Uh Oh......what happened to this steel? Take a look please :(

jonnymac44

jonnymac44

Joined
Sep 27, 2007
Messages
7,680
Hey guys,
Just got a batch of blades back from heat treat. Steel is Elmax powdered stainless. I started to clean a blade up for finishing and noticed some odd splotches in the steel as I went. I thought it might be some oxide stains that were superficial and kept going. Ended up grinding away a fair amount and cannot get it out. I put some more blades to the belt and have discovered that the entire batch has these discolored spots all over them.

Not sure exactly what it is, as I've not seen it before. This is not my first time using Elmax or this heat treater, so I'm at a loss. Does anyone have any ideas or clues as to what the problem is and where along the line it could have occurred? Bad batch of steel? Bad heat treat? Something I did?

These two pics are of one of the blades finished to 600 grit by hand. The spots are all different sizes, I used this one because it's a very large spot and I could get a good picture of it.

Thanks for any help.....not too happy about ten blades possibly being ruined:grumpy:

002.jpg


003.jpg
 
I don't have a clue other than to send it back to the heat treater or send them a picture. Maybe you can do a hardness test on the two areas to see if it didn't fully harden in that spot?
 
Not familiar with Elmax, however, I have seen somewhat similar random spotting (more of a mottling) on higher alloy steels that I have heat treated. I traced my problem back to insufficient soak times at temperature.

I would definitely start with the heat treat company. Another round of heat treat may be in order, provided they can assure that it will be done to specs.

Robert
 
Thanks for the input Robert. Tomorrow is Monday so I'll be on the phone with the heat treaters to see if we can figure something out. I hope they can be saved. That's a lot of grinding and work to get them all this far.

Robert Dark said:
Not familiar with Elmax, however, I have seen somewhat similar random spotting (more of a mottling) on higher alloy steels that I have heat treated. I traced my problem back to insufficient soak times at temperature.

I would definitely start with the heat treat company. Another round of heat treat may be in order, provided they can assure that it will be done to specs.

Robert
Click to expand...
 
Just a quick thought...bead blast finish, if they turn out to be only cosmetic and not different in hardness?
10 blades is a bit hmm?
 
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