the cutter flange on the back of the cutter head. One end of the cutter head flange is connected to the cutter head, and the other end is connected to the main drive bearing. When the main drive rotates, it transmits power to the cutter head for excavation operations.

The cutter flange is located between the cutter head and the main bearing

A piece of cutter flange (small steel ring inside) being processed and installed

In the industry, shield machines with a diameter of more than 12 meters are usually called super large diameter shield machines. But in fact, with technological progress and construction needs, the diameter of many shield machines currently exceeds 15 meters.

Especially in China, with the development of urbanization in recent years, more and more shield machines with a diameter of 15 meters or more appear in major cities. This is because the use of large-diameter shield machines can solve the construction needs of roads, tracks, and pipe networks at one time, reduce repetitive construction and reduce overall expenditures, and its advantages are obvious.

But when this level of shield machine is working, its propulsion is quite amazing. The "Chunfeng" shield machine used in Shenzhen has an excavation diameter of 15.8 meters and a total thrust of 24,600 tons, which is 24 times that of China's largest carrier rocket “Long March-5".

The "Chunfeng" is installed the cutter head

The huge propulsion and turning force of the cutter head make the forgings of the cutter flange and main bearing become larger and larger, and the weight is often more than 20 tons. At this time, an embarrassing problem will arise:

If the free forging process is used, the forgeability of the hydraulic press is no problem, but its four columns limit the maximum size of the workpiece; if the radial and axial rolling process is used, there are many such equipment in China, but most of them are designed for the manufacture of wind power flanges, and the rolling force is not enough to form.

Therefore, shield machine manufacturers can only turn to foreign companies that have heavy-duty ring rolling machines for help. However, due to the limited number of such equipment in the world and the long distance, the order cycle is usually 3-6 months. Obviously they can't wait.

In 2020, a main bearing with a diameter of 10 meters is being transported, and the bearing is sent from Europe to China

In May 2018, the IRAETA Nuclear and Heavy Equipment Division was put into operation. The division was equipped with a super-strong ring rolling machine with a maximum processing diameter of 16 meters, an axial rolling force of 1,250 tons, and a radial rolling force of 2,500 tons. The largest single piece weight is 200 tons, and the manufacturing capacity ranks among the top in the world. The service of this equipment undoubtedly solves the urgent need of the domestic shield industry.

In March of this year, a cutter flange with an outer diameter of 7.7 meters, a width of 0.8 meters on one side and a blanking weight of 47.8 tons completed the ring rolling process in only 20 minutes. This forging will be installed on a shield machine with a diameter of 15 meters.

Forgings like this have been installed in shield machines in Xi'an, Jinan, Guangzhou, Beijing, Zhuhai and other cities since 2019. Domestic manufacturing, domestic transportation, Chinese communication, convenient resources, and a drastically reduced delivery cycle greatly enhance the agility of the domestic shield machine supply chain. Designers, equipment manufacturers, and project managers can deal with complex challenges and emergencies more calmly.


IRAETA is a manufacturing concern that specializes mainly in a diversified range of products within the forgings industry. Our main products include discs, rings, hollows and special-shaped forgings; grinding balls, rods and liners, mainly used in fields such as wind power, nuclear power, UHV, petrochemical, offshore engineering, machinery manufacturing, mining and other fields.

IRAETA now has 1 sales company, 5 business divisions, 7 management centers and 1 overseas factory, covering an area of 350,000 m2 and having over 1,400 employees. For nearly half a century, IRAETA has always been steadfastly devoted to the forging industry. From offshore wind turbines on the Atlantic coast to the oil fields deep in the deserts of the Middle East, to mines in the lofty mountains of Peru, our products have made their mark. Adhering to the values of “honesty, humility, perseverance and work”, IRAETA is committed to creating sustainable value for global customers through high-quality products.


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