I-Beam and H-Beam Basics
An I-beam has a cross-section shaped like the letter I, with a vertical web and two horizontal flanges; when the flanges are wide and parallel, the section is commonly called an H-beam or wide flange beam. The web resists shear while the flanges carry the bending moment, which makes the profile extremely efficient for spanning loads. Hot rolled sections are produced in standardized series, of which HEA, HEB, and IPE are the most common in European and international practice.
Reading Section Designations
In the designation HEA 200, the letters identify the series and the number is the nominal height in millimeters. HEA 200 has an actual height of 190 mm with a flange width of 200 mm, while HEB 200 is 200 mm high with a 200 mm flange, and IPE 200 is 200 mm high with a 100 mm flange. The section tables list the exact dimensions, sectional area, weight per meter, and the moment of inertia and section modulus used in design calculations. Ordering should always state the series, size, grade, length, and standard.
Grade Options and Properties
Carbon steel grades commonly rolled in these series include S235JR, S275JR, and S355JR to EN 10025-2, ASTM A36, SS400 to JIS G3101, and Q235B and Q345B to Chinese standards. Minimum yield strengths range from 235 MPa for S235JR and Q235B, through 245 to 250 MPa for SS400 and A36, to 275 MPa for S275JR and 345 to 355 MPa for S355JR and Q345B. Tensile strengths range from about 400 to 630 MPa across these grades, and all are weldable with standard carbon steel consumables.
Choosing the Right Profile for the Frame
For floor and roof beams that carry load in one direction, IPE sections give the best strength-to-weight ratio. For columns and members that resist load in two directions, HEA or HEB wide flange sections are preferred because their wide flanges provide minor-axis stiffness and stable bearing surfaces. HEB is chosen when axial load dominates, such as tall columns and crane supports, and HEA when weight saving matters more than maximum capacity. The section is finalized by checking bending, shear, deflection, and buckling limits.
Fabrication and Surface Protection
Hot rolled beams are cut by band saw, drilled or punched for connections, and welded with fillet or groove welds as required. End plates and base plates are welded to columns, and stiffeners are added at concentrated loads. For corrosion protection, sections are supplied with shop primer, a full paint system, or hot-dip galvanizing for exposed structures, and mill test certificates accompany every delivery.
Frequently Asked Questions
Q: What is the difference between an I-beam and an H-beam?
An H-beam has wider flanges and a thicker web than a classic I-beam, giving more strength about the minor axis and a better bearing surface, while an I-beam is lighter and more efficient in pure bending.
Q: Is HEA 200 the same as HEB 200?
No. HEB 200 is heavier and stronger, with a full 200 mm height and thicker flanges, while HEA 200 is 190 mm high and about one-third lighter.
Q: Which grade should a small building frame use?
S235JR, A36, or Q235B is economical for light frames, with S275JR or S355JR selected when spans and loads increase.
Q: Can IPE beams be used as columns?
They can, but wide flange HEA or HEB sections are normally preferred for columns because of their better minor-axis stability.
Q: What lengths are hot rolled beams supplied in?
Standard lengths are 6, 12, and 15 meters, and beams can be cut to the exact lengths required by the shop drawing.