Structural Steel Weld Finishes and Coatings. This guide explains what a project team should clarify before fabrication or field work.
Separate three decisions
A structural weld has a required joint geometry and acceptance criteria. Its contour or mechanical finish is a second decision, and the corrosion-protection or fire-protection system is another. These requirements are related but should not be collapsed into a universal three-category code table.
As-welded and ground profiles
A weld may remain as welded after specified cleaning, or a drawing may require a particular contour or grinding operation. Do not grind a structural weld simply to make it look smoother: removal can affect its required section. Follow the drawings and obtain review where requirements are unclear.
Surface preparation for coatings
Cleaning, removal of contamination and the required surface profile depend on the selected coating system and substrate. Abrasive blasting is a preparation method, not a universal structural weld classification. Use the preparation specification supplied for the actual system.
Galvanizing and field repairs
Coordinate welded assembly details with the galvanizer before fabrication. If welding or damage affects an existing zinc coating, the specified preparation, welding controls and compatible repair system must be established. Field-applied zinc-rich repairs should not be represented as automatically identical to hot-dip galvanizing.
Fire protection
An intumescent system must follow its tested/listed design and manufacturer’s instructions, including compatible primer, preparation and coating thickness. Do not assume every weld must be ground flush or that one coating thickness provides every required fire-resistance rating.
Inspection and maintenance
Agree weld inspection and coating inspection responsibilities, acceptance criteria and records. Coating service life depends on exposure, preparation, application, detailing and maintenance; a generic 10-, 25- or 50-year promise is not a project specification.
What to include in a quotation request
Send the structural and fabrication information, weld symbols, finish requirements, exposure conditions, coating/fire-protection specification and installation scope. WRS can review the fabrication enquiry and identify items requiring clarification by the project designer or coating supplier.
Plan Your Next Project
Explore our commercial structural steel fabrication services and read the related project guide. For a scope review, send your drawings or photographs, project location and required fabrication or installation work.
Reference: CWB company certification. Confirm applicable standards, editions and project requirements with the responsible professionals.