Solar Tracker Steel: Torque Tubes, Piles & Purlins

Industrial Application Guide | Carbon Steel Tubes, Galvanized Structural Products and Steel Coil for Solar Tracker OEMsA utility-scale solar tracking system relies on more than photovoltaic modules and electric drives. Its mechanical structure may include rotating torque tubes, ground-mounted steel piles, purlins, bearing supports, connection plates and other engineered structural components.

Many of these parts are manufactured from carbon steel, structural hollow sections, galvanized sheet or formed steel profiles.

For solar tracker manufacturers, however, buying suitable steel involves more than choosing a common structural grade. A torque tube may experience bending and torsion under wind and operating loads. Foundation piles transfer forces into the soil, while mounting brackets and purlins must satisfy their own load and connection requirements.

The steel specification, forming route, protective coating and inspection plan must therefore match the particular component.

This guide explains how carbon steel enters the solar tracker manufacturing supply chain, which standards may apply to each product form, and what international OEMs should include when requesting quotations for steel tube, coil, plate and structural profiles.

1. How Carbon Steel Enters the Solar Tracker Supply Chain

Single-axis solar tracking systems rotate photovoltaic modules to follow a defined movement path during operation.

The structural design may include torque tubes, supporting posts or piles, bearings, brackets, rails and drive-system attachments.

Different manufacturers use different arrangements. Not every tracker uses identical tube cross-sections or supporting components.

A possible steel manufacturing supply chain includes:

Engineering approval of the tracker structure and material schedule.
Procurement of suitable hot-rolled steel coil, structural sections or galvanized flat products.
Coil slitting and preparation for tube or profile manufacturing.
Cold forming and welding of suitable torque tubes.
Cutting or forming ground-support members.
Fabrication of purlins, brackets and connection plates.
Application or verification of the specified corrosion protection.
Dimensional, material and coating inspection.
Packaging and delivery for subsequent tracker assembly.

Some manufacturers purchase finished structural tubing. Others purchase approved flat steel stock and manufacture tubes or profiles through their own forming lines.

The purchasing specification must identify which stage of this supply chain is included in the supplier’s quotation.

For an example of an established industry supply chain, JM Steel publicly describes its manufacturing of steel tubing for solar tracking systems.

This reference illustrates actual industrial practice. It does not imply that JM Steel is a customer of JUDE Carbon Steel.

2. What Steel Components Are Used in Solar Tracker Manufacturing?

Steel product requirements vary according to the approved tracker design.

Component	Potential starting material	Manufacturing route	Main purchasing concern
Tracker torque tube	Approved structural hollow section or suitable tube-making steel coil	Roll forming, welding and sizing	Section geometry, torsion, fatigue, wall thickness and weld quality
Foundation support pile	Approved structural section or specified steel pipe pile	Cutting, punching, drilling and coating	Structural capacity, soil conditions, corrosion and pile geometry
Solar tracker purlin	Suitable coated structural steel sheet or formed section	Slitting, roll forming and hole preparation	Yield strength, profile geometry, coating and connections
Bearing support plate	Approved carbon or structural steel plate	Profile cutting, drilling and assembly	Hole positions, loads, thickness and flatness
Module support rail	Design-approved formed steel or another specified material	Roll forming and fastening	Loads, section tolerances and compatibility
Connection bracket	Specified steel plate, sheet or formed stock	Cutting, bending and coating	Fastener interface, hole geometry and material grade
Drive-system mounting plate	Approved steel plate or fabricated stock	Cutting, drilling and joining	Alignment, loads, vibration and drawing tolerances

This material map is illustrative. It is not a complete bill of materials for a particular tracker manufacturer.

Some solar tracking systems also use aluminium, specialized bearings, polymers and other non-steel components.

Those components require separate purchasing specifications.

3. Torque Tubes: A Critical Structural Steel Component

A solar tracker torque tube is typically part of the rotating structure that supports and positions the photovoltaic modules.

Depending on the design, it can transfer torque while also resisting bending, local connection forces and other mechanical loads.

Torque tubes may be round, square, polygonal or another approved hollow-section geometry.

The appropriate configuration is determined by the tracker manufacturer.

Why Tube Geometry Matters

The section shape, wall thickness and dimensions influence torsional and bending behavior.

