Next silly salt pot question

[jdm61]

I have read and been told that you can take the edge/finish on a blade down pretty close to final grit, etc. if you are heat treating using HT salts because the salts prevent decarb. BUT, I have also been told that HT salts are quite corrosive and need to be washed off as soon as possible. So here is my quandry. I would like to get a HT salt rig and use it for all thermal cycling operations with the possible exception of annealing, because I worry about putting a salt covered blade into vermiculite for 8 hours. But what about the other operations? Will the salt start eating away at the steel in the time it takes for the blade to cool during normalizing cycles? Also, will the molten salt start to eat away the steel during the 10 minute or so soak time that is required for steels like the W2 that I will be using?

 

[Plain ol Bill]

No the salt will not cause any corrosion during the normalizing runs. In normalizing you take to non-magnetic and let the blade cool to room temperature. That does not take long. Now if you leave the salts on and take several days in a high humidity area you might have a problem
You will not experience any melting of any steel at critical temps even if you leave it in for a week (I don't reccomend this needless to say).
I normally take my blades to a good 500 finish and the edge at times will cut you when I start my salt tank process. I have not experienced any problems doing this. Just wash the blade off good and dry it after completion.

 

[Jared Stenoien]

The way I understand it (mind you I could be completely off base here) is that the actual salts aren't what are corroding your blade, it's the hydrophilic properties acting to pull moisture out of the air and holding them next to your blade. It seems like for annealing, normalizing, and general heat treating that you wouldn't have much of a problem with corrosion untill it dropped below 212 fahrenheit. Hopefully someone who knows more about them will step in and refudate/validate this.

 

[Kevin R. Cashen]

The low temp salts will pull water right out of the air and leave your blade dripping, but the high temp being sodium chloride based witll chew a blade up about as fast as if you had dipped it in brine and left it set. Also I cannot say this is the case, I can only speak from my experience, anytime I have normalized with the high temp salts on the blade exposed to all that oxygen resulted in a nasty decarb. The neutrality of these salts is critical to avoid such issues and I have found it bet to leave all the salts in the tube under a dusting of silicon carbide to maintain that neutrality.

 

[jdm61]

The low temp salts will pull water right out of the air and leave your blade dripping, but the high temp being sodium chloride based witll chew a blade up about as fast as if you had dipped it in brine and left it set. Also I cannot say this is the case, I can only speak from my experience, anytime I have normalized with the high temp salts on the blade exposed to all that oxygen resulted in a nasty decarb. The neutrality of these salts is critical to avoid such issues and I have found it bet to leave all the salts in the tube under a dusting of silicon carbide to maintain that neutrality.

Okay, Kevin........I'm not exactly sure what you said. How do you normalize before quenching and how many times do you do it? Does soaking the balde in the HT salts for a while reduce the need for pre-quench normalizing?