Hot Extruded Heavy Duty Profiles for Tunnel Boring Machines
Tunnel boring machines are among the largest pieces of equipment in civil engineering, used to excavate tunnels for railways, metros, roads, and utilities such as water, sewage, and pipelines. As a tunnel advances, the boring shield has to drive through ground that can change continuously, from stable rock to soft, water-bearing soils. Alignments like these are some of the most demanding situations in tunnel construction, and the steel profiles built into the shield have to carry heavy loads while doing real work inside the machine.
Heavy Profiles for Tunnel Boring Machines
Montanstahl produces a dedicated range of special profiles for boring machines, drawing on long-standing expertise at its German operation in Schwerte. These are robust sections, weighing up to 100 kg/m with widths up to 250 mm, and they do more than carry load: the hollow chambers running through them convey liquid concrete forward to the shield, reinforcing the walls of the freshly drilled tunnel. The profile shown here is a heavy custom section of 160 x 70 mm in carbon steel S355J2H, and every design detail is worked out together with the customer.
Seamless Hollow Sections by Hot Extrusion
Heavy duty hollow shapes like these are produced by hot extrusion. Montanstahl runs a hot extrusion press for hard metals that reaches a hydraulic pressure of 2,200 tonnes, which makes it possible to form seamless hollow profiles with chamber diagonals from 20 mm up to 165 mm, widths up to 255 mm, and bar lengths up to 16 metres. Because each chamber is extruded in one piece, there are no seams along the section. The profiles can be supplied with short delivery times and, when needed, in small batches.
Application Context
This case sits in Montanstahl’s tunnel engineering and building and construction work, where heavy custom profiles go straight into the machinery that builds infrastructure. A tunnel boring machine is a clear example: the profile has to take high mechanical loads and carry concrete to the shield, all while the machine pushes through changing ground. Profiles of this kind are produced to the customer’s design and supplied worldwide for tunnelling projects of every type.