These characteristics must match the approved engineering calculations and the bearing, coupling and drive interfaces.

A round structural tube cannot automatically replace a polygonal tube, even if the two products have similar cross-sectional areas.

The purchasing documents should identify:

Approved steel grade and product standard.
Tube cross-section and drawing number.
Outside dimensions and wall thickness.
Length and applicable tolerances.
Straightness and twist requirements.
Weld-seam requirements where applicable.
End preparation, holes and connection features.
Required corrosion protection.
Inspection documents and traceability.

Tube Manufacturing from Steel Coil

Some structural torque tubes may be produced from appropriate flat-rolled carbon steel.

The production sequence can involve slitting, forming, longitudinal welding and final sizing.

ASTM A1011/A1011M may be relevant to the starting hot-rolled sheet or strip where its specified grade is suitable.

However, an ASTM A1011-compliant coil is not automatically an ASTM A500-compliant finished tube.

The tube manufacturer must establish finished-product compliance separately.

Explore JUDE Carbon Steel Coil and Carbon and Alloy Steel Pipe for relevant product categories.

4. ASTM A500 and EN 10219 for Structural Torque Tubes

Structural hollow sections should be ordered under the product specification required by the approved design.

ASTM A500/A500M

ASTM A500/A500M covers applicable cold-formed welded and seamless carbon steel structural tubing in round and shaped sections.

It may be relevant for selected tracker structural members if the requested section, grade and service requirements are covered.

However, the standard does not independently qualify a tube for the cyclic loads and fatigue requirements of a particular solar tracker.

Low-temperature toughness, weld-joint performance and other project-specific tests may be necessary.

Official reference: ASTM A500/A500M-23.

EN 10219

For European-type orders, EN 10219 may apply to specified cold-formed welded structural hollow sections.

The relevant material grade, delivery condition and dimensional requirements must be identified in the purchase order.

EN 10219-1 addresses applicable technical delivery conditions, while EN 10219-2 provides corresponding dimensional and sectional requirements under the relevant edition.

When a design specifies S355J2H or another hollow-section grade, the buyer should verify the full designation and the applicable standard.

S355JR flat steel and S355J2H structural hollow sections are not automatically interchangeable product specifications.

Why a Common Pipe Grade Is Not Enough

Pressure-service or general-purpose steel pipe standards are not interchangeable with structural hollow-section standards.

For example, a pipe sold under ASTM A53 or ASTM A106 should not automatically be accepted as an ASTM A500 structural torque tube.

The correct choice depends on the approved design and the actual product specification.

5. Solar Tracker Foundation Piles: More Than Steel Grade

Ground-mounted photovoltaic trackers may use driven steel piles, structural sections or other foundation systems.

The selected foundation depends on geotechnical conditions, site loads, corrosion exposure and the tracker design.

Steel H-Beams, Channels and Formed Profiles

Some tracker systems use driven steel structural sections as ground supports.

The steel grade, section geometry and installation requirements should be specified by the project engineer.

Where structural profiles are required, buyers may review JUDE Carbon Steel Profiles.

Commercial availability of a particular H-beam or channel does not establish that it is approved for a solar tracker foundation.

Steel Pipe Piles

ASTM A252/A252M covers applicable cylindrical welded and seamless steel pipe piles.

It may be relevant where the approved foundation design calls for a corresponding circular steel pipe pile.

ASTM A252/A252M should not be assigned automatically to H-beams, C-shaped piles or every structural support tube.

Official reference: ASTM A252/A252M-26.

Soil and Installation Conditions

Foundation material selection should account for the project’s approved geotechnical investigation and installation method.

Relevant factors may include:

Ground conditions and installation resistance.
Axial and lateral structural loads.
Steel section or pile dimensions.
Connection geometry.
Expected site corrosion conditions.
Required corrosion allowance or coating system.
Inspection and installation acceptance criteria.

Steel material conformity alone cannot establish pile capacity or the suitability of a particular foundation design.

6. Galvanized Purlins and Cold-Formed Solar Profiles

Tracker purlins, rails and certain support sections may be produced from structural steel strip or sheet by cold forming.

In some designs, the starting material may be continuously coated structural steel, including zinc or zinc-magnesium coating systems.

