Rolled beam vs welded/fabricated beam

A rolled I/H beam and a welded/fabricated I/H beam can look very similar in a drawing, but they are produced in fundamentally different ways.

The distinction matters for:

• available dimensions;
• lead time and sourcing;
• weld inspection;
• tolerances;
• material traceability;
• fabrication documentation.

Neither route is automatically “better.” The correct choice depends on the design and project specification.

Hot-rolled beam

A hot-rolled section is formed as one piece in a section mill.

The hot steel passes through a sequence of rolls that progressively form the web and flanges into a standard profile such as:

• IPE;
• HEA/HEB/HEM;
• UB/UC;
• W-shape.

A rolled I/H section therefore does not have longitudinal welds joining its web to its flanges.

Its geometry comes from the mill’s roll series and the standardized section range.

Welded or fabricated beam

A fabricated I/H beam is built from separate plate components, typically:

• one web plate;
• two flange plates.

The plates are assembled and welded along the flange-to-web junctions.

This route allows the designer/fabricator to choose combinations of:

• depth;
• flange width;
• web thickness;
• flange thickness

that may not exist as a standard rolled section.

ArcelorMittal’s Orange Book, for example, includes design data for welded sections with explicit web and flange plate dimensions.

Main practical differences

Why use a fabricated beam?

Common reasons include:

• required section is larger than available rolled profiles;
• unusual flange width or web depth;
• optimization of web/flange thickness;
• tapered members;
• built-up girders;
• project-specific structural geometry.

Fabrication can also allow different plate thicknesses along the member or other optimized details, subject to the design code and fabrication specification.

Does welded mean lower quality?

No.

A properly designed and fabricated welded beam can be a high-quality structural product.

But the welds introduce additional manufacturing controls such as:

• qualified welding procedures;
• welder/operator qualification as applicable;
• weld preparation and fit-up;
• distortion control;
• NDT where specified;
• repair procedures;
• dimensional inspection.

Those controls do not exist in the same form for the web-to-flange junction of a one-piece rolled beam.

Are dimensions written the same way?

The core geometry is still described using h, b, tw and tf.

See How to read beam dimensions.

The difference is that a rolled profile has standardized root fillets and mill geometry, while a fabricated section is assembled from plates and welds.

Unit weight

For standard rolled sections, use the published mass per metre.

For fabricated sections, unit weight can often be calculated directly from the component plate areas and steel density, with appropriate allowance for weld metal and actual geometry where needed.

See How to calculate or look up steel-section unit weight.

Procurement questions for a fabricated section

An RFQ should define more than “welded beam.”

Check:

• member drawing / h, b, tw, tf;
• flange and web material grades;
• plate product standard;
• welding/execution standard;
• WPS/PQR requirements;
• NDT and acceptance criteria;
• dimensional tolerances;
• camber/sweep requirements;
• inspection certificate requirements;
• marking and heat traceability;
• surface treatment.

For a standard rolled beam, much of the geometry is already embedded in the section designation and dimensional standard.

MetalMate takeaway

A rolled beam is a standardized one-piece mill section; a fabricated beam is assembled from plates and welded. Fabrication offers geometric freedom, but it also adds welding, inspection and traceability requirements that must be specified in procurement.

Related Knowledge

• HEA, HEB, HEM and IPE sections
• How to read beam dimensions
• Steel-section unit weight

References

• ArcelorMittal Orange Book, European rolled beam families: https://orangebook.arcelormittal.com/beams
• ArcelorMittal Orange Book, Welded sections — dimensions and properties: https://orangebook.arcelormittal.com/node/184
• NEN, EN 10365:2026 — Hot rolled section dimensions and masses: https://www.nen.nl/en/nen-en-10365-2026-en-353950