Corten steel is the preferred material for decorative and architectural screens, prized for its distinctive rust patina, structural strength, and maintenance-free durability. Unlike ordinary carbon steel, however, weathering steel possesses unique alloy properties that require specialized techniques during processing, cutting, and fabrication. This AHL Group guide provides an in-depth analysis of weathering steel's processing characteristics, offering step-by-step operational methods to ensure the material's structural integrity and critical corrosion resistance are maintained throughout all fabrication stages—from simple drilling and installation to complex plasma cutting of custom patterns.
Before undertaking any modifications to AHL Corten steel screens, it is essential to fully comprehend their metallurgical characteristics under stress and high-temperature conditions.
Weathering steel falls under the category of high-strength low-alloy steel (HSLA). Its corrosion resistance stems from the presence of elements such as copper, phosphorus, silicon, nickel, and chromium. These elements form a dense, stable rust protective layer when subjected to alternating wet and dry weather cycles. While this layer acts as a protective barrier, these alloys subtly alter the steel's hardness and response to thermal cutting compared to ordinary steel.
The key differences in processing weathering steel lie in heat input management and rust layer reconstruction.
► Heat-Affected Zone (HAZ): Compared to ordinary steel, weathering steel exhibits slightly lower tolerance to heat input before excessive hardening occurs in the HAZ. While conventional welding and cutting parameters remain similar, precise control is critical.
► Integrity of Rust Layer: Each instance of cutting, drilling, or grinding disrupts the original surface rust layer. Proper post-processing must be performed immediately to ensure the newly exposed metal surface rapidly forms a new protective layer.
This method ensures all Corten metal screen retrofit projects meet the highest standards of quality and performance.
Successful weathering steel fabrication begins before the torch ignites or the drill spins.
Determine the desired aesthetic outcome and functional requirements. For structural screens, verify aperture dimensions, spacing, and edge distances against engineering specifications. Ensure high-quality consumables suitable for high-strength low-alloy steel are available (drill bits, plasma electrodes, cutting gas).
The choice of cutting method depends on the thickness of the weathering steel screen and the precision required for the pattern.
When drilling Corten steel, proper operation is critical to prevent drill bit damage caused by metal work hardening.
► Drill Bit Selection: Use sharp high-speed steel (HSS) cobalt alloy drill bits, as Corten steel has slightly higher hardness than ordinary steel.
► Rotational Speed: Employ low speed with high feed rate. Low speed minimizes heat generation.
► Lubrication: Always use high-quality cutting fluid or cutting oil. Coolant prevents overheating, the primary cause of work hardening and premature drill bit failure.
Hot-cut edges exhibit oxidized, uneven surfaces (scale) and hardened zones that must be removed.
► Deburring: Remove all oxide scale (hard residue) from the base of the thermal cut using a grinding wheel or file.
► Leveling: Lightly grind the newly cut edge to achieve the desired surface finish.
► Surface Treatment: After leveling the edge, wipe the area with a degreaser to remove grinding residue or oil before proceeding with oxide scale acceleration treatment.
The optimal cutting and drilling methods vary significantly depending on the thickness of weathering steel plates.
Thin screen panels are highly susceptible to thermal deformation during plasma or laser cutting. Higher cutting speeds should be employed, and the steel plate must be securely clamped to a rigid base (such as a water-cooled worktable or stable grid) to control heat dissipation and prevent distortion. For straight-line cutting, the shearing process is typically the optimal choice.
This thickness range is suitable for landscape screens and architectural partitions. Plasma cutting is typically the most efficient processing method. Maintain a clean cutting area and use optimal equipment parameters to minimize slag production, thereby reducing subsequent grinding time.
When processing structural or heavy-duty weathering steel, employ lower cutting speeds and higher amperage. Use cobalt alloy drill bits for drilling. Deep hole drilling may require the “peck drilling method” (frequent retraction of the drill bit) to clear chips and reapply lubrication.
The most critical step after modification is ensuring that newly exposed edges rapidly and uniformly develop a protective rust layer.