The specific grade and coating system must follow the approved tracker specification.

Structural Grade vs Forming Grade

Some coated steel designations are intended for general forming, while others identify structural mechanical properties.

For example, structural grades such as S350GD may be specified for certain continuously coated structural products under applicable EN requirements.

DX51D is a different designation associated with forming steel.

These products should not be considered interchangeable simply because both may have metallic coatings.

Roll-Forming Requirements

Cold-formed purlins may require controlled bend radii, section geometry, flatness, hole position and edge quality.

The steel must have suitable mechanical properties and formability for the actual production route.

A higher nominal yield strength does not automatically mean the material is easier to process or better suited to every section.

Coating Selection

Depending on the specified product, continuously galvanized or zinc-magnesium-coated steel may be used.

The buyer should identify the complete steel designation, coating type, coating mass and applicable standard.

For available product categories, see JUDE Galvanized Steel Coil and Galvanized Steel Sheet.

The supplier must confirm whether the required structural grade and coating combination are actually available.

7. Pre-Galvanized Steel vs Hot-Dip Galvanizing After Fabrication

Corrosion protection is a major purchasing consideration for outdoor solar tracker structures.

However, not all galvanized steel products are manufactured through the same coating route.

Continuously Coated Steel Coil

ASTM A653/A653M covers applicable steel sheet supplied with hot-dip zinc or zinc-iron alloy coatings in coil and cut-length forms.

It may be relevant for selected coated sheet products used in further manufacturing.

The order should identify the substrate steel grade and the coating designation separately.

Official reference: ASTM A653/A653M-25a.

Hot-Dip Galvanizing of Fabricated Steel

ASTM A123/A123M covers hot-dip zinc coatings on applicable iron and steel products, including certain fabricated structural steel articles.

It may be relevant where the approved manufacturing process requires galvanizing after fabrication.

However, this is not the same product scope as continuously galvanized steel sheet.

Official reference: ASTM A123/A123M-24.

Why the Difference Matters

Issue	Pre-Coated Sheet	Post-Fabrication Galvanizing
Typical starting material	Coated steel coil or sheet	Suitable steel fabrication before coating
Relevant ASTM reference	A653/A653M where applicable	A123/A123M where applicable
Forming and cutting	Coating behavior and exposed edges require review	Fabrication generally precedes coating
Important inspection	Substrate grade, coating designation, formed surface	Coating conformity on the fabricated article
Final acceptance	Approved component specification	Approved component specification

The final coating route should be approved before production.

Pre-galvanized material must not be substituted for a component specified for galvanizing after fabrication without technical approval.

8. Wind Loading, Torsion and Fatigue: What Steel Buyers Must Understand

Solar tracking systems are exposed to outdoor environmental loads throughout their service life.

Wind can generate structural actions on the photovoltaic module array and supporting components.

Tracker movement and variable wind conditions can also create repeated loading.

For torque tubes, connections and supporting members, the responsible engineer may need to assess:

Bending and torsional demand.
Section stiffness and deformation.
Local buckling where relevant.
Weld and connection fatigue.
Bearing and coupling interfaces.
Dynamic structural response.
Wind-related operating and stow conditions.
Temperature and environmental effects.

These are engineering design and system validation requirements.

A structural steel mill certificate does not independently guarantee the complete tracker’s ability to withstand a specified wind speed or operate for a particular number of cycles.

Why Higher Strength Is Not Always a Complete Solution

Higher yield strength may be useful for some structural design conditions, but it does not automatically improve stiffness, fatigue performance, weld quality or corrosion resistance.

Changing a torque tube from one grade to another can require fresh analysis of the tube section, connections and manufacturing process.

Material substitution must therefore be approved by the tracker design authority.

9. Corrosion Conditions Differ Between Solar Farm Locations

Solar farms may be located in deserts, agricultural regions, coastal areas and other outdoor environments.

Corrosion exposure can vary significantly among these locations.

Factors requiring evaluation include:

Atmospheric moisture and condensation.
Salt deposition in coastal or saline environments.
Industrial atmospheric contaminants.
Soil chemistry and moisture at foundation members.
Standing water and poorly drained connections.
Cut edges, weld areas and coating damage.
Maintenance and installation practices.

