Continuing on our series from before Christmas, we have added a few more weld defects.
Weld Crater is the unfilled end of a weld. The full cross section of weld is not filled and is considered a weld defect.
Weld Crater Definition
Cause
A crater pipe forms during the final solidified weld pool and is often associated with some gas porosity. This imperfection results from shrinkage on weld pool solidification. Consequently, conditions which exaggerate the liquid to solid volume change will promote its formation. What is Undercutting in Welding. Undercutting is a crater or groove that occurs near the toe of the weld. Undercutting in welding occurs when the weld metal failed to fill-in the grooved area. The result of which is a weak weld that is prone to cracking along the toes. In that case, the edge of the weld assumes a U-shape. Figure 1: Crater cracks occur when the weld pool does not have enough volume after cooling to overcome shrinkage stresses. One of the primary objectives of any weld fabrication is to prevent weld defects.
- stopping the arc too soon, not waiting to fill the weld end – crater
Crater Pipe In Welding Electrodes
Why is a crater a defect
- can lead to cracking of weld, by leaving a “weak” spot in the end of the weld
How to Prevent the Problem
- when stopping welds allow the weld puddle to fill before stopping the arc.
How to Repair
- Lightly grind the area where the crater has formed
- Backfill the area with a crater to repair
For information on previous topics, select below.
Until next week,
Bonnie Pankratz
Crater Cracks In Welds
bonnie@axisinspection.com