Ferritic Stainless Steel Profiles for Solar Panel Tracking Structures
A client in the photovoltaic energy sector required custom stainless steel profiles for a prototype of a new solar panel model. The panel system was designed to track the sun’s trajectory from east to west, and was installed in the Pyrenees mountain range between France and Spain, where the structure experiences a temperature range of 60°C between summer highs of +40°C and winter lows of -20°C. For a precision tracking system, this temperature variation posed a direct engineering problem: thermal expansion and contraction of the structural frame would introduce positional error into the panel rotation mechanism. The solution required a structural material with a coefficient of thermal expansion close to that of S275 structural steel, which pointed to ferritic stainless steel. Montanstahl manufactured tailor-made H-beams in 410S ferritic stainless steel and double-C sections in 304L using laser welding, and delivered them in lengths up to 12 metres.
Why Ferritic Stainless Steel for a Solar Tracking System
A sun-tracking solar panel system rotates continuously to follow the sun’s arc. Any thermal expansion or contraction of the structural frame introduces angular error into the drive mechanism, reducing energy capture efficiency and potentially causing mechanical stress on the tracking bearings and actuators. Standard austenitic stainless steels such as 304L and 316L have a coefficient of thermal expansion of approximately 17 µm/(m·K), significantly higher than that of carbon structural steel at around 12 µm/(m·K). Ferritic stainless steel 410S has a coefficient of thermal expansion of approximately 10 µm/(m·K), closely matching carbon steel S275 and minimising differential expansion between the stainless steel profiles and the carbon steel components of the wider structure. For a mountain environment with a 60°C annual temperature range, this difference in thermal behaviour is the engineering justification for specifying a ferritic grade rather than the more commonly available austenitic alternatives.
410S H-Beams up to 12 m and 304L Double-C Sections, Both Laser Welded
Montanstahl produced two distinct profile types for the prototype solar panel structure. The primary structural members were special H-beams in 410S ferritic stainless steel, in sizes 100×55×4×6 mm and 80×46×4×5 mm, supplied in lengths of 11.8 to 12 metres. The secondary sections were custom double-C shaped profiles in 304L austenitic stainless steel, sized 69×19 mm and 120×18 mm, used for the panel mounting and connection elements where the differential expansion constraint was less critical and 304L’s superior corrosion resistance and availability made it the appropriate choice. Both profile types were produced using laser welding, which allowed the non-standard cross-section geometries and the difficult-to-source ferritic grade to be combined in a single production programme. The 410S H-beam geometry does not exist in any standard hot-rolled catalogue: laser welding from flat plate is the only production route that makes a custom ferritic stainless steel beam commercially viable at prototype quantities.
Application Context
This project sits within Montanstahl’s Energy & Power Generation segment, where laser welded special profiles in stainless and structural steel are specified for renewable energy infrastructure requiring corrosion resistance, dimensional stability, and material properties beyond what standard hot-rolled sections can provide. Solar tracking systems in exposed mountain or desert environments represent a demanding structural application where thermal expansion, corrosion resistance, and long service life all need to be addressed in the material and section selection. Montanstahl’s ability to produce custom profiles in ferritic grades such as 410S, which are not available as standard hot-rolled structural sections, makes laser welding the enabling technology for this class of application. Profiles of this type are produced to order and supplied to renewable energy projects worldwide.