A single coating designation does not guarantee the same service life at every solar farm.

In some projects, a more demanding corrosion protection strategy may be necessary.

The applicable coating system should be selected according to the project environment, design requirements and verified product performance.

10. What Should Be Inspected Before Steel Is Shipped?

Incoming material and pre-shipment inspection help identify errors before steel enters a production line or installation project.

Structural Steel Tube Inspection

Depending on the governing product specification and OEM requirements, checks may include:

Correct steel grade and product standard.
Material certificate and heat or batch traceability.
Section dimensions and wall thickness.
Straightness, twist and length.
Weld-seam condition and specified tests.
Hole positions and cut-edge quality where applicable.
Coating and packaging condition.

Galvanized Coil Inspection

Coated coil orders may require verification of:

Substrate grade and steel standard.
Nominal thickness and coil width.
Coating type and designation.
Surface condition and coating defects.
Mechanical test results where specified.
Coil inside diameter and weight.
Material identification and packing.

Structural Profiles and Plates

Support piles, purlins and mounting plates may require dimensional checks, correct grade identification, surface inspection and supplementary testing where specified.

The exact acceptance criteria must be established by the purchase contract and governing standards.

See JUDE Carbon Steel Quality Control for the company’s published inspection and quality procedures.

11. Illustrative Material BOM for Solar Tracker OEMs

The following table is a purchasing template. It does not represent a specific solar tracker’s approved engineering design.

Item	Component	Potential steel product	Required RFQ information
01	Tracker torque tube	Design-approved structural tube	Steel grade, tube standard, section drawing, wall thickness and quantity
02	Tube-making starting material	Approved hot-rolled steel coil	Substrate designation, thickness, width, forming and welding requirements
03	Foundation support pile	Specified structural section or pipe pile	Section type, dimensions, grade, length and corrosion requirements
04	Solar tracker purlin	Approved structural coated coil or formed profile	Grade, coating, thickness, profile drawing and quantities
05	Bearing support plate	Specified carbon or structural steel plate	Thickness, geometry, holes, edge finishing and inspection
06	Connection bracket	Approved steel sheet or plate	Drawing, material, coating and required fabrication scope
07	Drive mounting plate	Design-approved structural steel plate	Loads, dimensions, alignment, material grade and quantity

The material for each component must be approved by the tracker engineer or equipment manufacturer.

A supplier’s standard structural steel range does not establish that every listed product can be supplied in the exact grade and dimensions required by an OEM.

12. What Should International Buyers Include in a Steel RFQ?

An accurate quotation requires the intended component and material specification.

For solar tracker manufacturers, the following information is particularly useful.

Material Specification

Required steel grade and complete product standard.
Specified standard edition.
Tube, plate, coil or structural profile product form.
Required mechanical properties and additional tests.
Approved coating type and coating standard.

Dimensions and Manufacturing

Tube section drawing and wall thickness.
Structural profile dimensions and length.
Coil thickness, width, inside diameter and weight.
Hole positions, end details and cutting requirements.
Required tolerances and surface finish.
Approved CAD and PDF drawings.

Quality and Commercial Details

Material test certificates and traceability.
Coating verification and supplementary testing.
Trial order quantity and forecast production volume.
Packaging and shipping requirements.
Destination country or port.
Requested Incoterms and delivery schedule.
Applicable origin or project-specific purchasing restrictions.

Example Solar Tracker Steel RFQ Email

Subject: RFQ – Carbon Steel Torque Tubes, Galvanized Piles and Purlin Materials for Solar Tracker Manufacturing

We manufacture structural components for utility-scale solar tracking systems and are sourcing carbon steel tubes, structural profiles, galvanized steel coil and mounting plate materials.

Please review our approved material schedule and component drawings.

Each item identifies the required grade, product standard, dimensions, corrosion protection, quantity and inspection requirements.

For torque tube materials, please confirm available hollow-section grades, cross-sections, wall thicknesses, length tolerances and weld-related documentation.

For galvanized coil or structural products, please confirm the available substrate grades, coating designations, processing capabilities and material certificates.

Any proposed material substitution, coating change or dimensional deviation should be submitted separately for engineering approval.

Please provide a quotation including material availability, processing scope, quality documentation, packaging, quotation validity, lead time and delivery terms.

