Cracked Echo Lite

[Kieran Morrison]

So my mate cracked his echo about a week ago, started off tiny, and now its almost the whole way round. its at the chainstay, right next to the weld for the bottom chainstay onto the seat tube under the freewheel. When it got bigger, he drilled small holes in it and it seems to have stopped. would welding just make this weaker? should it be fine now that each end is drilled or is it new frame time?

cheers

[Alex Dark]

When you weld you create a HAZ ( heat affected zone ) the rapid heating and cooling of the welding process removes all the heat treating from this area. As I understand it most frames are usually at a T6 treatment when bought, when the haz occurs it degrades this to 0 temper creating a far weaker area.

This can be understood by looking at the yield strength for a given alloy at zero temper and T6 temper.

In addition to this, crystallization occurs that weakens the integral structure of the aluminium.

Somebody on here will no doubt have a better explanation than me, and I apologise if im wrong!

Alex

[BradJohnson]

When you weld you create a HAZ ( heat affected zone ) the rapid heating and cooling of the welding process removes all the heat treating from this area. As I understand it most frames are usually at a T6 treatment when bought, when the haz occurs it degrades this to 0 temper creating a far weaker area.

This can be understood by looking at the yield strength for a given alloy at zero temper and T6 temper.

In addition to this, crystallization occurs that weakens the integral structure of the aluminium.

Somebody on here will no doubt have a better explanation than me, and I apologise if im wrong!

Alex

You need to get out more

[Martin Reynolds]

You need to get out more

For knowing about metals and their characteristics?

Hes a workshop engineer, thats why he knows his stuff