Welded connections

Shop-welded by default, site-welded by exception — and inspected like it matters.

Welded connections — Steel Frame Construction

Last updated 2026-07-28 by the BuildPedia Editorial Team.

What is Welded connections?

Welding is how steel connections are made in the fabrication shop: controlled environment, qualified welders, jigs, and inspection before paint. On site it is the exception, reserved for splices that must be continuous, special details and rectification — because site welding is expensive, weather-limited, access-constrained and hard to inspect well. When site welding is specified, it arrives with the full apparatus of welding quality control: approved procedures, qualified welders, and non-destructive testing per the specification.

The quality chain starts with the paperwork. Every weld has a Welding Procedure Specification — process, consumables, preparation, preheat, interpass temperature — and every welder is qualified to the procedure. Consumables are stored and dried per the manufacturer; a damp low-hydrogen electrode introduces hydrogen into a restrained joint and hydrogen cracks follow hours later. Preheat and interpass temperatures on thick or highly restrained joints are measured and recorded, not estimated by hand and prayer.

Inspection is layered: visual examination of every completed weld for profile, undercut, cracks and finish; then NDT — magnetic particle for surface cracks, ultrasonic for internal fusion — on the specified sample, 100% on critical joints. Defects are gouged out and re-welded under the same procedure, with the repair itself re-inspected. Site welds earn their keep where nothing else will do — full-strength moment splices, heavy section continuity — and everywhere else the correct response to a proposed site weld is a better bolted detail.

How does Welded connections work, step by step?

Step 1: Approve procedures and qualify welders

Approve procedures and qualify welders — Welded connections, step 1

Welding Procedure Specifications are approved for each joint type, position and thickness; welder qualifications are verified current and matching the procedure. Consumables are logged into controlled storage with drying records where required.

Step 2: Prepare and fit the joint

Prepare and fit the joint — Welded connections, step 2

Edge preparation, root gap and alignment are checked against the WPS before arc strikes metal. Tack welds — made under the same procedure — hold the fit; weather protection goes up for wind and moisture, because a weld made in the rain is a weld that will be gouged out.

Step 3: Weld with controlled heat input

Weld with controlled heat input — Welded connections, step 3

Preheat is applied and verified where specified; the weld is run in the designed pass sequence with interpass temperatures monitored. On thick restrained joints the thermal discipline is the quality control — cracking is a temperature event as much as a technique one.

Step 4: Inspect visually, then NDT

Inspect visually, then NDT — Welded connections, step 4

Every weld gets visual examination after cleaning; the specified NDT follows — MPI for surface, UT for volume — by qualified examiners with recorded results. Acceptance criteria come from the specification, not the examiner's mood.

Step 5: Repair, re-inspect and record

Repair, re-inspect and record — Welded connections, step 5

Defects are excavated and repaired under the WPS, then re-inspected by the same methods. The weld map, welder log, consumable records, NDT reports and repair records form the welded connection QA file — a welded joint without records is an unknown joint.

What are the benefits of Welded connections?

What are the limitations of Welded connections?

What is Welded connections best suited for?

What plant does Welded connections need?

How is Welded connections quality-checked?

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