Burn marks or dark coloration in steel

N

Newcomer

Joined
Mar 7, 2009
Messages
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Curious if someone can shed some light on a problem, at least I think it's a problem, related to the dark areas or discoloration on my blades?

I'm grinding BG42 and have noticed areas where the steel is discolored. It's shiny as hell, but dark.

My questions are:

1) Did I burn the steel?
2) Does it even matter at this pre-heat treat stage?
3) How do I get it out other than by re-grinding?
4) Can I leave it like that and just sand it out after the heat treat?

Any info from someone knowledgeable about this would be most appreciated.

Thanks.
 
Welcome to Bladeforums. You may want to post these questions in the Knife Makers Forums here. There are a lot of very talented people there that can answer your questions better than I.

Tom
 
Welcome to BF, take a look at the forums that may give you more specific answers. I'm sure a mod will steer you to the right one.
 
Hi,

Welcome! It does sound as if you burned the steel. And that part of your blade is now toast. You will need to remove metal to back behind the damaged parts to get to good steel again.

To prevent this from happening again, you need to keep your blank cool. Keep your grinding belt/wheel clean and not too worn. It must cut freely. If you want to remove steel faster, use a coarser grit. Don't push harder! Cool your blank by dunking it in to cold water often. Don't be in a rush. Take your time. It feels too hot to hold in your bare hand, it's too hot.

dalee
 
Newcomer said:
Curious if someone can shed some light on a problem, at least I think it's a problem, related to the dark areas or discoloration on my blades?

I'm grinding BG42 and have noticed areas where the steel is discolored. It's shiny as hell, but dark.

My questions are:

1) Did I burn the steel?
2) Does it even matter at this pre-heat treat stage?
3) How do I get it out other than by re-grinding?
4) Can I leave it like that and just sand it out after the heat treat?

Any info from someone knowledgeable about this would be most appreciated.

Thanks.
Click to expand...
1. It is a sign of too much heat, it may just be heating of the surface which will be fine(you just need to remove a little metal to reveal the good steel)
2. If this is before you even ht, then it makes no difference.
3. sandpaper will be fine for removing it
4. Clean it after you heat treat.
 
Thanks to all who responded! I had a heck of time getting signed on again...computer gremlins, I guess.
 
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