Newly cut, drilled, or ground steel surfaces are highly susceptible to severe corrosion (pitting) before a stable rust layer forms. Without prompt treatment, these areas will experience rapid and uneven rusting. The goal is to initiate the formation of a protective rust layer as quickly as possible—this is known as accelerating rust layer generation on cut Corten steel.
AHL Group recommends a simple method:
► Degreasing: Ensure the area is free of oil, grease, and dirt.
► Spray Treatment: Using a spray bottle, apply a mixture of water and a small amount of salt (table salt or sea salt), or a weak acid solution (such as vinegar) to the freshly cut edges.
► Repeat Cycle: Spray 1-3 times daily for several days, ensuring the area is completely dry after each application. This process accelerates the initial weathering cycle, achieving an ideal color and sealing the edges.
Once new edges successfully form a rust protective layer, the entire metal screen panel will exhibit uniform performance. The corrosion resistance of modified areas will match that of the original steel plate, ensuring the enduring durability and structural integrity of the entire Corten privacy screen.
► CNC Precision Machining: Custom architectural screens are almost exclusively produced using computer numerical control (CNC) plasma or laser cutting technology, ensuring flawless replication of multi-panel decorative weathering steel screens at scale.
► Bending Process: Weathering steel can be successfully bent using standard bending machines. However, due to its higher yield strength, it may require greater pressure capacity and stronger springback compensation compared to ordinary steel.
► Hole Sizing: Installation holes should be slightly larger than fastener diameters (recommended clearance: 1-2 mm). This design accommodates metal thermal expansion and contraction, effectively preventing panel warping and stress cracking.
► Concealed Fasteners: For optimal aesthetics, AHL recommends suspending panels using concealed hanging plates or Z-shaped hanging systems instead of exposed surface bolts.
When integrating multiple panels, special attention must be paid to joint gaps. Maintaining consistent spacing (typically 10-20 mm) is crucial for managing thermal expansion and contraction while ensuring rainwater flows smoothly away. This prevents water from pooling and concentrating along panel edges.
Post-modification inspection is critical to ensuring the structural integrity and aesthetic appeal of the garden screen.
Inspect the screen against the original CAD files, paying particular attention to intricate patterns. Check for excessive taper (bevel) or severe hardening on cut surfaces, especially when using plasma cutting. Poor cut quality may indicate improper current or speed settings.
Ensure drill holes are burr-free. Test-fit all hardware (bolts, anchors) to verify smooth insertion and confirm hole dimensions accommodate thermal expansion displacement.
Visually inspect all modified areas for stress cracks, paying particular attention to tightly curved sections or sharp internal angles left by cutting. Where possible, incorporate rounded corners to minimize stress concentration points and maintain the screen's long-term toughness.
Using AHL Corten outdoor screen materials unleashes design creativity while ensuring exceptional material durability. By respecting the unique metallurgical properties of weathering steel—particularly through proper cutting and drilling techniques, controlled heat input, and prioritizing the restoration of protective rust layers on cut edges—the transformed screens maintain full corrosion resistance and structural integrity for decades. Always adhere to AHL processing best practices to transform raw steel into timeless architectural elements.
Understanding the Processing Properties of Weathering Steel
Before undertaking any modifications to AHL Corten steel screens, it is essential to fully comprehend their metallurgical characteristics under stress and high-temperature conditions.
Unique Properties of Weathering Steel
Weathering steel falls under the category of high-strength low-alloy steel (HSLA). Its corrosion resistance stems from the presence of elements such as copper, phosphorus, silicon, nickel, and chromium. These elements form a dense, stable rust protective layer when subjected to alternating wet and dry weather cycles. While this layer acts as a protective barrier, these alloys subtly alter the steel's hardness and response to thermal cutting compared to ordinary steel.
How Corten Steel Differs from Ordinary Steel in Processing
The key differences in processing weathering steel lie in heat input management and rust layer reconstruction.
► Heat-Affected Zone (HAZ): Compared to ordinary steel, weathering steel exhibits slightly lower tolerance to heat input before excessive hardening occurs in the HAZ. While conventional welding and cutting parameters remain similar, precise control is critical.
