CWB Welding Inspector Level 1 cheat sheet

Visual inspection is an NDT method performed before, during, and after welding; it detects surface and near-surface discontinuities only, not internal flaws.

Inspect 100% of accessible weld surface where practical; typical coverage is the full weld face plus at least 25 mm (1 in) of adjacent base metal on each side unless a standard specifies otherwise.

Lighting rule: illumination at the inspection surface should be at least 500 lux (about 50 fc) for general work and 1000 lux or more for fine detail; verify with a calibrated light meter.

Visual acuity: inspectors typically need corrected near vision of 20/20 (Jaeger J1 at 300 mm) and periodic re-examination per employer or code requirements.

Common visual discontinuities: undercut, overlap, spatter, arc strikes, porosity at surface, incomplete fusion at the face, crater cracks, misalignment (hi-lo), and excessive reinforcement.

Weld reinforcement limits are code-specific; typical limits are 3 mm (1/8 in) excess face reinforcement and 1.5 mm (1/16 in) for butt joints in some structural codes.

Undercut acceptance usually depends on depth and length: many structural codes allow up to 0.8 mm (1/32 in) shallow undercut but restrict deeper undercut to limited cumulative length.

Use a weld gauge, fillet gauge, or bridge cam gauge to measure leg size, throat, reinforcement, undercut depth, and misalignment rather than estimating by eye.

SMAW (stick): consumable electrode coated with flux; electrode classification E7018 means 70 ksi minimum tensile, all-position (1), low-hydrogen iron powder coating (8).

GMAW: continuous wire electrode with external shielding gas; transfer modes are short-circuit, globular, spray, and pulsed; short-circuit is used for thin material and out-of-position work.

FCAW: tubular wire with internal flux; self-shielded (no external gas) or gas-shielded; higher deposition than SMAW and tolerant of wind when self-shielded.

GTAW: non-consumable tungsten electrode with separate filler and inert shielding gas; used for root passes, thin material, and code-quality work on stainless and aluminum.

SAW: arc submerged under a granular flux blanket; high deposition, only flat or horizontal positions, typically mechanized.

Typical shielding gases: 100% CO2 or 75% Ar/25% CO2 for carbon steel GMAW; argon/helium mixes for aluminum; argon for GTAW on most metals.

Polarity rules: DCEP (electrode positive) gives deeper penetration and is standard for GMAW; DCEN is used for GTAW on steel; AC is common for GTAW on aluminum to break the oxide.

Welding current, voltage, travel speed, and electrode angle control bead shape; excessive current causes spatter, undercut, and burn-through; too little causes lack of fusion.

CWB Certification is administered by the Canadian Welding Bureau under CSA W47.1 (steel), CSA W47.2 (aluminum), and CSA W186 (reinforcing steel).

CSA W47.1 divides fabricators into Divisions 1, 2, and 3 based on welding engineering and quality control capability; Division 1 requires the highest level of in-house engineering and QC.

CWB certification covers company certification (fabricator) and individual welder qualification; welder qualification is specific to process, position, and joint type.

Welder performance qualification tests follow CSA W47.1 Annex or the applicable code; test welds are visually inspected and may be bend tested or radiographed.

ASME Section IX governs welding procedure and performance qualification for pressure equipment; a WPS must be supported by a qualified PQR.

AWS D1.1 governs structural steel welding; it defines prequalified joint details, WPS requirements, and visual acceptance criteria for statically and cyclically loaded structures.

A WPS (welding procedure specification) is a written document; the PQR (procedure qualification record) is the objective evidence that the procedure produces sound welds.

Certification is not permanent: welders must be requalified after extended interruption of welding, a change of process or position, or failure of production welds per code rules.

Inspection sequence: verify base metal and consumables, check fit-up and joint preparation, monitor preheat and interpass temperature, observe root and fill passes, then final visual and dimensional check.

Preheat is verified with temperature-indicating crayons, contact thermometers, or infrared devices; measure at a specified distance from the joint per the WPS.

Weld measurement tools: fillet weld gauge (leg and throat), bridge cam gauge (undercut, reinforcement, pit depth), and taper gauge (root gap and misalignment).

Hi-lo (misalignment) limit in many structural codes is 10% of plate thickness, not to exceed 3 mm (1/8 in) for butt joints.

Fillet weld size is measured by leg length; the theoretical throat equals 0.707 times the leg length for a 45-degree equal-leg fillet.

Dimensional checks include overall length, camber, sweep, squareness, and distortion; record readings against drawing tolerances.

Nonconformance handling: mark the location, record the discontinuity, issue a report, and route to the responsible engineer for disposition (repair, accept, or reject).

Inspection records should identify the WPS, welder ID, date, ambient conditions, and measured values so the report is traceable to the weld.

A welding inspection report typically contains project identification, WPS and welder ID, joint location, inspection method, findings, and inspector signature and date.

Inspection and Test Plan (ITP) lists hold points and witness points where the inspector must sign off before work proceeds.

Safety: arc welding produces ultraviolet and infrared radiation; a welding helmet with the correct shade lens is required (shade 10-13 for typical arc currents).

Fume control: local exhaust ventilation or respiratory protection is required where welding fume exposure exceeds occupational limits; galvanized steel fume requires extra precautions.

Electric shock risk: welding circuits should be dry, insulated, and grounded; never weld in wet conditions without proper PPE and isolation.

Fire prevention: remove combustibles within 11 m (35 ft) of the work, use fire blankets, and post a fire watch where required by hot work permits.

Compressed gas cylinders must be secured upright, separated from fuel gas by at least 6 m (20 ft) or a fire-rated barrier, and fitted with flashback arrestors.

Personal protective equipment includes flame-resistant clothing, leather gloves, safety glasses under the helmet, and hearing protection in high-noise areas.