Non-Magnetic Stainless Steel Beams for MRI Equipment Support in Switzerland
A private medical clinic in Lugano required structural beams to support new MRI equipment. The structural challenge was unusually constrained: the beams had to fit within a maximum section height of 160 mm while achieving a minimum moment of inertia of 80.7 × 10⁶ mm⁴, and had to be manufactured from a material with minimal magnetic permeability to avoid interference with the imaging system. Stainless steel 304L (1.4307) met the magnetic permeability requirement at substantially lower cost than specialist non-magnetic alloys such as 316LN or 1.4435. Montanstahl engineered a custom three-web beam geometry, produced it by laser fusion, cut the 6.65 m beams to length within two days of final on-site measurement, and later replicated the concept at larger scale for a second clinic.
Why MRI Rooms Require Non-Magnetic Structural Steel
MRI systems generate powerful magnetic fields. Any ferromagnetic material in the room, including the structural steel supporting the equipment, can distort the magnetic field, degrade image quality, and in extreme cases create safety hazards from projectile effects. Structural support beams therefore have to be manufactured from materials with low relative magnetic permeability. Stainless steel 304L sits at the low end of the permeability range for austenitic grades and is significantly cheaper than the specialist low-permeability alloys sometimes specified for MRI environments. For this clinic in Lugano, 304L provided the combination of magnetic performance, mechanical strength, and cost-effectiveness the project required.
Three-Web Design, 26 kg/m Lighter, Cut to Length in Two Days
The section height constraint of 160 mm and the minimum inertia requirement of 80.7 × 10⁶ mm⁴ could not be met by a standard beam geometry within those dimensional limits. Montanstahl engineered a three-web beam cross-section that achieved the required structural performance at 26 kg/m less than the alternative two-web design, while remaining within the height constraint and being easier to weld. The laser fusion process delivered full penetration welds on the thin webs with minimal heat distortion. Following final on-site measurement, the 6.65 m beams were precision cut and delivered within two days. The same structural concept was subsequently scaled up for a second clinic installation requiring heavier sections up to 245 kg/m, confirming the replicability of the design approach.
Application Context
This project is part of Montanstahl’s Medical & Healthcare segment, where laser fused special beams in non-magnetic stainless steel are specified for MRI room structures, medical equipment support, and healthcare facility applications where standard structural steel cannot be used. When dimensional constraints, inertia requirements, and magnetic permeability limits combine, custom section design and laser welding are the production route that makes the component possible. Montanstahl engineers and supplies custom stainless steel structural sections for medical and precision industrial applications worldwide.