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Cutting edge warps zig zag after partial quench


rrnsss

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Dear all,

When I do an edge quench or a partial quench, my cutting edge warps in a zig -zag fashion.


YouTube - Learning to blacksmith Warping problems

I am using HCHCS.

It has been abused by me , gone through at least 40 heats , this was my first piece ever and I have abused it due to lack of skill.


I anneal the steel 3 times and let it cool overnight before I grind it with a hand cranked grinder and quench it.

YouTube - Learning to Blacksmith - Annealing


The same steel quenched with out any edge warping when the knife was heavier. However, I did not abuse that workpiece as I did this one.


Kindly help.


Ramachandran Subramanian

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I would say it is likely to be your quenching technique. What sort of oil are you quenching in? It could be that you are getting the edge too hot when you quench. Also, make sure you don't move the blade side to side in the oil. If your edge were thinner then that would be a problem, but it looks pretty thick.

forgive me if you answered those questions in the videos, my sound card isn't working and I can't lip read :rolleyes:

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Ramachandran,
do you know the actual type of steel? If you do there are plenty of resources on the web to tell you how to quench / heat treat a particular grade / alloy of steel. I agree with Dave that you may be getting the steel too hot. Also you may want to heat the back of the blade and let the colors run to the edge rather than heating the whole blade.
Good luck

Edited by Doug C
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Dear Forumites,

I am happy to report that the second attempt at quenching was successful and did not cause any additional warping. So, what fixed it? I do not know as I did many things all at once.

1) I annealed the steel 3 times last night and let it rest
2) I coated the blade with clay ( which I did not do last time )
3) I heated the spine and let the colour bleed into the edge and did not heat it too much.
4) I checked with a magnet before quenching
5) I did a partial or edge quench in cooking oil ( I did it in water last time ) .

It seems to have worked.

This is actually my first knife even though I abandoned it after I cracked the tip and broke the tang. Anyway, after I did my second knife successfully, I had the confidence to go back and resurrect the abandoned piece. I learnt that I need to cut off the cracked part as it kept creeping into the blade no matter how hard I tried to avoid it. That made my blade a little smaller, but it is still big enough to cut vegetables.

I am embarrassed to say that I used an angle grinder on the portion where I had a MS bit welded on. It was too ugly and I could not remove it with a file or my hand cranked grinding wheel. But the deep curve gave it an exotic look. (trying to put a positive spin on things )

Anyway here are the pictures



img0220o.th.jpg
img0219v.th.jpg
img0217tzh.th.jpg
img0216fxd.th.jpg

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