Frequently Asked Questions

1. What type of steel is used for solar tracker torque tubes?

Solar tracker manufacturers may use approved carbon or structural steel hollow sections. The exact material grade and tube geometry depend on the tracker design, required structural performance and applicable product standard.

2. Can ASTM A500 structural tubing be used for solar tracking systems?

It may be suitable for certain approved designs, but ASTM A500 conformity alone does not establish fatigue, wind-load or complete tracker system approval. Additional requirements may apply.

3. Is S355 steel suitable for every solar tracker torque tube?

No. S355 identifies a family of structural steel grades and designations. The exact product form, grade suffix, applicable standard and manufacturing conditions must follow the approved design.

4. Can an ASTM A1011 steel coil be used to manufacture structural torque tubes?

Potentially, if the approved flat steel grade is suitable for the intended tube-manufacturing process. Finished tubing must separately meet its applicable structural product specification and OEM requirements.

5. Does ASTM A252 cover all types of solar mounting piles?

No. ASTM A252/A252M applies to specified cylindrical steel pipe piles. H-beams, channels and other structural pile shapes require their own approved specifications.

6. Are solar tracker purlins always made from pre-galvanized steel?

No. Coating and manufacturing routes differ by design. Some formed components use continuously coated steel, while others require separate protective treatment after fabrication.

7. Is zinc-magnesium-coated steel automatically better than galvanized steel?

No universal conclusion is appropriate. Coating performance depends on the specific coating system, thickness, test conditions, environmental exposure, forming and component details.

8. Can G90 galvanized sheet replace any solar structural steel?

No. G90 is a coating designation under the applicable ASTM system. It does not specify the required structural grade, profile dimensions, fatigue performance or suitability for a tracker component.

9. Why are tube straightness and section tolerances important?

They can influence assembly fit, bearing alignment and connection geometry. Exact acceptance limits must come from the relevant tube specification and approved tracker drawings.

10. Does a steel MTC certify the wind resistance of a completed tracker?

No. A material test certificate documents requirements related to the steel product. Tracker wind resistance depends on the complete structure, connections, foundations and validated engineering design.

11. Can JUDE quote steel for overseas solar tracking system manufacturers?

JUDE lists carbon steel coil, pipe, galvanized products and structural steel profiles. Buyers can submit approved specifications for a feasibility and quotation review. Availability of particular grades and processing services must be confirmed.

12. What should be included in the first solar tracker steel inquiry?

Send the steel grade, product standard, section or coil dimensions, approved drawings, coating requirements, quantity, required documentation and delivery destination.

Request Carbon and Galvanized Steel for Solar Tracker Manufacturing

JUDE Carbon Steel supplies industrial carbon steel and coated steel product categories for manufacturing and engineering procurement.

For solar tracker OEMs, structural fabricators and photovoltaic mounting system manufacturers, JUDE can review requirements for approved steel tubes, structural profiles, galvanized sheet and coil, and selected plate materials.

Relevant steel categories:

To request a quotation, provide:

Approved material standard and complete steel grade.
Torque tube or structural profile drawings.
Wall thickness, coil width or plate dimensions.
Coating type, designation and inspection requirements.
Material certificates and any additional tests.
Order quantity and repeat-purchase forecast.
Delivery location and requested commercial terms.

Contact JUDE Carbon Steel: Request a Steel Material Quotation.

Email your BOM and technical drawings: carbon@jiscojude.com.

The formal quotation should confirm actual grade availability, dimensions, processing scope, coating requirements, inspection documentation, price and delivery feasibility.

JUDE’s supply of steel raw materials does not independently establish that it manufactures complete tracking systems or certifies tracker wind resistance, fatigue performance or foundation capacity.

Import eligibility, domestic-content provisions, trade remedies, export controls and other destination-specific requirements must be reviewed before placing an international order.

Technical References

Engineering and procurement notice: This article provides general raw-material procurement guidance for solar tracker component manufacturing. It is not a completed structural design, product certification, wind-load analysis, fatigue-life guarantee, corrosion-life guarantee or foundation approval. Material selection, component geometry, coating, fabrication, testing and final system acceptance must follow the approved OEM drawings, project specifications and applicable regulations.