WC-515 08/15 ©Lincoln Global, Inc. All Rights Reserved.

Heat Affected Zone Crack(Underbead Crack)

Crater Crack Transverse Crack

Longitudinal Crack(Centerline Crack)

» Joint Restraint » Improper Bead Shape

» High Carbon/Alloy Content » Low Melting Point Contaminants

» Hydrogen Pickup » Rapid Cooling Rate

Possible Causes Excess HydrogenHigh Carbon/Alloy Content in Base MetalHigh Residual Stress Levels

Possible Cures Use Low Hydrogen ConsumablesControl Hydrogen Content in Weld MetalIncrease Pre-HeatIncrease Post-Heat

Possible Causes Inadequate Crater Fill

Possible Cures Backstep at the End of the WeldUser Crater Fill Machine Settings

Possible Causes Excess HydrogenExcess Strength in Weld MetalHigh Residual Stress Levels

Possible Cures Increase Pre-HeatUse Lower Strength Consumables (consistent with design requirements)Increase Post-Heat

Possible Causes Improper Width to Depth RatioLow Melting Point ContaminantsConcave Weld Surface

Possible Cures Use Width to Depth Ratio of 1:1 to 1.4:1Limit Excess PenetrationDecrease Voltage and/or Travel Speed

DURING FABRICATION

Why Welds Crack

WC-515 08/15 ©Lincoln Global, Inc. All Rights Reserved.