I have a question regarding welds. As an example, if I need or specify a 2" lg fillet weld, I have been in the habit of specifying (2) 1" welds spaced at say 1 1/2" crs.
My reasoning is that if a crack develops in the 2" weld, it will propagate and eventually fail. Whereas, in the event of a crack in one of the 1" welds, the other will hold and repairs can be done.
My question is, why would some PE’s be adverse to this and request continuous welds in the drawing mark ups before certifying.
The starts and stops of a weld are a typical location for discontinuities. By making two welds rather than one, one doubles their chances of having a discontinuity that could result in a failure.
One of the most common crack in a weld is a crater crack or shrinkage crack at the end of the weld. In Structural Steel Fabrication I probably find 1500 crater cracks to any other type of welding crack on new construction. On existing structures crack when found where either crater or shrinkage cracks missed during fabrication or fatigue cracking.
The starts and stops are also a stress concentrators, look for fatigue cracking to start here.
At the starts and stops expect to find more martensite (Hard and brittle) during to rapid cooling.
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