forge temps...help me out a bit...

S

SkaerE

Joined
Sep 9, 2001
Messages
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ok, saw that the reil burner should heat a 300 cu in area up to welding temps.

how hot is "welding temp"?

i am debating how big to make the chamber of my molten salt bath, ideally i would have about 3'' space all around the 3.5'' salt tube. unfortunetly that gives me about 800 cu in of room to heat.

i probably only need to heat it up to about 1600-1700 because i just want it to heat treat O1 and 1095 and the like. no welding, just normalizing and hardening temps.

think one burner could do that? maybe i should reduce the amount of space around my salt tube? i want a decent amount though to minimize hot spots in the salt.

thanks


EDITED: ok, now i rethunk some things ;) gave myself 2'' around the tube and 12.5'' tall. total gives me 357 cu in to heat up (its actually 552 cu in if you include the tube and salts). shouldnt be too hard w/one burner. still like some input from others though.
 
Welding heat is around 2300F I have never thought about welding in a salt pot. Is that the question? I wonder if it would work. I think you would be fine with one burner. People use one burner venturi type with forges all the time and with more area inside. You only need about 1500F for heat-treating and 1600F for normalizing. Maintaining the temp is the real trick. I use a pyrometer and regulate the flame.
 
naw, definitly not welding in a salt pot. i just want it for heat treat (normalizing, anealing, hardening) of O1 and 10-series steels.

we'll see how it works cause i cast it last night ;)

2'' space around the salt tube, 2''+ refractory and pearlite around that as insulation. one burner about 1'' from the bottom on a tangent to the chamber.

hopefully that will do it
 
You do realize that betwixt the time you pull the O1 out of the salt pot and get it into the oil quench it will debarborize a little(?).

RL
 
I dont see how it can decarb because it is not exposed to oxygen. The surface is wet and protected. It is under liquid heat the entire soak time. Roger where did you hear this? I may be wrong.
 
hmmm. i've read that the molten salt adheres to the blade somewhat giving it a coating of sorts to keep oxygen off of the blade. even when a blade is taken out to be anealed the salt will harden on the blade. when quenched the salt breaks off of the blade. while i have not yet tried (hopefully soon) i think that the blade will be coated enough to prevent any/vast majority of scale.
 
The only thing I have heard about was that the salts, depending on which ones you use whether they be barium chloride, sodium chloride, calcium chloride, etc tend not to be "neutral." I am not sure to what degree which ones suck the carbon out of your steel, but there is a rectifying procedure out there to bring your salts back to neutral.

Heatbath has a product called Nu-Sal, which is supposed to be a neutral salt. the only problem I have with them is they won't sell me less than 400 pounds. I am using a 50/50 mix of NaCl and CaCl2. I got it on sale at Home Depot. A 50 lb bag of each. So for 100 lbs of salt I paid less than $10. If I start to see funny results after a while I will just change out my salt.

The rectifying process involves adding some sort of chemical(I cant remember what it is right now) and then immersing a graphite rod into the molten salt for one hour for every 4 hours that the salts were used. Heck at the rate that I make knives, 4 hours of molten salt HT time will be about 3 years.:)

Hope this helped, from the little playing I have done with my new setup, the salt does stick to the blade and protects it from the O2. It does not always come of when quench in oil, but it comes off when quenched in water.

Edited to add: Hey ShaerE, I forgot to say that that "Hot Spot" mentioned in the other post was not a hot spot in the molten salt. My thermocouple is just submerged in the salt from the top. The hot spot I saw was where the burner inlet is. Basically the refractory and one corner of the welded on square base glow birghter than the rest of the insulation. There is so much circulation in the salt bath that I dont think it will be an issue. But I have been wrong before, at least once.;)
 
Hey sorry about that...lol...I bought NaCl, Sodium Chloride (Rock Salt) and CaCl2, Calcium Chloride (Ice melting Salts). Plain old stuff from Home Depot/Menards/Lowes. Just look for the most pure CaCl2 they have. Some brands have other chemicals in them besides water. None will read 100% NaCl2 because they are not anhydrous.

But they melt at some where around 1250 to 1300, well that is where they start to freeze anyway. I dont know what their max temp is, but I know of guys using it to HT stainles, so at least in the 1900 range.
 
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