salt bath vs oven

From my understanding some alloys, like the more complex tool and stainless steels, are not all that good at transmitting heat so you will have the thinner parts converting to austinite while the thicker parts are still pearlite (a mixture of cementite and ferrite, just to jog memories of some). The strain of it can establish cracking in the blade due to the difference in the sizes of the two iron crystals. That's why it is recommended when working with these steels that a soak at around 1400° is recommended prior to full austinzing so that the thick and thin sections of the blade convert more at the same time. This is not an issue with simpler alloys with lower chromium. However, the higher rate of heat transfer with the molten salts makes this problem worse.

Then there are the safety issues associated with molten salt pots that have to be considered. Getting splashed with 1450-1500° molten salt could ruin your whole day if you aren't wearing safety garments and a full face shield.

Doug
 
well yeah, the rapid heat transfer coupled with high carbon/alloy content, and probable flaws, inclusions and impurities in the steel, AND blade geometry or “design flaws” would multiply the possible negative effects of rapid heating.

... and also the salt contamination of the quench oil.

I guess those are the main disadvantages, from a purely metallurgical standpoint.
 
You know, just about every time I have myself convinced that I really need a high temperature molten salt pot, I run across something that changes my mind.

Doug
 
… probably better industrially suited for lower carbon/alloy steels and less problematic geometries and parts.
 
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