► Integrity of Rust Layer: Each instance of cutting, drilling, or grinding disrupts the original surface rust layer. Proper post-processing must be performed immediately to ensure the newly exposed metal surface rapidly forms a new protective layer.
Comprehensive Modification Corten Screens Guide
This method ensures all Corten metal screen retrofit projects meet the highest standards of quality and performance.
1. Pre-Construction Planning and Design
Successful weathering steel fabrication begins before the torch ignites or the drill spins.
Project Assessment and Material Preparation
Determine the desired aesthetic outcome and functional requirements. For structural screens, verify aperture dimensions, spacing, and edge distances against engineering specifications. Ensure high-quality consumables suitable for high-strength low-alloy steel are available (drill bits, plasma electrodes, cutting gas).
2. Cutting Methods and Applications
The choice of cutting method depends on the thickness of the weathering steel screen and the precision required for the pattern.
Mechanical, Thermal, and Hydro-Abrasive Options
| Method |
Application | Pros | Cons |
| Plasma Cutting (Thermal) |
Intricate decorative patterns, general straight cuts (most common). | Fast, relatively inexpensive, excellent for non-ferrous and alloy steel. | Leaves a Heat Affected Zone (HAZ); requires cleanup of dross. |
| Laser Cutting (Thermal) |
Extremely complex, high-precision designs (e.g., detailed tree patterns). | Highest accuracy, minimal HAZ, smooth edge finish. | High equipment cost; slower on very thick plates. |
| Waterjet (Hydro-Abrasive) |
Any pattern where zero HAZ or edge hardening is required. | No heat distortion, clean edges; ideal for precision fittings. | Slowest method; higher cost per unit time. |
| Shearing (Mechanical) |
Straight cuts on thin gauge screens (up to 6mm). | Fastest and cheapest for straight lines; no HAZ. | Limited to straight cuts; creates slight edge distortion. |
3. Drilling and Hole Formation
When drilling Corten steel, proper operation is critical to prevent drill bit damage caused by metal work hardening.
Drill Bit Selection, Speed, and Feed Rate
► Drill Bit Selection: Use sharp high-speed steel (HSS) cobalt alloy drill bits, as Corten steel has slightly higher hardness than ordinary steel.
► Rotational Speed: Employ low speed with high feed rate. Low speed minimizes heat generation.
► Lubrication: Always use high-quality cutting fluid or cutting oil. Coolant prevents overheating, the primary cause of work hardening and premature drill bit failure.
4. Edge Treatment and Surface Finishing
Hot-cut edges exhibit oxidized, uneven surfaces (scale) and hardened zones that must be removed.
Deburring, Leveling, and Surface Treatment
► Deburring: Remove all oxide scale (hard residue) from the base of the thermal cut using a grinding wheel or file.
► Leveling: Lightly grind the newly cut edge to achieve the desired surface finish.
► Surface Treatment: After leveling the edge, wipe the area with a degreaser to remove grinding residue or oil before proceeding with oxide scale acceleration treatment.
Technical Considerations for Different Thicknesses
The optimal cutting and drilling methods vary significantly depending on the thickness of weathering steel plates.
Handling Thin Specification Screen Panels (1-3 mm)
Thin screen panels are highly susceptible to thermal deformation during plasma or laser cutting. Higher cutting speeds should be employed, and the steel plate must be securely clamped to a rigid base (such as a water-cooled worktable or stable grid) to control heat dissipation and prevent distortion. For straight-line cutting, the shearing process is typically the optimal choice.
Processing Specifications for Medium-Thick Panels(3-6 mm)
This thickness range is suitable for landscape screens and architectural partitions. Plasma cutting is typically the most efficient processing method. Maintain a clean cutting area and use optimal equipment parameters to minimize slag production, thereby reducing subsequent grinding time.
