Cable billet metallography

sunshadow

sunshadow

Joined
Oct 2, 2006
Messages
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Just thought I'd share some quick and dirty micros of a cable billet I welded up a couple weeks ago
Air cooled and sampled after the weld, 2%nital etch

Note the insane amount of decarb (bright white) surrounded by pearlite (which would actually be usable steel if HT instead of air cooled)


Cable_25X.jpg

25x

Cable_100X.jpg

100x

Cable_200X.jpg

200x

Cable_500X.jpg

500x

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I've wondered about the affect forging/welding heats had on the small wire strands of cable.


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Id also like to know how deep this was taken.

Also if you could provide some info on what flux you used, how much, what the steel was like etc then that would be great.

I actually know next to nothing about metalurgy so Im basically just nodding my head with my hand on my chin trying to look like I know what everyones talking about!

Jamie
 
Really amazing shots!!
Very much interested in the type of structure found at the boundary between cable strands.
I'll keep watching.
Thanks for sharing!
 
The picture quality is wonderful:thumbup:

I weld all my cable inside stainless tubing to reduce what is happening in the photos. No O2 no decarb. How much it affects this, would be useful to know. One aspect of canister welding is you can accomplish the forge in one heat and one pressing. You have a much smaller chance of screwing it up.:eek::D

Fred
 
jamiemackie said:
Id also like to know how deep this was taken.

Also if you could provide some info on what flux you used, how much, what the steel was like etc then that would be great.

I actually know next to nothing about metalurgy so Im basically just nodding my head with my hand on my chin trying to look like I know what everyones talking about!

Jamie
Click to expand...

Approximately midradius
Flux was lots of 20 mule team borax applied as soon as the piece started to get warm enough for it to stick and coated on enough to keep the surface wet with it at all times.

I'm wondering if carbon is diffusing into the flux:eek:

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Looks like the grains are pearlite [ .80 C ] with ferrite grain boundaries. The curious part is that the boundaries between the strands have far smaller grain size !! I'd really like to know what the chemical composition of those boundaries !
In the center of the 25X photo there is a black spot - is this a void ?
 
I believe that is indeed an interstrand void. That was an off-cut right at the end of the solid part of the billet. I usually sample the ends of my billets to make sure that the welds are good to the ends.
I wish I had access to a SEM so I could poke around and do microchem analysis. The SEM microchem work one of our labs does is truly impressive!
I have SERIOUS microscope envy!


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