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Old 04-05-2014, 07:33 PM
Doug Lester Doug Lester is offline
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Join Date: Sep 2006
Location: Decatur, IL
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Off hand I would say that you really overheated the blades and you had some scale build up. Yes, you can grind it out but I would also worry about what you did to grain growth.

What you need to do to prevent this is to try to catch the steel at just the point it goes non-magnetic and then try to get it just a little brighter and hold it there for at least 2-3 minutes then quench.

To repair any grain growth that you might have done I recommend that you repeat the normalization for three more times trying to make sure that the steel doesn't more than just a little above non-magnetic. If that is L6 you do have the advantage that it has vanadium in it that will put a drag on grain growth so you could cross your fingers and omit re-normalization.

One of the problems with the steel is, assuming that it is correct that it's L6, is that it has a wide range on the carbon content. It can go from 0.70-0.90% carbon and that difference is significant. On the lower end you can do a shorter soak at 1550-1600?. If the carbon content is towards the higher end then you have more carbides to dissolve and the possibility of more retained austinite that can be formed.

I'll give you the advice that is usually given to beginners. Go with a known steel and actually I would recommend against tool steels unless you have the assay for that melt you are using or you will still be close to using mystery metal. Keep it simple, as in simple alloys. Something like 1080, 1084, 80CrV2 or 5160 would be a good choice.

Doug


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