Melt through that creates a ripple is a sign of ______ weld penetration.

• A. Poor
• B. Burn through
• C. Inadequate
• D. Good

Answer: (D)

Penetration is about how deeply the weld metal fuses into the base metal. When the heat and travel speed are balanced in GMAW, the molten metal can flow through the joint and fuse the metal on both sides. Seeing a ripple pattern as the weld is laid down often means the metal has penetrated through to the far side, indicating the weld has achieved good penetration. This fusion-through-the-thickness shows the joint is fully fused rather than just melted superficially. If heat is too low, penetration is inadequate, with poor fusion and gaps. If heat is too high, you risk burn-through, which is undesirable. So a melt-through that creates a ripple aligns with good weld penetration.