Quote:
Originally Posted by MikeK
What you did created detrimental modifications in the grain structure of the rolled sheet used to produce the two overlapping blades. The welding added stress risers in the absolute wrong places. You now have a DANGEROUS fan.
Welding the four overlap joints of the two blades- two in front, two in the back, has made the fan far more prone to sudden blade loss than the riveted construction. You have concentrated the flexing directly across your weld beads. The grain structure in the steel sheet metal the blades are made from is refined, compressed, and stretched directionally during the rolling process. Essentially a type of forging. Your weld bead destroyed that. It annealed the metal and left a soft line with much less spring than the rest of the blade.
The fact that you now have many years of accumulated stress from dynamic flex on that fan makes it a real time bomb.
Didn't you post this under a different screen name 5 years & 11 months ago? My response was the same back then.
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Thanks for the response. Don't know if it was me who posted back then. In that period I was working over seas for a extended period of time and on returning to the US had a hospital stay for quite a while and was not on the Internet. I will look into another fan today.