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Scott A. Roush

test ingots... crucible steel?

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Hi folks... I have a special project that may involve crucible steel (not sure if I will pursue pattern yet). I have an A6 size crucible. Is it worth starting with smaller charges to make smaller 'test ingots'? I'm assuming that with a given size crucible there is an charging size.... but I wonder about starting with smaller crucibles and doing these 'tests'.. Does this make sense or is it something other people do?

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I have done crucible steel runs a few times, with only one turning out satisfactory, mostly because I am hardheaded and make the crucibles, and did not own a scale at the time to measure out the charges. But it seems to me that a larger thermal mass will help increase the chance of getting a good melt. Also if you are starting with unknown material for the charge, the larger crucible will give you a greater margin of error as far as getting the carbon content close to want you want. Hope this might help.

Edited by brandon p

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I have done crucible steel runs a few times, with only one turning out satisfactory, mostly because I am hardheaded and make the crucibles, and did not own a scale at the time to measure out the charges. But it seems to me that a larger thermal mass will help increase the chance of getting a good melt. Also if you are starting with unknown material for the charge, the larger crucible will give you a greater margin of error as far as getting the carbon content close to want you want. Hope this might help.

Thanks Brandon... yes.. I can see how decreasing the size could increase the margin of error. That makes a lot of sense.

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Scott,

I would start with the size of the final object you are going to make and assume a loss of about 25% while processing the ingot. I have very little experience in the steel range but did make some very high carbon steel ingots * 1.3% C to 1.87% carbon long ago....I suggest graphite crucible, really clean starting materials and sizing the crucible to be about half full when liquid. Big ingots become hard to forge .

Good Luck

Jan

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Scott,

I would start with the size of the final object you are going to make and assume a loss of about 25% while processing the ingot. I have very little experience in the steel range but did make some very high carbon steel ingots * 1.3% C to 1.87% carbon long ago....I suggest graphite crucible, really clean starting materials and sizing the crucible to be about half full when liquid. Big ingots become hard to forge .

Good Luck

Jan

Thanks Jan... Okay I guess this was another point for this question... the actual blade I would like to make is a smallish hinomaki type folder... with scale liners being the same material as the blade. But... an ingot in an A6 crucible would be quite a bit more than this.... which is great in terms of having excess material.. but the forging frightens me. :-)

 

I have an A6 clay graphite crucible arriving today.

 

I also have other methods that I will be using for this project. The main thing is that I figure out a way to utilize a customer's cast iron plowshare for a blade..whether it's from the crucible, hearth or forge/hammer.

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Scott,

 

I know nothing about plows or plow shares . Are you sure the plow share is made of cast iron?

 

Jan

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Scott,

 

I know nothing about plows or plow shares . Are you sure the plow share is made of cast iron?

 

Jan

Yes.... It's a type made by John Deere sometime in the mid-late 1800s. From the research I've done it's either the type called 'chilled cast' where the edge was cooled rapidly to make harder and polishable OR... the edge was decarburized into high carbon steel. The main body is cast iron.. but the edge and a portion of the back sparks like 'very high carbon'. So far all sample pieces have crumbled under the hammer..whether cast iron or whatever the edge material is. So I'm going to play with decarbing in the hearth, a crucible melt and I thought I would try layering it up with steel in a sealed, welded can and try to get it to stick by doing an extended soak just below it's melting point. I told the guy I'd play around a bit and if everything fails then please send me a file. :-) I also have a field stone from the guy's family farm I'm supposed to use. If this guy wasn't such a good customer... ;-)

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Scott, an A6 will make a nice big ingot, not counting my failed homemade crucibles, all I've used was an A4. You can always make a big ingot and cut it up into smaller pieces. Remember that the clay graphite crucibles will usually add carbon.

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Scott, an A6 will make a nice big ingot, not counting my failed homemade crucibles, all I've used was an A4. You can always make a big ingot and cut it up into smaller pieces. Remember that the clay graphite crucibles will usually add carbon.

oh thanks for reminding me. I knew that last year.. and then I forgot.

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