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Discussion Starter · #1 ·
Hi

While I was cleaning my bike I found something new around the bottom bracket welding. This weld has become dark and I don´t know what it can mean.

What do you think?



Thanks in advance
 

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Is it just me or soes anyone else see what might be cracks on that weld? Right below the discoloration and a little further down that joint. Also there is a dark line on 2 of the puddles just below the discoloration. (I have never welded Ti before.)
 

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mullet dew said:
Is it just me or soes anyone else see what might be cracks on that weld? Right below the discoloration and a little further down that joint. Also there is a dark line on 2 of the puddles just below the discoloration. (I have never welded Ti before.)
Looks like quite a bit of the actual weld bead is crackling. Have no idea why or what that means, but it was the first thing I noticed...
 

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I think the cracks are "alpha case", a brittle phase formed at high temperature in the presence of oxygen. Looks like the welder tried to polish it away, but was only partially successful. The purple is a high-temperature oxide and was always there.
 

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Discussion Starter · #8 ·
steadite said:
I think the cracks are "alpha case", a brittle phase formed at high temperature in the presence of oxygen. Looks like the welder tried to polish it away, but was only partially successful. The purple is a high-temperature oxide and was always there.
So, is it normal or do I have to look down every 5 minutes while I riding?:D
 
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