In buildings, bridges and industrial structures, H-beam and I-beam are the two most commonly used structural steel beams. Although they look similar, they differ significantly in design, mechanical properties and application scenarios.
This article will compare H-beam and I-beam from multiple perspectives, including structural characteristics, material properties, manufacturing process, application scenarios and economic efficiency, to help engineers and purchasers make a scientific choice.
Comparison of structural design and mechanical properties
Cross-sectional characteristics
H-beam:
The width of the flange of H-beam is close to the height of the web, and the inner and outer surfaces of the flange are parallel and the thickness is uniform. Common specifications include 1507557 mm (web height flange width web thickness flange thickness). This design makes it have higher bending strength when subjected to vertical loads.
I-beam:
The flange of I-beam is narrow and gradually thinner towards the end, and the web is higher but thinner. This structure makes it more suitable for bearing unidirectional bending loads, such as the main beam design of bridges.
Differences in mechanical properties
Bending capacity:
H-beam has a wider and thicker flange and higher bending stiffness, which is suitable for large-span structures (such as factories and high-rise buildings). Q345B material H-beam has a yield strength of up to 345 MPa, which is suitable for heavy-load scenarios.
Shear resistance:
I-beam webs are taller and have more uniform shear stress distribution, so they perform better in scenarios that require high shear resistance, such as bridge supports.
Materials and manufacturing process
Material standards
H-beam:
Common materials include Q235B, Q345B (Chinese standards), and ASTM A36, SS400 (international standards). H-beams comply with ASTM, JIS and other multinational certifications and are suitable for global projects.
I-beam:
Mostly using ASTM A992 or S235JR, which has a lower carbon content and better welding performance, suitable for scenes requiring complex connections.
Manufacturing process
H-beam:
Mainly hot-rolled, some high-end products are welded (“hot-rolled welding” process). The surface of hot-rolled H-beam can be galvanized, painted, etc. to improve corrosion resistance.
I-beam:
Usually formed by hot rolling in one step, the process is simple and the cost is low, but the size specifications are limited.
Application scenarios
Typical applications of H-shaped steel
Building structures:
Applicable to columns and beams of high-rise buildings, “residential wall supports” and “steel structure
Industrial equipment:
Bases or brackets for heavy machinery, installation frames for single-beam safety light curtains, requiring high stability and load-bearing capacity.
Solar energy projects:
Hot-dip galvanized H-shaped steel (“Gal. Thickness: 86um”) is commonly used in solar support systems and has strong weather resistance.
Application areas of I-shaped steel
Bridge engineering:
Due to its high shear resistance, it is often used in the main beams and diaphragms of bridges.
Lightweight structures:
Such as warehouse roof trusses, the lightweight design of I-shaped steel can reduce overall costs.
Economical and purchasing considerations
Cost comparison
H-beam: The price range is 500-1100 USD/ton, depending on the material and process (e.g. galvanized steel is 20% more expensive than ordinary black steel). Bulk purchases (minimum order quantity 1-10 tons) can reduce costs.
I-beam: Usually 10-15% cheaper than H-beam, but the subsequent processing costs (such as welding reinforcement) need to be considered.
Selection suggestions
Scenarios where H-beam is preferred:
- High bending strength and large span support are required (such as factory columns).
- Structures with complex forces in multiple directions (such as buildings in earthquake zones).
Scenarios where I-beam is preferred:
- Budget is limited and the load direction is single (such as warehouse beams).
- Temporary structures that need to be installed quickly.
FAQ
Can H-beam and I-beam be used interchangeably?
No. The mechanical properties of the two are significantly different, and the choice must be based on the calculation results of the structural engineer. , H-beam replacing I-beam may cause local stress concentration.
How to identify high-quality H/I-beam?
Check the material certificate (such as ASTM or GB standard).
Observe whether the surface treatment is uniform (such as no detachment of the galvanized layer)