Introduction to Forged Hollows

Forged hollows are widely used in high temperature/pressure and other harsh conditions, such as hydrogenation reactors, nuclear reactor pressure vessels, evaporators, submarine oil and gas pipelines, etc., thanks to their durability, anti-corrosion features, high strength and long service life. IRAETA uses high-precision CNC rolling mills to manufacture forged hollows using the ring forging process, which, aside from shortening the lead time, also assures compact internal structure, fine grains and complete circumferential flow of workpieces, thus further improving the strength, wear resistance and fatigue resistance. Also, all kinds of workpieces with variable diameter can be manufactured using molds of different shapes. 

An efficient manufacturing method for reactor cylinder sections

The SMS Meer super-rolling mill imported by IRAETA, can manufacture rings with a maximum diameter of 16 m and height of 3 m using the rolling process (ring rolling). The globally-advanced and renowned near-net shape forming manufacturing process, is applicable for forming rings and forged hollows. Forged hollows manufactured in this way are superior to the ones produced by traditional processes such as free forging, casting, plate rolling, in the following aspects:

Faster delivery 

The process can ensure one-time forming with high quality surfaces and uniform cylinder thickness. At the same time, it can use direct quenched-tempered heat treatment, and does not require rough machining processes, all of which helps reduce machining time and improves efficiency. 

Larger size 

Unlike traditional press reaming process restricted by press column spacings, this process ensures workpieces with larger diameters can be manufactured.

Better performance 

Compared with large-scale forged hollows manufactured using free-forging, casting, plate rolling, etc., the compact structure, finer grains, circumferentially arrayed fibers and rational streamline distribution of rolled parts, ensures greater mechanical strength, higher impact toughness and higher fatigue resistance. 



Carbon steel, alloy steel, stainless steel, nickel-base alloy steel, copper alloy, aluminum alloy, titanium alloy

Diameter Range

≤ 16m

Cylinder Height


Piece Weight Range

≤ 200 tons

Thermal treatment

Normalizing, hardening and tempering, tempering, annealing, solid solution, and aging

Heat Treatment

Normalizing, thermal refining, tempering, annealing, solution annealing, precipitation strengthening


Destructive and non-destructive test


5-axis machining center, precision CNC vertical & horizontal lathe, CNC drilling machine



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