Built-Up H-Beam vs Hot-Rolled: When to Use Each

A built-up H-beam is welded from steel plates, so its depth, flange width and thickness can be chosen to match the load. A hot-rolled H-beam comes from a mill in standard sizes. The better choice depends on whether a standard section fits the design, how long the beam must be, and how the project is scheduled.

What a built-up H-beam is

A built-up H-beam is made by welding two flange plates to a web plate. Because the plates are cut to the design, the designer can change the web depth along the member, use a thinner web where shear is low, or select different flange sizes at the top and bottom. This is how the tapered rafters and columns of pre-engineered steel buildings are made.

Hot-rolled sections follow standard sizes and are produced in the range of grades and lengths that a mill offers. A general description of common structural steel sections and grades shows how widely they are used.

When built-up sections make sense

• Long spans and deep members, where the required depth is beyond the standard range
• Tapered members, where the moment diagram allows material to be removed away from the high-moment zone
• Special flange sizes, for example to connect to a particular base plate or crane rail
• Repeated frames, where the saving in steel repeats across many bays

Our guide to pre-engineered steel buildings versus conventional steel buildings explains where tapered built-up frames fit.

When hot-rolled sections are the simpler choice

Hot-rolled beams suit moderate spans, secondary framing and short members where a standard size is enough. There is no long weld to inspect, and the fabrication is mostly cutting, drilling and connection work. For a small project, the time saved in welding can outweigh the material saved by a tailored section.

What to check in a welded section

The strength of a built-up beam depends on the weld, so the weld quality matters more than it does for a rolled beam. Ask the fabricator for:

• The welding procedure and welder qualifications used for the web-to-flange weld
• The inspection method and records, including visual and non-destructive testing where required
• The straightness and camber tolerance after welding, and how distortion is corrected
• Material traceability from the plate to the finished member

Our guide to bolted and welded connections covers how connection welds are checked.

How Truong Thinh fabricates beams

At Truong Thinh, built-up H-beam sections are fabricated from plate in the Vinh Tan factory, and the quality control department inspects dimensions and welds to AWS D1.1 before delivery. The factory holds ISO 9001:2015 and an EN ISO 3834-2:2021 welding quality certificate issued by Bureau Veritas, as listed on the company facts page. For the process from model to delivery, see steel beam fabrication for H-beam and built-up sections.

If your project needs fabricated beams, send the drawings, the grade and the delivery window, and request a fabrication quotation from our engineering team.

Frequently Asked Questions