Direct Answer
Structural steel beams are fabricated by: receiving rolled section material with mill certifications, cutting to length, laying out and drilling bolt holes, cutting copes, welding connection plates (shear tabs, stiffeners, end plates), blasting, priming, and final inspection before shipping. Most modern shops use CNC beam lines for automated drilling and cutting, driven by DSTV files from the detailer.
Full Explanation
The fabrication sequence: (1) Material receiving — section size and material cert verified against the shop order. (2) Layout — piece mark, length, and hole locations marked. (3) CNC processing — holes drilled, cuts made, copes burned on a CNC beam line or drill line. (4) Assembly — connection plates welded per shop drawing weld symbols by a certified welder. (5) Surface prep — blast cleaning to specified SSPC standard. (6) Priming — primer applied to specified DFT. (7) QC inspection — dimensions, holes, welds, and finish verified. (8) Marking — piece mark stamped or painted per project spec. (9) Shipping — sorted by assembly, loaded per erection sequence.
What This Means for Your Shop
Each step in this sequence is a quality gate. Skipping or rushing any step creates defects that compound. A hole in the wrong location discovered at step 8 is far more expensive than one caught at step 2.
Common Mistakes
Processing material before CNC programs are verified against the approved drawings. A single transposed digit in a hole location can require redrilling or replacement of an entire member.
Recommended Process
Implement a first-article inspection: fabricate one piece per piece mark type, inspect completely, and sign off before running the full quantity. This is especially important for complex assemblies with multiple connection conditions.