What Is an H-Beam and How Does It Differ from an I-Beam?
An H-beam is a hot rolled structural section whose flanges and web are arranged at right angles, with a cross-sectional area distribution optimised for bending. Because material is placed where it resists stress most efficiently, the section delivers a high strength-to-weight ratio: it bends strongly in both principal axes, erects quickly on site, saves steel weight and reduces overall frame cost.
The familiar I-beam differs in proportion rather than in principle. A rolled I-beam has inclined inner flange faces and a comparatively thin web, while an H-beam uses parallel flange faces with a web thickness closer to the flange thickness. Parallel flanges make bolted connections, welding and beam-to-column detailing simpler and more predictable.
Steel Grades and Applicable Standards
| Grade | Standard | Min. yield strength | Tensile strength |
|---|---|---|---|
| A36 | ASTM A36 | 250 MPa | 400 - 550 MPa |
| A992 | ASTM A992 | 345 - 450 MPa | 450 MPa min |
| S275JR | EN 10025-2 | 275 MPa | 410 - 560 MPa |
| S355JR | EN 10025-2 | 355 MPa | 470 - 630 MPa |
| Q235B | GB/T 700 | 235 MPa | 370 - 500 MPa |
| Q355B | GB/T 1591 | 355 MPa | 470 - 630 MPa |
| SS400 | JIS G3101 | 245 MPa | 400 - 510 MPa |
Grades in the same strength class are broadly interchangeable in design, but the governing project specification always takes precedence. It is worth noting that ASTM A53 and ASTM A106 are specifications for steel pipe rather than for wide flange sections, so structural beams should be ordered against A36 or A992, EN 10025-2, GB/T 700 or GB/T 1591, and JIS G3101 instead.
Section Sizes and Mass per Metre
| Series | Section (H x B x tw x tf, mm) | Mass per metre |
|---|---|---|
| HW | 100 x 100 x 6 x 8 | 17.2 kg/m |
| HW | 150 x 150 x 7 x 10 | 31.5 kg/m |
| HW | 200 x 200 x 8 x 12 | 49.9 kg/m |
| HW | 250 x 250 x 9 x 14 | 71.8 kg/m |
| HW | 300 x 300 x 10 x 15 | 94.0 kg/m |
| HW | 400 x 400 x 13 x 21 | 172 kg/m |
| HN | 300 x 150 x 6.5 x 9 | 36.7 kg/m |
| HN | 400 x 200 x 8 x 13 | 66.0 kg/m |
| HN | 500 x 200 x 10 x 16 | 89.6 kg/m |
HW sections are the wide, near-square columns used for compression members, while HN sections are narrow and deep, which suits long-span beams. Standard delivery lengths are 6 m to 12 m, with cut-to-length, drilling, cambering and welded fabrication available before shipment.
Dimensional Tolerances and Quality Control
Depth and flange width tolerance to EN 10034 or ASTM A6, checkable against the mill certificate
Mill test certificates issued to EN 10204 3.1 with heat number traceability
Surface inspection for laps, seams, scale and roll marks before packing
Independent third-party inspection can be arranged when the buyer requires it
Loading plans, bundle strapping and corrosion protection matched to sea freight
Certified production follows an ISO 9001 quality management system, so each heat can be traced from steelmaking through rolling to the finished bundle.
Applications
Hot rolled H-beams and I-beams are the backbone of industrial construction: plant buildings, mezzanine floors, crane runways, bridge girders, equipment skids, transmission towers, workshop frames and temporary support structures. Their regular geometry also makes them convenient for retrofitting, since standard connection plates and clamps fit without site modification.
FAQ About H-Beam and I-Beam Sections
Q: What is the difference between an H-beam and an I-beam?
An H-beam has parallel flange faces and a thicker web relative to its flanges, giving near-equal bending capacity in both axes, whereas a rolled I-beam has inclined inner flange faces and a thinner web.
Q: Which steel grades are used for H-beams?
Common choices are ASTM A36 and A992, EN 10025-2 S275JR and S355JR, GB/T 700 Q235B, GB/T 1591 Q355B and JIS G3101 SS400, selected according to the required yield strength and design code.
Q: Can ASTM A53 or A106 be used for beams?
No. Both are pipe specifications; structural sections should be supplied to ASTM A36 or A992, EN 10025-2, GB/T 700 or GB/T 1591, or JIS G3101.
Q: What lengths and sizes are available?
Sections range from 100 x 100 mm up to 400 x 400 mm and beyond in the HW series, with HN beam sections up to 500 x 200 mm, normally supplied in 6 m to 12 m lengths.
Q: How is the weight of a beam calculated?
Multiply the published mass per metre by the ordered length; for example an HN 400 x 200 x 8 x 13 section at 66.0 kg/m gives 792 kg over 12 m.
Q: Are galvanized or welded H sections available?
Yes. Sections can be hot dip galvanized or fabricated from plate into welded H shapes when a non-standard size or a heavier flange is required.