High-Strength UPN & UPE Channels for Structural Applications
ASTM A572 is a high-strength low-alloy (HSLA) structural steel strengthened through controlled additions of columbium (niobium) and vanadium.
Compared with conventional carbon steel such as ASTM A36, A572 provides a significantly higher yield strength, allowing designers to reduce section thickness and overall structural weight without compromising load-bearing performance.
ASTM A572 HSLA steel channels are therefore an ideal choice for structural applications requiring higher strength, improved efficiency, and weight optimization, especially in modern construction and industrial projects.
ASTM A572 Steel Channel Overview
ASTM A572 steel sections are available in three strength grades:
Grade 42
Grade 50
Grade 55
Among them, ASTM A572 Grade 50 is the most commonly specified grade due to its balanced combination of strength, weldability, and cost efficiency.
A572 channels are typically supplied in European standard channel profiles, including:
UPN channels (tapered flange channels)
UPE channels (parallel flange channels)
Product Description – ASTM A572-50 Steel Channel
Item: ASTM A572-50 HSLA Steel Channel
Standard: ASTM A572 / A572M
Available Profiles: UPN & UPE
Length: 3 m, 6 m, or cut-to-length as required
Surface Treatment:
As-rolled (non-treatment)
Galvanized
Primed / painted
Customization:
Special channel sizes, lengths, and surface treatments are available upon request.
Dimensional Range
UPN Channel Range
Web depth: 80 – 200 mm
Web thickness: 6 – 8.5 mm
Flange width: 45 – 75 mm
Flange thickness: 8 – 11.5 mm
UPE Channel Range
Web depth: 80 – 200 mm
Web thickness: 4.5 – 5.2 mm
Flange width: 40 – 76 mm
Flange thickness: 7.4 – 9.0 mm
Chemical Composition (Heat Analysis, % max)
| Grade | C | Mn | Si | P | S |
|---|---|---|---|---|---|
| A572 Gr 42 | 0.21 | 1.35 | 0.40 | 0.04 | 0.05 |
| A572 Gr 50 | 0.23 | 1.35 | 0.40 | 0.04 | 0.05 |
| A572 Gr 55 | 0.25 | 1.35 | 0.40 | 0.04 | 0.05 |
Micro-alloying elements such as columbium and vanadium are added in controlled amounts to achieve higher strength and grain refinement.
Mechanical Properties
| Grade | Yield Strength (min) | Tensile Strength (min) |
|---|---|---|
| A572 Gr 42 | 42 ksi (290 MPa) | 60 ksi (415 MPa) |
| A572 Gr 50 | 50 ksi (345 MPa) | 65 ksi (450 MPa) |
| A572 Gr 55 | 55 ksi (380 MPa) | 70 ksi (485 MPa) |
Key advantage:
A572 Grade 50 offers approximately 40% higher yield strength than ASTM A36, enabling lighter and more efficient channel designs.
ASTM A572-50 UPN Channel Dimensions
| Size | Depth (mm) | Flange Width (mm) | Web Thickness (mm) | Flange Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| UPN 80 | 80 | 45 | 6 | 8 | 8.64 |
| UPN 100 | 100 | 50 | 6 | 8.5 | 10.6 |
| UPN 120 | 120 | 55 | 7 | 9 | 13.4 |
| UPN 140 | 140 | 60 | 7 | 10 | 16.0 |
| UPN 160 | 160 | 65 | 7.5 | 10.5 | 18.8 |
| UPN 180 | 180 | 70 | 8 | 11 | 22.0 |
| UPN 200 | 200 | 75 | 8.5 | 11.5 | 25.3 |
ASTM A572-50 UPE Channel Dimensions
| Size | Depth (mm) | Flange Width (mm) | Web Thickness (mm) | Flange Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| UPE 80 | 80 | 40 | 4.5 | 7.4 | 7.05 |
| UPE 100 | 100 | 46 | 4.5 | 7.6 | 8.59 |
| UPE 120 | 120 | 52 | 4.8 | 7.8 | 10.4 |
| UPE 140 | 140 | 58 | 4.9 | 8.1 | 12.3 |
| UPE 160 | 160 | 64 | 5.0 | 8.4 | 14.2 |
| UPE 180 | 180 | 70 | 5.1 | 8.7 | 16.3 |
| UPE 200 | 200 | 76 | 5.2 | 9.0 | 18.4 |
Key Advantages of ASTM A572-50 Steel Channels
High Strength-to-Weight Ratio
Reduces structural weight while maintaining load-bearing capacity.
Improved Structural Efficiency
Ideal for designs where thinner sections are required.
Excellent Weldability
Suitable for common welding methods with proper procedure control.
Versatile Profiles
Available in both UPN and UPE channel types for different structural needs.
Cost-Effective Alternative to Carbon Steel
Lower total project cost due to reduced steel consumption.
ASTM A572-50 HSLA steel channels combine high yield strength, good weldability, and structural efficiency, making them an excellent alternative to conventional carbon steel channels.
With standardized UPN and UPE profiles, they are well suited for both general construction and demanding structural applications where strength optimization and weight reduction are critical.
Q What makes A572 steel high strength and weldable?
A A572 is a high-strength, low-alloy (HSLA) steel that achieves enhanced yield strength through controlled addition of manganese, vanadium, and sometimes niobium. Its fine-grain microstructure ensures both toughness and excellent weldability, making it suitable for structural applications that require on-site welding without extensive preheating.
Q How does welding affect A572 steel?
A Although A572 has a low carbon equivalent, excessive heat input during welding can lead to localized softening in the heat-affected zone (HAZ) or distortion in thick plates. Using low-hydrogen electrodes and controlling interpass temperature ensures that the welded joint maintains the specified mechanical properties.
Q What are the impact toughness limitations of different A572 grades?
A Impact toughness decreases as the steel's yield strength increases. For instance, Grade 50 provides sufficient toughness for building frames, whereas Grade 70 is better suited for heavy industrial structures or bridges, especially in cold environments, where low-temperature fracture resistance is critical.
Q How does A572 compare with conventional mild steels like A36?
A Compared with A36, A572 offers significantly higher yield strength (50–70 ksi vs 36 ksi) and improved toughness. This allows structural members to be thinner and lighter, reducing material costs and overall weight while maintaining structural performance. However, higher-strength plates require stricter welding and fabrication control.
Q Where is A572 typically used?
A A572 is widely applied in bridges, high-rise buildings, stadiums, and heavy industrial structures. Its combination of strength, weldability, and toughness makes it a versatile choice for projects requiring high-performance steel with reliable structural integrity.
Q What fabrication considerations should engineers keep in mind?
A Even though A572 is easier to weld than quenched-and-tempered steels, engineers must consider preheating for thick plates, carefully plan welding sequences to reduce residual stresses, and perform inspection on critical welds and HAZ to ensure compliance with mechanical specifications.