Which: re-rivet or weld?

The article mentioned clinching, and it tested as slightly better than welding in fatigue life. One assumes that rivets will be at least that good.

But how does this help if the alloy isn't weldable, with welds becoming brittle?

Deep but narrow welds can fracture easily. There was an military airplane crash that was traced to an electron-beam plug weld being used to prevent rotation of two forged components that were screwed together, this component being flight critical. Weld cracked, parts unscrewed, control was lost, aircraft was lost.

Don't know if this applies to cars, but the story popped up on the mention of deep narrow welds.

Joe Gwinn

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Joe Gwinn
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Lasers produce a much smaller heat-affected zone, and some other parameters are quite different from those produced by arc welding.

Here is some info. Note that there are many different types of AHSS, which have quite different properties:

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I haven't explored fatigue properties, but I'm leaving that alone for now and leaving it to the editors of Shop Floor Lasers. I'm listed on the masthead but I'm actually not going to do much with it.

Well, the welding scene is changing a great deal. I'll know more in February or so. We have another new magazine on the way. d8-)

Reply to
Ed Huntress

[snip]

Interesting. While they didn't mention fatigue properties, they did mention the the stronger the steel the weaker the weld, so there may be an issue here. Thus, rivets.

I think the issue was that the plug area wasn't large enough, and I'd bet that the mating parts were able to wiggle just enough to fatigue the weld metal, which was probably in the as-quenched state. Maybe if the welded assembly had been heat treated it would have been OK, but nobody was interested after the crash, and that part was made as a single forging thereafter.

When does welding fatigue set in? I mean of editors.

Joe Gwinn

Reply to
Joe Gwinn

LOL! I guess it depends on how curious one is. If you aren't obsessively curious, it's not a good career. If you are obsessively curious, it's one of the best.

Reply to
Ed Huntress

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