Dealing with Decarb in multiple normalaztion cycle's, coarse spheroid annealed steels

kuraki said:
Sorry I just realized there could be some misinterpretation here. I was talking .020 total, which would be .010 per side.
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Same here. I leave the blade 0.020" thicker than I used to, and grind it off post heat treat.
 
Willie71 said:
The risk in doing this is cooling too slow between cycles if using a hypereuctoid steel. This can cause undesirable structures in the steel. I'd have to look up the technicalities to explain it better.
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Hi Willie,
thanks for the info. I do notice in a foil packet the steel cools a bit slower, do you think it is significantly slow to affect normalising? Do you think a very soft plate quench might help when using stainless foil during normalising 52100 and W2??
 
ndp_2010 said:
Hi Willie,
thanks for the info. I do notice in a foil packet the steel cools a bit slower, do you think it is significantly slow to affect normalising? Do you think a very soft plate quench might help when using stainless foil during normalising 52100 and W2??
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I think that is a good question. By the way, a plate quench could create some parts of martensite, that would not be normalizing.
Without the plate quench, in my opinion, the cooling rate would not be significantly affected, but i have concerns it could be uneven and that would influence the normalization where eveness it's the key word. Antiscale compound poses less problems in that regard but it is not completely decarb-proof, so allow enough thickness and then grind cool without affecting the normalized microstructure.
 
ndp_2010 said:
Hi Willie,
thanks for the info. I do notice in a foil packet the steel cools a bit slower, do you think it is significantly slow to affect normalising? Do you think a very soft plate quench might help when using stainless foil during normalising 52100 and W2??
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I don't know if you can post links to other forums but Keven Cashen thinks foil shouldn't give many issues. I have also read a few posts on this forum recommending foil.
 
whiteyluvsrum said:
I don't know if you can post links to other forums but Keven Cashen thinks foil shouldn't give many issues. I have also read a few posts on this forum recommending foil.
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Interesting, it was Kevin at a hammer in a couple years ago who suggested I not use foil. :confused:
 
ndp_2010 said:
Cheers for the info. Will keep looking into it to see what I come up with.
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This was posted by Kevin on another board.

Quote Originally Posted by Dan Pierson View Post
Thanks Kevin. That gives rise to a couple more questions from a stock removal viewpoint:

Is there any disadvantage to just wrapping the steel in an HT foil package and leaving it there through the
whole process? The foil will slow cooling a little of course.

Would it be better to normalize and get the carbides set up before grinding the blade or wait until the
grinding stresses can be dealt with at the same time?
The foil shouldn't give too many issues and may cut back on scaling an decarb. However it is for these reasons that I would do my normalizing before annealing or grinding, a simple flat bar of steel would be far easier to normalize than a blade and things would be in great condition for subsequent annealing. After grinding the best way to deal with any stress/strain issues from that operation would be a quick stress relieve. i am still debating on whether we need a separate "stress relieving" thread.
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Maybe it was something specific about 52100 which was the steel we were talking about.
 
Karl Anderson addressed this really well on the first page- I'd just add that, from a blacksmith's point of view, the most likely cause is that your forge is way more oxygen rich than it needs to be. Almost every metalworker who hasn't mastered forge welding does the same thing, sets their forge to a highly oxidizing atmosphere.
1600 F in a properly adjusted propane forge should give you just a bit of scale, and negligible surface decarb.

edit: oops, that's already been pretty well discussed on page 2. Rule of thumb is that you should have some yellow flame, at least a couple inches long, coming out the forge opening, visible in shadow or dim light. Much harder to get the right mix in the sunshine...
 
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