GMAW Welding Level 2 Practice Test

Whiskers show up when the filler wire is fed too far ahead of the molten weld pool. In gas metal arc welding, keep the wire tip within or just at the front edge of the puddle so the molten metal from the wire fuses smoothly into the leading edge. If the wire is pushed past that leading edge, the tip continues to melt and deposit metal ahead of the pool without proper fusion, which cools into thin, hairlike projections along the bead—these are the whiskers. Maintaining proper wire stickout and keeping the arc aligned with the front of the pool helps prevent this defect. Pushing behind the pool would deposit metal behind the bead and disrupt fusion at the front, a high shielding gas flow tends to cause porosity or instability rather than whiskers, and an incorrect electrode angle changes bead shape but isn’t the typical cause of whiskers.