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(ProQuest: ... denotes formulae omitted.)
A booklet on weld design recently appeared on my desk. It contains this statement:
"Intermittent fillet welds are used in some work where the loads are small. They reduce the cost of welding and also reduce distortion."
In a general way, these two sentences are probably correct.
However, neither is universally true. In this column, we'll re-examine intermittent fillet welds to see what they do and don't do.
When I started welding, intermittent fillet welds were an obvious choice for connections that did not require the strength of a continuous fillet weld.
The process I was using was stick: I can't say shielded metal arc, because back then, we were using bare electrodes.
With stick, it was easy to make intermittent fillet welds: After making the required length of weld, one would fill the crater and break the arc. Then the welder would move to the next location, re-strike the electrode, and continue.
With stick welding, the arc had to be stopped, the stub removed, and a new electrode inserted in the stinger due to the finite length of the filler metal - even when the welds were continuous. So, whether making intermittent or continuous welds, the welder always made a series of segments.
For continuous welds, the segments were joined end to end. For intermittent welds, ideally each segment consumed one electrode, and the segments were gapped.
Perhaps the welder used a travel speed of 10 ipm when welding with stick. Certainly, the welder could "index" ahead to the start of the next segment of intermittent weld faster. Where the design permitted intermittent fillet welds, they cost less than...