CWS Welding cheat sheet

OSHA 29 CFR 1910.252 covers general-industry welding, cutting, and brazing; 29 CFR 1926 Subpart J covers construction welding.

Hot work requires at least 35 ft clearance from combustibles or adequate guards; a fire watch is maintained during work and at least 30 min after when needed.

Acetylene cylinder delivery pressure must not exceed 15 psig; cylinders are stored upright with valve protection caps in place.

Local exhaust ventilation at the arc controls metal fume; OSHA permissible exposure limits apply to fume constituents such as manganese.

Filter lens shade is selected by welding process and arc current; arc eye is UV photokeratitis caused by inadequate eye protection.

Porosity causes include moisture, oil, paint, rust, low current, long arc, high travel speed, and lost or inadequate shielding gas.

Undercut causes include excessive current, long arc, incorrect electrode angle, and fast travel; lack of fusion causes include low heat input, fast travel, poor access, and contamination.

PT and MT detect surface-breaking discontinuities; UT and RT detect volumetric/internal discontinuities; VT is performed before, during, and after welding.

A WPS is qualified by a PQR under a code such as AWS D1.1 or ASME IX; welder performance qualification is separate and tests the individual welder.

Total weld cost = labor + consumables + equipment + overhead + rework; labor and overhead usually dominate manual welding cost.

Operating factor = arc-on time ÷ total work time; typical values are about 20–40% for manual SMAW, 40–60% for semi-automatic GMAW, and 60–80% for mechanized welding.

Labor cost per weld = (arc time ÷ operating factor) × labor rate.

Heat input (kJ/in) = (voltage × amperage × 60) ÷ (travel speed in in/min × 1000).

Steel wire deposition rate (lb/h) ≈ 13.1 × (wire diameter in)² × wire feed speed (in/min), adjusted for transfer efficiency.

Takt time = available production time ÷ customer demand; it sets the required pace of a welding cell.

OEE = availability × performance × quality.

Lean welding targets the seven wastes; waiting, rework, overprocessing, and inventory are common high-impact targets in weld shops.

First-pass yield = good first-time units ÷ total units; rework cost often exceeds the original weld cost, so defect prevention is usually cheaper than repair.

The welding supervisor verifies that the approved WPS is available at the point of use and that each welder is qualified for process, position, thickness, and material.

Code compliance records include WPS, PQR, welder performance qualifications, inspection reports, NCRs, and calibration records.

A pre-shift huddle communicates hazards, quality alerts, production targets, and assignments; it is kept short and documented.

Closed-loop communication: the sender states the message, the receiver repeats it back, and the sender confirms understanding.

Root cause analysis uses 5 Whys and fishbone diagrams covering man, machine, material, method, measurement, and environment.

Corrective action removes the root cause of a nonconformity; containment only stops the immediate nonconforming product from moving forward.

Supervisory KPIs include first-pass yield, rework percentage, schedule adherence, weld repair rate, and TRIR.

TRIR = recordable cases × 200,000 ÷ total hours worked.

An NCR triggers a disposition such as use-as-is, repair, rework, or reject and must remain traceable to the affected weld.