What Defines a Heavy H Beam
A heavy H beam is a hot rolled structural section whose flange thickness, web thickness and mass per metre sit above the light and medium ranges used for purlins, roof rails and secondary framing. The H geometry places most of the material in two parallel flanges, so section modulus per kilogram of steel is higher than that of an I beam with the same nominal depth. In commercial practice the heavy range starts near 60 kg/m: European HEB series above HEB 200 and Chinese HN series of 400 mm depth and greater fall in this group, while IPE and lighter HN sections are treated as medium sections.
Parallel flanges are the second defining feature. They accept bolted end plates and welded moment connections without tapered washers, and the straight inner flange faces allow shear studs, stiffeners and cleats to be welded with standard fixtures. This is why heavy H sections are usually specified for columns, transfer beams and crane gantry legs rather than for simple floor beams.
Section Dimensions and Nominal Mass
Dimensions below follow EN 10365 for European HEB and IPE series and GB/T 11263 for Chinese HW and HN series. Mass per metre is a nominal value; dimensional tolerance on depth, flange width and web eccentricity is governed by the relevant rolling standard for each series.
| Designation | Dimensional standard | h x b (mm) | t w (mm) | t f (mm) | Mass (kg/m) |
|---|---|---|---|---|---|
| HEB 200 | EN 10365 | 200 x 200 | 9 | 15 | 61.3 |
| HEB 300 | EN 10365 | 300 x 300 | 11 | 19 | 117 |
| IPE 300 | EN 10365 | 300 x 150 | 7.1 | 10.7 | 42.2 |
| HW 200 x 200 | GB/T 11263 | 200 x 200 | 8 | 12 | 49.9 |
| HN 400 x 200 | GB/T 11263 | 400 x 200 | 8 | 13 | 66.0 |
Depth, flange width and thickness determine the plastic section modulus used in the resistance check to EN 1993-1-1 or AISC 360. When a design is governed by deflection rather than strength, a deeper heavy section with thinner flanges usually uses less steel than a shallower heavy section with thick flanges, so the flange-to-web ratio should be checked before the order is placed.
Steel Grades and Mechanical Properties
Heavy H beams are supplied in the grade named on the drawing, and the yield strength used in design must be taken at the correct thickness class because the tabulated value decreases as the section gets thicker.
| Grade | Standard | ReH min (MPa) | Tensile strength (MPa) | Impact requirement |
|---|---|---|---|---|
| A36 | ASTM A36/A36M | 250 | 400 - 550 | Not required |
| A992 | ASTM A992/A992M | 345 - 450 | 450 min | Not required |
| S235JR | EN 10025-2 | 235 up to 16 mm | 360 - 510 | 27 J at +20 C |
| S355JR | EN 10025-2 | 355 up to 16 mm | 470 - 630 | 27 J at +20 C |
| Q355B | GB/T 1591-2018 | 355 up to 16 mm | 470 - 630 | 27 J at +20 C |
A36 and A992 are the usual choices for North American work, S235JR and S355JR for European projects, and Q355B for domestic Chinese structures. Grades within one series can normally be welded to each other without a change of consumable, but the design yield strength must always be taken from the lower grade of the joint.
Rolling Practice, Tolerances and Delivery Condition
Heavy sections are rolled at 1,100 - 1,250 C in universal mills, which refines the grain structure and closes internal porosity. The section leaves the last stand with parallel flange faces and then passes through straightening rolls that remove bow and sweep. Delivery condition is as-rolled unless the purchase order calls for normalising, thermo-mechanical rolling or a specific surface treatment.
Shape tolerance is commonly specified to EN 10034 for I and H sections, with out-of-straightness, flange squareness and web off-centre limits stated as fractions of the nominal dimensions. For Chinese HW and HN series the dimensional and mass tolerances of GB/T 11263 apply. Where a project combines both series, the two tolerance systems should be stated separately in the inspection plan because they are not identical.
Welding, Bolting and Corrosion Protection
Shop fabrication of heavy H beams uses submerged arc welding for flange and web butt joints and gas metal arc welding for stiffeners and end plates. Common acceptance criteria are AWS D1.1/D1.1M or EN 1090-2 at execution class EXC2; EXC3 is normally requested for crane gantries and dynamically loaded structures. High strength structural bolting follows ASTM F3125 or EN 15048, with the tightening method and inspection frequency agreed before assembly.
For outdoor or humid service, hot dip galvanizing to ASTM A123/A123M or EN ISO 1461 gives a coating thickness linked to steel thickness and is the most common protection for heavy sections. Where a project requires a painted finish, the steel surface is prepared to the grade stated in the coating specification before the primer is applied.
Frequently Asked Questions
Q: Is a heavy H beam the same as a wide flange beam?
A: Functionally yes. Heavy H beam is the trading term for hot rolled parallel flange sections above roughly 60 kg/m, while wide flange is the North American name for the same geometry. Both are ordered against a dimensional standard and a steel grade, for example A992 for a wide flange or S355JR for a European HEB section.
Q: Why does the yield strength of S355JR change with thickness?
A: EN 10025-2 classifies yield strength by thickness class, using 355 MPa for material up to 16 mm and lower values for thicker sections. Because heavy H beams have thick flanges, the design check must use the value for the actual flange thickness, not the headline figure.
Q: Which is more economical, a heavier section or a fabricated plate girder?
A: A rolled heavy H beam is normally cheaper per tonne because it has no weld volume and no welding distortion, provided a standard section satisfies the required section modulus. A plate girder becomes competitive only when the span or load needs a section deeper than the largest rolled profile available.
Q: What impact test should be specified for cold climate projects?
A: EN 10025-2 grades with J0 and J2 suffixes give 27 J at 0 C and at minus 20 C respectively, which covers most winter conditions. For service temperatures near minus 60 C, a quenched and tempered grade tested at that temperature is specified instead of a normalised structural grade.
Q: How is a heavy H beam inspected before shipment?
A: Inspection usually covers grade certification, dimensional check of depth, flange width and thickness, straightness, and visual examination of surface defects. Ultrasonic examination of the flanges is added when the beam will carry dynamic loads or will be welded into a primary tension member.
Q: Can heavy H beams be supplied pre-galvanized and cut to length?
A: Yes. Sections are commonly cut to length, drilled or coped before galvanizing so that all cut edges receive coating, then shipped with the coating thickness recorded against EN ISO 1461 or ASTM A123/A123M. Cutting or welding after galvanizing requires the damaged zone to be repaired with a zinc-rich coating.