🔥Welding Defects – Causes, Effects & Prevention Welding is a critical process in fabrication, but even a small defect can compromise safety, performance, and service life. Here are the most common welding defects every QA/QC engineer, fabricator, and inspector should be aware of: 🔹Porosity – Gas pockets in the weld caused by contamination, moisture, or improper shielding gas. 🔹Slag Inclusion – Non-metallic materials trapped inside the weld due to poor cleaning or incorrect electrode angle. 🔹