Hybrid Rail Profiles for Portal Car Wash Tracks
The tracks of a portal car wash sit in the floor of a space that is open to the public, permanently wet and full of detergent, and they carry a vehicle across their entire length. That combination rules out most standard rail sections. A customer needed a low profile rail in hot rolled carbon steel S355J2 and, alongside it, a corrosion resistant version of the same section. Montanstahl answered with a hybrid profile, hot rolling the upper part of the rail and then joining it to a standard flat bar by laser welding, and delivered the section in both carbon steel and stainless steel 304L.
A Rail That Has to Stay Low and Carry a Car
In an automatic portal car wash the vehicle stays where it is while the system moves it along tracks installed in pairs and passes over it during the washing cycle. Because the washing area is open to the public, the customer requires a low profile rail that minimises the risk of tripping, so the section cannot simply be made taller to gain stiffness. Assembly imposes its own limits, since relatively tight tolerances are needed both on the shape and on the saw cutting if the track segments are to line up without shimming. At the same time the rail has to provide adequate load capacity and resist the abrasion of rolling wear as well as corrosion in an environment that is permanently wet and dirty. Rails and guiding sections with this mix of demands are typical of the transportation and railways sector, where the profile is loaded, exposed and expected to last.
Two Materials, One Geometry and a Limit on Torsion
The customer was looking for the profile in hot rolled carbon steel S355J2 and, in parallel, for a corrosion resistant alternative in the same geometry, which is where the difficulties began. The first was metallurgical, since the alloy had to stop the corrosion that a car wash floor inevitably produces. The second was technological, because the chosen material and the shape of the rail had to be compatible with a production route that could deliver both, and a section optimised for the rolling mill is not automatically a section that a different process can reproduce. The third was dimensional, with torsion capped at 0.35 mm per metre, a figure that matters because a rail that twists along its length lifts one edge of the running surface and loads the wheels unevenly. Taken together these constraints pointed away from a single production technology, and the answer was an entirely new approach for this component, a hybrid profile.
Application Context
Stainless steel 304L was selected to give the rail its corrosion resistance, and the section was built as a hybrid profile using two production technologies in sequence. The upper part of the rail, the shaped head that carries the wheel, was produced by hot rolling, then laser welded to a standard flat bar forming the base. This split keeps the complex geometry where it is needed and uses a stock cross-section for the rest, which controls both cost and distortion. Testing on the initial prototype recorded a maximum torsion of 0.3293 and 0.3020 mm, inside the limit the customer had set, and both the carbon steel and the stainless steel versions were delivered. Combining technologies in this way is a standard option within the Montanstahl range of special profiles, and the possibilities for hybrid and composite sections are described in the technical Q&A.