Key Considerations for Processing Thick Weathering Steel Screens (6 mm and above)
When processing structural or heavy-duty weathering steel, employ lower cutting speeds and higher amperage. Use cobalt alloy drill bits for drilling. Deep hole drilling may require the “peck drilling method” (frequent retraction of the drill bit) to clear chips and reapply lubrication.
Preserving Corrosion Resistance After Modification
The most critical step after modification is ensuring that newly exposed edges rapidly and uniformly develop a protective rust layer.
Importance of Edge Weathering Treatment
Newly cut, drilled, or ground steel surfaces are highly susceptible to severe corrosion (pitting) before a stable rust layer forms. Without prompt treatment, these areas will experience rapid and uneven rusting. The goal is to initiate the formation of a protective rust layer as quickly as possible—this is known as accelerating rust layer generation on cut Corten steel.
Accelerating Rust Layer Formation on Cut Surfaces
AHL Group recommends a simple method:
► Degreasing: Ensure the area is free of oil, grease, and dirt.
► Spray Treatment: Using a spray bottle, apply a mixture of water and a small amount of salt (table salt or sea salt), or a weak acid solution (such as vinegar) to the freshly cut edges.
► Repeat Cycle: Spray 1-3 times daily for several days, ensuring the area is completely dry after each application. This process accelerates the initial weathering cycle, achieving an ideal color and sealing the edges.
Long-Term Performance of Modified Areas
Once new edges successfully form a rust protective layer, the entire metal screen panel will exhibit uniform performance. The corrosion resistance of modified areas will match that of the original steel plate, ensuring the enduring durability and structural integrity of the entire Corten privacy screen.
Advanced Fabrication Techniques
Custom Shapes and Patterns Production
► CNC Precision Machining: Custom architectural screens are almost exclusively produced using computer numerical control (CNC) plasma or laser cutting technology, ensuring flawless replication of multi-panel decorative weathering steel screens at scale.
► Bending Process: Weathering steel can be successfully bent using standard bending machines. However, due to its higher yield strength, it may require greater pressure capacity and stronger springback compensation compared to ordinary steel.
Mounting Holes and Hardware Configuration
► Hole Sizing: Installation holes should be slightly larger than fastener diameters (recommended clearance: 1-2 mm). This design accommodates metal thermal expansion and contraction, effectively preventing panel warping and stress cracking.
► Concealed Fasteners: For optimal aesthetics, AHL recommends suspending panels using concealed hanging plates or Z-shaped hanging systems instead of exposed surface bolts.
Integrating Multiple Panels and Segments
When integrating multiple panels, special attention must be paid to joint gaps. Maintaining consistent spacing (typically 10-20 mm) is crucial for managing thermal expansion and contraction while ensuring rainwater flows smoothly away. This prevents water from pooling and concentrating along panel edges.
Quality Control and Inspection
Post-modification inspection is critical to ensuring the structural integrity and aesthetic appeal of the garden screen.
Cutting Quality and Precision Verification
Inspect the screen against the original CAD files, paying particular attention to intricate patterns. Check for excessive taper (bevel) or severe hardening on cut surfaces, especially when using plasma cutting. Poor cut quality may indicate improper current or speed settings.
Drilling and Hardware Testing
Ensure drill holes are burr-free. Test-fit all hardware (bolts, anchors) to verify smooth insertion and confirm hole dimensions accommodate thermal expansion displacement.
Ensuring Structural Integrity After Modifications
Visually inspect all modified areas for stress cracks, paying particular attention to tightly curved sections or sharp internal angles left by cutting. Where possible, incorporate rounded corners to minimize stress concentration points and maintain the screen's long-term toughness.
Conclusion: Define Your Outdoor Space with Corten Steel Screens
Using AHL Corten outdoor screen materials unleashes design creativity while ensuring exceptional material durability. By respecting the unique metallurgical properties of weathering steel—particularly through proper cutting and drilling techniques, controlled heat input, and prioritizing the restoration of protective rust layers on cut edges—the transformed screens maintain full corrosion resistance and structural integrity for decades. Always adhere to AHL processing best practices to transform raw steel into timeless architectural elements.
